-/* Global common subexpression elimination/Partial redundancy elimination
- and global constant/copy propagation for GNU compiler.
- Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
- 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
+/* Partial redundancy elimination / Hoisting for RTL.
+ Copyright (C) 1997-2014 Free Software Foundation, Inc.
This file is part of GCC.
/* TODO
- reordering of memory allocation and freeing to be more space efficient
- - do rough calc of how many regs are needed in each block, and a rough
- calc of how many regs are available in each class and use that to
- throttle back the code in cases where RTX_COST is minimal.
- - a store to the same address as a load does not kill the load if the
- source of the store is also the destination of the load. Handling this
- allows more load motion, particularly out of loops.
-
+ - calc rough register pressure information and use the info to drive all
+ kinds of code motion (including code hoisting) in a unified way.
*/
/* References searched while implementing this.
#include "system.h"
#include "coretypes.h"
#include "tm.h"
+#include "diagnostic-core.h"
#include "toplev.h"
+#include "hard-reg-set.h"
#include "rtl.h"
#include "tree.h"
#include "tm_p.h"
#include "regs.h"
-#include "hard-reg-set.h"
+#include "ira.h"
#include "flags.h"
#include "insn-config.h"
#include "recog.h"
-#include "basic-block.h"
-#include "output.h"
+#include "predict.h"
+#include "vec.h"
+#include "hashtab.h"
+#include "hash-set.h"
+#include "machmode.h"
+#include "input.h"
#include "function.h"
+#include "dominance.h"
+#include "cfg.h"
+#include "cfgrtl.h"
+#include "cfganal.h"
+#include "lcm.h"
+#include "cfgcleanup.h"
+#include "basic-block.h"
#include "expr.h"
#include "except.h"
#include "ggc.h"
#include "cselib.h"
#include "intl.h"
#include "obstack.h"
-#include "timevar.h"
#include "tree-pass.h"
-#include "hashtab.h"
+#include "hash-table.h"
#include "df.h"
#include "dbgcnt.h"
#include "target.h"
+#include "gcse.h"
/* We support GCSE via Partial Redundancy Elimination. PRE optimizations
are a superset of those done by classic GCSE.
- We perform the following steps:
-
- 1) Compute table of places where registers are set.
-
- 2) Perform copy/constant propagation.
-
- 3) Perform global cse using lazy code motion if not optimizing
- for size, or code hoisting if we are.
-
- 4) Perform another pass of copy/constant propagation. Try to bypass
- conditional jumps if the condition can be computed from a value of
- an incoming edge.
-
- Two passes of copy/constant propagation are done because the first one
- enables more GCSE and the second one helps to clean up the copies that
- GCSE creates. This is needed more for PRE than for Classic because Classic
- GCSE will try to use an existing register containing the common
- subexpression rather than create a new one. This is harder to do for PRE
- because of the code motion (which Classic GCSE doesn't do).
+ Two passes of copy/constant propagation are done around PRE or hoisting
+ because the first one enables more GCSE and the second one helps to clean
+ up the copies that PRE and HOIST create. This is needed more for PRE than
+ for HOIST because code hoisting will try to use an existing register
+ containing the common subexpression rather than create a new one. This is
+ harder to do for PRE because of the code motion (which HOIST doesn't do).
Expressions we are interested in GCSE-ing are of the form
(set (pseudo-reg) (expression)).
\f
/* GCSE global vars. */
+struct target_gcse default_target_gcse;
+#if SWITCHABLE_TARGET
+struct target_gcse *this_target_gcse = &default_target_gcse;
+#endif
+
/* Set to non-zero if CSE should run after all GCSE optimizations are done. */
int flag_rerun_cse_after_global_opts;
/* An obstack for our working variables. */
static struct obstack gcse_obstack;
-struct reg_use {rtx reg_rtx; };
-
/* Hash table of expressions. */
-struct expr
+struct gcse_expr
{
- /* The expression (SET_SRC for expressions, PATTERN for assignments). */
+ /* The expression. */
rtx expr;
/* Index in the available expression bitmaps. */
int bitmap_index;
/* Next entry with the same hash. */
- struct expr *next_same_hash;
+ struct gcse_expr *next_same_hash;
/* List of anticipatable occurrences in basic blocks in the function.
An "anticipatable occurrence" is one that is the first occurrence in the
basic block, the operands are not modified in the basic block prior
to the occurrence and the output is not used between the start of
the block and the occurrence. */
- struct occr *antic_occr;
+ struct gcse_occr *antic_occr;
/* List of available occurrence in basic blocks in the function.
An "available occurrence" is one that is the last occurrence in the
basic block and the operands are not modified by following statements in
the basic block [including this insn]. */
- struct occr *avail_occr;
+ struct gcse_occr *avail_occr;
/* Non-null if the computation is PRE redundant.
The value is the newly created pseudo-reg to record a copy of the
expression in all the places that reach the redundant copy. */
rtx reaching_reg;
+ /* Maximum distance in instructions this expression can travel.
+ We avoid moving simple expressions for more than a few instructions
+ to keep register pressure under control.
+ A value of "0" removes restrictions on how far the expression can
+ travel. */
+ int max_distance;
};
/* Occurrence of an expression.
There is one per basic block. If a pattern appears more than once the
last appearance is used [or first for anticipatable expressions]. */
-struct occr
+struct gcse_occr
{
/* Next occurrence of this expression. */
- struct occr *next;
+ struct gcse_occr *next;
/* The insn that computes the expression. */
- rtx insn;
+ rtx_insn *insn;
/* Nonzero if this [anticipatable] occurrence has been deleted. */
char deleted_p;
/* Nonzero if this [available] occurrence has been copied to
char copied_p;
};
-/* Expression and copy propagation hash tables.
+typedef struct gcse_occr *occr_t;
+
+/* Expression hash tables.
Each hash table is an array of buckets.
??? It is known that if it were an array of entries, structure elements
`next_same_hash' and `bitmap_index' wouldn't be necessary. However, it is
[one could build a mapping table without holes afterwards though].
Someday I'll perform the computation and figure it out. */
-struct hash_table_d
+struct gcse_hash_table_d
{
/* The table itself.
This is an array of `expr_hash_table_size' elements. */
- struct expr **table;
+ struct gcse_expr **table;
/* Size of the hash table, in elements. */
unsigned int size;
/* Number of hash table elements. */
unsigned int n_elems;
-
- /* Whether the table is expression of copy propagation one. */
- int set_p;
};
/* Expression hash table. */
-static struct hash_table_d expr_hash_table;
-
-/* Copy propagation hash table. */
-static struct hash_table_d set_hash_table;
+static struct gcse_hash_table_d expr_hash_table;
/* This is a list of expressions which are MEMs and will be used by load
or store motion.
- Load motion tracks MEMs which aren't killed by
- anything except itself. (i.e., loads and stores to a single location).
+ Load motion tracks MEMs which aren't killed by anything except itself,
+ i.e. loads and stores to a single location.
We can then allow movement of these MEM refs with a little special
allowance. (all stores copy the same value to the reaching reg used
for the loads). This means all values used to store into memory must have
- no side effects so we can re-issue the setter value.
- Store Motion uses this structure as an expression table to track stores
- which look interesting, and might be moveable towards the exit block. */
+ no side effects so we can re-issue the setter value. */
struct ls_expr
{
- struct expr * expr; /* Gcse expression reference for LM. */
+ struct gcse_expr * expr; /* Gcse expression reference for LM. */
rtx pattern; /* Pattern of this mem. */
rtx pattern_regs; /* List of registers mentioned by the mem. */
- rtx loads; /* INSN list of loads seen. */
- rtx stores; /* INSN list of stores seen. */
+ rtx_insn_list *loads; /* INSN list of loads seen. */
+ rtx_insn_list *stores; /* INSN list of stores seen. */
struct ls_expr * next; /* Next in the list. */
int invalid; /* Invalid for some reason. */
int index; /* If it maps to a bitmap index. */
rtx reaching_reg; /* Register to use when re-writing. */
};
-/* Array of implicit set patterns indexed by basic block index. */
-static rtx *implicit_sets;
-
/* Head of the list of load/store memory refs. */
static struct ls_expr * pre_ldst_mems = NULL;
+struct pre_ldst_expr_hasher : typed_noop_remove <ls_expr>
+{
+ typedef ls_expr value_type;
+ typedef value_type compare_type;
+ static inline hashval_t hash (const value_type *);
+ static inline bool equal (const value_type *, const compare_type *);
+};
+
+/* Hashtable helpers. */
+inline hashval_t
+pre_ldst_expr_hasher::hash (const value_type *x)
+{
+ int do_not_record_p = 0;
+ return
+ hash_rtx (x->pattern, GET_MODE (x->pattern), &do_not_record_p, NULL, false);
+}
+
+static int expr_equiv_p (const_rtx, const_rtx);
+
+inline bool
+pre_ldst_expr_hasher::equal (const value_type *ptr1,
+ const compare_type *ptr2)
+{
+ return expr_equiv_p (ptr1->pattern, ptr2->pattern);
+}
+
/* Hashtable for the load/store memory refs. */
-static htab_t pre_ldst_table = NULL;
+static hash_table<pre_ldst_expr_hasher> *pre_ldst_table;
/* Bitmap containing one bit for each register in the program.
Used when performing GCSE to track which registers have been set since
/* Array, indexed by basic block number for a list of insns which modify
memory within that block. */
-static rtx * modify_mem_list;
+static vec<rtx_insn *> *modify_mem_list;
static bitmap modify_mem_list_set;
-/* This array parallels modify_mem_list, but is kept canonicalized. */
-static rtx * canon_modify_mem_list;
+typedef struct modify_pair_s
+{
+ rtx dest; /* A MEM. */
+ rtx dest_addr; /* The canonical address of `dest'. */
+} modify_pair;
+
+
+/* This array parallels modify_mem_list, except that it stores MEMs
+ being set and their canonicalized memory addresses. */
+static vec<modify_pair> *canon_modify_mem_list;
/* Bitmap indexed by block numbers to record which blocks contain
function calls. */
static int gcse_subst_count;
/* Number of copy instructions created. */
static int gcse_create_count;
-/* Number of local constants propagated. */
-static int local_const_prop_count;
-/* Number of local copies propagated. */
-static int local_copy_prop_count;
-/* Number of global constants propagated. */
-static int global_const_prop_count;
-/* Number of global copies propagated. */
-static int global_copy_prop_count;
+\f
+/* Doing code hoisting. */
+static bool doing_code_hoisting_p = false;
\f
/* For available exprs */
static sbitmap *ae_kill;
\f
+/* Data stored for each basic block. */
+struct bb_data
+{
+ /* Maximal register pressure inside basic block for given register class
+ (defined only for the pressure classes). */
+ int max_reg_pressure[N_REG_CLASSES];
+ /* Recorded register pressure of basic block before trying to hoist
+ an expression. Will be used to restore the register pressure
+ if the expression should not be hoisted. */
+ int old_pressure;
+ /* Recorded register live_in info of basic block during code hoisting
+ process. BACKUP is used to record live_in info before trying to
+ hoist an expression, and will be used to restore LIVE_IN if the
+ expression should not be hoisted. */
+ bitmap live_in, backup;
+};
+
+#define BB_DATA(bb) ((struct bb_data *) (bb)->aux)
+
+static basic_block curr_bb;
+
+/* Current register pressure for each pressure class. */
+static int curr_reg_pressure[N_REG_CLASSES];
+\f
+
static void compute_can_copy (void);
static void *gmalloc (size_t) ATTRIBUTE_MALLOC;
static void *gcalloc (size_t, size_t) ATTRIBUTE_MALLOC;
static void *gcse_alloc (unsigned long);
static void alloc_gcse_mem (void);
static void free_gcse_mem (void);
-static void hash_scan_insn (rtx, struct hash_table_d *);
-static void hash_scan_set (rtx, rtx, struct hash_table_d *);
-static void hash_scan_clobber (rtx, rtx, struct hash_table_d *);
-static void hash_scan_call (rtx, rtx, struct hash_table_d *);
-static int want_to_gcse_p (rtx);
-static bool gcse_constant_p (const_rtx);
-static int oprs_unchanged_p (const_rtx, const_rtx, int);
-static int oprs_anticipatable_p (const_rtx, const_rtx);
-static int oprs_available_p (const_rtx, const_rtx);
-static void insert_expr_in_table (rtx, enum machine_mode, rtx, int, int,
- struct hash_table_d *);
-static void insert_set_in_table (rtx, rtx, struct hash_table_d *);
-static unsigned int hash_expr (const_rtx, enum machine_mode, int *, int);
-static unsigned int hash_set (int, int);
-static int expr_equiv_p (const_rtx, const_rtx);
+static void hash_scan_insn (rtx_insn *, struct gcse_hash_table_d *);
+static void hash_scan_set (rtx, rtx_insn *, struct gcse_hash_table_d *);
+static void hash_scan_clobber (rtx, rtx_insn *, struct gcse_hash_table_d *);
+static void hash_scan_call (rtx, rtx_insn *, struct gcse_hash_table_d *);
+static int want_to_gcse_p (rtx, int *);
+static int oprs_unchanged_p (const_rtx, const rtx_insn *, int);
+static int oprs_anticipatable_p (const_rtx, const rtx_insn *);
+static int oprs_available_p (const_rtx, const rtx_insn *);
+static void insert_expr_in_table (rtx, machine_mode, rtx_insn *, int, int,
+ int, struct gcse_hash_table_d *);
+static unsigned int hash_expr (const_rtx, machine_mode, int *, int);
static void record_last_reg_set_info (rtx, int);
-static void record_last_mem_set_info (rtx);
+static void record_last_mem_set_info (rtx_insn *);
static void record_last_set_info (rtx, const_rtx, void *);
-static void compute_hash_table (struct hash_table_d *);
-static void alloc_hash_table (struct hash_table_d *, int);
-static void free_hash_table (struct hash_table_d *);
-static void compute_hash_table_work (struct hash_table_d *);
-static void dump_hash_table (FILE *, const char *, struct hash_table_d *);
-static struct expr *lookup_set (unsigned int, struct hash_table_d *);
-static struct expr *next_set (unsigned int, struct expr *);
-static void reset_opr_set_tables (void);
-static int oprs_not_set_p (const_rtx, const_rtx);
-static void mark_call (rtx);
-static void mark_set (rtx, rtx);
-static void mark_clobber (rtx, rtx);
-static void mark_oprs_set (rtx);
-static void alloc_cprop_mem (int, int);
-static void free_cprop_mem (void);
-static void compute_transp (const_rtx, int, sbitmap *, int);
-static void compute_transpout (void);
+static void compute_hash_table (struct gcse_hash_table_d *);
+static void alloc_hash_table (struct gcse_hash_table_d *);
+static void free_hash_table (struct gcse_hash_table_d *);
+static void compute_hash_table_work (struct gcse_hash_table_d *);
+static void dump_hash_table (FILE *, const char *, struct gcse_hash_table_d *);
+static void compute_transp (const_rtx, int, sbitmap *);
static void compute_local_properties (sbitmap *, sbitmap *, sbitmap *,
- struct hash_table_d *);
-static void compute_cprop_data (void);
-static void find_used_regs (rtx *, void *);
-static int try_replace_reg (rtx, rtx, rtx);
-static struct expr *find_avail_set (int, rtx);
-static int cprop_jump (basic_block, rtx, rtx, rtx, rtx);
+ struct gcse_hash_table_d *);
static void mems_conflict_for_gcse_p (rtx, const_rtx, void *);
static int load_killed_in_block_p (const_basic_block, int, const_rtx, int);
static void canon_list_insert (rtx, const_rtx, void *);
-static int cprop_insn (rtx);
-static void find_implicit_sets (void);
-static int one_cprop_pass (void);
-static bool constprop_register (rtx, rtx, rtx);
-static struct expr *find_bypass_set (int, int);
-static bool reg_killed_on_edge (const_rtx, const_edge);
-static int bypass_block (basic_block, rtx, rtx);
-static int bypass_conditional_jumps (void);
static void alloc_pre_mem (int, int);
static void free_pre_mem (void);
-static void compute_pre_data (void);
-static int pre_expr_reaches_here_p (basic_block, struct expr *,
+static struct edge_list *compute_pre_data (void);
+static int pre_expr_reaches_here_p (basic_block, struct gcse_expr *,
basic_block);
-static void insert_insn_end_basic_block (struct expr *, basic_block, int);
-static void pre_insert_copy_insn (struct expr *, rtx);
+static void insert_insn_end_basic_block (struct gcse_expr *, basic_block);
+static void pre_insert_copy_insn (struct gcse_expr *, rtx_insn *);
static void pre_insert_copies (void);
static int pre_delete (void);
-static int pre_gcse (void);
+static int pre_gcse (struct edge_list *);
static int one_pre_gcse_pass (void);
static void add_label_notes (rtx, rtx);
static void alloc_code_hoist_mem (int, int);
static void free_code_hoist_mem (void);
static void compute_code_hoist_vbeinout (void);
static void compute_code_hoist_data (void);
-static int hoist_expr_reaches_here_p (basic_block, int, basic_block, char *);
+static int should_hoist_expr_to_dom (basic_block, struct gcse_expr *, basic_block,
+ sbitmap, int, int *, enum reg_class,
+ int *, bitmap, rtx_insn *);
static int hoist_code (void);
+static enum reg_class get_regno_pressure_class (int regno, int *nregs);
+static enum reg_class get_pressure_class_and_nregs (rtx_insn *insn, int *nregs);
static int one_code_hoisting_pass (void);
-static rtx process_insert_insn (struct expr *);
-static int pre_edge_insert (struct edge_list *, struct expr **);
-static int pre_expr_reaches_here_p_work (basic_block, struct expr *,
+static rtx_insn *process_insert_insn (struct gcse_expr *);
+static int pre_edge_insert (struct edge_list *, struct gcse_expr **);
+static int pre_expr_reaches_here_p_work (basic_block, struct gcse_expr *,
basic_block, char *);
static struct ls_expr * ldst_entry (rtx);
static void free_ldst_entry (struct ls_expr *);
-static void free_ldst_mems (void);
+static void free_ld_motion_mems (void);
static void print_ldst_list (FILE *);
static struct ls_expr * find_rtx_in_ldst (rtx);
-static inline struct ls_expr * first_ls_expr (void);
-static inline struct ls_expr * next_ls_expr (struct ls_expr *);
static int simple_mem (const_rtx);
static void invalidate_any_buried_refs (rtx);
static void compute_ld_motion_mems (void);
static void trim_ld_motion_mems (void);
-static void update_ld_motion_stores (struct expr *);
-static void free_insn_expr_list_list (rtx *);
+static void update_ld_motion_stores (struct gcse_expr *);
static void clear_modify_mem_tables (void);
static void free_modify_mem_tables (void);
-static rtx gcse_emit_move_after (rtx, rtx, rtx);
-static void local_cprop_find_used_regs (rtx *, void *);
-static bool do_local_cprop (rtx, rtx);
-static int local_cprop_pass (void);
+static rtx gcse_emit_move_after (rtx, rtx, rtx_insn *);
static bool is_too_expensive (const char *);
#define GNEW(T) ((T *) gmalloc (sizeof (T)))
\f
/* Misc. utilities. */
-/* Nonzero for each mode that supports (set (reg) (reg)).
- This is trivially true for integer and floating point values.
- It may or may not be true for condition codes. */
-static char can_copy[(int) NUM_MACHINE_MODES];
+#define can_copy \
+ (this_target_gcse->x_can_copy)
+#define can_copy_init_p \
+ (this_target_gcse->x_can_copy_init_p)
/* Compute which modes support reg/reg copy operations. */
#ifdef AVOID_CCMODE_COPIES
can_copy[i] = 0;
#else
- reg = gen_rtx_REG ((enum machine_mode) i, LAST_VIRTUAL_REGISTER + 1);
+ reg = gen_rtx_REG ((machine_mode) i, LAST_VIRTUAL_REGISTER + 1);
insn = emit_insn (gen_rtx_SET (VOIDmode, reg, reg));
if (recog (PATTERN (insn), insn, NULL) >= 0)
can_copy[i] = 1;
/* Returns whether the mode supports reg/reg copy operations. */
bool
-can_copy_p (enum machine_mode mode)
+can_copy_p (machine_mode mode)
{
- static bool can_copy_init_p = false;
-
if (! can_copy_init_p)
{
compute_can_copy ();
return can_copy[mode] != 0;
}
-
\f
/* Cover function to xmalloc to record bytes allocated. */
alloc_gcse_mem (void)
{
/* Allocate vars to track sets of regs. */
- reg_set_bitmap = BITMAP_ALLOC (NULL);
+ reg_set_bitmap = ALLOC_REG_SET (NULL);
/* Allocate array to keep a list of insns which modify memory in each
- basic block. */
- modify_mem_list = GCNEWVEC (rtx, last_basic_block);
- canon_modify_mem_list = GCNEWVEC (rtx, last_basic_block);
+ basic block. The two typedefs are needed to work around the
+ pre-processor limitation with template types in macro arguments. */
+ typedef vec<rtx_insn *> vec_rtx_heap;
+ typedef vec<modify_pair> vec_modify_pair_heap;
+ modify_mem_list = GCNEWVEC (vec_rtx_heap, last_basic_block_for_fn (cfun));
+ canon_modify_mem_list = GCNEWVEC (vec_modify_pair_heap,
+ last_basic_block_for_fn (cfun));
modify_mem_list_set = BITMAP_ALLOC (NULL);
blocks_with_calls = BITMAP_ALLOC (NULL);
}
static void
free_gcse_mem (void)
{
+ FREE_REG_SET (reg_set_bitmap);
+
free_modify_mem_tables ();
BITMAP_FREE (modify_mem_list_set);
BITMAP_FREE (blocks_with_calls);
least once and expression would contain the same value if the computation
was moved to the beginning of the block.
- We call this routine for cprop, pre and code hoisting. They all compute
+ We call this routine for pre and code hoisting. They all compute
basically the same information and thus can easily share this code.
TRANSP, COMP, and ANTLOC are destination sbitmaps for recording local
properties. If NULL, then it is not necessary to compute or record that
particular property.
- TABLE controls which hash table to look at. If it is set hash table,
- additionally, TRANSP is computed as ~TRANSP, since this is really cprop's
- ABSALTERED. */
+ TABLE controls which hash table to look at. */
static void
compute_local_properties (sbitmap *transp, sbitmap *comp, sbitmap *antloc,
- struct hash_table_d *table)
+ struct gcse_hash_table_d *table)
{
unsigned int i;
/* Initialize any bitmaps that were passed in. */
if (transp)
{
- if (table->set_p)
- sbitmap_vector_zero (transp, last_basic_block);
- else
- sbitmap_vector_ones (transp, last_basic_block);
+ bitmap_vector_ones (transp, last_basic_block_for_fn (cfun));
}
if (comp)
- sbitmap_vector_zero (comp, last_basic_block);
+ bitmap_vector_clear (comp, last_basic_block_for_fn (cfun));
if (antloc)
- sbitmap_vector_zero (antloc, last_basic_block);
+ bitmap_vector_clear (antloc, last_basic_block_for_fn (cfun));
for (i = 0; i < table->size; i++)
{
- struct expr *expr;
+ struct gcse_expr *expr;
for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash)
{
int indx = expr->bitmap_index;
- struct occr *occr;
+ struct gcse_occr *occr;
/* The expression is transparent in this block if it is not killed.
We start by assuming all are transparent [none are killed], and
then reset the bits for those that are. */
if (transp)
- compute_transp (expr->expr, indx, transp, table->set_p);
+ compute_transp (expr->expr, indx, transp);
/* The occurrences recorded in antic_occr are exactly those that
we want to set to nonzero in ANTLOC. */
if (antloc)
for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
{
- SET_BIT (antloc[BLOCK_FOR_INSN (occr->insn)->index], indx);
+ bitmap_set_bit (antloc[BLOCK_FOR_INSN (occr->insn)->index], indx);
/* While we're scanning the table, this is a good place to
initialize this. */
if (comp)
for (occr = expr->avail_occr; occr != NULL; occr = occr->next)
{
- SET_BIT (comp[BLOCK_FOR_INSN (occr->insn)->index], indx);
+ bitmap_set_bit (comp[BLOCK_FOR_INSN (occr->insn)->index], indx);
/* While we're scanning the table, this is a good place to
initialize this. */
static struct reg_avail_info *reg_avail_info;
static basic_block current_bb;
-
/* See whether X, the source of a set, is something we want to consider for
GCSE. */
static int
-want_to_gcse_p (rtx x)
+want_to_gcse_p (rtx x, int *max_distance_ptr)
{
#ifdef STACK_REGS
/* On register stack architectures, don't GCSE constants from the
x = avoid_constant_pool_reference (x);
#endif
+ /* GCSE'ing constants:
+
+ We do not specifically distinguish between constant and non-constant
+ expressions in PRE and Hoist. We use set_src_cost below to limit
+ the maximum distance simple expressions can travel.
+
+ Nevertheless, constants are much easier to GCSE, and, hence,
+ it is easy to overdo the optimizations. Usually, excessive PRE and
+ Hoisting of constant leads to increased register pressure.
+
+ RA can deal with this by rematerialing some of the constants.
+ Therefore, it is important that the back-end generates sets of constants
+ in a way that allows reload rematerialize them under high register
+ pressure, i.e., a pseudo register with REG_EQUAL to constant
+ is set only once. Failing to do so will result in IRA/reload
+ spilling such constants under high register pressure instead of
+ rematerializing them. */
+
switch (GET_CODE (x))
{
case REG:
case SUBREG:
- case CONST_INT:
- case CONST_DOUBLE:
- case CONST_FIXED:
- case CONST_VECTOR:
case CALL:
return 0;
+ CASE_CONST_ANY:
+ if (!doing_code_hoisting_p)
+ /* Do not PRE constants. */
+ return 0;
+
+ /* FALLTHRU */
+
default:
+ if (doing_code_hoisting_p)
+ /* PRE doesn't implement max_distance restriction. */
+ {
+ int cost;
+ int max_distance;
+
+ gcc_assert (!optimize_function_for_speed_p (cfun)
+ && optimize_function_for_size_p (cfun));
+ cost = set_src_cost (x, 0);
+
+ if (cost < COSTS_N_INSNS (GCSE_UNRESTRICTED_COST))
+ {
+ max_distance = (GCSE_COST_DISTANCE_RATIO * cost) / 10;
+ if (max_distance == 0)
+ return 0;
+
+ gcc_assert (max_distance > 0);
+ }
+ else
+ max_distance = 0;
+
+ if (max_distance_ptr)
+ *max_distance_ptr = max_distance;
+ }
+
return can_assign_to_reg_without_clobbers_p (x);
}
}
/* Used internally by can_assign_to_reg_without_clobbers_p. */
-static GTY(()) rtx test_insn;
+static GTY(()) rtx_insn *test_insn;
/* Return true if we can assign X to a pseudo register such that the
resulting insn does not result in clobbering a hard register as a
{
int num_clobbers = 0;
int icode;
+ bool can_assign = false;
/* If this is a valid operand, we are OK. If it's VOIDmode, we aren't. */
if (general_operand (x, GET_MODE (x)))
gen_rtx_REG (word_mode,
FIRST_PSEUDO_REGISTER * 2),
const0_rtx));
- NEXT_INSN (test_insn) = PREV_INSN (test_insn) = 0;
+ SET_NEXT_INSN (test_insn) = SET_PREV_INSN (test_insn) = 0;
+ INSN_LOCATION (test_insn) = UNKNOWN_LOCATION;
}
/* Now make an insn like the one we would make when GCSE'ing and see if
SET_SRC (PATTERN (test_insn)) = x;
icode = recog (PATTERN (test_insn), test_insn, &num_clobbers);
- if (icode < 0)
- return false;
- if (num_clobbers > 0 && added_clobbers_hard_reg_p (icode))
- return false;
+ /* If the test insn is valid and doesn't need clobbers, and the target also
+ has no objections, we're good. */
+ if (icode >= 0
+ && (num_clobbers == 0 || !added_clobbers_hard_reg_p (icode))
+ && ! (targetm.cannot_copy_insn_p
+ && targetm.cannot_copy_insn_p (test_insn)))
+ can_assign = true;
- if (targetm.cannot_copy_insn_p && targetm.cannot_copy_insn_p (test_insn))
- return false;
+ /* Make sure test_insn doesn't have any pointers into GC space. */
+ SET_SRC (PATTERN (test_insn)) = NULL_RTX;
- return true;
+ return can_assign;
}
/* Return nonzero if the operands of expression X are unchanged from the
or from INSN to the end of INSN's basic block (if AVAIL_P != 0). */
static int
-oprs_unchanged_p (const_rtx x, const_rtx insn, int avail_p)
+oprs_unchanged_p (const_rtx x, const rtx_insn *insn, int avail_p)
{
int i, j;
enum rtx_code code;
}
case MEM:
- if (load_killed_in_block_p (current_bb, DF_INSN_LUID (insn),
- x, avail_p))
+ if (! flag_gcse_lm
+ || load_killed_in_block_p (current_bb, DF_INSN_LUID (insn),
+ x, avail_p))
return 0;
else
return oprs_unchanged_p (XEXP (x, 0), insn, avail_p);
case PC:
case CC0: /*FIXME*/
case CONST:
- case CONST_INT:
- case CONST_DOUBLE:
- case CONST_FIXED:
- case CONST_VECTOR:
+ CASE_CONST_ANY:
case SYMBOL_REF:
case LABEL_REF:
case ADDR_VEC:
return 1;
}
-/* Used for communication between mems_conflict_for_gcse_p and
- load_killed_in_block_p. Nonzero if mems_conflict_for_gcse_p finds a
- conflict between two memory references. */
-static int gcse_mems_conflict_p;
+/* Info passed from load_killed_in_block_p to mems_conflict_for_gcse_p. */
+
+struct mem_conflict_info
+{
+ /* A memory reference for a load instruction, mems_conflict_for_gcse_p will
+ see if a memory store conflicts with this memory load. */
+ const_rtx mem;
-/* Used for communication between mems_conflict_for_gcse_p and
- load_killed_in_block_p. A memory reference for a load instruction,
- mems_conflict_for_gcse_p will see if a memory store conflicts with
- this memory load. */
-static const_rtx gcse_mem_operand;
+ /* True if mems_conflict_for_gcse_p finds a conflict between two memory
+ references. */
+ bool conflict;
+};
-/* DEST is the output of an instruction. If it is a memory reference, and
- possibly conflicts with the load found in gcse_mem_operand, then set
- gcse_mems_conflict_p to a nonzero value. */
+/* DEST is the output of an instruction. If it is a memory reference and
+ possibly conflicts with the load found in DATA, then communicate this
+ information back through DATA. */
static void
mems_conflict_for_gcse_p (rtx dest, const_rtx setter ATTRIBUTE_UNUSED,
- void *data ATTRIBUTE_UNUSED)
+ void *data)
{
+ struct mem_conflict_info *mci = (struct mem_conflict_info *) data;
+
while (GET_CODE (dest) == SUBREG
|| GET_CODE (dest) == ZERO_EXTRACT
|| GET_CODE (dest) == STRICT_LOW_PART)
/* If we are setting a MEM in our list of specially recognized MEMs,
don't mark as killed this time. */
-
- if (expr_equiv_p (dest, gcse_mem_operand) && pre_ldst_mems != NULL)
+ if (pre_ldst_mems != NULL && expr_equiv_p (dest, mci->mem))
{
if (!find_rtx_in_ldst (dest))
- gcse_mems_conflict_p = 1;
+ mci->conflict = true;
return;
}
- if (true_dependence (dest, GET_MODE (dest), gcse_mem_operand,
- rtx_addr_varies_p))
- gcse_mems_conflict_p = 1;
+ if (true_dependence (dest, GET_MODE (dest), mci->mem))
+ mci->conflict = true;
}
/* Return nonzero if the expression in X (a memory reference) is killed
AVAIL_P to 0. */
static int
-load_killed_in_block_p (const_basic_block bb, int uid_limit, const_rtx x, int avail_p)
+load_killed_in_block_p (const_basic_block bb, int uid_limit, const_rtx x,
+ int avail_p)
{
- rtx list_entry = modify_mem_list[bb->index];
+ vec<rtx_insn *> list = modify_mem_list[bb->index];
+ rtx_insn *setter;
+ unsigned ix;
/* If this is a readonly then we aren't going to be changing it. */
if (MEM_READONLY_P (x))
return 0;
- while (list_entry)
+ FOR_EACH_VEC_ELT_REVERSE (list, ix, setter)
{
- rtx setter;
+ struct mem_conflict_info mci;
+
/* Ignore entries in the list that do not apply. */
if ((avail_p
- && DF_INSN_LUID (XEXP (list_entry, 0)) < uid_limit)
+ && DF_INSN_LUID (setter) < uid_limit)
|| (! avail_p
- && DF_INSN_LUID (XEXP (list_entry, 0)) > uid_limit))
- {
- list_entry = XEXP (list_entry, 1);
- continue;
- }
-
- setter = XEXP (list_entry, 0);
+ && DF_INSN_LUID (setter) > uid_limit))
+ continue;
/* If SETTER is a call everything is clobbered. Note that calls
to pure functions are never put on the list, so we need not
return 1;
/* SETTER must be an INSN of some kind that sets memory. Call
- note_stores to examine each hunk of memory that is modified.
-
- The note_stores interface is pretty limited, so we have to
- communicate via global variables. Yuk. */
- gcse_mem_operand = x;
- gcse_mems_conflict_p = 0;
- note_stores (PATTERN (setter), mems_conflict_for_gcse_p, NULL);
- if (gcse_mems_conflict_p)
+ note_stores to examine each hunk of memory that is modified. */
+ mci.mem = x;
+ mci.conflict = false;
+ note_stores (PATTERN (setter), mems_conflict_for_gcse_p, &mci);
+ if (mci.conflict)
return 1;
- list_entry = XEXP (list_entry, 1);
}
return 0;
}
the start of INSN's basic block up to but not including INSN. */
static int
-oprs_anticipatable_p (const_rtx x, const_rtx insn)
+oprs_anticipatable_p (const_rtx x, const rtx_insn *insn)
{
return oprs_unchanged_p (x, insn, 0);
}
INSN to the end of INSN's basic block. */
static int
-oprs_available_p (const_rtx x, const_rtx insn)
+oprs_available_p (const_rtx x, const rtx_insn *insn)
{
return oprs_unchanged_p (x, insn, 1);
}
the current size of the hash table to be probed. */
static unsigned int
-hash_expr (const_rtx x, enum machine_mode mode, int *do_not_record_p,
+hash_expr (const_rtx x, machine_mode mode, int *do_not_record_p,
int hash_table_size)
{
unsigned int hash;
*do_not_record_p = 0;
- hash = hash_rtx (x, mode, do_not_record_p,
- NULL, /*have_reg_qty=*/false);
- return hash % hash_table_size;
-}
-
-/* Hash a set of register REGNO.
-
- Sets are hashed on the register that is set. This simplifies the PRE copy
- propagation code.
-
- ??? May need to make things more elaborate. Later, as necessary. */
-
-static unsigned int
-hash_set (int regno, int hash_table_size)
-{
- unsigned int hash;
-
- hash = regno;
+ hash = hash_rtx (x, mode, do_not_record_p, NULL, /*have_reg_qty=*/false);
return hash % hash_table_size;
}
It is only used if X is a CONST_INT.
ANTIC_P is nonzero if X is an anticipatable expression.
- AVAIL_P is nonzero if X is an available expression. */
+ AVAIL_P is nonzero if X is an available expression.
+
+ MAX_DISTANCE is the maximum distance in instructions this expression can
+ be moved. */
static void
-insert_expr_in_table (rtx x, enum machine_mode mode, rtx insn, int antic_p,
- int avail_p, struct hash_table_d *table)
+insert_expr_in_table (rtx x, machine_mode mode, rtx_insn *insn,
+ int antic_p,
+ int avail_p, int max_distance, struct gcse_hash_table_d *table)
{
int found, do_not_record_p;
unsigned int hash;
- struct expr *cur_expr, *last_expr = NULL;
- struct occr *antic_occr, *avail_occr;
+ struct gcse_expr *cur_expr, *last_expr = NULL;
+ struct gcse_occr *antic_occr, *avail_occr;
hash = hash_expr (x, mode, &do_not_record_p, table->size);
if (! found)
{
- cur_expr = GOBNEW (struct expr);
- bytes_used += sizeof (struct expr);
+ cur_expr = GOBNEW (struct gcse_expr);
+ bytes_used += sizeof (struct gcse_expr);
if (table->table[hash] == NULL)
/* This is the first pattern that hashed to this index. */
table->table[hash] = cur_expr;
cur_expr->next_same_hash = NULL;
cur_expr->antic_occr = NULL;
cur_expr->avail_occr = NULL;
+ gcc_assert (max_distance >= 0);
+ cur_expr->max_distance = max_distance;
}
+ else
+ gcc_assert (cur_expr->max_distance == max_distance);
/* Now record the occurrence(s). */
if (antic_p)
else
{
/* First occurrence of this expression in this basic block. */
- antic_occr = GOBNEW (struct occr);
- bytes_used += sizeof (struct occr);
+ antic_occr = GOBNEW (struct gcse_occr);
+ bytes_used += sizeof (struct gcse_occr);
antic_occr->insn = insn;
antic_occr->next = cur_expr->antic_occr;
antic_occr->deleted_p = 0;
else
{
/* First occurrence of this expression in this basic block. */
- avail_occr = GOBNEW (struct occr);
- bytes_used += sizeof (struct occr);
+ avail_occr = GOBNEW (struct gcse_occr);
+ bytes_used += sizeof (struct gcse_occr);
avail_occr->insn = insn;
avail_occr->next = cur_expr->avail_occr;
avail_occr->deleted_p = 0;
}
}
-/* Insert pattern X in INSN in the hash table.
- X is a SET of a reg to either another reg or a constant.
- If it is already present, record it as the last occurrence in INSN's
- basic block. */
-
-static void
-insert_set_in_table (rtx x, rtx insn, struct hash_table_d *table)
-{
- int found;
- unsigned int hash;
- struct expr *cur_expr, *last_expr = NULL;
- struct occr *cur_occr;
-
- gcc_assert (GET_CODE (x) == SET && REG_P (SET_DEST (x)));
-
- hash = hash_set (REGNO (SET_DEST (x)), table->size);
-
- cur_expr = table->table[hash];
- found = 0;
-
- while (cur_expr && 0 == (found = expr_equiv_p (cur_expr->expr, x)))
- {
- /* If the expression isn't found, save a pointer to the end of
- the list. */
- last_expr = cur_expr;
- cur_expr = cur_expr->next_same_hash;
- }
-
- if (! found)
- {
- cur_expr = GOBNEW (struct expr);
- bytes_used += sizeof (struct expr);
- if (table->table[hash] == NULL)
- /* This is the first pattern that hashed to this index. */
- table->table[hash] = cur_expr;
- else
- /* Add EXPR to end of this hash chain. */
- last_expr->next_same_hash = cur_expr;
-
- /* Set the fields of the expr element.
- We must copy X because it can be modified when copy propagation is
- performed on its operands. */
- cur_expr->expr = copy_rtx (x);
- cur_expr->bitmap_index = table->n_elems++;
- cur_expr->next_same_hash = NULL;
- cur_expr->antic_occr = NULL;
- cur_expr->avail_occr = NULL;
- }
-
- /* Now record the occurrence. */
- cur_occr = cur_expr->avail_occr;
-
- if (cur_occr
- && BLOCK_FOR_INSN (cur_occr->insn) == BLOCK_FOR_INSN (insn))
- {
- /* Found another instance of the expression in the same basic block.
- Prefer this occurrence to the currently recorded one. We want
- the last one in the block and the block is scanned from start
- to end. */
- cur_occr->insn = insn;
- }
- else
- {
- /* First occurrence of this expression in this basic block. */
- cur_occr = GOBNEW (struct occr);
- bytes_used += sizeof (struct occr);
- cur_occr->insn = insn;
- cur_occr->next = cur_expr->avail_occr;
- cur_occr->deleted_p = 0;
- cur_expr->avail_occr = cur_occr;
- }
-}
-
-/* Determine whether the rtx X should be treated as a constant for
- the purposes of GCSE's constant propagation. */
-
-static bool
-gcse_constant_p (const_rtx x)
-{
- /* Consider a COMPARE of two integers constant. */
- if (GET_CODE (x) == COMPARE
- && CONST_INT_P (XEXP (x, 0))
- && CONST_INT_P (XEXP (x, 1)))
- return true;
-
- /* Consider a COMPARE of the same registers is a constant
- if they are not floating point registers. */
- if (GET_CODE(x) == COMPARE
- && REG_P (XEXP (x, 0)) && REG_P (XEXP (x, 1))
- && REGNO (XEXP (x, 0)) == REGNO (XEXP (x, 1))
- && ! FLOAT_MODE_P (GET_MODE (XEXP (x, 0)))
- && ! FLOAT_MODE_P (GET_MODE (XEXP (x, 1))))
- return true;
-
- /* Since X might be inserted more than once we have to take care that it
- is sharable. */
- return CONSTANT_P (x) && (GET_CODE (x) != CONST || shared_const_p (x));
-}
-
-/* Scan pattern PAT of INSN and add an entry to the hash TABLE (set or
- expression one). */
+/* Scan SET present in INSN and add an entry to the hash TABLE. */
static void
-hash_scan_set (rtx pat, rtx insn, struct hash_table_d *table)
+hash_scan_set (rtx set, rtx_insn *insn, struct gcse_hash_table_d *table)
{
- rtx src = SET_SRC (pat);
- rtx dest = SET_DEST (pat);
+ rtx src = SET_SRC (set);
+ rtx dest = SET_DEST (set);
rtx note;
if (GET_CODE (src) == CALL)
else if (REG_P (dest))
{
unsigned int regno = REGNO (dest);
- rtx tmp;
+ int max_distance = 0;
/* See if a REG_EQUAL note shows this equivalent to a simpler expression.
redundant constants, addresses or other expressions that are
constructed with multiple instructions.
- However, keep the original SRC if INSN is a simple reg-reg move. In
+ However, keep the original SRC if INSN is a simple reg-reg move.
In this case, there will almost always be a REG_EQUAL note on the
insn that sets SRC. By recording the REG_EQUAL value here as SRC
for INSN, we miss copy propagation opportunities and we perform the
if (note != 0
&& REG_NOTE_KIND (note) == REG_EQUAL
&& !REG_P (src)
- && (table->set_p
- ? gcse_constant_p (XEXP (note, 0))
- : want_to_gcse_p (XEXP (note, 0))))
- src = XEXP (note, 0), pat = gen_rtx_SET (VOIDmode, dest, src);
+ && want_to_gcse_p (XEXP (note, 0), NULL))
+ src = XEXP (note, 0), set = gen_rtx_SET (VOIDmode, dest, src);
/* Only record sets of pseudo-regs in the hash table. */
- if (! table->set_p
- && regno >= FIRST_PSEUDO_REGISTER
+ if (regno >= FIRST_PSEUDO_REGISTER
/* Don't GCSE something if we can't do a reg/reg copy. */
&& can_copy_p (GET_MODE (dest))
/* GCSE commonly inserts instruction after the insn. We can't
can't do the same thing at the rtl level. */
&& !can_throw_internal (insn)
/* Is SET_SRC something we want to gcse? */
- && want_to_gcse_p (src)
+ && want_to_gcse_p (src, &max_distance)
/* Don't CSE a nop. */
- && ! set_noop_p (pat)
+ && ! set_noop_p (set)
/* Don't GCSE if it has attached REG_EQUIV note.
At this point this only function parameters should have
REG_EQUIV notes and if the argument slot is used somewhere
int avail_p = (oprs_available_p (src, insn)
&& ! JUMP_P (insn));
- insert_expr_in_table (src, GET_MODE (dest), insn, antic_p, avail_p, table);
+ insert_expr_in_table (src, GET_MODE (dest), insn, antic_p, avail_p,
+ max_distance, table);
}
-
- /* Record sets for constant/copy propagation. */
- else if (table->set_p
- && regno >= FIRST_PSEUDO_REGISTER
- && ((REG_P (src)
- && REGNO (src) >= FIRST_PSEUDO_REGISTER
- && can_copy_p (GET_MODE (dest))
- && REGNO (src) != regno)
- || gcse_constant_p (src))
- /* A copy is not available if its src or dest is subsequently
- modified. Here we want to search from INSN+1 on, but
- oprs_available_p searches from INSN on. */
- && (insn == BB_END (BLOCK_FOR_INSN (insn))
- || (tmp = next_nonnote_insn (insn)) == NULL_RTX
- || BLOCK_FOR_INSN (tmp) != BLOCK_FOR_INSN (insn)
- || oprs_available_p (pat, tmp)))
- insert_set_in_table (pat, insn, table);
}
/* In case of store we want to consider the memory value as available in
the REG stored in that memory. This makes it possible to remove
else if (flag_gcse_las && REG_P (src) && MEM_P (dest))
{
unsigned int regno = REGNO (src);
+ int max_distance = 0;
- /* Do not do this for constant/copy propagation. */
- if (! table->set_p
- /* Only record sets of pseudo-regs in the hash table. */
- && regno >= FIRST_PSEUDO_REGISTER
+ /* Only record sets of pseudo-regs in the hash table. */
+ if (regno >= FIRST_PSEUDO_REGISTER
/* Don't GCSE something if we can't do a reg/reg copy. */
&& can_copy_p (GET_MODE (src))
/* GCSE commonly inserts instruction after the insn. We can't
do that easily for EH edges so disable GCSE on these for now. */
&& !can_throw_internal (insn)
/* Is SET_DEST something we want to gcse? */
- && want_to_gcse_p (dest)
+ && want_to_gcse_p (dest, &max_distance)
/* Don't CSE a nop. */
- && ! set_noop_p (pat)
+ && ! set_noop_p (set)
/* Don't GCSE if it has attached REG_EQUIV note.
At this point this only function parameters should have
REG_EQUIV notes and if the argument slot is used somewhere
/* Record the memory expression (DEST) in the hash table. */
insert_expr_in_table (dest, GET_MODE (dest), insn,
- antic_p, avail_p, table);
+ antic_p, avail_p, max_distance, table);
}
}
}
static void
-hash_scan_clobber (rtx x ATTRIBUTE_UNUSED, rtx insn ATTRIBUTE_UNUSED,
- struct hash_table_d *table ATTRIBUTE_UNUSED)
+hash_scan_clobber (rtx x ATTRIBUTE_UNUSED, rtx_insn *insn ATTRIBUTE_UNUSED,
+ struct gcse_hash_table_d *table ATTRIBUTE_UNUSED)
{
/* Currently nothing to do. */
}
static void
-hash_scan_call (rtx x ATTRIBUTE_UNUSED, rtx insn ATTRIBUTE_UNUSED,
- struct hash_table_d *table ATTRIBUTE_UNUSED)
+hash_scan_call (rtx x ATTRIBUTE_UNUSED, rtx_insn *insn ATTRIBUTE_UNUSED,
+ struct gcse_hash_table_d *table ATTRIBUTE_UNUSED)
{
/* Currently nothing to do. */
}
-/* Process INSN and add hash table entries as appropriate.
-
- Only available expressions that set a single pseudo-reg are recorded.
-
- Single sets in a PARALLEL could be handled, but it's an extra complication
- that isn't dealt with right now. The trick is handling the CLOBBERs that
- are also in the PARALLEL. Later.
-
- If SET_P is nonzero, this is for the assignment hash table,
- otherwise it is for the expression hash table. */
+/* Process INSN and add hash table entries as appropriate. */
static void
-hash_scan_insn (rtx insn, struct hash_table_d *table)
+hash_scan_insn (rtx_insn *insn, struct gcse_hash_table_d *table)
{
rtx pat = PATTERN (insn);
int i;
if (GET_CODE (pat) == SET)
hash_scan_set (pat, insn, table);
+
+ else if (GET_CODE (pat) == CLOBBER)
+ hash_scan_clobber (pat, insn, table);
+
+ else if (GET_CODE (pat) == CALL)
+ hash_scan_call (pat, insn, table);
+
else if (GET_CODE (pat) == PARALLEL)
for (i = 0; i < XVECLEN (pat, 0); i++)
{
else if (GET_CODE (x) == CALL)
hash_scan_call (x, insn, table);
}
-
- else if (GET_CODE (pat) == CLOBBER)
- hash_scan_clobber (pat, insn, table);
- else if (GET_CODE (pat) == CALL)
- hash_scan_call (pat, insn, table);
}
+/* Dump the hash table TABLE to file FILE under the name NAME. */
+
static void
-dump_hash_table (FILE *file, const char *name, struct hash_table_d *table)
+dump_hash_table (FILE *file, const char *name, struct gcse_hash_table_d *table)
{
int i;
/* Flattened out table, so it's printed in proper order. */
- struct expr **flat_table;
+ struct gcse_expr **flat_table;
unsigned int *hash_val;
- struct expr *expr;
+ struct gcse_expr *expr;
- flat_table = XCNEWVEC (struct expr *, table->n_elems);
+ flat_table = XCNEWVEC (struct gcse_expr *, table->n_elems);
hash_val = XNEWVEC (unsigned int, table->n_elems);
for (i = 0; i < (int) table->size; i++)
if (flat_table[i] != 0)
{
expr = flat_table[i];
- fprintf (file, "Index %d (hash value %d)\n ",
- expr->bitmap_index, hash_val[i]);
+ fprintf (file, "Index %d (hash value %d; max distance %d)\n ",
+ expr->bitmap_index, hash_val[i], expr->max_distance);
print_rtl (file, expr->expr);
fprintf (file, "\n");
}
}
}
-
/* Record all of the canonicalized MEMs of record_last_mem_set_info's insn.
Note we store a pair of elements in the list, so they have to be
taken off pairwise. */
static void
-canon_list_insert (rtx dest ATTRIBUTE_UNUSED, const_rtx unused1 ATTRIBUTE_UNUSED,
+canon_list_insert (rtx dest ATTRIBUTE_UNUSED, const_rtx x ATTRIBUTE_UNUSED,
void * v_insn)
{
rtx dest_addr, insn;
int bb;
+ modify_pair pair;
while (GET_CODE (dest) == SUBREG
|| GET_CODE (dest) == ZERO_EXTRACT
insn = (rtx) v_insn;
bb = BLOCK_FOR_INSN (insn)->index;
- canon_modify_mem_list[bb] =
- alloc_EXPR_LIST (VOIDmode, dest_addr, canon_modify_mem_list[bb]);
- canon_modify_mem_list[bb] =
- alloc_EXPR_LIST (VOIDmode, dest, canon_modify_mem_list[bb]);
+ pair.dest = dest;
+ pair.dest_addr = dest_addr;
+ canon_modify_mem_list[bb].safe_push (pair);
}
/* Record memory modification information for INSN. We do not actually care
a CALL_INSN). We merely need to record which insns modify memory. */
static void
-record_last_mem_set_info (rtx insn)
+record_last_mem_set_info (rtx_insn *insn)
{
- int bb = BLOCK_FOR_INSN (insn)->index;
+ int bb;
+
+ if (! flag_gcse_lm)
+ return;
/* load_killed_in_block_p will handle the case of calls clobbering
everything. */
- modify_mem_list[bb] = alloc_INSN_LIST (insn, modify_mem_list[bb]);
+ bb = BLOCK_FOR_INSN (insn)->index;
+ modify_mem_list[bb].safe_push (insn);
bitmap_set_bit (modify_mem_list_set, bb);
if (CALL_P (insn))
- {
- /* Note that traversals of this loop (other than for free-ing)
- will break after encountering a CALL_INSN. So, there's no
- need to insert a pair of items, as canon_list_insert does. */
- canon_modify_mem_list[bb] =
- alloc_INSN_LIST (insn, canon_modify_mem_list[bb]);
- bitmap_set_bit (blocks_with_calls, bb);
- }
+ bitmap_set_bit (blocks_with_calls, bb);
else
note_stores (PATTERN (insn), canon_list_insert, (void*) insn);
}
static void
record_last_set_info (rtx dest, const_rtx setter ATTRIBUTE_UNUSED, void *data)
{
- rtx last_set_insn = (rtx) data;
+ rtx_insn *last_set_insn = (rtx_insn *) data;
if (GET_CODE (dest) == SUBREG)
dest = SUBREG_REG (dest);
record_last_mem_set_info (last_set_insn);
}
-/* Top level function to create an expression or assignment hash table.
+/* Top level function to create an expression hash table.
Expression entries are placed in the hash table if
- they are of the form (set (pseudo-reg) src),
- src is something we want to perform GCSE on,
- none of the operands are subsequently modified in the block
- Assignment entries are placed in the hash table if
- - they are of the form (set (pseudo-reg) src),
- - src is something we want to perform const/copy propagation on,
- - none of the operands or target are subsequently modified in the block
-
Currently src must be a pseudo-reg or a const_int.
TABLE is the table computed. */
static void
-compute_hash_table_work (struct hash_table_d *table)
+compute_hash_table_work (struct gcse_hash_table_d *table)
{
int i;
for (i = 0; i < max_reg_num (); ++i)
reg_avail_info[i].last_bb = NULL;
- FOR_EACH_BB (current_bb)
+ FOR_EACH_BB_FN (current_bb, cfun)
{
- rtx insn;
+ rtx_insn *insn;
unsigned int regno;
/* First pass over the instructions records information used to
determine when registers and memory are first and last set. */
FOR_BB_INSNS (current_bb, insn)
{
- if (! INSN_P (insn))
+ if (!NONDEBUG_INSN_P (insn))
continue;
if (CALL_P (insn))
{
- for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
- if (TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
- record_last_reg_set_info (insn, regno);
+ hard_reg_set_iterator hrsi;
+ EXECUTE_IF_SET_IN_HARD_REG_SET (regs_invalidated_by_call,
+ 0, regno, hrsi)
+ record_last_reg_set_info (insn, regno);
- mark_call (insn);
+ if (! RTL_CONST_OR_PURE_CALL_P (insn))
+ record_last_mem_set_info (insn);
}
note_stores (PATTERN (insn), record_last_set_info, insn);
}
- /* Insert implicit sets in the hash table. */
- if (table->set_p
- && implicit_sets[current_bb->index] != NULL_RTX)
- hash_scan_set (implicit_sets[current_bb->index],
- BB_HEAD (current_bb), table);
-
/* The next pass builds the hash table. */
FOR_BB_INSNS (current_bb, insn)
- if (INSN_P (insn))
+ if (NONDEBUG_INSN_P (insn))
hash_scan_insn (insn, table);
}
}
/* Allocate space for the set/expr hash TABLE.
- It is used to determine the number of buckets to use.
- SET_P determines whether set or expression table will
- be created. */
+ It is used to determine the number of buckets to use. */
static void
-alloc_hash_table (struct hash_table_d *table, int set_p)
+alloc_hash_table (struct gcse_hash_table_d *table)
{
int n;
Making it an odd number is simplest for now.
??? Later take some measurements. */
table->size |= 1;
- n = table->size * sizeof (struct expr *);
- table->table = GNEWVAR (struct expr *, n);
- table->set_p = set_p;
+ n = table->size * sizeof (struct gcse_expr *);
+ table->table = GNEWVAR (struct gcse_expr *, n);
}
/* Free things allocated by alloc_hash_table. */
static void
-free_hash_table (struct hash_table_d *table)
+free_hash_table (struct gcse_hash_table_d *table)
{
free (table->table);
}
-/* Compute the hash TABLE for doing copy/const propagation or
- expression hash table. */
+/* Compute the expression hash table TABLE. */
static void
-compute_hash_table (struct hash_table_d *table)
+compute_hash_table (struct gcse_hash_table_d *table)
{
/* Initialize count of number of entries in hash table. */
table->n_elems = 0;
- memset (table->table, 0, table->size * sizeof (struct expr *));
+ memset (table->table, 0, table->size * sizeof (struct gcse_expr *));
compute_hash_table_work (table);
}
\f
/* Expression tracking support. */
-/* Lookup REGNO in the set TABLE. The result is a pointer to the
- table entry, or NULL if not found. */
-
-static struct expr *
-lookup_set (unsigned int regno, struct hash_table_d *table)
-{
- unsigned int hash = hash_set (regno, table->size);
- struct expr *expr;
-
- expr = table->table[hash];
-
- while (expr && REGNO (SET_DEST (expr->expr)) != regno)
- expr = expr->next_same_hash;
-
- return expr;
-}
-
-/* Return the next entry for REGNO in list EXPR. */
-
-static struct expr *
-next_set (unsigned int regno, struct expr *expr)
-{
- do
- expr = expr->next_same_hash;
- while (expr && REGNO (SET_DEST (expr->expr)) != regno);
-
- return expr;
-}
-
-/* Like free_INSN_LIST_list or free_EXPR_LIST_list, except that the node
- types may be mixed. */
-
-static void
-free_insn_expr_list_list (rtx *listp)
-{
- rtx list, next;
-
- for (list = *listp; list ; list = next)
- {
- next = XEXP (list, 1);
- if (GET_CODE (list) == EXPR_LIST)
- free_EXPR_LIST_node (list);
- else
- free_INSN_LIST_node (list);
- }
-
- *listp = NULL;
-}
-
/* Clear canon_modify_mem_list and modify_mem_list tables. */
static void
clear_modify_mem_tables (void)
EXECUTE_IF_SET_IN_BITMAP (modify_mem_list_set, 0, i, bi)
{
- free_INSN_LIST_list (modify_mem_list + i);
- free_insn_expr_list_list (canon_modify_mem_list + i);
+ modify_mem_list[i].release ();
+ canon_modify_mem_list[i].release ();
}
bitmap_clear (modify_mem_list_set);
bitmap_clear (blocks_with_calls);
modify_mem_list = 0;
canon_modify_mem_list = 0;
}
-
-/* Reset tables used to keep track of what's still available [since the
- start of the block]. */
+\f
+/* For each block, compute whether X is transparent. X is either an
+ expression or an assignment [though we don't care which, for this context
+ an assignment is treated as an expression]. For each block where an
+ element of X is modified, reset the INDX bit in BMAP. */
static void
-reset_opr_set_tables (void)
-{
- /* Maintain a bitmap of which regs have been set since beginning of
- the block. */
- CLEAR_REG_SET (reg_set_bitmap);
-
- /* Also keep a record of the last instruction to modify memory.
- For now this is very trivial, we only record whether any memory
- location has been modified. */
- clear_modify_mem_tables ();
-}
-
-/* Return nonzero if the operands of X are not set before INSN in
- INSN's basic block. */
-
-static int
-oprs_not_set_p (const_rtx x, const_rtx insn)
+compute_transp (const_rtx x, int indx, sbitmap *bmap)
{
int i, j;
enum rtx_code code;
const char *fmt;
+ /* repeat is used to turn tail-recursion into iteration since GCC
+ can't do it when there's no return value. */
+ repeat:
+
if (x == 0)
- return 1;
+ return;
code = GET_CODE (x);
switch (code)
{
+ case REG:
+ {
+ df_ref def;
+ for (def = DF_REG_DEF_CHAIN (REGNO (x));
+ def;
+ def = DF_REF_NEXT_REG (def))
+ bitmap_clear_bit (bmap[DF_REF_BB (def)->index], indx);
+ }
+
+ return;
+
+ case MEM:
+ if (! MEM_READONLY_P (x))
+ {
+ bitmap_iterator bi;
+ unsigned bb_index;
+ rtx x_addr;
+
+ x_addr = get_addr (XEXP (x, 0));
+ x_addr = canon_rtx (x_addr);
+
+ /* First handle all the blocks with calls. We don't need to
+ do any list walking for them. */
+ EXECUTE_IF_SET_IN_BITMAP (blocks_with_calls, 0, bb_index, bi)
+ {
+ bitmap_clear_bit (bmap[bb_index], indx);
+ }
+
+ /* Now iterate over the blocks which have memory modifications
+ but which do not have any calls. */
+ EXECUTE_IF_AND_COMPL_IN_BITMAP (modify_mem_list_set,
+ blocks_with_calls,
+ 0, bb_index, bi)
+ {
+ vec<modify_pair> list
+ = canon_modify_mem_list[bb_index];
+ modify_pair *pair;
+ unsigned ix;
+
+ FOR_EACH_VEC_ELT_REVERSE (list, ix, pair)
+ {
+ rtx dest = pair->dest;
+ rtx dest_addr = pair->dest_addr;
+
+ if (canon_true_dependence (dest, GET_MODE (dest),
+ dest_addr, x, x_addr))
+ {
+ bitmap_clear_bit (bmap[bb_index], indx);
+ break;
+ }
+ }
+ }
+ }
+
+ x = XEXP (x, 0);
+ goto repeat;
+
case PC:
- case CC0:
+ case CC0: /*FIXME*/
case CONST:
- case CONST_INT:
- case CONST_DOUBLE:
- case CONST_FIXED:
- case CONST_VECTOR:
+ CASE_CONST_ANY:
case SYMBOL_REF:
case LABEL_REF:
case ADDR_VEC:
case ADDR_DIFF_VEC:
- return 1;
-
- case MEM:
- if (load_killed_in_block_p (BLOCK_FOR_INSN (insn),
- DF_INSN_LUID (insn), x, 0))
- return 0;
- else
- return oprs_not_set_p (XEXP (x, 0), insn);
-
- case REG:
- return ! REGNO_REG_SET_P (reg_set_bitmap, REGNO (x));
+ return;
default:
break;
needed at this level, change it into iteration.
This function is called enough to be worth it. */
if (i == 0)
- return oprs_not_set_p (XEXP (x, i), insn);
+ {
+ x = XEXP (x, i);
+ goto repeat;
+ }
- if (! oprs_not_set_p (XEXP (x, i), insn))
- return 0;
+ compute_transp (XEXP (x, i), indx, bmap);
}
else if (fmt[i] == 'E')
for (j = 0; j < XVECLEN (x, i); j++)
- if (! oprs_not_set_p (XVECEXP (x, i, j), insn))
- return 0;
+ compute_transp (XVECEXP (x, i, j), indx, bmap);
}
-
- return 1;
-}
-
-/* Mark things set by a CALL. */
-
-static void
-mark_call (rtx insn)
-{
- if (! RTL_CONST_OR_PURE_CALL_P (insn))
- record_last_mem_set_info (insn);
-}
-
-/* Mark things set by a SET. */
-
-static void
-mark_set (rtx pat, rtx insn)
-{
- rtx dest = SET_DEST (pat);
-
- while (GET_CODE (dest) == SUBREG
- || GET_CODE (dest) == ZERO_EXTRACT
- || GET_CODE (dest) == STRICT_LOW_PART)
- dest = XEXP (dest, 0);
-
- if (REG_P (dest))
- SET_REGNO_REG_SET (reg_set_bitmap, REGNO (dest));
- else if (MEM_P (dest))
- record_last_mem_set_info (insn);
-
- if (GET_CODE (SET_SRC (pat)) == CALL)
- mark_call (insn);
-}
-
-/* Record things set by a CLOBBER. */
-
-static void
-mark_clobber (rtx pat, rtx insn)
-{
- rtx clob = XEXP (pat, 0);
-
- while (GET_CODE (clob) == SUBREG || GET_CODE (clob) == STRICT_LOW_PART)
- clob = XEXP (clob, 0);
-
- if (REG_P (clob))
- SET_REGNO_REG_SET (reg_set_bitmap, REGNO (clob));
- else
- record_last_mem_set_info (insn);
-}
-
-/* Record things set by INSN.
- This data is used by oprs_not_set_p. */
-
-static void
-mark_oprs_set (rtx insn)
-{
- rtx pat = PATTERN (insn);
- int i;
-
- if (GET_CODE (pat) == SET)
- mark_set (pat, insn);
- else if (GET_CODE (pat) == PARALLEL)
- for (i = 0; i < XVECLEN (pat, 0); i++)
- {
- rtx x = XVECEXP (pat, 0, i);
-
- if (GET_CODE (x) == SET)
- mark_set (x, insn);
- else if (GET_CODE (x) == CLOBBER)
- mark_clobber (x, insn);
- else if (GET_CODE (x) == CALL)
- mark_call (insn);
- }
-
- else if (GET_CODE (pat) == CLOBBER)
- mark_clobber (pat, insn);
- else if (GET_CODE (pat) == CALL)
- mark_call (insn);
-}
-
-\f
-/* Compute copy/constant propagation working variables. */
-
-/* Local properties of assignments. */
-static sbitmap *cprop_pavloc;
-static sbitmap *cprop_absaltered;
-
-/* Global properties of assignments (computed from the local properties). */
-static sbitmap *cprop_avin;
-static sbitmap *cprop_avout;
-
-/* Allocate vars used for copy/const propagation. N_BLOCKS is the number of
- basic blocks. N_SETS is the number of sets. */
-
-static void
-alloc_cprop_mem (int n_blocks, int n_sets)
-{
- cprop_pavloc = sbitmap_vector_alloc (n_blocks, n_sets);
- cprop_absaltered = sbitmap_vector_alloc (n_blocks, n_sets);
-
- cprop_avin = sbitmap_vector_alloc (n_blocks, n_sets);
- cprop_avout = sbitmap_vector_alloc (n_blocks, n_sets);
-}
-
-/* Free vars used by copy/const propagation. */
-
-static void
-free_cprop_mem (void)
-{
- sbitmap_vector_free (cprop_pavloc);
- sbitmap_vector_free (cprop_absaltered);
- sbitmap_vector_free (cprop_avin);
- sbitmap_vector_free (cprop_avout);
-}
-
-/* For each block, compute whether X is transparent. X is either an
- expression or an assignment [though we don't care which, for this context
- an assignment is treated as an expression]. For each block where an
- element of X is modified, set (SET_P == 1) or reset (SET_P == 0) the INDX
- bit in BMAP. */
-
-static void
-compute_transp (const_rtx x, int indx, sbitmap *bmap, int set_p)
-{
- int i, j;
- enum rtx_code code;
- const char *fmt;
-
- /* repeat is used to turn tail-recursion into iteration since GCC
- can't do it when there's no return value. */
- repeat:
-
- if (x == 0)
- return;
-
- code = GET_CODE (x);
- switch (code)
- {
- case REG:
- if (set_p)
- {
- df_ref def;
- for (def = DF_REG_DEF_CHAIN (REGNO (x));
- def;
- def = DF_REF_NEXT_REG (def))
- SET_BIT (bmap[DF_REF_BB (def)->index], indx);
- }
- else
- {
- df_ref def;
- for (def = DF_REG_DEF_CHAIN (REGNO (x));
- def;
- def = DF_REF_NEXT_REG (def))
- RESET_BIT (bmap[DF_REF_BB (def)->index], indx);
- }
-
- return;
-
- case MEM:
- if (! MEM_READONLY_P (x))
- {
- bitmap_iterator bi;
- unsigned bb_index;
-
- /* First handle all the blocks with calls. We don't need to
- do any list walking for them. */
- EXECUTE_IF_SET_IN_BITMAP (blocks_with_calls, 0, bb_index, bi)
- {
- if (set_p)
- SET_BIT (bmap[bb_index], indx);
- else
- RESET_BIT (bmap[bb_index], indx);
- }
-
- /* Now iterate over the blocks which have memory modifications
- but which do not have any calls. */
- EXECUTE_IF_AND_COMPL_IN_BITMAP (modify_mem_list_set,
- blocks_with_calls,
- 0, bb_index, bi)
- {
- rtx list_entry = canon_modify_mem_list[bb_index];
-
- while (list_entry)
- {
- rtx dest, dest_addr;
-
- /* LIST_ENTRY must be an INSN of some kind that sets memory.
- Examine each hunk of memory that is modified. */
-
- dest = XEXP (list_entry, 0);
- list_entry = XEXP (list_entry, 1);
- dest_addr = XEXP (list_entry, 0);
-
- if (canon_true_dependence (dest, GET_MODE (dest), dest_addr,
- x, NULL_RTX, rtx_addr_varies_p))
- {
- if (set_p)
- SET_BIT (bmap[bb_index], indx);
- else
- RESET_BIT (bmap[bb_index], indx);
- break;
- }
- list_entry = XEXP (list_entry, 1);
- }
- }
- }
-
- x = XEXP (x, 0);
- goto repeat;
-
- case PC:
- case CC0: /*FIXME*/
- case CONST:
- case CONST_INT:
- case CONST_DOUBLE:
- case CONST_FIXED:
- case CONST_VECTOR:
- case SYMBOL_REF:
- case LABEL_REF:
- case ADDR_VEC:
- case ADDR_DIFF_VEC:
- return;
-
- default:
- break;
- }
-
- for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
- {
- if (fmt[i] == 'e')
- {
- /* If we are about to do the last recursive call
- needed at this level, change it into iteration.
- This function is called enough to be worth it. */
- if (i == 0)
- {
- x = XEXP (x, i);
- goto repeat;
- }
-
- compute_transp (XEXP (x, i), indx, bmap, set_p);
- }
- else if (fmt[i] == 'E')
- for (j = 0; j < XVECLEN (x, i); j++)
- compute_transp (XVECEXP (x, i, j), indx, bmap, set_p);
- }
-}
-
-/* Top level routine to do the dataflow analysis needed by copy/const
- propagation. */
-
-static void
-compute_cprop_data (void)
-{
- compute_local_properties (cprop_absaltered, cprop_pavloc, NULL, &set_hash_table);
- compute_available (cprop_pavloc, cprop_absaltered,
- cprop_avout, cprop_avin);
-}
-\f
-/* Copy/constant propagation. */
-
-/* Maximum number of register uses in an insn that we handle. */
-#define MAX_USES 8
-
-/* Table of uses found in an insn.
- Allocated statically to avoid alloc/free complexity and overhead. */
-static struct reg_use reg_use_table[MAX_USES];
-
-/* Index into `reg_use_table' while building it. */
-static int reg_use_count;
-
-/* Set up a list of register numbers used in INSN. The found uses are stored
- in `reg_use_table'. `reg_use_count' is initialized to zero before entry,
- and contains the number of uses in the table upon exit.
-
- ??? If a register appears multiple times we will record it multiple times.
- This doesn't hurt anything but it will slow things down. */
-
-static void
-find_used_regs (rtx *xptr, void *data ATTRIBUTE_UNUSED)
-{
- int i, j;
- enum rtx_code code;
- const char *fmt;
- rtx x = *xptr;
-
- /* repeat is used to turn tail-recursion into iteration since GCC
- can't do it when there's no return value. */
- repeat:
- if (x == 0)
- return;
-
- code = GET_CODE (x);
- if (REG_P (x))
- {
- if (reg_use_count == MAX_USES)
- return;
-
- reg_use_table[reg_use_count].reg_rtx = x;
- reg_use_count++;
- }
-
- /* Recursively scan the operands of this expression. */
-
- for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
- {
- if (fmt[i] == 'e')
- {
- /* If we are about to do the last recursive call
- needed at this level, change it into iteration.
- This function is called enough to be worth it. */
- if (i == 0)
- {
- x = XEXP (x, 0);
- goto repeat;
- }
-
- find_used_regs (&XEXP (x, i), data);
- }
- else if (fmt[i] == 'E')
- for (j = 0; j < XVECLEN (x, i); j++)
- find_used_regs (&XVECEXP (x, i, j), data);
- }
-}
-
-/* Try to replace all non-SET_DEST occurrences of FROM in INSN with TO.
- Returns nonzero is successful. */
-
-static int
-try_replace_reg (rtx from, rtx to, rtx insn)
-{
- rtx note = find_reg_equal_equiv_note (insn);
- rtx src = 0;
- int success = 0;
- rtx set = single_set (insn);
-
- /* Usually we substitute easy stuff, so we won't copy everything.
- We however need to take care to not duplicate non-trivial CONST
- expressions. */
- to = copy_rtx (to);
-
- validate_replace_src_group (from, to, insn);
- if (num_changes_pending () && apply_change_group ())
- success = 1;
-
- /* Try to simplify SET_SRC if we have substituted a constant. */
- if (success && set && CONSTANT_P (to))
- {
- src = simplify_rtx (SET_SRC (set));
-
- if (src)
- validate_change (insn, &SET_SRC (set), src, 0);
- }
-
- /* If there is already a REG_EQUAL note, update the expression in it
- with our replacement. */
- if (note != 0 && REG_NOTE_KIND (note) == REG_EQUAL)
- set_unique_reg_note (insn, REG_EQUAL,
- simplify_replace_rtx (XEXP (note, 0), from, to));
- if (!success && set && reg_mentioned_p (from, SET_SRC (set)))
- {
- /* If above failed and this is a single set, try to simplify the source of
- the set given our substitution. We could perhaps try this for multiple
- SETs, but it probably won't buy us anything. */
- src = simplify_replace_rtx (SET_SRC (set), from, to);
-
- if (!rtx_equal_p (src, SET_SRC (set))
- && validate_change (insn, &SET_SRC (set), src, 0))
- success = 1;
-
- /* If we've failed to do replacement, have a single SET, don't already
- have a note, and have no special SET, add a REG_EQUAL note to not
- lose information. */
- if (!success && note == 0 && set != 0
- && GET_CODE (SET_DEST (set)) != ZERO_EXTRACT
- && GET_CODE (SET_DEST (set)) != STRICT_LOW_PART)
- note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (src));
- }
-
- /* REG_EQUAL may get simplified into register.
- We don't allow that. Remove that note. This code ought
- not to happen, because previous code ought to synthesize
- reg-reg move, but be on the safe side. */
- if (note && REG_NOTE_KIND (note) == REG_EQUAL && REG_P (XEXP (note, 0)))
- remove_note (insn, note);
-
- return success;
-}
-
-/* Find a set of REGNOs that are available on entry to INSN's block. Returns
- NULL no such set is found. */
-
-static struct expr *
-find_avail_set (int regno, rtx insn)
-{
- /* SET1 contains the last set found that can be returned to the caller for
- use in a substitution. */
- struct expr *set1 = 0;
-
- /* Loops are not possible here. To get a loop we would need two sets
- available at the start of the block containing INSN. i.e. we would
- need two sets like this available at the start of the block:
-
- (set (reg X) (reg Y))
- (set (reg Y) (reg X))
-
- This can not happen since the set of (reg Y) would have killed the
- set of (reg X) making it unavailable at the start of this block. */
- while (1)
- {
- rtx src;
- struct expr *set = lookup_set (regno, &set_hash_table);
-
- /* Find a set that is available at the start of the block
- which contains INSN. */
- while (set)
- {
- if (TEST_BIT (cprop_avin[BLOCK_FOR_INSN (insn)->index],
- set->bitmap_index))
- break;
- set = next_set (regno, set);
- }
-
- /* If no available set was found we've reached the end of the
- (possibly empty) copy chain. */
- if (set == 0)
- break;
-
- gcc_assert (GET_CODE (set->expr) == SET);
-
- src = SET_SRC (set->expr);
-
- /* We know the set is available.
- Now check that SRC is ANTLOC (i.e. none of the source operands
- have changed since the start of the block).
-
- If the source operand changed, we may still use it for the next
- iteration of this loop, but we may not use it for substitutions. */
-
- if (gcse_constant_p (src) || oprs_not_set_p (src, insn))
- set1 = set;
-
- /* If the source of the set is anything except a register, then
- we have reached the end of the copy chain. */
- if (! REG_P (src))
- break;
-
- /* Follow the copy chain, i.e. start another iteration of the loop
- and see if we have an available copy into SRC. */
- regno = REGNO (src);
- }
-
- /* SET1 holds the last set that was available and anticipatable at
- INSN. */
- return set1;
-}
-
-/* Subroutine of cprop_insn that tries to propagate constants into
- JUMP_INSNS. JUMP must be a conditional jump. If SETCC is non-NULL
- it is the instruction that immediately precedes JUMP, and must be a
- single SET of a register. FROM is what we will try to replace,
- SRC is the constant we will try to substitute for it. Returns nonzero
- if a change was made. */
-
-static int
-cprop_jump (basic_block bb, rtx setcc, rtx jump, rtx from, rtx src)
-{
- rtx new_rtx, set_src, note_src;
- rtx set = pc_set (jump);
- rtx note = find_reg_equal_equiv_note (jump);
-
- if (note)
- {
- note_src = XEXP (note, 0);
- if (GET_CODE (note_src) == EXPR_LIST)
- note_src = NULL_RTX;
- }
- else note_src = NULL_RTX;
-
- /* Prefer REG_EQUAL notes except those containing EXPR_LISTs. */
- set_src = note_src ? note_src : SET_SRC (set);
-
- /* First substitute the SETCC condition into the JUMP instruction,
- then substitute that given values into this expanded JUMP. */
- if (setcc != NULL_RTX
- && !modified_between_p (from, setcc, jump)
- && !modified_between_p (src, setcc, jump))
- {
- rtx setcc_src;
- rtx setcc_set = single_set (setcc);
- rtx setcc_note = find_reg_equal_equiv_note (setcc);
- setcc_src = (setcc_note && GET_CODE (XEXP (setcc_note, 0)) != EXPR_LIST)
- ? XEXP (setcc_note, 0) : SET_SRC (setcc_set);
- set_src = simplify_replace_rtx (set_src, SET_DEST (setcc_set),
- setcc_src);
- }
- else
- setcc = NULL_RTX;
-
- new_rtx = simplify_replace_rtx (set_src, from, src);
-
- /* If no simplification can be made, then try the next register. */
- if (rtx_equal_p (new_rtx, SET_SRC (set)))
- return 0;
-
- /* If this is now a no-op delete it, otherwise this must be a valid insn. */
- if (new_rtx == pc_rtx)
- delete_insn (jump);
- else
- {
- /* Ensure the value computed inside the jump insn to be equivalent
- to one computed by setcc. */
- if (setcc && modified_in_p (new_rtx, setcc))
- return 0;
- if (! validate_unshare_change (jump, &SET_SRC (set), new_rtx, 0))
- {
- /* When (some) constants are not valid in a comparison, and there
- are two registers to be replaced by constants before the entire
- comparison can be folded into a constant, we need to keep
- intermediate information in REG_EQUAL notes. For targets with
- separate compare insns, such notes are added by try_replace_reg.
- When we have a combined compare-and-branch instruction, however,
- we need to attach a note to the branch itself to make this
- optimization work. */
-
- if (!rtx_equal_p (new_rtx, note_src))
- set_unique_reg_note (jump, REG_EQUAL, copy_rtx (new_rtx));
- return 0;
- }
-
- /* Remove REG_EQUAL note after simplification. */
- if (note_src)
- remove_note (jump, note);
- }
-
-#ifdef HAVE_cc0
- /* Delete the cc0 setter. */
- if (setcc != NULL && CC0_P (SET_DEST (single_set (setcc))))
- delete_insn (setcc);
-#endif
-
- global_const_prop_count++;
- if (dump_file != NULL)
- {
- fprintf (dump_file,
- "GLOBAL CONST-PROP: Replacing reg %d in jump_insn %d with constant ",
- REGNO (from), INSN_UID (jump));
- print_rtl (dump_file, src);
- fprintf (dump_file, "\n");
- }
- purge_dead_edges (bb);
-
- /* If a conditional jump has been changed into unconditional jump, remove
- the jump and make the edge fallthru - this is always called in
- cfglayout mode. */
- if (new_rtx != pc_rtx && simplejump_p (jump))
- {
- edge e;
- edge_iterator ei;
-
- for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ei_next (&ei))
- if (e->dest != EXIT_BLOCK_PTR
- && BB_HEAD (e->dest) == JUMP_LABEL (jump))
- {
- e->flags |= EDGE_FALLTHRU;
- break;
- }
- delete_insn (jump);
- }
-
- return 1;
-}
-
-static bool
-constprop_register (rtx insn, rtx from, rtx to)
-{
- rtx sset;
-
- /* Check for reg or cc0 setting instructions followed by
- conditional branch instructions first. */
- if ((sset = single_set (insn)) != NULL
- && NEXT_INSN (insn)
- && any_condjump_p (NEXT_INSN (insn)) && onlyjump_p (NEXT_INSN (insn)))
- {
- rtx dest = SET_DEST (sset);
- if ((REG_P (dest) || CC0_P (dest))
- && cprop_jump (BLOCK_FOR_INSN (insn), insn, NEXT_INSN (insn), from, to))
- return 1;
- }
-
- /* Handle normal insns next. */
- if (NONJUMP_INSN_P (insn)
- && try_replace_reg (from, to, insn))
- return 1;
-
- /* Try to propagate a CONST_INT into a conditional jump.
- We're pretty specific about what we will handle in this
- code, we can extend this as necessary over time.
-
- Right now the insn in question must look like
- (set (pc) (if_then_else ...)) */
- else if (any_condjump_p (insn) && onlyjump_p (insn))
- return cprop_jump (BLOCK_FOR_INSN (insn), NULL, insn, from, to);
- return 0;
-}
-
-/* Perform constant and copy propagation on INSN.
- The result is nonzero if a change was made. */
-
-static int
-cprop_insn (rtx insn)
-{
- struct reg_use *reg_used;
- int changed = 0;
- rtx note;
-
- if (!INSN_P (insn))
- return 0;
-
- reg_use_count = 0;
- note_uses (&PATTERN (insn), find_used_regs, NULL);
-
- note = find_reg_equal_equiv_note (insn);
-
- /* We may win even when propagating constants into notes. */
- if (note)
- find_used_regs (&XEXP (note, 0), NULL);
-
- for (reg_used = ®_use_table[0]; reg_use_count > 0;
- reg_used++, reg_use_count--)
- {
- unsigned int regno = REGNO (reg_used->reg_rtx);
- rtx pat, src;
- struct expr *set;
-
- /* If the register has already been set in this block, there's
- nothing we can do. */
- if (! oprs_not_set_p (reg_used->reg_rtx, insn))
- continue;
-
- /* Find an assignment that sets reg_used and is available
- at the start of the block. */
- set = find_avail_set (regno, insn);
- if (! set)
- continue;
-
- pat = set->expr;
- /* ??? We might be able to handle PARALLELs. Later. */
- gcc_assert (GET_CODE (pat) == SET);
-
- src = SET_SRC (pat);
-
- /* Constant propagation. */
- if (gcse_constant_p (src))
- {
- if (constprop_register (insn, reg_used->reg_rtx, src))
- {
- changed = 1;
- global_const_prop_count++;
- if (dump_file != NULL)
- {
- fprintf (dump_file, "GLOBAL CONST-PROP: Replacing reg %d in ", regno);
- fprintf (dump_file, "insn %d with constant ", INSN_UID (insn));
- print_rtl (dump_file, src);
- fprintf (dump_file, "\n");
- }
- if (INSN_DELETED_P (insn))
- return 1;
- }
- }
- else if (REG_P (src)
- && REGNO (src) >= FIRST_PSEUDO_REGISTER
- && REGNO (src) != regno)
- {
- if (try_replace_reg (reg_used->reg_rtx, src, insn))
- {
- changed = 1;
- global_copy_prop_count++;
- if (dump_file != NULL)
- {
- fprintf (dump_file, "GLOBAL COPY-PROP: Replacing reg %d in insn %d",
- regno, INSN_UID (insn));
- fprintf (dump_file, " with reg %d\n", REGNO (src));
- }
-
- /* The original insn setting reg_used may or may not now be
- deletable. We leave the deletion to flow. */
- /* FIXME: If it turns out that the insn isn't deletable,
- then we may have unnecessarily extended register lifetimes
- and made things worse. */
- }
- }
- }
-
- if (changed && DEBUG_INSN_P (insn))
- return 0;
-
- return changed;
-}
-
-/* Like find_used_regs, but avoid recording uses that appear in
- input-output contexts such as zero_extract or pre_dec. This
- restricts the cases we consider to those for which local cprop
- can legitimately make replacements. */
-
-static void
-local_cprop_find_used_regs (rtx *xptr, void *data)
-{
- rtx x = *xptr;
-
- if (x == 0)
- return;
-
- switch (GET_CODE (x))
- {
- case ZERO_EXTRACT:
- case SIGN_EXTRACT:
- case STRICT_LOW_PART:
- return;
-
- case PRE_DEC:
- case PRE_INC:
- case POST_DEC:
- case POST_INC:
- case PRE_MODIFY:
- case POST_MODIFY:
- /* Can only legitimately appear this early in the context of
- stack pushes for function arguments, but handle all of the
- codes nonetheless. */
- return;
-
- case SUBREG:
- /* Setting a subreg of a register larger than word_mode leaves
- the non-written words unchanged. */
- if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) > BITS_PER_WORD)
- return;
- break;
-
- default:
- break;
- }
-
- find_used_regs (xptr, data);
-}
-
-/* Try to perform local const/copy propagation on X in INSN. */
-
-static bool
-do_local_cprop (rtx x, rtx insn)
-{
- rtx newreg = NULL, newcnst = NULL;
-
- /* Rule out USE instructions and ASM statements as we don't want to
- change the hard registers mentioned. */
- if (REG_P (x)
- && (REGNO (x) >= FIRST_PSEUDO_REGISTER
- || (GET_CODE (PATTERN (insn)) != USE
- && asm_noperands (PATTERN (insn)) < 0)))
- {
- cselib_val *val = cselib_lookup (x, GET_MODE (x), 0);
- struct elt_loc_list *l;
-
- if (!val)
- return false;
- for (l = val->locs; l; l = l->next)
- {
- rtx this_rtx = l->loc;
- rtx note;
-
- if (gcse_constant_p (this_rtx))
- newcnst = this_rtx;
- if (REG_P (this_rtx) && REGNO (this_rtx) >= FIRST_PSEUDO_REGISTER
- /* Don't copy propagate if it has attached REG_EQUIV note.
- At this point this only function parameters should have
- REG_EQUIV notes and if the argument slot is used somewhere
- explicitly, it means address of parameter has been taken,
- so we should not extend the lifetime of the pseudo. */
- && (!(note = find_reg_note (l->setting_insn, REG_EQUIV, NULL_RTX))
- || ! MEM_P (XEXP (note, 0))))
- newreg = this_rtx;
- }
- if (newcnst && constprop_register (insn, x, newcnst))
- {
- if (dump_file != NULL)
- {
- fprintf (dump_file, "LOCAL CONST-PROP: Replacing reg %d in ",
- REGNO (x));
- fprintf (dump_file, "insn %d with constant ",
- INSN_UID (insn));
- print_rtl (dump_file, newcnst);
- fprintf (dump_file, "\n");
- }
- local_const_prop_count++;
- return true;
- }
- else if (newreg && newreg != x && try_replace_reg (x, newreg, insn))
- {
- if (dump_file != NULL)
- {
- fprintf (dump_file,
- "LOCAL COPY-PROP: Replacing reg %d in insn %d",
- REGNO (x), INSN_UID (insn));
- fprintf (dump_file, " with reg %d\n", REGNO (newreg));
- }
- local_copy_prop_count++;
- return true;
- }
- }
- return false;
-}
-
-/* Do local const/copy propagation (i.e. within each basic block). */
-
-static int
-local_cprop_pass (void)
-{
- basic_block bb;
- rtx insn;
- struct reg_use *reg_used;
- bool changed = false;
-
- cselib_init (0);
- FOR_EACH_BB (bb)
- {
- FOR_BB_INSNS (bb, insn)
- {
- if (INSN_P (insn))
- {
- rtx note = find_reg_equal_equiv_note (insn);
- do
- {
- reg_use_count = 0;
- note_uses (&PATTERN (insn), local_cprop_find_used_regs,
- NULL);
- if (note)
- local_cprop_find_used_regs (&XEXP (note, 0), NULL);
-
- for (reg_used = ®_use_table[0]; reg_use_count > 0;
- reg_used++, reg_use_count--)
- {
- if (do_local_cprop (reg_used->reg_rtx, insn))
- {
- changed = true;
- break;
- }
- }
- if (INSN_DELETED_P (insn))
- break;
- }
- while (reg_use_count);
- }
- cselib_process_insn (insn);
- }
-
- /* Forget everything at the end of a basic block. */
- cselib_clear_table ();
- }
-
- cselib_finish ();
-
- return changed;
-}
-
-/* Similar to get_condition, only the resulting condition must be
- valid at JUMP, instead of at EARLIEST.
-
- This differs from noce_get_condition in ifcvt.c in that we prefer not to
- settle for the condition variable in the jump instruction being integral.
- We prefer to be able to record the value of a user variable, rather than
- the value of a temporary used in a condition. This could be solved by
- recording the value of *every* register scanned by canonicalize_condition,
- but this would require some code reorganization. */
-
-rtx
-fis_get_condition (rtx jump)
-{
- return get_condition (jump, NULL, false, true);
-}
-
-/* Check the comparison COND to see if we can safely form an implicit set from
- it. COND is either an EQ or NE comparison. */
-
-static bool
-implicit_set_cond_p (const_rtx cond)
-{
- const enum machine_mode mode = GET_MODE (XEXP (cond, 0));
- const_rtx cst = XEXP (cond, 1);
-
- /* We can't perform this optimization if either operand might be or might
- contain a signed zero. */
- if (HONOR_SIGNED_ZEROS (mode))
- {
- /* It is sufficient to check if CST is or contains a zero. We must
- handle float, complex, and vector. If any subpart is a zero, then
- the optimization can't be performed. */
- /* ??? The complex and vector checks are not implemented yet. We just
- always return zero for them. */
- if (GET_CODE (cst) == CONST_DOUBLE)
- {
- REAL_VALUE_TYPE d;
- REAL_VALUE_FROM_CONST_DOUBLE (d, cst);
- if (REAL_VALUES_EQUAL (d, dconst0))
- return 0;
- }
- else
- return 0;
- }
-
- return gcse_constant_p (cst);
-}
-
-/* Find the implicit sets of a function. An "implicit set" is a constraint
- on the value of a variable, implied by a conditional jump. For example,
- following "if (x == 2)", the then branch may be optimized as though the
- conditional performed an "explicit set", in this example, "x = 2". This
- function records the set patterns that are implicit at the start of each
- basic block.
-
- FIXME: This would be more effective if critical edges are pre-split. As
- it is now, we can't record implicit sets for blocks that have
- critical successor edges. This results in missed optimizations
- and in more (unnecessary) work in cfgcleanup.c:thread_jump(). */
-
-static void
-find_implicit_sets (void)
-{
- basic_block bb, dest;
- unsigned int count;
- rtx cond, new_rtx;
-
- count = 0;
- FOR_EACH_BB (bb)
- /* Check for more than one successor. */
- if (EDGE_COUNT (bb->succs) > 1)
- {
- cond = fis_get_condition (BB_END (bb));
-
- if (cond
- && (GET_CODE (cond) == EQ || GET_CODE (cond) == NE)
- && REG_P (XEXP (cond, 0))
- && REGNO (XEXP (cond, 0)) >= FIRST_PSEUDO_REGISTER
- && implicit_set_cond_p (cond))
- {
- dest = GET_CODE (cond) == EQ ? BRANCH_EDGE (bb)->dest
- : FALLTHRU_EDGE (bb)->dest;
-
- if (dest
- /* Record nothing for a critical edge. */
- && single_pred_p (dest)
- && dest != EXIT_BLOCK_PTR)
- {
- new_rtx = gen_rtx_SET (VOIDmode, XEXP (cond, 0),
- XEXP (cond, 1));
- implicit_sets[dest->index] = new_rtx;
- if (dump_file)
- {
- fprintf(dump_file, "Implicit set of reg %d in ",
- REGNO (XEXP (cond, 0)));
- fprintf(dump_file, "basic block %d\n", dest->index);
- }
- count++;
- }
- }
- }
-
- if (dump_file)
- fprintf (dump_file, "Found %d implicit sets\n", count);
-}
-
-/* Bypass conditional jumps. */
-
-/* The value of last_basic_block at the beginning of the jump_bypass
- pass. The use of redirect_edge_and_branch_force may introduce new
- basic blocks, but the data flow analysis is only valid for basic
- block indices less than bypass_last_basic_block. */
-
-static int bypass_last_basic_block;
-
-/* Find a set of REGNO to a constant that is available at the end of basic
- block BB. Returns NULL if no such set is found. Based heavily upon
- find_avail_set. */
-
-static struct expr *
-find_bypass_set (int regno, int bb)
-{
- struct expr *result = 0;
-
- for (;;)
- {
- rtx src;
- struct expr *set = lookup_set (regno, &set_hash_table);
-
- while (set)
- {
- if (TEST_BIT (cprop_avout[bb], set->bitmap_index))
- break;
- set = next_set (regno, set);
- }
-
- if (set == 0)
- break;
-
- gcc_assert (GET_CODE (set->expr) == SET);
-
- src = SET_SRC (set->expr);
- if (gcse_constant_p (src))
- result = set;
-
- if (! REG_P (src))
- break;
-
- regno = REGNO (src);
- }
- return result;
-}
-
-
-/* Subroutine of bypass_block that checks whether a pseudo is killed by
- any of the instructions inserted on an edge. Jump bypassing places
- condition code setters on CFG edges using insert_insn_on_edge. This
- function is required to check that our data flow analysis is still
- valid prior to commit_edge_insertions. */
-
-static bool
-reg_killed_on_edge (const_rtx reg, const_edge e)
-{
- rtx insn;
-
- for (insn = e->insns.r; insn; insn = NEXT_INSN (insn))
- if (INSN_P (insn) && reg_set_p (reg, insn))
- return true;
-
- return false;
-}
-
-/* Subroutine of bypass_conditional_jumps that attempts to bypass the given
- basic block BB which has more than one predecessor. If not NULL, SETCC
- is the first instruction of BB, which is immediately followed by JUMP_INSN
- JUMP. Otherwise, SETCC is NULL, and JUMP is the first insn of BB.
- Returns nonzero if a change was made.
-
- During the jump bypassing pass, we may place copies of SETCC instructions
- on CFG edges. The following routine must be careful to pay attention to
- these inserted insns when performing its transformations. */
-
-static int
-bypass_block (basic_block bb, rtx setcc, rtx jump)
-{
- rtx insn, note;
- edge e, edest;
- int i, change;
- int may_be_loop_header;
- unsigned removed_p;
- edge_iterator ei;
-
- insn = (setcc != NULL) ? setcc : jump;
-
- /* Determine set of register uses in INSN. */
- reg_use_count = 0;
- note_uses (&PATTERN (insn), find_used_regs, NULL);
- note = find_reg_equal_equiv_note (insn);
- if (note)
- find_used_regs (&XEXP (note, 0), NULL);
-
- may_be_loop_header = false;
- FOR_EACH_EDGE (e, ei, bb->preds)
- if (e->flags & EDGE_DFS_BACK)
- {
- may_be_loop_header = true;
- break;
- }
-
- change = 0;
- for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
- {
- removed_p = 0;
-
- if (e->flags & EDGE_COMPLEX)
- {
- ei_next (&ei);
- continue;
- }
-
- /* We can't redirect edges from new basic blocks. */
- if (e->src->index >= bypass_last_basic_block)
- {
- ei_next (&ei);
- continue;
- }
-
- /* The irreducible loops created by redirecting of edges entering the
- loop from outside would decrease effectiveness of some of the following
- optimizations, so prevent this. */
- if (may_be_loop_header
- && !(e->flags & EDGE_DFS_BACK))
- {
- ei_next (&ei);
- continue;
- }
-
- for (i = 0; i < reg_use_count; i++)
- {
- struct reg_use *reg_used = ®_use_table[i];
- unsigned int regno = REGNO (reg_used->reg_rtx);
- basic_block dest, old_dest;
- struct expr *set;
- rtx src, new_rtx;
-
- set = find_bypass_set (regno, e->src->index);
-
- if (! set)
- continue;
-
- /* Check the data flow is valid after edge insertions. */
- if (e->insns.r && reg_killed_on_edge (reg_used->reg_rtx, e))
- continue;
-
- src = SET_SRC (pc_set (jump));
-
- if (setcc != NULL)
- src = simplify_replace_rtx (src,
- SET_DEST (PATTERN (setcc)),
- SET_SRC (PATTERN (setcc)));
-
- new_rtx = simplify_replace_rtx (src, reg_used->reg_rtx,
- SET_SRC (set->expr));
-
- /* Jump bypassing may have already placed instructions on
- edges of the CFG. We can't bypass an outgoing edge that
- has instructions associated with it, as these insns won't
- get executed if the incoming edge is redirected. */
-
- if (new_rtx == pc_rtx)
- {
- edest = FALLTHRU_EDGE (bb);
- dest = edest->insns.r ? NULL : edest->dest;
- }
- else if (GET_CODE (new_rtx) == LABEL_REF)
- {
- dest = BLOCK_FOR_INSN (XEXP (new_rtx, 0));
- /* Don't bypass edges containing instructions. */
- edest = find_edge (bb, dest);
- if (edest && edest->insns.r)
- dest = NULL;
- }
- else
- dest = NULL;
-
- /* Avoid unification of the edge with other edges from original
- branch. We would end up emitting the instruction on "both"
- edges. */
-
- if (dest && setcc && !CC0_P (SET_DEST (PATTERN (setcc)))
- && find_edge (e->src, dest))
- dest = NULL;
-
- old_dest = e->dest;
- if (dest != NULL
- && dest != old_dest
- && dest != EXIT_BLOCK_PTR)
- {
- redirect_edge_and_branch_force (e, dest);
-
- /* Copy the register setter to the redirected edge.
- Don't copy CC0 setters, as CC0 is dead after jump. */
- if (setcc)
- {
- rtx pat = PATTERN (setcc);
- if (!CC0_P (SET_DEST (pat)))
- insert_insn_on_edge (copy_insn (pat), e);
- }
-
- if (dump_file != NULL)
- {
- fprintf (dump_file, "JUMP-BYPASS: Proved reg %d "
- "in jump_insn %d equals constant ",
- regno, INSN_UID (jump));
- print_rtl (dump_file, SET_SRC (set->expr));
- fprintf (dump_file, "\nBypass edge from %d->%d to %d\n",
- e->src->index, old_dest->index, dest->index);
- }
- change = 1;
- removed_p = 1;
- break;
- }
- }
- if (!removed_p)
- ei_next (&ei);
- }
- return change;
-}
-
-/* Find basic blocks with more than one predecessor that only contain a
- single conditional jump. If the result of the comparison is known at
- compile-time from any incoming edge, redirect that edge to the
- appropriate target. Returns nonzero if a change was made.
-
- This function is now mis-named, because we also handle indirect jumps. */
-
-static int
-bypass_conditional_jumps (void)
-{
- basic_block bb;
- int changed;
- rtx setcc;
- rtx insn;
- rtx dest;
-
- /* Note we start at block 1. */
- if (ENTRY_BLOCK_PTR->next_bb == EXIT_BLOCK_PTR)
- return 0;
-
- bypass_last_basic_block = last_basic_block;
- mark_dfs_back_edges ();
-
- changed = 0;
- FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb,
- EXIT_BLOCK_PTR, next_bb)
- {
- /* Check for more than one predecessor. */
- if (!single_pred_p (bb))
- {
- setcc = NULL_RTX;
- FOR_BB_INSNS (bb, insn)
- if (DEBUG_INSN_P (insn))
- continue;
- else if (NONJUMP_INSN_P (insn))
- {
- if (setcc)
- break;
- if (GET_CODE (PATTERN (insn)) != SET)
- break;
-
- dest = SET_DEST (PATTERN (insn));
- if (REG_P (dest) || CC0_P (dest))
- setcc = insn;
- else
- break;
- }
- else if (JUMP_P (insn))
- {
- if ((any_condjump_p (insn) || computed_jump_p (insn))
- && onlyjump_p (insn))
- changed |= bypass_block (bb, setcc, insn);
- break;
- }
- else if (INSN_P (insn))
- break;
- }
- }
-
- /* If we bypassed any register setting insns, we inserted a
- copy on the redirected edge. These need to be committed. */
- if (changed)
- commit_edge_insertions ();
-
- return changed;
}
\f
/* Compute PRE+LCM working variables. */
/* Local properties of expressions. */
+
/* Nonzero for expressions that are transparent in the block. */
static sbitmap *transp;
-/* Nonzero for expressions that are transparent at the end of the block.
- This is only zero for expressions killed by abnormal critical edge
- created by a calls. */
-static sbitmap *transpout;
-
/* Nonzero for expressions that are computed (available) in the block. */
static sbitmap *comp;
/* Nonzero for expressions which should be deleted in a specific block. */
static sbitmap *pre_delete_map;
-/* Contains the edge_list returned by pre_edge_lcm. */
-static struct edge_list *edge_list;
-
/* Allocate vars used for PRE analysis. */
static void
pre_optimal = pre_redundant = pre_insert_map = pre_delete_map = NULL;
}
-/* Top level routine to do the dataflow analysis needed by PRE. */
+/* Remove certain expressions from anticipatable and transparent
+ sets of basic blocks that have incoming abnormal edge.
+ For PRE remove potentially trapping expressions to avoid placing
+ them on abnormal edges. For hoisting remove memory references that
+ can be clobbered by calls. */
static void
-compute_pre_data (void)
+prune_expressions (bool pre_p)
{
- sbitmap trapping_expr;
- basic_block bb;
+ sbitmap prune_exprs;
+ struct gcse_expr *expr;
unsigned int ui;
+ basic_block bb;
- compute_local_properties (transp, comp, antloc, &expr_hash_table);
- sbitmap_vector_zero (ae_kill, last_basic_block);
-
- /* Collect expressions which might trap. */
- trapping_expr = sbitmap_alloc (expr_hash_table.n_elems);
- sbitmap_zero (trapping_expr);
+ prune_exprs = sbitmap_alloc (expr_hash_table.n_elems);
+ bitmap_clear (prune_exprs);
for (ui = 0; ui < expr_hash_table.size; ui++)
{
- struct expr *e;
- for (e = expr_hash_table.table[ui]; e != NULL; e = e->next_same_hash)
- if (may_trap_p (e->expr))
- SET_BIT (trapping_expr, e->bitmap_index);
- }
+ for (expr = expr_hash_table.table[ui]; expr; expr = expr->next_same_hash)
+ {
+ /* Note potentially trapping expressions. */
+ if (may_trap_p (expr->expr))
+ {
+ bitmap_set_bit (prune_exprs, expr->bitmap_index);
+ continue;
+ }
- /* Compute ae_kill for each basic block using:
+ if (!pre_p && MEM_P (expr->expr))
+ /* Note memory references that can be clobbered by a call.
+ We do not split abnormal edges in hoisting, so would
+ a memory reference get hoisted along an abnormal edge,
+ it would be placed /before/ the call. Therefore, only
+ constant memory references can be hoisted along abnormal
+ edges. */
+ {
+ if (GET_CODE (XEXP (expr->expr, 0)) == SYMBOL_REF
+ && CONSTANT_POOL_ADDRESS_P (XEXP (expr->expr, 0)))
+ continue;
- ~(TRANSP | COMP)
- */
+ if (MEM_READONLY_P (expr->expr)
+ && !MEM_VOLATILE_P (expr->expr)
+ && MEM_NOTRAP_P (expr->expr))
+ /* Constant memory reference, e.g., a PIC address. */
+ continue;
+
+ /* ??? Optimally, we would use interprocedural alias
+ analysis to determine if this mem is actually killed
+ by this call. */
+
+ bitmap_set_bit (prune_exprs, expr->bitmap_index);
+ }
+ }
+ }
- FOR_EACH_BB (bb)
+ FOR_EACH_BB_FN (bb, cfun)
{
edge e;
edge_iterator ei;
/* If the current block is the destination of an abnormal edge, we
- kill all trapping expressions because we won't be able to properly
- place the instruction on the edge. So make them neither
- anticipatable nor transparent. This is fairly conservative. */
+ kill all trapping (for PRE) and memory (for hoist) expressions
+ because we won't be able to properly place the instruction on
+ the edge. So make them neither anticipatable nor transparent.
+ This is fairly conservative.
+
+ ??? For hoisting it may be necessary to check for set-and-jump
+ instructions here, not just for abnormal edges. The general problem
+ is that when an expression cannot not be placed right at the end of
+ a basic block we should account for any side-effects of a subsequent
+ jump instructions that could clobber the expression. It would
+ be best to implement this check along the lines of
+ should_hoist_expr_to_dom where the target block is already known
+ and, hence, there's no need to conservatively prune expressions on
+ "intermediate" set-and-jump instructions. */
FOR_EACH_EDGE (e, ei, bb->preds)
- if (e->flags & EDGE_ABNORMAL)
+ if ((e->flags & EDGE_ABNORMAL)
+ && (pre_p || CALL_P (BB_END (e->src))))
{
- sbitmap_difference (antloc[bb->index], antloc[bb->index], trapping_expr);
- sbitmap_difference (transp[bb->index], transp[bb->index], trapping_expr);
+ bitmap_and_compl (antloc[bb->index],
+ antloc[bb->index], prune_exprs);
+ bitmap_and_compl (transp[bb->index],
+ transp[bb->index], prune_exprs);
break;
}
+ }
+
+ sbitmap_free (prune_exprs);
+}
+
+/* It may be necessary to insert a large number of insns on edges to
+ make the existing occurrences of expressions fully redundant. This
+ routine examines the set of insertions and deletions and if the ratio
+ of insertions to deletions is too high for a particular expression, then
+ the expression is removed from the insertion/deletion sets.
+
+ N_ELEMS is the number of elements in the hash table. */
+
+static void
+prune_insertions_deletions (int n_elems)
+{
+ sbitmap_iterator sbi;
+ sbitmap prune_exprs;
+
+ /* We always use I to iterate over blocks/edges and J to iterate over
+ expressions. */
+ unsigned int i, j;
+
+ /* Counts for the number of times an expression needs to be inserted and
+ number of times an expression can be removed as a result. */
+ int *insertions = GCNEWVEC (int, n_elems);
+ int *deletions = GCNEWVEC (int, n_elems);
+
+ /* Set of expressions which require too many insertions relative to
+ the number of deletions achieved. We will prune these out of the
+ insertion/deletion sets. */
+ prune_exprs = sbitmap_alloc (n_elems);
+ bitmap_clear (prune_exprs);
+
+ /* Iterate over the edges counting the number of times each expression
+ needs to be inserted. */
+ for (i = 0; i < (unsigned) n_edges_for_fn (cfun); i++)
+ {
+ EXECUTE_IF_SET_IN_BITMAP (pre_insert_map[i], 0, j, sbi)
+ insertions[j]++;
+ }
+
+ /* Similarly for deletions, but those occur in blocks rather than on
+ edges. */
+ for (i = 0; i < (unsigned) last_basic_block_for_fn (cfun); i++)
+ {
+ EXECUTE_IF_SET_IN_BITMAP (pre_delete_map[i], 0, j, sbi)
+ deletions[j]++;
+ }
+
+ /* Now that we have accurate counts, iterate over the elements in the
+ hash table and see if any need too many insertions relative to the
+ number of evaluations that can be removed. If so, mark them in
+ PRUNE_EXPRS. */
+ for (j = 0; j < (unsigned) n_elems; j++)
+ if (deletions[j]
+ && ((unsigned) insertions[j] / deletions[j]) > MAX_GCSE_INSERTION_RATIO)
+ bitmap_set_bit (prune_exprs, j);
+
+ /* Now prune PRE_INSERT_MAP and PRE_DELETE_MAP based on PRUNE_EXPRS. */
+ EXECUTE_IF_SET_IN_BITMAP (prune_exprs, 0, j, sbi)
+ {
+ for (i = 0; i < (unsigned) n_edges_for_fn (cfun); i++)
+ bitmap_clear_bit (pre_insert_map[i], j);
+
+ for (i = 0; i < (unsigned) last_basic_block_for_fn (cfun); i++)
+ bitmap_clear_bit (pre_delete_map[i], j);
+ }
+
+ sbitmap_free (prune_exprs);
+ free (insertions);
+ free (deletions);
+}
+
+/* Top level routine to do the dataflow analysis needed by PRE. */
+
+static struct edge_list *
+compute_pre_data (void)
+{
+ struct edge_list *edge_list;
+ basic_block bb;
+
+ compute_local_properties (transp, comp, antloc, &expr_hash_table);
+ prune_expressions (true);
+ bitmap_vector_clear (ae_kill, last_basic_block_for_fn (cfun));
+
+ /* Compute ae_kill for each basic block using:
+
+ ~(TRANSP | COMP)
+ */
- sbitmap_a_or_b (ae_kill[bb->index], transp[bb->index], comp[bb->index]);
- sbitmap_not (ae_kill[bb->index], ae_kill[bb->index]);
+ FOR_EACH_BB_FN (bb, cfun)
+ {
+ bitmap_ior (ae_kill[bb->index], transp[bb->index], comp[bb->index]);
+ bitmap_not (ae_kill[bb->index], ae_kill[bb->index]);
}
edge_list = pre_edge_lcm (expr_hash_table.n_elems, transp, comp, antloc,
antloc = NULL;
sbitmap_vector_free (ae_kill);
ae_kill = NULL;
- sbitmap_free (trapping_expr);
+
+ prune_insertions_deletions (expr_hash_table.n_elems);
+
+ return edge_list;
}
\f
/* PRE utilities */
the closest such expression. */
static int
-pre_expr_reaches_here_p_work (basic_block occr_bb, struct expr *expr, basic_block bb, char *visited)
+pre_expr_reaches_here_p_work (basic_block occr_bb, struct gcse_expr *expr,
+ basic_block bb, char *visited)
{
edge pred;
edge_iterator ei;
{
basic_block pred_bb = pred->src;
- if (pred->src == ENTRY_BLOCK_PTR
+ if (pred->src == ENTRY_BLOCK_PTR_FOR_FN (cfun)
/* Has predecessor has already been visited? */
|| visited[pred_bb->index])
;/* Nothing to do. */
/* Does this predecessor generate this expression? */
- else if (TEST_BIT (comp[pred_bb->index], expr->bitmap_index))
+ else if (bitmap_bit_p (comp[pred_bb->index], expr->bitmap_index))
{
/* Is this the occurrence we're looking for?
Note that there's only one generating occurrence per block
visited[pred_bb->index] = 1;
}
/* Ignore this predecessor if it kills the expression. */
- else if (! TEST_BIT (transp[pred_bb->index], expr->bitmap_index))
+ else if (! bitmap_bit_p (transp[pred_bb->index], expr->bitmap_index))
visited[pred_bb->index] = 1;
/* Neither gen nor kill. */
memory allocated for that function is returned. */
static int
-pre_expr_reaches_here_p (basic_block occr_bb, struct expr *expr, basic_block bb)
+pre_expr_reaches_here_p (basic_block occr_bb, struct gcse_expr *expr, basic_block bb)
{
int rval;
- char *visited = XCNEWVEC (char, last_basic_block);
+ char *visited = XCNEWVEC (char, last_basic_block_for_fn (cfun));
rval = pre_expr_reaches_here_p_work (occr_bb, expr, bb, visited);
return rval;
}
\f
+/* Generate RTL to copy an EXPR to its `reaching_reg' and return it. */
-/* Given an expr, generate RTL which we can insert at the end of a BB,
- or on an edge. Set the block number of any insns generated to
- the value of BB. */
-
-static rtx
-process_insert_insn (struct expr *expr)
+static rtx_insn *
+process_insert_insn (struct gcse_expr *expr)
{
rtx reg = expr->reaching_reg;
+ /* Copy the expression to make sure we don't have any sharing issues. */
rtx exp = copy_rtx (expr->expr);
- rtx pat;
+ rtx_insn *pat;
start_sequence ();
emit_move_insn (reg, exp);
/* Otherwise, make a new insn to compute this expression and make sure the
- insn will be recognized (this also adds any needed CLOBBERs). Copy the
- expression to make sure we don't have any sharing issues. */
+ insn will be recognized (this also adds any needed CLOBBERs). */
else
{
- rtx insn = emit_insn (gen_rtx_SET (VOIDmode, reg, exp));
+ rtx_insn *insn = emit_insn (gen_rtx_SET (VOIDmode, reg, exp));
- if (insn_invalid_p (insn))
+ if (insn_invalid_p (insn, false))
gcc_unreachable ();
}
-
pat = get_insns ();
end_sequence ();
/* Add EXPR to the end of basic block BB.
- This is used by both the PRE and code hoisting.
-
- For PRE, we want to verify that the expr is either transparent
- or locally anticipatable in the target block. This check makes
- no sense for code hoisting. */
+ This is used by both the PRE and code hoisting. */
static void
-insert_insn_end_basic_block (struct expr *expr, basic_block bb, int pre)
+insert_insn_end_basic_block (struct gcse_expr *expr, basic_block bb)
{
- rtx insn = BB_END (bb);
- rtx new_insn;
+ rtx_insn *insn = BB_END (bb);
+ rtx_insn *new_insn;
rtx reg = expr->reaching_reg;
int regno = REGNO (reg);
- rtx pat, pat_end;
+ rtx_insn *pat, *pat_end;
pat = process_insert_insn (expr);
gcc_assert (pat && INSN_P (pat));
&& (!single_succ_p (bb)
|| single_succ_edge (bb)->flags & EDGE_ABNORMAL)))
{
-#ifdef HAVE_cc0
- rtx note;
-#endif
- /* It should always be the case that we can put these instructions
- anywhere in the basic block with performing PRE optimizations.
- Check this. */
- gcc_assert (!NONJUMP_INSN_P (insn) || !pre
- || TEST_BIT (antloc[bb->index], expr->bitmap_index)
- || TEST_BIT (transp[bb->index], expr->bitmap_index));
-
- /* If this is a jump table, then we can't insert stuff here. Since
- we know the previous real insn must be the tablejump, we insert
- the new instruction just before the tablejump. */
- if (GET_CODE (PATTERN (insn)) == ADDR_VEC
- || GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
- insn = prev_real_insn (insn);
-
#ifdef HAVE_cc0
/* FIXME: 'twould be nice to call prev_cc0_setter here but it aborts
if cc0 isn't set. */
- note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX);
+ rtx note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX);
if (note)
- insn = XEXP (note, 0);
+ insn = safe_as_a <rtx_insn *> (XEXP (note, 0));
else
{
- rtx maybe_cc0_setter = prev_nonnote_insn (insn);
+ rtx_insn *maybe_cc0_setter = prev_nonnote_insn (insn);
if (maybe_cc0_setter
&& INSN_P (maybe_cc0_setter)
&& sets_cc0_p (PATTERN (maybe_cc0_setter)))
/* Keeping in mind targets with small register classes and parameters
in registers, we search backward and place the instructions before
the first parameter is loaded. Do this for everyone for consistency
- and a presumption that we'll get better code elsewhere as well.
-
- It should always be the case that we can put these instructions
- anywhere in the basic block with performing PRE optimizations.
- Check this. */
-
- gcc_assert (!pre
- || TEST_BIT (antloc[bb->index], expr->bitmap_index)
- || TEST_BIT (transp[bb->index], expr->bitmap_index));
+ and a presumption that we'll get better code elsewhere as well. */
/* Since different machines initialize their parameter registers
in different orders, assume nothing. Collect the set of all
the expressions fully redundant. */
static int
-pre_edge_insert (struct edge_list *edge_list, struct expr **index_map)
+pre_edge_insert (struct edge_list *edge_list, struct gcse_expr **index_map)
{
int e, i, j, num_edges, set_size, did_insert = 0;
sbitmap *inserted;
set_size = pre_insert_map[0]->size;
num_edges = NUM_EDGES (edge_list);
inserted = sbitmap_vector_alloc (num_edges, expr_hash_table.n_elems);
- sbitmap_vector_zero (inserted, num_edges);
+ bitmap_vector_clear (inserted, num_edges);
for (e = 0; e < num_edges; e++)
{
{
SBITMAP_ELT_TYPE insert = pre_insert_map[e]->elms[i];
- for (j = indx; insert && j < (int) expr_hash_table.n_elems; j++, insert >>= 1)
+ for (j = indx;
+ insert && j < (int) expr_hash_table.n_elems;
+ j++, insert >>= 1)
if ((insert & 1) != 0 && index_map[j]->reaching_reg != NULL_RTX)
{
- struct expr *expr = index_map[j];
- struct occr *occr;
+ struct gcse_expr *expr = index_map[j];
+ struct gcse_occr *occr;
/* Now look at each deleted occurrence of this expression. */
for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
/* Insert this expression on this edge if it would
reach the deleted occurrence in BB. */
- if (!TEST_BIT (inserted[e], j))
+ if (!bitmap_bit_p (inserted[e], j))
{
- rtx insn;
+ rtx_insn *insn;
edge eg = INDEX_EDGE (edge_list, e);
/* We can't insert anything on an abnormal and
now. */
if (eg->flags & EDGE_ABNORMAL)
- insert_insn_end_basic_block (index_map[j], bb, 0);
+ insert_insn_end_basic_block (index_map[j], bb);
else
{
insn = process_insert_insn (index_map[j]);
}
update_ld_motion_stores (expr);
- SET_BIT (inserted[e], j);
+ bitmap_set_bit (inserted[e], j);
did_insert = 1;
gcse_create_count++;
}
MEM <- reaching_reg. */
static void
-pre_insert_copy_insn (struct expr *expr, rtx insn)
+pre_insert_copy_insn (struct gcse_expr *expr, rtx_insn *insn)
{
rtx reg = expr->reaching_reg;
int regno = REGNO (reg);
pre_insert_copies (void)
{
unsigned int i, added_copy;
- struct expr *expr;
- struct occr *occr;
- struct occr *avail;
+ struct gcse_expr *expr;
+ struct gcse_occr *occr;
+ struct gcse_occr *avail;
/* For each available expression in the table, copy the result to
`reaching_reg' if the expression reaches a deleted one.
Need to do some profiling. */
for (i = 0; i < expr_hash_table.size; i++)
- for (expr = expr_hash_table.table[i]; expr != NULL; expr = expr->next_same_hash)
+ for (expr = expr_hash_table.table[i]; expr; expr = expr->next_same_hash)
{
/* If the basic block isn't reachable, PPOUT will be TRUE. However,
we don't want to insert a copy here because the expression may not
for (avail = expr->avail_occr; avail != NULL; avail = avail->next)
{
- rtx insn = avail->insn;
+ rtx_insn *insn = avail->insn;
/* No need to handle this one if handled already. */
if (avail->copied_p)
continue;
/* Don't handle this one if it's a redundant one. */
- if (INSN_DELETED_P (insn))
+ if (insn->deleted ())
continue;
/* Or if the expression doesn't reach the deleted one. */
}
}
+struct set_data
+{
+ rtx_insn *insn;
+ const_rtx set;
+ int nsets;
+};
+
+/* Increment number of sets and record set in DATA. */
+
+static void
+record_set_data (rtx dest, const_rtx set, void *data)
+{
+ struct set_data *s = (struct set_data *)data;
+
+ if (GET_CODE (set) == SET)
+ {
+ /* We allow insns having multiple sets, where all but one are
+ dead as single set insns. In the common case only a single
+ set is present, so we want to avoid checking for REG_UNUSED
+ notes unless necessary. */
+ if (s->nsets == 1
+ && find_reg_note (s->insn, REG_UNUSED, SET_DEST (s->set))
+ && !side_effects_p (s->set))
+ s->nsets = 0;
+
+ if (!s->nsets)
+ {
+ /* Record this set. */
+ s->nsets += 1;
+ s->set = set;
+ }
+ else if (!find_reg_note (s->insn, REG_UNUSED, dest)
+ || side_effects_p (set))
+ s->nsets += 1;
+ }
+}
+
+static const_rtx
+single_set_gcse (rtx_insn *insn)
+{
+ struct set_data s;
+ rtx pattern;
+
+ gcc_assert (INSN_P (insn));
+
+ /* Optimize common case. */
+ pattern = PATTERN (insn);
+ if (GET_CODE (pattern) == SET)
+ return pattern;
+
+ s.insn = insn;
+ s.nsets = 0;
+ note_stores (pattern, record_set_data, &s);
+
+ /* Considered invariant insns have exactly one set. */
+ gcc_assert (s.nsets == 1);
+ return s.set;
+}
+
/* Emit move from SRC to DEST noting the equivalence with expression computed
in INSN. */
+
static rtx
-gcse_emit_move_after (rtx src, rtx dest, rtx insn)
+gcse_emit_move_after (rtx dest, rtx src, rtx_insn *insn)
{
- rtx new_rtx;
- rtx set = single_set (insn), set2;
+ rtx_insn *new_rtx;
+ const_rtx set = single_set_gcse (insn);
+ rtx set2;
rtx note;
- rtx eqv;
+ rtx eqv = NULL_RTX;
/* This should never fail since we're creating a reg->reg copy
we've verified to be valid. */
new_rtx = emit_insn_after (gen_move_insn (dest, src), insn);
- /* Note the equivalence for local CSE pass. */
+ /* Note the equivalence for local CSE pass. Take the note from the old
+ set if there was one. Otherwise record the SET_SRC from the old set
+ unless DEST is also an operand of the SET_SRC. */
set2 = single_set (new_rtx);
if (!set2 || !rtx_equal_p (SET_DEST (set2), dest))
return new_rtx;
if ((note = find_reg_equal_equiv_note (insn)))
eqv = XEXP (note, 0);
- else
+ else if (! REG_P (dest)
+ || ! reg_mentioned_p (dest, SET_SRC (set)))
eqv = SET_SRC (set);
- set_unique_reg_note (new_rtx, REG_EQUAL, copy_insn_1 (eqv));
+ if (eqv != NULL_RTX)
+ set_unique_reg_note (new_rtx, REG_EQUAL, copy_insn_1 (eqv));
return new_rtx;
}
/* Delete redundant computations.
Deletion is done by changing the insn to copy the `reaching_reg' of
the expression into the result of the SET. It is left to later passes
- (cprop, cse2, flow, combine, regmove) to propagate the copy or eliminate it.
+ to propagate the copy or eliminate it.
- Returns nonzero if a change is made. */
+ Return nonzero if a change is made. */
static int
pre_delete (void)
{
unsigned int i;
int changed;
- struct expr *expr;
- struct occr *occr;
+ struct gcse_expr *expr;
+ struct gcse_occr *occr;
changed = 0;
for (i = 0; i < expr_hash_table.size; i++)
- for (expr = expr_hash_table.table[i];
- expr != NULL;
- expr = expr->next_same_hash)
+ for (expr = expr_hash_table.table[i]; expr; expr = expr->next_same_hash)
{
int indx = expr->bitmap_index;
- /* We only need to search antic_occr since we require
- ANTLOC != 0. */
-
+ /* We only need to search antic_occr since we require ANTLOC != 0. */
for (occr = expr->antic_occr; occr != NULL; occr = occr->next)
{
- rtx insn = occr->insn;
+ rtx_insn *insn = occr->insn;
rtx set;
basic_block bb = BLOCK_FOR_INSN (insn);
/* We only delete insns that have a single_set. */
- if (TEST_BIT (pre_delete_map[bb->index], indx)
+ if (bitmap_bit_p (pre_delete_map[bb->index], indx)
&& (set = single_set (insn)) != 0
&& dbg_cnt (pre_insn))
{
if (expr->reaching_reg == NULL)
expr->reaching_reg = gen_reg_rtx_and_attrs (SET_DEST (set));
- gcse_emit_move_after (expr->reaching_reg, SET_DEST (set), insn);
+ gcse_emit_move_after (SET_DEST (set), expr->reaching_reg, insn);
delete_insn (insn);
occr->deleted_p = 1;
changed = 1;
redundancies. */
static int
-pre_gcse (void)
+pre_gcse (struct edge_list *edge_list)
{
unsigned int i;
int did_insert, changed;
- struct expr **index_map;
- struct expr *expr;
+ struct gcse_expr **index_map;
+ struct gcse_expr *expr;
/* Compute a mapping from expression number (`bitmap_index') to
hash table entry. */
- index_map = XCNEWVEC (struct expr *, expr_hash_table.n_elems);
+ index_map = XCNEWVEC (struct gcse_expr *, expr_hash_table.n_elems);
for (i = 0; i < expr_hash_table.size; i++)
- for (expr = expr_hash_table.table[i]; expr != NULL; expr = expr->next_same_hash)
+ for (expr = expr_hash_table.table[i]; expr; expr = expr->next_same_hash)
index_map[expr->bitmap_index] = expr;
/* Delete the redundant insns first so that
gcse_create_count = 0;
/* Return if there's nothing to do, or it is too expensive. */
- if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1
+ if (n_basic_blocks_for_fn (cfun) <= NUM_FIXED_BLOCKS + 1
|| is_too_expensive (_("PRE disabled")))
return 0;
gcc_obstack_init (&gcse_obstack);
alloc_gcse_mem ();
- alloc_hash_table (&expr_hash_table, 0);
+ alloc_hash_table (&expr_hash_table);
add_noreturn_fake_exit_edges ();
if (flag_gcse_lm)
compute_ld_motion_mems ();
compute_hash_table (&expr_hash_table);
- trim_ld_motion_mems ();
+ if (flag_gcse_lm)
+ trim_ld_motion_mems ();
if (dump_file)
dump_hash_table (dump_file, "Expression", &expr_hash_table);
if (expr_hash_table.n_elems > 0)
{
- alloc_pre_mem (last_basic_block, expr_hash_table.n_elems);
- compute_pre_data ();
- changed |= pre_gcse ();
+ struct edge_list *edge_list;
+ alloc_pre_mem (last_basic_block_for_fn (cfun), expr_hash_table.n_elems);
+ edge_list = compute_pre_data ();
+ changed |= pre_gcse (edge_list);
free_edge_list (edge_list);
free_pre_mem ();
}
- free_ldst_mems ();
+ if (flag_gcse_lm)
+ free_ld_motion_mems ();
remove_fake_exit_edges ();
free_hash_table (&expr_hash_table);
if (dump_file)
{
fprintf (dump_file, "PRE GCSE of %s, %d basic blocks, %d bytes needed, ",
- current_function_name (), n_basic_blocks, bytes_used);
+ current_function_name (), n_basic_blocks_for_fn (cfun),
+ bytes_used);
fprintf (dump_file, "%d substs, %d insns created\n",
gcse_subst_count, gcse_create_count);
}
such a LABEL_REF, so we don't have to handle REG_LABEL_TARGET
notes. */
gcc_assert (!JUMP_P (insn));
- add_reg_note (insn, REG_LABEL_OPERAND, XEXP (x, 0));
+ add_reg_note (insn, REG_LABEL_OPERAND, LABEL_REF_LABEL (x));
- if (LABEL_P (XEXP (x, 0)))
- LABEL_NUSES (XEXP (x, 0))++;
+ if (LABEL_P (LABEL_REF_LABEL (x)))
+ LABEL_NUSES (LABEL_REF_LABEL (x))++;
return;
}
}
}
-/* Compute transparent outgoing information for each block.
-
- An expression is transparent to an edge unless it is killed by
- the edge itself. This can only happen with abnormal control flow,
- when the edge is traversed through a call. This happens with
- non-local labels and exceptions.
-
- This would not be necessary if we split the edge. While this is
- normally impossible for abnormal critical edges, with some effort
- it should be possible with exception handling, since we still have
- control over which handler should be invoked. But due to increased
- EH table sizes, this may not be worthwhile. */
-
-static void
-compute_transpout (void)
-{
- basic_block bb;
- unsigned int i;
- struct expr *expr;
-
- sbitmap_vector_ones (transpout, last_basic_block);
-
- FOR_EACH_BB (bb)
- {
- /* Note that flow inserted a nop at the end of basic blocks that
- end in call instructions for reasons other than abnormal
- control flow. */
- if (! CALL_P (BB_END (bb)))
- continue;
-
- for (i = 0; i < expr_hash_table.size; i++)
- for (expr = expr_hash_table.table[i]; expr ; expr = expr->next_same_hash)
- if (MEM_P (expr->expr))
- {
- if (GET_CODE (XEXP (expr->expr, 0)) == SYMBOL_REF
- && CONSTANT_POOL_ADDRESS_P (XEXP (expr->expr, 0)))
- continue;
-
- /* ??? Optimally, we would use interprocedural alias
- analysis to determine if this mem is actually killed
- by this call. */
- RESET_BIT (transpout[bb->index], expr->bitmap_index);
- }
- }
-}
-
/* Code Hoisting variables and subroutines. */
/* Very busy expressions. */
static sbitmap *hoist_vbein;
static sbitmap *hoist_vbeout;
-/* Hoistable expressions. */
-static sbitmap *hoist_exprs;
-
/* ??? We could compute post dominators and run this algorithm in
reverse to perform tail merging, doing so would probably be
more effective than the tail merging code in jump.c.
hoist_vbein = sbitmap_vector_alloc (n_blocks, n_exprs);
hoist_vbeout = sbitmap_vector_alloc (n_blocks, n_exprs);
- hoist_exprs = sbitmap_vector_alloc (n_blocks, n_exprs);
- transpout = sbitmap_vector_alloc (n_blocks, n_exprs);
}
/* Free vars used for code hoisting analysis. */
sbitmap_vector_free (hoist_vbein);
sbitmap_vector_free (hoist_vbeout);
- sbitmap_vector_free (hoist_exprs);
- sbitmap_vector_free (transpout);
free_dominance_info (CDI_DOMINATORS);
}
int changed, passes;
basic_block bb;
- sbitmap_vector_zero (hoist_vbeout, last_basic_block);
- sbitmap_vector_zero (hoist_vbein, last_basic_block);
+ bitmap_vector_clear (hoist_vbeout, last_basic_block_for_fn (cfun));
+ bitmap_vector_clear (hoist_vbein, last_basic_block_for_fn (cfun));
passes = 0;
changed = 1;
/* We scan the blocks in the reverse order to speed up
the convergence. */
- FOR_EACH_BB_REVERSE (bb)
+ FOR_EACH_BB_REVERSE_FN (bb, cfun)
{
- if (bb->next_bb != EXIT_BLOCK_PTR)
- sbitmap_intersection_of_succs (hoist_vbeout[bb->index],
- hoist_vbein, bb->index);
+ if (bb->next_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
+ {
+ bitmap_intersection_of_succs (hoist_vbeout[bb->index],
+ hoist_vbein, bb);
+
+ /* Include expressions in VBEout that are calculated
+ in BB and available at its end. */
+ bitmap_ior (hoist_vbeout[bb->index],
+ hoist_vbeout[bb->index], comp[bb->index]);
+ }
- changed |= sbitmap_a_or_b_and_c_cg (hoist_vbein[bb->index],
+ changed |= bitmap_or_and (hoist_vbein[bb->index],
antloc[bb->index],
hoist_vbeout[bb->index],
transp[bb->index]);
}
if (dump_file)
- fprintf (dump_file, "hoisting vbeinout computation: %d passes\n", passes);
+ {
+ fprintf (dump_file, "hoisting vbeinout computation: %d passes\n", passes);
+
+ FOR_EACH_BB_FN (bb, cfun)
+ {
+ fprintf (dump_file, "vbein (%d): ", bb->index);
+ dump_bitmap_file (dump_file, hoist_vbein[bb->index]);
+ fprintf (dump_file, "vbeout(%d): ", bb->index);
+ dump_bitmap_file (dump_file, hoist_vbeout[bb->index]);
+ }
+ }
}
/* Top level routine to do the dataflow analysis needed by code hoisting. */
compute_code_hoist_data (void)
{
compute_local_properties (transp, comp, antloc, &expr_hash_table);
- compute_transpout ();
+ prune_expressions (false);
compute_code_hoist_vbeinout ();
calculate_dominance_info (CDI_DOMINATORS);
if (dump_file)
fprintf (dump_file, "\n");
}
-/* Determine if the expression identified by EXPR_INDEX would
- reach BB unimpared if it was placed at the end of EXPR_BB.
+/* Update register pressure for BB when hoisting an expression from
+ instruction FROM, if live ranges of inputs are shrunk. Also
+ maintain live_in information if live range of register referred
+ in FROM is shrunk.
+
+ Return 0 if register pressure doesn't change, otherwise return
+ the number by which register pressure is decreased.
+
+ NOTE: Register pressure won't be increased in this function. */
+
+static int
+update_bb_reg_pressure (basic_block bb, rtx_insn *from)
+{
+ rtx dreg;
+ rtx_insn *insn;
+ basic_block succ_bb;
+ df_ref use, op_ref;
+ edge succ;
+ edge_iterator ei;
+ int decreased_pressure = 0;
+ int nregs;
+ enum reg_class pressure_class;
+
+ FOR_EACH_INSN_USE (use, from)
+ {
+ dreg = DF_REF_REAL_REG (use);
+ /* The live range of register is shrunk only if it isn't:
+ 1. referred on any path from the end of this block to EXIT, or
+ 2. referred by insns other than FROM in this block. */
+ FOR_EACH_EDGE (succ, ei, bb->succs)
+ {
+ succ_bb = succ->dest;
+ if (succ_bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
+ continue;
+
+ if (bitmap_bit_p (BB_DATA (succ_bb)->live_in, REGNO (dreg)))
+ break;
+ }
+ if (succ != NULL)
+ continue;
+
+ op_ref = DF_REG_USE_CHAIN (REGNO (dreg));
+ for (; op_ref; op_ref = DF_REF_NEXT_REG (op_ref))
+ {
+ if (!DF_REF_INSN_INFO (op_ref))
+ continue;
+
+ insn = DF_REF_INSN (op_ref);
+ if (BLOCK_FOR_INSN (insn) == bb
+ && NONDEBUG_INSN_P (insn) && insn != from)
+ break;
+ }
+
+ pressure_class = get_regno_pressure_class (REGNO (dreg), &nregs);
+ /* Decrease register pressure and update live_in information for
+ this block. */
+ if (!op_ref && pressure_class != NO_REGS)
+ {
+ decreased_pressure += nregs;
+ BB_DATA (bb)->max_reg_pressure[pressure_class] -= nregs;
+ bitmap_clear_bit (BB_DATA (bb)->live_in, REGNO (dreg));
+ }
+ }
+ return decreased_pressure;
+}
+
+/* Determine if the expression EXPR should be hoisted to EXPR_BB up in
+ flow graph, if it can reach BB unimpared. Stop the search if the
+ expression would need to be moved more than DISTANCE instructions.
+
+ DISTANCE is the number of instructions through which EXPR can be
+ hoisted up in flow graph.
+
+ BB_SIZE points to an array which contains the number of instructions
+ for each basic block.
+
+ PRESSURE_CLASS and NREGS are register class and number of hard registers
+ for storing EXPR.
+
+ HOISTED_BBS points to a bitmap indicating basic blocks through which
+ EXPR is hoisted.
+
+ FROM is the instruction from which EXPR is hoisted.
It's unclear exactly what Muchnick meant by "unimpared". It seems
to me that the expression must either be computed or transparent in
paths. */
static int
-hoist_expr_reaches_here_p (basic_block expr_bb, int expr_index, basic_block bb, char *visited)
+should_hoist_expr_to_dom (basic_block expr_bb, struct gcse_expr *expr,
+ basic_block bb, sbitmap visited, int distance,
+ int *bb_size, enum reg_class pressure_class,
+ int *nregs, bitmap hoisted_bbs, rtx_insn *from)
{
+ unsigned int i;
edge pred;
edge_iterator ei;
+ sbitmap_iterator sbi;
int visited_allocated_locally = 0;
+ int decreased_pressure = 0;
+ if (flag_ira_hoist_pressure)
+ {
+ /* Record old information of basic block BB when it is visited
+ at the first time. */
+ if (!bitmap_bit_p (hoisted_bbs, bb->index))
+ {
+ struct bb_data *data = BB_DATA (bb);
+ bitmap_copy (data->backup, data->live_in);
+ data->old_pressure = data->max_reg_pressure[pressure_class];
+ }
+ decreased_pressure = update_bb_reg_pressure (bb, from);
+ }
+ /* Terminate the search if distance, for which EXPR is allowed to move,
+ is exhausted. */
+ if (distance > 0)
+ {
+ if (flag_ira_hoist_pressure)
+ {
+ /* Prefer to hoist EXPR if register pressure is decreased. */
+ if (decreased_pressure > *nregs)
+ distance += bb_size[bb->index];
+ /* Let EXPR be hoisted through basic block at no cost if one
+ of following conditions is satisfied:
+
+ 1. The basic block has low register pressure.
+ 2. Register pressure won't be increases after hoisting EXPR.
+
+ Constant expressions is handled conservatively, because
+ hoisting constant expression aggressively results in worse
+ code. This decision is made by the observation of CSiBE
+ on ARM target, while it has no obvious effect on other
+ targets like x86, x86_64, mips and powerpc. */
+ else if (CONST_INT_P (expr->expr)
+ || (BB_DATA (bb)->max_reg_pressure[pressure_class]
+ >= ira_class_hard_regs_num[pressure_class]
+ && decreased_pressure < *nregs))
+ distance -= bb_size[bb->index];
+ }
+ else
+ distance -= bb_size[bb->index];
+
+ if (distance <= 0)
+ return 0;
+ }
+ else
+ gcc_assert (distance == 0);
if (visited == NULL)
{
visited_allocated_locally = 1;
- visited = XCNEWVEC (char, last_basic_block);
+ visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+ bitmap_clear (visited);
}
FOR_EACH_EDGE (pred, ei, bb->preds)
{
basic_block pred_bb = pred->src;
- if (pred->src == ENTRY_BLOCK_PTR)
+ if (pred->src == ENTRY_BLOCK_PTR_FOR_FN (cfun))
break;
else if (pred_bb == expr_bb)
continue;
- else if (visited[pred_bb->index])
+ else if (bitmap_bit_p (visited, pred_bb->index))
continue;
-
- /* Does this predecessor generate this expression? */
- else if (TEST_BIT (comp[pred_bb->index], expr_index))
+ else if (! bitmap_bit_p (transp[pred_bb->index], expr->bitmap_index))
break;
- else if (! TEST_BIT (transp[pred_bb->index], expr_index))
- break;
-
/* Not killed. */
else
{
- visited[pred_bb->index] = 1;
- if (! hoist_expr_reaches_here_p (expr_bb, expr_index,
- pred_bb, visited))
+ bitmap_set_bit (visited, pred_bb->index);
+ if (! should_hoist_expr_to_dom (expr_bb, expr, pred_bb,
+ visited, distance, bb_size,
+ pressure_class, nregs,
+ hoisted_bbs, from))
break;
}
}
if (visited_allocated_locally)
- free (visited);
+ {
+ /* If EXPR can be hoisted to expr_bb, record basic blocks through
+ which EXPR is hoisted in hoisted_bbs. */
+ if (flag_ira_hoist_pressure && !pred)
+ {
+ /* Record the basic block from which EXPR is hoisted. */
+ bitmap_set_bit (visited, bb->index);
+ EXECUTE_IF_SET_IN_BITMAP (visited, 0, i, sbi)
+ bitmap_set_bit (hoisted_bbs, i);
+ }
+ sbitmap_free (visited);
+ }
return (pred == NULL);
}
\f
-/* Actually perform code hoisting. */
+/* Find occurrence in BB. */
+
+static struct gcse_occr *
+find_occr_in_bb (struct gcse_occr *occr, basic_block bb)
+{
+ /* Find the right occurrence of this expression. */
+ while (occr && BLOCK_FOR_INSN (occr->insn) != bb)
+ occr = occr->next;
+
+ return occr;
+}
+
+/* Actually perform code hoisting.
+
+ The code hoisting pass can hoist multiple computations of the same
+ expression along dominated path to a dominating basic block, like
+ from b2/b3 to b1 as depicted below:
+
+ b1 ------
+ /\ |
+ / \ |
+ bx by distance
+ / \ |
+ / \ |
+ b2 b3 ------
+
+ Unfortunately code hoisting generally extends the live range of an
+ output pseudo register, which increases register pressure and hurts
+ register allocation. To address this issue, an attribute MAX_DISTANCE
+ is computed and attached to each expression. The attribute is computed
+ from rtx cost of the corresponding expression and it's used to control
+ how long the expression can be hoisted up in flow graph. As the
+ expression is hoisted up in flow graph, GCC decreases its DISTANCE
+ and stops the hoist if DISTANCE reaches 0. Code hoisting can decrease
+ register pressure if live ranges of inputs are shrunk.
+
+ Option "-fira-hoist-pressure" implements register pressure directed
+ hoist based on upper method. The rationale is:
+ 1. Calculate register pressure for each basic block by reusing IRA
+ facility.
+ 2. When expression is hoisted through one basic block, GCC checks
+ the change of live ranges for inputs/output. The basic block's
+ register pressure will be increased because of extended live
+ range of output. However, register pressure will be decreased
+ if the live ranges of inputs are shrunk.
+ 3. After knowing how hoisting affects register pressure, GCC prefers
+ to hoist the expression if it can decrease register pressure, by
+ increasing DISTANCE of the corresponding expression.
+ 4. If hoisting the expression increases register pressure, GCC checks
+ register pressure of the basic block and decrease DISTANCE only if
+ the register pressure is high. In other words, expression will be
+ hoisted through at no cost if the basic block has low register
+ pressure.
+ 5. Update register pressure information for basic blocks through
+ which expression is hoisted. */
+
+static int
+hoist_code (void)
+{
+ basic_block bb, dominated;
+ vec<basic_block> dom_tree_walk;
+ unsigned int dom_tree_walk_index;
+ vec<basic_block> domby;
+ unsigned int i, j, k;
+ struct gcse_expr **index_map;
+ struct gcse_expr *expr;
+ int *to_bb_head;
+ int *bb_size;
+ int changed = 0;
+ struct bb_data *data;
+ /* Basic blocks that have occurrences reachable from BB. */
+ bitmap from_bbs;
+ /* Basic blocks through which expr is hoisted. */
+ bitmap hoisted_bbs = NULL;
+ bitmap_iterator bi;
+
+ /* Compute a mapping from expression number (`bitmap_index') to
+ hash table entry. */
+
+ index_map = XCNEWVEC (struct gcse_expr *, expr_hash_table.n_elems);
+ for (i = 0; i < expr_hash_table.size; i++)
+ for (expr = expr_hash_table.table[i]; expr; expr = expr->next_same_hash)
+ index_map[expr->bitmap_index] = expr;
+
+ /* Calculate sizes of basic blocks and note how far
+ each instruction is from the start of its block. We then use this
+ data to restrict distance an expression can travel. */
+
+ to_bb_head = XCNEWVEC (int, get_max_uid ());
+ bb_size = XCNEWVEC (int, last_basic_block_for_fn (cfun));
+
+ FOR_EACH_BB_FN (bb, cfun)
+ {
+ rtx_insn *insn;
+ int to_head;
+
+ to_head = 0;
+ FOR_BB_INSNS (bb, insn)
+ {
+ /* Don't count debug instructions to avoid them affecting
+ decision choices. */
+ if (NONDEBUG_INSN_P (insn))
+ to_bb_head[INSN_UID (insn)] = to_head++;
+ }
-static int
-hoist_code (void)
-{
- basic_block bb, dominated;
- VEC (basic_block, heap) *domby;
- unsigned int i,j;
- struct expr **index_map;
- struct expr *expr;
- int changed = 0;
+ bb_size[bb->index] = to_head;
+ }
- sbitmap_vector_zero (hoist_exprs, last_basic_block);
+ gcc_assert (EDGE_COUNT (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs) == 1
+ && (EDGE_SUCC (ENTRY_BLOCK_PTR_FOR_FN (cfun), 0)->dest
+ == ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb));
- /* Compute a mapping from expression number (`bitmap_index') to
- hash table entry. */
+ from_bbs = BITMAP_ALLOC (NULL);
+ if (flag_ira_hoist_pressure)
+ hoisted_bbs = BITMAP_ALLOC (NULL);
- index_map = XCNEWVEC (struct expr *, expr_hash_table.n_elems);
- for (i = 0; i < expr_hash_table.size; i++)
- for (expr = expr_hash_table.table[i]; expr != NULL; expr = expr->next_same_hash)
- index_map[expr->bitmap_index] = expr;
+ dom_tree_walk = get_all_dominated_blocks (CDI_DOMINATORS,
+ ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb);
/* Walk over each basic block looking for potentially hoistable
expressions, nothing gets hoisted from the entry block. */
- FOR_EACH_BB (bb)
+ FOR_EACH_VEC_ELT (dom_tree_walk, dom_tree_walk_index, bb)
{
- int found = 0;
- int insn_inserted_p;
+ domby = get_dominated_to_depth (CDI_DOMINATORS, bb, MAX_HOIST_DEPTH);
+
+ if (domby.length () == 0)
+ continue;
- domby = get_dominated_by (CDI_DOMINATORS, bb);
/* Examine each expression that is very busy at the exit of this
block. These are the potentially hoistable expressions. */
- for (i = 0; i < hoist_vbeout[bb->index]->n_bits; i++)
+ for (i = 0; i < SBITMAP_SIZE (hoist_vbeout[bb->index]); i++)
{
- int hoistable = 0;
-
- if (TEST_BIT (hoist_vbeout[bb->index], i)
- && TEST_BIT (transpout[bb->index], i))
+ if (bitmap_bit_p (hoist_vbeout[bb->index], i))
{
+ int nregs = 0;
+ enum reg_class pressure_class = NO_REGS;
+ /* Current expression. */
+ struct gcse_expr *expr = index_map[i];
+ /* Number of occurrences of EXPR that can be hoisted to BB. */
+ int hoistable = 0;
+ /* Occurrences reachable from BB. */
+ vec<occr_t> occrs_to_hoist = vNULL;
+ /* We want to insert the expression into BB only once, so
+ note when we've inserted it. */
+ int insn_inserted_p;
+ occr_t occr;
+
+ /* If an expression is computed in BB and is available at end of
+ BB, hoist all occurrences dominated by BB to BB. */
+ if (bitmap_bit_p (comp[bb->index], i))
+ {
+ occr = find_occr_in_bb (expr->antic_occr, bb);
+
+ if (occr)
+ {
+ /* An occurrence might've been already deleted
+ while processing a dominator of BB. */
+ if (!occr->deleted_p)
+ {
+ gcc_assert (NONDEBUG_INSN_P (occr->insn));
+ hoistable++;
+ }
+ }
+ else
+ hoistable++;
+ }
+
/* We've found a potentially hoistable expression, now
we look at every block BB dominates to see if it
computes the expression. */
- for (j = 0; VEC_iterate (basic_block, domby, j, dominated); j++)
+ FOR_EACH_VEC_ELT (domby, j, dominated)
{
+ int max_distance;
+
/* Ignore self dominance. */
if (bb == dominated)
continue;
/* We've found a dominated block, now see if it computes
the busy expression and whether or not moving that
expression to the "beginning" of that block is safe. */
- if (!TEST_BIT (antloc[dominated->index], i))
+ if (!bitmap_bit_p (antloc[dominated->index], i))
continue;
- /* Note if the expression would reach the dominated block
- unimpared if it was placed at the end of BB.
+ occr = find_occr_in_bb (expr->antic_occr, dominated);
+ gcc_assert (occr);
+
+ /* An occurrence might've been already deleted
+ while processing a dominator of BB. */
+ if (occr->deleted_p)
+ continue;
+ gcc_assert (NONDEBUG_INSN_P (occr->insn));
+
+ max_distance = expr->max_distance;
+ if (max_distance > 0)
+ /* Adjust MAX_DISTANCE to account for the fact that
+ OCCR won't have to travel all of DOMINATED, but
+ only part of it. */
+ max_distance += (bb_size[dominated->index]
+ - to_bb_head[INSN_UID (occr->insn)]);
+
+ pressure_class = get_pressure_class_and_nregs (occr->insn,
+ &nregs);
+
+ /* Note if the expression should be hoisted from the dominated
+ block to BB if it can reach DOMINATED unimpared.
Keep track of how many times this expression is hoistable
from a dominated block into BB. */
- if (hoist_expr_reaches_here_p (bb, i, dominated, NULL))
- hoistable++;
+ if (should_hoist_expr_to_dom (bb, expr, dominated, NULL,
+ max_distance, bb_size,
+ pressure_class, &nregs,
+ hoisted_bbs, occr->insn))
+ {
+ hoistable++;
+ occrs_to_hoist.safe_push (occr);
+ bitmap_set_bit (from_bbs, dominated->index);
+ }
}
/* If we found more than one hoistable occurrence of this
- expression, then note it in the bitmap of expressions to
+ expression, then note it in the vector of expressions to
hoist. It makes no sense to hoist things which are computed
in only one BB, and doing so tends to pessimize register
allocation. One could increase this value to try harder
the vast majority of hoistable expressions are only movable
from two successors, so raising this threshold is likely
to nullify any benefit we get from code hoisting. */
- if (hoistable > 1)
+ if (hoistable > 1 && dbg_cnt (hoist_insn))
{
- SET_BIT (hoist_exprs[bb->index], i);
- found = 1;
+ /* If (hoistable != vec::length), then there is
+ an occurrence of EXPR in BB itself. Don't waste
+ time looking for LCA in this case. */
+ if ((unsigned) hoistable == occrs_to_hoist.length ())
+ {
+ basic_block lca;
+
+ lca = nearest_common_dominator_for_set (CDI_DOMINATORS,
+ from_bbs);
+ if (lca != bb)
+ /* Punt, it's better to hoist these occurrences to
+ LCA. */
+ occrs_to_hoist.release ();
+ }
}
- }
- }
- /* If we found nothing to hoist, then quit now. */
- if (! found)
- {
- VEC_free (basic_block, heap, domby);
- continue;
- }
+ else
+ /* Punt, no point hoisting a single occurrence. */
+ occrs_to_hoist.release ();
- /* Loop over all the hoistable expressions. */
- for (i = 0; i < hoist_exprs[bb->index]->n_bits; i++)
- {
- /* We want to insert the expression into BB only once, so
- note when we've inserted it. */
- insn_inserted_p = 0;
+ if (flag_ira_hoist_pressure
+ && !occrs_to_hoist.is_empty ())
+ {
+ /* Increase register pressure of basic blocks to which
+ expr is hoisted because of extended live range of
+ output. */
+ data = BB_DATA (bb);
+ data->max_reg_pressure[pressure_class] += nregs;
+ EXECUTE_IF_SET_IN_BITMAP (hoisted_bbs, 0, k, bi)
+ {
+ data = BB_DATA (BASIC_BLOCK_FOR_FN (cfun, k));
+ data->max_reg_pressure[pressure_class] += nregs;
+ }
+ }
+ else if (flag_ira_hoist_pressure)
+ {
+ /* Restore register pressure and live_in info for basic
+ blocks recorded in hoisted_bbs when expr will not be
+ hoisted. */
+ EXECUTE_IF_SET_IN_BITMAP (hoisted_bbs, 0, k, bi)
+ {
+ data = BB_DATA (BASIC_BLOCK_FOR_FN (cfun, k));
+ bitmap_copy (data->live_in, data->backup);
+ data->max_reg_pressure[pressure_class]
+ = data->old_pressure;
+ }
+ }
- /* These tests should be the same as the tests above. */
- if (TEST_BIT (hoist_exprs[bb->index], i))
- {
- /* We've found a potentially hoistable expression, now
- we look at every block BB dominates to see if it
- computes the expression. */
- for (j = 0; VEC_iterate (basic_block, domby, j, dominated); j++)
+ if (flag_ira_hoist_pressure)
+ bitmap_clear (hoisted_bbs);
+
+ insn_inserted_p = 0;
+
+ /* Walk through occurrences of I'th expressions we want
+ to hoist to BB and make the transformations. */
+ FOR_EACH_VEC_ELT (occrs_to_hoist, j, occr)
{
- /* Ignore self dominance. */
- if (bb == dominated)
- continue;
+ rtx_insn *insn;
+ const_rtx set;
- /* We've found a dominated block, now see if it computes
- the busy expression and whether or not moving that
- expression to the "beginning" of that block is safe. */
- if (!TEST_BIT (antloc[dominated->index], i))
- continue;
+ gcc_assert (!occr->deleted_p);
+
+ insn = occr->insn;
+ set = single_set_gcse (insn);
+
+ /* Create a pseudo-reg to store the result of reaching
+ expressions into. Get the mode for the new pseudo
+ from the mode of the original destination pseudo.
- /* The expression is computed in the dominated block and
- it would be safe to compute it at the start of the
- dominated block. Now we have to determine if the
- expression would reach the dominated block if it was
- placed at the end of BB. */
- if (hoist_expr_reaches_here_p (bb, i, dominated, NULL))
+ It is important to use new pseudos whenever we
+ emit a set. This will allow reload to use
+ rematerialization for such registers. */
+ if (!insn_inserted_p)
+ expr->reaching_reg
+ = gen_reg_rtx_and_attrs (SET_DEST (set));
+
+ gcse_emit_move_after (SET_DEST (set), expr->reaching_reg,
+ insn);
+ delete_insn (insn);
+ occr->deleted_p = 1;
+ changed = 1;
+ gcse_subst_count++;
+
+ if (!insn_inserted_p)
{
- struct expr *expr = index_map[i];
- struct occr *occr = expr->antic_occr;
- rtx insn;
- rtx set;
-
- /* Find the right occurrence of this expression. */
- while (BLOCK_FOR_INSN (occr->insn) != dominated && occr)
- occr = occr->next;
-
- gcc_assert (occr);
- insn = occr->insn;
- set = single_set (insn);
- gcc_assert (set);
-
- /* Create a pseudo-reg to store the result of reaching
- expressions into. Get the mode for the new pseudo
- from the mode of the original destination pseudo. */
- if (expr->reaching_reg == NULL)
- expr->reaching_reg
- = gen_reg_rtx_and_attrs (SET_DEST (set));
-
- gcse_emit_move_after (expr->reaching_reg, SET_DEST (set), insn);
- delete_insn (insn);
- occr->deleted_p = 1;
- changed = 1;
- gcse_subst_count++;
-
- if (!insn_inserted_p)
- {
- insert_insn_end_basic_block (index_map[i], bb, 0);
- insn_inserted_p = 1;
- }
+ insert_insn_end_basic_block (expr, bb);
+ insn_inserted_p = 1;
}
}
+
+ occrs_to_hoist.release ();
+ bitmap_clear (from_bbs);
}
}
- VEC_free (basic_block, heap, domby);
+ domby.release ();
}
+ dom_tree_walk.release ();
+ BITMAP_FREE (from_bbs);
+ if (flag_ira_hoist_pressure)
+ BITMAP_FREE (hoisted_bbs);
+
+ free (bb_size);
+ free (to_bb_head);
free (index_map);
return changed;
}
+/* Return pressure class and number of needed hard registers (through
+ *NREGS) of register REGNO. */
+static enum reg_class
+get_regno_pressure_class (int regno, int *nregs)
+{
+ if (regno >= FIRST_PSEUDO_REGISTER)
+ {
+ enum reg_class pressure_class;
+
+ pressure_class = reg_allocno_class (regno);
+ pressure_class = ira_pressure_class_translate[pressure_class];
+ *nregs
+ = ira_reg_class_max_nregs[pressure_class][PSEUDO_REGNO_MODE (regno)];
+ return pressure_class;
+ }
+ else if (! TEST_HARD_REG_BIT (ira_no_alloc_regs, regno)
+ && ! TEST_HARD_REG_BIT (eliminable_regset, regno))
+ {
+ *nregs = 1;
+ return ira_pressure_class_translate[REGNO_REG_CLASS (regno)];
+ }
+ else
+ {
+ *nregs = 0;
+ return NO_REGS;
+ }
+}
+
+/* Return pressure class and number of hard registers (through *NREGS)
+ for destination of INSN. */
+static enum reg_class
+get_pressure_class_and_nregs (rtx_insn *insn, int *nregs)
+{
+ rtx reg;
+ enum reg_class pressure_class;
+ const_rtx set = single_set_gcse (insn);
+
+ reg = SET_DEST (set);
+ if (GET_CODE (reg) == SUBREG)
+ reg = SUBREG_REG (reg);
+ if (MEM_P (reg))
+ {
+ *nregs = 0;
+ pressure_class = NO_REGS;
+ }
+ else
+ {
+ gcc_assert (REG_P (reg));
+ pressure_class = reg_allocno_class (REGNO (reg));
+ pressure_class = ira_pressure_class_translate[pressure_class];
+ *nregs
+ = ira_reg_class_max_nregs[pressure_class][GET_MODE (SET_SRC (set))];
+ }
+ return pressure_class;
+}
+
+/* Increase (if INCR_P) or decrease current register pressure for
+ register REGNO. */
+static void
+change_pressure (int regno, bool incr_p)
+{
+ int nregs;
+ enum reg_class pressure_class;
+
+ pressure_class = get_regno_pressure_class (regno, &nregs);
+ if (! incr_p)
+ curr_reg_pressure[pressure_class] -= nregs;
+ else
+ {
+ curr_reg_pressure[pressure_class] += nregs;
+ if (BB_DATA (curr_bb)->max_reg_pressure[pressure_class]
+ < curr_reg_pressure[pressure_class])
+ BB_DATA (curr_bb)->max_reg_pressure[pressure_class]
+ = curr_reg_pressure[pressure_class];
+ }
+}
+
+/* Calculate register pressure for each basic block by walking insns
+ from last to first. */
+static void
+calculate_bb_reg_pressure (void)
+{
+ int i;
+ unsigned int j;
+ rtx_insn *insn;
+ basic_block bb;
+ bitmap curr_regs_live;
+ bitmap_iterator bi;
+
+
+ ira_setup_eliminable_regset ();
+ curr_regs_live = BITMAP_ALLOC (®_obstack);
+ FOR_EACH_BB_FN (bb, cfun)
+ {
+ curr_bb = bb;
+ BB_DATA (bb)->live_in = BITMAP_ALLOC (NULL);
+ BB_DATA (bb)->backup = BITMAP_ALLOC (NULL);
+ bitmap_copy (BB_DATA (bb)->live_in, df_get_live_in (bb));
+ bitmap_copy (curr_regs_live, df_get_live_out (bb));
+ for (i = 0; i < ira_pressure_classes_num; i++)
+ curr_reg_pressure[ira_pressure_classes[i]] = 0;
+ EXECUTE_IF_SET_IN_BITMAP (curr_regs_live, 0, j, bi)
+ change_pressure (j, true);
+
+ FOR_BB_INSNS_REVERSE (bb, insn)
+ {
+ rtx dreg;
+ int regno;
+ df_ref def, use;
+
+ if (! NONDEBUG_INSN_P (insn))
+ continue;
+
+ FOR_EACH_INSN_DEF (def, insn)
+ {
+ dreg = DF_REF_REAL_REG (def);
+ gcc_assert (REG_P (dreg));
+ regno = REGNO (dreg);
+ if (!(DF_REF_FLAGS (def)
+ & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
+ {
+ if (bitmap_clear_bit (curr_regs_live, regno))
+ change_pressure (regno, false);
+ }
+ }
+
+ FOR_EACH_INSN_USE (use, insn)
+ {
+ dreg = DF_REF_REAL_REG (use);
+ gcc_assert (REG_P (dreg));
+ regno = REGNO (dreg);
+ if (bitmap_set_bit (curr_regs_live, regno))
+ change_pressure (regno, true);
+ }
+ }
+ }
+ BITMAP_FREE (curr_regs_live);
+
+ if (dump_file == NULL)
+ return;
+
+ fprintf (dump_file, "\nRegister Pressure: \n");
+ FOR_EACH_BB_FN (bb, cfun)
+ {
+ fprintf (dump_file, " Basic block %d: \n", bb->index);
+ for (i = 0; (int) i < ira_pressure_classes_num; i++)
+ {
+ enum reg_class pressure_class;
+
+ pressure_class = ira_pressure_classes[i];
+ if (BB_DATA (bb)->max_reg_pressure[pressure_class] == 0)
+ continue;
+
+ fprintf (dump_file, " %s=%d\n", reg_class_names[pressure_class],
+ BB_DATA (bb)->max_reg_pressure[pressure_class]);
+ }
+ }
+ fprintf (dump_file, "\n");
+}
+
/* Top level routine to perform one code hoisting (aka unification) pass
Return nonzero if a change was made. */
gcse_create_count = 0;
/* Return if there's nothing to do, or it is too expensive. */
- if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1
+ if (n_basic_blocks_for_fn (cfun) <= NUM_FIXED_BLOCKS + 1
|| is_too_expensive (_("GCSE disabled")))
return 0;
+ doing_code_hoisting_p = true;
+
+ /* Calculate register pressure for each basic block. */
+ if (flag_ira_hoist_pressure)
+ {
+ regstat_init_n_sets_and_refs ();
+ ira_set_pseudo_classes (false, dump_file);
+ alloc_aux_for_blocks (sizeof (struct bb_data));
+ calculate_bb_reg_pressure ();
+ regstat_free_n_sets_and_refs ();
+ }
+
/* We need alias. */
init_alias_analysis ();
gcc_obstack_init (&gcse_obstack);
alloc_gcse_mem ();
- alloc_hash_table (&expr_hash_table, 0);
+ alloc_hash_table (&expr_hash_table);
compute_hash_table (&expr_hash_table);
if (dump_file)
dump_hash_table (dump_file, "Code Hosting Expressions", &expr_hash_table);
if (expr_hash_table.n_elems > 0)
{
- alloc_code_hoist_mem (last_basic_block, expr_hash_table.n_elems);
+ alloc_code_hoist_mem (last_basic_block_for_fn (cfun),
+ expr_hash_table.n_elems);
compute_code_hoist_data ();
changed = hoist_code ();
free_code_hoist_mem ();
}
+ if (flag_ira_hoist_pressure)
+ {
+ free_aux_for_blocks ();
+ free_reg_info ();
+ }
free_hash_table (&expr_hash_table);
free_gcse_mem ();
obstack_free (&gcse_obstack, NULL);
if (dump_file)
{
fprintf (dump_file, "HOIST of %s, %d basic blocks, %d bytes needed, ",
- current_function_name (), n_basic_blocks, bytes_used);
+ current_function_name (), n_basic_blocks_for_fn (cfun),
+ bytes_used);
fprintf (dump_file, "%d substs, %d insns created\n",
gcse_subst_count, gcse_create_count);
}
+ doing_code_hoisting_p = false;
+
return changed;
}
\f
-/* Here we provide the things required to do store motion towards
- the exit. In order for this to be effective, gcse also needed to
- be taught how to move a load when it is kill only by a store to itself.
+/* Here we provide the things required to do store motion towards the exit.
+ In order for this to be effective, gcse also needed to be taught how to
+ move a load when it is killed only by a store to itself.
int i;
float a[10];
of the loop.
The 'Load Motion' referred to and implemented in this file is
- an enhancement to gcse which when using edge based lcm, recognizes
+ an enhancement to gcse which when using edge based LCM, recognizes
this situation and allows gcse to move the load out of the loop.
Once gcse has hoisted the load, store motion can then push this
load towards the exit, and we end up with no loads or stores of 'i'
in the loop. */
-static hashval_t
-pre_ldst_expr_hash (const void *p)
-{
- int do_not_record_p = 0;
- const struct ls_expr *const x = (const struct ls_expr *) p;
- return hash_rtx (x->pattern, GET_MODE (x->pattern), &do_not_record_p, NULL, false);
-}
-
-static int
-pre_ldst_expr_eq (const void *p1, const void *p2)
-{
- const struct ls_expr *const ptr1 = (const struct ls_expr *) p1,
- *const ptr2 = (const struct ls_expr *) p2;
- return expr_equiv_p (ptr1->pattern, ptr2->pattern);
-}
-
/* This will search the ldst list for a matching expression. If it
doesn't find one, we create one and initialize it. */
int do_not_record_p = 0;
struct ls_expr * ptr;
unsigned int hash;
- void **slot;
+ ls_expr **slot;
struct ls_expr e;
hash = hash_rtx (x, GET_MODE (x), &do_not_record_p,
NULL, /*have_reg_qty=*/false);
e.pattern = x;
- slot = htab_find_slot_with_hash (pre_ldst_table, &e, hash, INSERT);
+ slot = pre_ldst_table->find_slot_with_hash (&e, hash, INSERT);
if (*slot)
- return (struct ls_expr *)*slot;
+ return *slot;
ptr = XNEW (struct ls_expr);
ptr->expr = NULL;
ptr->pattern = x;
ptr->pattern_regs = NULL_RTX;
- ptr->loads = NULL_RTX;
- ptr->stores = NULL_RTX;
+ ptr->loads = NULL;
+ ptr->stores = NULL;
ptr->reaching_reg = NULL_RTX;
ptr->invalid = 0;
ptr->index = 0;
/* Free up all memory associated with the ldst list. */
static void
-free_ldst_mems (void)
+free_ld_motion_mems (void)
{
- if (pre_ldst_table)
- htab_delete (pre_ldst_table);
+ delete pre_ldst_table;
pre_ldst_table = NULL;
while (pre_ldst_mems)
fprintf (file, "LDST list: \n");
- for (ptr = first_ls_expr (); ptr != NULL; ptr = next_ls_expr (ptr))
+ for (ptr = pre_ldst_mems; ptr != NULL; ptr = ptr->next)
{
fprintf (file, " Pattern (%3d): ", ptr->index);
find_rtx_in_ldst (rtx x)
{
struct ls_expr e;
- void **slot;
+ ls_expr **slot;
if (!pre_ldst_table)
return NULL;
e.pattern = x;
- slot = htab_find_slot (pre_ldst_table, &e, NO_INSERT);
- if (!slot || ((struct ls_expr *)*slot)->invalid)
+ slot = pre_ldst_table->find_slot (&e, NO_INSERT);
+ if (!slot || (*slot)->invalid)
return NULL;
- return (struct ls_expr *) *slot;
-}
-
-/* Return first item in the list. */
-
-static inline struct ls_expr *
-first_ls_expr (void)
-{
- return pre_ldst_mems;
-}
-
-/* Return the next item in the list after the specified one. */
-
-static inline struct ls_expr *
-next_ls_expr (struct ls_expr * ptr)
-{
- return ptr->next;
+ return *slot;
}
\f
/* Load Motion for loads which only kill themselves. */
-/* Return true if x is a simple MEM operation, with no registers or
- side effects. These are the types of loads we consider for the
- ld_motion list, otherwise we let the usual aliasing take care of it. */
+/* Return true if x, a MEM, is a simple access with no side effects.
+ These are the types of loads we consider for the ld_motion list,
+ otherwise we let the usual aliasing take care of it. */
static int
simple_mem (const_rtx x)
{
- if (! MEM_P (x))
- return 0;
-
if (MEM_VOLATILE_P (x))
return 0;
return 0;
/* If we are handling exceptions, we must be careful with memory references
- that may trap. If we are not, the behavior is undefined, so we may just
+ that may trap. If we are not, the behavior is undefined, so we may just
continue. */
- if (flag_non_call_exceptions && may_trap_p (x))
+ if (cfun->can_throw_non_call_exceptions && may_trap_p (x))
return 0;
if (side_effects_p (x))
{
struct ls_expr * ptr;
basic_block bb;
- rtx insn;
+ rtx_insn *insn;
pre_ldst_mems = NULL;
- pre_ldst_table = htab_create (13, pre_ldst_expr_hash,
- pre_ldst_expr_eq, NULL);
+ pre_ldst_table = new hash_table<pre_ldst_expr_hasher> (13);
- FOR_EACH_BB (bb)
+ FOR_EACH_BB_FN (bb, cfun)
{
FOR_BB_INSNS (bb, insn)
{
{
rtx src = SET_SRC (PATTERN (insn));
rtx dest = SET_DEST (PATTERN (insn));
+ rtx note = find_reg_equal_equiv_note (insn);
+ rtx src_eq;
/* Check for a simple LOAD... */
if (MEM_P (src) && simple_mem (src))
invalidate_any_buried_refs (src);
}
+ if (note != 0 && REG_NOTE_KIND (note) == REG_EQUAL)
+ src_eq = XEXP (note, 0);
+ else
+ src_eq = NULL_RTX;
+
+ if (src_eq != NULL_RTX
+ && !(MEM_P (src_eq) && simple_mem (src_eq)))
+ invalidate_any_buried_refs (src_eq);
+
/* Check for stores. Don't worry about aliased ones, they
will block any movement we might do later. We only care
about this exact pattern since those are the only
while (ptr != NULL)
{
- struct expr * expr;
+ struct gcse_expr * expr;
/* Delete if entry has been made invalid. */
if (! ptr->invalid)
break;
}
else
- expr = (struct expr *) 0;
+ expr = (struct gcse_expr *) 0;
if (expr)
{
else
{
*last = ptr->next;
- htab_remove_elt_with_hash (pre_ldst_table, ptr, ptr->hash_index);
+ pre_ldst_table->remove_elt_with_hash (ptr, ptr->hash_index);
free_ldst_entry (ptr);
ptr = * last;
}
correct value in the reaching register for the loads. */
static void
-update_ld_motion_stores (struct expr * expr)
+update_ld_motion_stores (struct gcse_expr * expr)
{
struct ls_expr * mem_ptr;
for ( ; list != NULL_RTX; list = XEXP (list, 1))
{
- rtx insn = XEXP (list, 0);
+ rtx_insn *insn = as_a <rtx_insn *> (XEXP (list, 0));
rtx pat = PATTERN (insn);
rtx src = SET_SRC (pat);
rtx reg = expr->reaching_reg;
if (dump_file)
{
fprintf (dump_file, "PRE: store updated with reaching reg ");
- print_rtl (dump_file, expr->reaching_reg);
+ print_rtl (dump_file, reg);
fprintf (dump_file, ":\n ");
print_inline_rtx (dump_file, insn, 8);
fprintf (dump_file, "\n");
which have a couple switch statements. Rather than simply
threshold the number of blocks, uses something with a more
graceful degradation. */
- if (n_edges > 20000 + n_basic_blocks * 4)
+ if (n_edges_for_fn (cfun) > 20000 + n_basic_blocks_for_fn (cfun) * 4)
{
warning (OPT_Wdisabled_optimization,
"%s: %d basic blocks and %d edges/basic block",
- pass, n_basic_blocks, n_edges / n_basic_blocks);
+ pass, n_basic_blocks_for_fn (cfun),
+ n_edges_for_fn (cfun) / n_basic_blocks_for_fn (cfun));
return true;
}
- /* If allocating memory for the cprop bitmap would take up too much
+ /* If allocating memory for the dataflow bitmaps would take up too much
storage it's better just to disable the optimization. */
- if ((n_basic_blocks
+ if ((n_basic_blocks_for_fn (cfun)
* SBITMAP_SET_SIZE (max_reg_num ())
* sizeof (SBITMAP_ELT_TYPE)) > MAX_GCSE_MEMORY)
{
warning (OPT_Wdisabled_optimization,
"%s: %d basic blocks and %d registers",
- pass, n_basic_blocks, max_reg_num ());
+ pass, n_basic_blocks_for_fn (cfun), max_reg_num ());
return true;
}
return false;
}
-
\f
-/* Main function for the CPROP pass. */
-
-static int
-one_cprop_pass (void)
+static unsigned int
+execute_rtl_pre (void)
{
- int changed = 0;
-
- /* Return if there's nothing to do, or it is too expensive. */
- if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1
- || is_too_expensive (_ ("const/copy propagation disabled")))
- return 0;
-
- global_const_prop_count = local_const_prop_count = 0;
- global_copy_prop_count = local_copy_prop_count = 0;
-
- bytes_used = 0;
- gcc_obstack_init (&gcse_obstack);
- alloc_gcse_mem ();
-
- /* Do a local const/copy propagation pass first. The global pass
- only handles global opportunities.
- If the local pass changes something, remove any unreachable blocks
- because the CPROP global dataflow analysis may get into infinite
- loops for CFGs with unreachable blocks.
-
- FIXME: This local pass should not be necessary after CSE (but for
- some reason it still is). It is also (proven) not necessary
- to run the local pass right after FWPWOP.
-
- FIXME: The global analysis would not get into infinite loops if it
- would use the DF solver (via df_simple_dataflow) instead of
- the solver implemented in this file. */
- if (local_cprop_pass ())
- {
- delete_unreachable_blocks ();
- df_analyze ();
- }
-
- /* Determine implicit sets. */
- implicit_sets = XCNEWVEC (rtx, last_basic_block);
- find_implicit_sets ();
-
- alloc_hash_table (&set_hash_table, 1);
- compute_hash_table (&set_hash_table);
-
- /* Free implicit_sets before peak usage. */
- free (implicit_sets);
- implicit_sets = NULL;
-
- if (dump_file)
- dump_hash_table (dump_file, "SET", &set_hash_table);
- if (set_hash_table.n_elems > 0)
- {
- basic_block bb;
- rtx insn;
-
- alloc_cprop_mem (last_basic_block, set_hash_table.n_elems);
- compute_cprop_data ();
-
- FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb, EXIT_BLOCK_PTR, next_bb)
- {
- /* Reset tables used to keep track of what's still valid [since
- the start of the block]. */
- reset_opr_set_tables ();
+ int changed;
+ delete_unreachable_blocks ();
+ df_analyze ();
+ changed = one_pre_gcse_pass ();
+ flag_rerun_cse_after_global_opts |= changed;
+ if (changed)
+ cleanup_cfg (0);
+ return 0;
+}
- FOR_BB_INSNS (bb, insn)
- if (INSN_P (insn))
- {
- changed |= cprop_insn (insn);
-
- /* Keep track of everything modified by this insn. */
- /* ??? Need to be careful w.r.t. mods done to INSN.
- Don't call mark_oprs_set if we turned the
- insn into a NOTE. */
- if (! NOTE_P (insn))
- mark_oprs_set (insn);
- }
- }
+static unsigned int
+execute_rtl_hoist (void)
+{
+ int changed;
+ delete_unreachable_blocks ();
+ df_analyze ();
+ changed = one_code_hoisting_pass ();
+ flag_rerun_cse_after_global_opts |= changed;
+ if (changed)
+ cleanup_cfg (0);
+ return 0;
+}
- changed |= bypass_conditional_jumps ();
- free_cprop_mem ();
- }
+namespace {
- free_hash_table (&set_hash_table);
- free_gcse_mem ();
- obstack_free (&gcse_obstack, NULL);
+const pass_data pass_data_rtl_pre =
+{
+ RTL_PASS, /* type */
+ "rtl pre", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ TV_PRE, /* tv_id */
+ PROP_cfglayout, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_df_finish, /* todo_flags_finish */
+};
- if (dump_file)
- {
- fprintf (dump_file, "CPROP of %s, %d basic blocks, %d bytes needed, ",
- current_function_name (), n_basic_blocks, bytes_used);
- fprintf (dump_file, "%d local const props, %d local copy props, ",
- local_const_prop_count, local_copy_prop_count);
- fprintf (dump_file, "%d global const props, %d global copy props\n\n",
- global_const_prop_count, global_copy_prop_count);
- }
+class pass_rtl_pre : public rtl_opt_pass
+{
+public:
+ pass_rtl_pre (gcc::context *ctxt)
+ : rtl_opt_pass (pass_data_rtl_pre, ctxt)
+ {}
- return changed;
-}
+ /* opt_pass methods: */
+ virtual bool gate (function *);
+ virtual unsigned int execute (function *) { return execute_rtl_pre (); }
-\f
-/* All the passes implemented in this file. Each pass has its
- own gate and execute function, and at the end of the file a
- pass definition for passes.c.
+}; // class pass_rtl_pre
- We do not construct an accurate cfg in functions which call
+/* We do not construct an accurate cfg in functions which call
setjmp, so none of these passes runs if the function calls
setjmp.
FIXME: Should just handle setjmp via REG_SETJMP notes. */
-static bool
-gate_rtl_cprop (void)
+bool
+pass_rtl_pre::gate (function *fun)
{
return optimize > 0 && flag_gcse
- && !cfun->calls_setjmp
- && dbg_cnt (cprop);
+ && !fun->calls_setjmp
+ && optimize_function_for_speed_p (fun)
+ && dbg_cnt (pre);
}
-static unsigned int
-execute_rtl_cprop (void)
+} // anon namespace
+
+rtl_opt_pass *
+make_pass_rtl_pre (gcc::context *ctxt)
{
- delete_unreachable_blocks ();
- df_set_flags (DF_LR_RUN_DCE);
- df_analyze ();
- flag_rerun_cse_after_global_opts |= one_cprop_pass ();
- return 0;
+ return new pass_rtl_pre (ctxt);
}
-static bool
-gate_rtl_pre (void)
+namespace {
+
+const pass_data pass_data_rtl_hoist =
{
- return optimize > 0 && flag_gcse
- && !cfun->calls_setjmp
- && optimize_function_for_speed_p (cfun)
- && dbg_cnt (pre);
-}
+ RTL_PASS, /* type */
+ "hoist", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ TV_HOIST, /* tv_id */
+ PROP_cfglayout, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_df_finish, /* todo_flags_finish */
+};
-static unsigned int
-execute_rtl_pre (void)
+class pass_rtl_hoist : public rtl_opt_pass
{
- delete_unreachable_blocks ();
- df_analyze ();
- flag_rerun_cse_after_global_opts |= one_pre_gcse_pass ();
- return 0;
-}
+public:
+ pass_rtl_hoist (gcc::context *ctxt)
+ : rtl_opt_pass (pass_data_rtl_hoist, ctxt)
+ {}
-static bool
-gate_rtl_hoist (void)
+ /* opt_pass methods: */
+ virtual bool gate (function *);
+ virtual unsigned int execute (function *) { return execute_rtl_hoist (); }
+
+}; // class pass_rtl_hoist
+
+bool
+pass_rtl_hoist::gate (function *)
{
return optimize > 0 && flag_gcse
&& !cfun->calls_setjmp
&& dbg_cnt (hoist);
}
-static unsigned int
-execute_rtl_hoist (void)
-{
- delete_unreachable_blocks ();
- df_analyze ();
- flag_rerun_cse_after_global_opts |= one_code_hoisting_pass ();
- return 0;
-}
+} // anon namespace
-struct rtl_opt_pass pass_rtl_cprop =
+rtl_opt_pass *
+make_pass_rtl_hoist (gcc::context *ctxt)
{
- {
- RTL_PASS,
- "cprop", /* name */
- gate_rtl_cprop, /* gate */
- execute_rtl_cprop, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_CPROP, /* tv_id */
- PROP_cfglayout, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_df_finish | TODO_verify_rtl_sharing |
- TODO_dump_func |
- TODO_verify_flow | TODO_ggc_collect /* todo_flags_finish */
- }
-};
+ return new pass_rtl_hoist (ctxt);
+}
-struct rtl_opt_pass pass_rtl_pre =
-{
- {
- RTL_PASS,
- "rtl pre", /* name */
- gate_rtl_pre, /* gate */
- execute_rtl_pre, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_PRE, /* tv_id */
- PROP_cfglayout, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_df_finish | TODO_verify_rtl_sharing |
- TODO_dump_func |
- TODO_verify_flow | TODO_ggc_collect /* todo_flags_finish */
- }
-};
+/* Reset all state within gcse.c so that we can rerun the compiler
+ within the same process. For use by toplev::finalize. */
-struct rtl_opt_pass pass_rtl_hoist =
+void
+gcse_c_finalize (void)
{
- {
- RTL_PASS,
- "hoist", /* name */
- gate_rtl_hoist, /* gate */
- execute_rtl_hoist, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_HOIST, /* tv_id */
- PROP_cfglayout, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_df_finish | TODO_verify_rtl_sharing |
- TODO_dump_func |
- TODO_verify_flow | TODO_ggc_collect /* todo_flags_finish */
- }
-};
+ test_insn = NULL;
+}
#include "gt-gcse.h"
projects / gcc.git / blobdiff