/* RTL dead code elimination.
- Copyright (C) 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 2005-2019 Free Software Foundation, Inc.
This file is part of GCC.
#include "config.h"
#include "system.h"
#include "coretypes.h"
-#include "hashtab.h"
-#include "tm.h"
+#include "backend.h"
#include "rtl.h"
#include "tree.h"
-#include "regs.h"
-#include "hard-reg-set.h"
-#include "flags.h"
+#include "predict.h"
#include "df.h"
-#include "cselib.h"
+#include "memmodel.h"
+#include "tm_p.h"
+#include "emit-rtl.h" /* FIXME: Can go away once crtl is moved to rtl.h. */
+#include "cfgrtl.h"
+#include "cfgbuild.h"
+#include "cfgcleanup.h"
#include "dce.h"
-#include "timevar.h"
+#include "valtrack.h"
#include "tree-pass.h"
#include "dbgcnt.h"
-DEF_VEC_I(int);
-DEF_VEC_ALLOC_I(int,heap);
-
/* -------------------------------------------------------------------------
Core mark/delete routines
we don't want to reenter it. */
static bool df_in_progress = false;
+/* True if we are allowed to alter the CFG in this pass. */
+static bool can_alter_cfg = false;
+
/* Instructions that have been marked but whose dependencies have not
yet been processed. */
-static VEC(rtx,heap) *worklist;
+static vec<rtx_insn *> worklist;
/* Bitmap of instructions marked as needed indexed by INSN_UID. */
static sbitmap marked;
static bitmap_obstack dce_blocks_bitmap_obstack;
static bitmap_obstack dce_tmp_bitmap_obstack;
+static bool find_call_stack_args (rtx_call_insn *, bool, bool, bitmap);
/* A subroutine for which BODY is part of the instruction being tested;
either the top-level pattern, or an element of a PARALLEL. The
return false;
default:
- if (volatile_refs_p (body))
- return false;
-
- if (flag_non_call_exceptions && may_trap_p (body))
- return false;
-
- return true;
+ return !volatile_refs_p (body);
}
}
the DCE pass. */
static bool
-deletable_insn_p (rtx insn, bool fast)
+deletable_insn_p (rtx_insn *insn, bool fast, bitmap arg_stores)
{
rtx body, x;
int i;
+ df_ref def;
if (CALL_P (insn)
/* We cannot delete calls inside of the recursive dce because
/* We can delete dead const or pure calls as long as they do not
infinite loop. */
&& (RTL_CONST_OR_PURE_CALL_P (insn)
- && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)))
- return true;
-
+ && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn))
+ /* Don't delete calls that may throw if we cannot do so. */
+ && ((cfun->can_delete_dead_exceptions && can_alter_cfg)
+ || insn_nothrow_p (insn)))
+ return find_call_stack_args (as_a <rtx_call_insn *> (insn), false,
+ fast, arg_stores);
+
+ /* Don't delete jumps, notes and the like. */
if (!NONJUMP_INSN_P (insn))
return false;
+ /* Don't delete insns that may throw if we cannot do so. */
+ if (!(cfun->can_delete_dead_exceptions && can_alter_cfg)
+ && !insn_nothrow_p (insn))
+ return false;
+
+ /* If INSN sets a global_reg, leave it untouched. */
+ FOR_EACH_INSN_DEF (def, insn)
+ if (HARD_REGISTER_NUM_P (DF_REF_REGNO (def))
+ && global_regs[DF_REF_REGNO (def)])
+ return false;
+ /* Initialization of pseudo PIC register should never be removed. */
+ else if (DF_REF_REG (def) == pic_offset_table_rtx
+ && REGNO (pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER)
+ return false;
+
+ /* Callee-save restores are needed. */
+ if (RTX_FRAME_RELATED_P (insn)
+ && crtl->shrink_wrapped_separate
+ && find_reg_note (insn, REG_CFA_RESTORE, NULL))
+ return false;
+
body = PATTERN (insn);
switch (GET_CODE (body))
{
case USE:
+ case VAR_LOCATION:
return false;
case CLOBBER:
+ case CLOBBER_HIGH:
if (fast)
{
/* A CLOBBER of a dead pseudo register serves no purpose.
/* Return true if INSN has been marked as needed. */
static inline int
-marked_insn_p (rtx insn)
+marked_insn_p (rtx_insn *insn)
{
/* Artificial defs are always needed and they do not have an insn.
We should never see them here. */
gcc_assert (insn);
- return TEST_BIT (marked, INSN_UID (insn));
+ return bitmap_bit_p (marked, INSN_UID (insn));
}
the worklist. */
static void
-mark_insn (rtx insn, bool fast)
+mark_insn (rtx_insn *insn, bool fast)
{
if (!marked_insn_p (insn))
{
if (!fast)
- VEC_safe_push (rtx, heap, worklist, insn);
- SET_BIT (marked, INSN_UID (insn));
+ worklist.safe_push (insn);
+ bitmap_set_bit (marked, INSN_UID (insn));
if (dump_file)
fprintf (dump_file, " Adding insn %d to worklist\n", INSN_UID (insn));
+ if (CALL_P (insn)
+ && !df_in_progress
+ && !SIBLING_CALL_P (insn)
+ && (RTL_CONST_OR_PURE_CALL_P (insn)
+ && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn))
+ && ((cfun->can_delete_dead_exceptions && can_alter_cfg)
+ || insn_nothrow_p (insn)))
+ find_call_stack_args (as_a <rtx_call_insn *> (insn), true, fast, NULL);
}
}
mark_nonreg_stores_1 (rtx dest, const_rtx pattern, void *data)
{
if (GET_CODE (pattern) != CLOBBER && !REG_P (dest))
- mark_insn ((rtx) data, true);
+ {
+ gcc_checking_assert (GET_CODE (pattern) != CLOBBER_HIGH);
+ mark_insn ((rtx_insn *) data, true);
+ }
}
mark_nonreg_stores_2 (rtx dest, const_rtx pattern, void *data)
{
if (GET_CODE (pattern) != CLOBBER && !REG_P (dest))
- mark_insn ((rtx) data, false);
+ {
+ gcc_checking_assert (GET_CODE (pattern) != CLOBBER_HIGH);
+ mark_insn ((rtx_insn *) data, false);
+ }
}
/* Mark INSN if BODY stores to a non-register destination. */
static void
-mark_nonreg_stores (rtx body, rtx insn, bool fast)
+mark_nonreg_stores (rtx body, rtx_insn *insn, bool fast)
{
if (fast)
note_stores (body, mark_nonreg_stores_1, insn);
}
-/* Delete all REG_EQUAL notes of the registers INSN writes, to prevent
- bad dangling REG_EQUAL notes. */
+/* Return true if a store to SIZE bytes, starting OFF bytes from stack pointer,
+ is a call argument store, and clear corresponding bits from SP_BYTES
+ bitmap if it is. */
-static void
-delete_corresponding_reg_eq_notes (rtx insn)
+static bool
+check_argument_store (HOST_WIDE_INT size, HOST_WIDE_INT off,
+ HOST_WIDE_INT min_sp_off, HOST_WIDE_INT max_sp_off,
+ bitmap sp_bytes)
{
- df_ref *def_rec;
- for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
+ HOST_WIDE_INT byte;
+ for (byte = off; byte < off + size; byte++)
+ {
+ if (byte < min_sp_off
+ || byte >= max_sp_off
+ || !bitmap_clear_bit (sp_bytes, byte - min_sp_off))
+ return false;
+ }
+ return true;
+}
+
+
+/* Try to find all stack stores of CALL_INSN arguments if
+ ACCUMULATE_OUTGOING_ARGS. If all stack stores have been found
+ and it is therefore safe to eliminate the call, return true,
+ otherwise return false. This function should be first called
+ with DO_MARK false, and only when the CALL_INSN is actually
+ going to be marked called again with DO_MARK true. */
+
+static bool
+find_call_stack_args (rtx_call_insn *call_insn, bool do_mark, bool fast,
+ bitmap arg_stores)
+{
+ rtx p;
+ rtx_insn *insn, *prev_insn;
+ bool ret;
+ HOST_WIDE_INT min_sp_off, max_sp_off;
+ bitmap sp_bytes;
+
+ gcc_assert (CALL_P (call_insn));
+ if (!ACCUMULATE_OUTGOING_ARGS)
+ return true;
+
+ if (!do_mark)
+ {
+ gcc_assert (arg_stores);
+ bitmap_clear (arg_stores);
+ }
+
+ min_sp_off = INTTYPE_MAXIMUM (HOST_WIDE_INT);
+ max_sp_off = 0;
+
+ /* First determine the minimum and maximum offset from sp for
+ stored arguments. */
+ for (p = CALL_INSN_FUNCTION_USAGE (call_insn); p; p = XEXP (p, 1))
+ if (GET_CODE (XEXP (p, 0)) == USE
+ && MEM_P (XEXP (XEXP (p, 0), 0)))
+ {
+ rtx mem = XEXP (XEXP (p, 0), 0), addr;
+ HOST_WIDE_INT off = 0, size;
+ if (!MEM_SIZE_KNOWN_P (mem) || !MEM_SIZE (mem).is_constant (&size))
+ return false;
+ addr = XEXP (mem, 0);
+ if (GET_CODE (addr) == PLUS
+ && REG_P (XEXP (addr, 0))
+ && CONST_INT_P (XEXP (addr, 1)))
+ {
+ off = INTVAL (XEXP (addr, 1));
+ addr = XEXP (addr, 0);
+ }
+ if (addr != stack_pointer_rtx)
+ {
+ if (!REG_P (addr))
+ return false;
+ /* If not fast, use chains to see if addr wasn't set to
+ sp + offset. */
+ if (!fast)
+ {
+ df_ref use;
+ struct df_link *defs;
+ rtx set;
+
+ FOR_EACH_INSN_USE (use, call_insn)
+ if (rtx_equal_p (addr, DF_REF_REG (use)))
+ break;
+
+ if (use == NULL)
+ return false;
+
+ for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
+ if (! DF_REF_IS_ARTIFICIAL (defs->ref))
+ break;
+
+ if (defs == NULL)
+ return false;
+
+ set = single_set (DF_REF_INSN (defs->ref));
+ if (!set)
+ return false;
+
+ if (GET_CODE (SET_SRC (set)) != PLUS
+ || XEXP (SET_SRC (set), 0) != stack_pointer_rtx
+ || !CONST_INT_P (XEXP (SET_SRC (set), 1)))
+ return false;
+
+ off += INTVAL (XEXP (SET_SRC (set), 1));
+ }
+ else
+ return false;
+ }
+ min_sp_off = MIN (min_sp_off, off);
+ max_sp_off = MAX (max_sp_off, off + size);
+ }
+
+ if (min_sp_off >= max_sp_off)
+ return true;
+ sp_bytes = BITMAP_ALLOC (NULL);
+
+ /* Set bits in SP_BYTES bitmap for bytes relative to sp + min_sp_off
+ which contain arguments. Checking has been done in the previous
+ loop. */
+ for (p = CALL_INSN_FUNCTION_USAGE (call_insn); p; p = XEXP (p, 1))
+ if (GET_CODE (XEXP (p, 0)) == USE
+ && MEM_P (XEXP (XEXP (p, 0), 0)))
+ {
+ rtx mem = XEXP (XEXP (p, 0), 0), addr;
+ HOST_WIDE_INT off = 0, byte, size;
+ /* Checked in the previous iteration. */
+ size = MEM_SIZE (mem).to_constant ();
+ addr = XEXP (mem, 0);
+ if (GET_CODE (addr) == PLUS
+ && REG_P (XEXP (addr, 0))
+ && CONST_INT_P (XEXP (addr, 1)))
+ {
+ off = INTVAL (XEXP (addr, 1));
+ addr = XEXP (addr, 0);
+ }
+ if (addr != stack_pointer_rtx)
+ {
+ df_ref use;
+ struct df_link *defs;
+ rtx set;
+
+ FOR_EACH_INSN_USE (use, call_insn)
+ if (rtx_equal_p (addr, DF_REF_REG (use)))
+ break;
+
+ for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
+ if (! DF_REF_IS_ARTIFICIAL (defs->ref))
+ break;
+
+ set = single_set (DF_REF_INSN (defs->ref));
+ off += INTVAL (XEXP (SET_SRC (set), 1));
+ }
+ for (byte = off; byte < off + size; byte++)
+ {
+ if (!bitmap_set_bit (sp_bytes, byte - min_sp_off))
+ gcc_unreachable ();
+ }
+ }
+
+ /* Walk backwards, looking for argument stores. The search stops
+ when seeing another call, sp adjustment or memory store other than
+ argument store. */
+ ret = false;
+ for (insn = PREV_INSN (call_insn); insn; insn = prev_insn)
{
- df_ref def = *def_rec;
- unsigned int regno = DF_REF_REGNO (def);
- /* This loop is a little tricky. We cannot just go down the
- chain because it is being modified by the actions in the
- loop. So we just get the head. We plan to drain the list
- anyway. */
- while (DF_REG_EQ_USE_CHAIN (regno))
+ rtx set, mem, addr;
+ HOST_WIDE_INT off;
+
+ if (insn == BB_HEAD (BLOCK_FOR_INSN (call_insn)))
+ prev_insn = NULL;
+ else
+ prev_insn = PREV_INSN (insn);
+
+ if (CALL_P (insn))
+ break;
+
+ if (!NONDEBUG_INSN_P (insn))
+ continue;
+
+ set = single_set (insn);
+ if (!set || SET_DEST (set) == stack_pointer_rtx)
+ break;
+
+ if (!MEM_P (SET_DEST (set)))
+ continue;
+
+ mem = SET_DEST (set);
+ addr = XEXP (mem, 0);
+ off = 0;
+ if (GET_CODE (addr) == PLUS
+ && REG_P (XEXP (addr, 0))
+ && CONST_INT_P (XEXP (addr, 1)))
{
- df_ref eq_use = DF_REG_EQ_USE_CHAIN (regno);
- rtx noted_insn = DF_REF_INSN (eq_use);
- rtx note = find_reg_note (noted_insn, REG_EQUAL, NULL_RTX);
- if (!note)
- note = find_reg_note (noted_insn, REG_EQUIV, NULL_RTX);
-
- /* This assert is generally triggered when someone deletes a
- REG_EQUAL or REG_EQUIV note by hacking the list manually
- rather than calling remove_note. */
- gcc_assert (note);
- remove_note (noted_insn, note);
+ off = INTVAL (XEXP (addr, 1));
+ addr = XEXP (addr, 0);
+ }
+ if (addr != stack_pointer_rtx)
+ {
+ if (!REG_P (addr))
+ break;
+ if (!fast)
+ {
+ df_ref use;
+ struct df_link *defs;
+ rtx set;
+
+ FOR_EACH_INSN_USE (use, insn)
+ if (rtx_equal_p (addr, DF_REF_REG (use)))
+ break;
+
+ if (use == NULL)
+ break;
+
+ for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
+ if (! DF_REF_IS_ARTIFICIAL (defs->ref))
+ break;
+
+ if (defs == NULL)
+ break;
+
+ set = single_set (DF_REF_INSN (defs->ref));
+ if (!set)
+ break;
+
+ if (GET_CODE (SET_SRC (set)) != PLUS
+ || XEXP (SET_SRC (set), 0) != stack_pointer_rtx
+ || !CONST_INT_P (XEXP (SET_SRC (set), 1)))
+ break;
+
+ off += INTVAL (XEXP (SET_SRC (set), 1));
+ }
+ else
+ break;
+ }
+
+ HOST_WIDE_INT size;
+ if (!MEM_SIZE_KNOWN_P (mem)
+ || !MEM_SIZE (mem).is_constant (&size)
+ || !check_argument_store (size, off, min_sp_off,
+ max_sp_off, sp_bytes))
+ break;
+
+ if (!deletable_insn_p (insn, fast, NULL))
+ break;
+
+ if (do_mark)
+ mark_insn (insn, fast);
+ else
+ bitmap_set_bit (arg_stores, INSN_UID (insn));
+
+ if (bitmap_empty_p (sp_bytes))
+ {
+ ret = true;
+ break;
}
}
+
+ BITMAP_FREE (sp_bytes);
+ if (!ret && arg_stores)
+ bitmap_clear (arg_stores);
+
+ return ret;
}
+/* Remove all REG_EQUAL and REG_EQUIV notes referring to the registers INSN
+ writes to. */
+
+static void
+remove_reg_equal_equiv_notes_for_defs (rtx_insn *insn)
+{
+ df_ref def;
+
+ FOR_EACH_INSN_DEF (def, insn)
+ remove_reg_equal_equiv_notes_for_regno (DF_REF_REGNO (def));
+}
+
+/* Scan all BBs for debug insns and reset those that reference values
+ defined in unmarked insns. */
+
+static void
+reset_unmarked_insns_debug_uses (void)
+{
+ basic_block bb;
+ rtx_insn *insn, *next;
+
+ FOR_EACH_BB_REVERSE_FN (bb, cfun)
+ FOR_BB_INSNS_REVERSE_SAFE (bb, insn, next)
+ if (DEBUG_INSN_P (insn))
+ {
+ df_ref use;
+
+ FOR_EACH_INSN_USE (use, insn)
+ {
+ struct df_link *defs;
+ for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
+ {
+ rtx_insn *ref_insn;
+ if (DF_REF_IS_ARTIFICIAL (defs->ref))
+ continue;
+ ref_insn = DF_REF_INSN (defs->ref);
+ if (!marked_insn_p (ref_insn))
+ break;
+ }
+ if (!defs)
+ continue;
+ /* ??? FIXME could we propagate the values assigned to
+ each of the DEFs? */
+ INSN_VAR_LOCATION_LOC (insn) = gen_rtx_UNKNOWN_VAR_LOC ();
+ df_insn_rescan_debug_internal (insn);
+ break;
+ }
+ }
+}
+
/* Delete every instruction that hasn't been marked. */
static void
delete_unmarked_insns (void)
{
basic_block bb;
- rtx insn, next;
+ rtx_insn *insn, *next;
bool must_clean = false;
- FOR_EACH_BB (bb)
- FOR_BB_INSNS_SAFE (bb, insn, next)
- if (INSN_P (insn))
+ FOR_EACH_BB_REVERSE_FN (bb, cfun)
+ FOR_BB_INSNS_REVERSE_SAFE (bb, insn, next)
+ if (NONDEBUG_INSN_P (insn))
{
+ rtx turn_into_use = NULL_RTX;
+
/* Always delete no-op moves. */
if (noop_move_p (insn))
- ;
+ {
+ if (RTX_FRAME_RELATED_P (insn))
+ turn_into_use
+ = find_reg_note (insn, REG_CFA_RESTORE, NULL);
+ if (turn_into_use && REG_P (XEXP (turn_into_use, 0)))
+ turn_into_use = XEXP (turn_into_use, 0);
+ else
+ turn_into_use = NULL_RTX;
+ }
/* Otherwise rely only on the DCE algorithm. */
else if (marked_insn_p (insn))
continue;
+ /* Beware that reaching a dbg counter limit here can result
+ in miscompiled file. This occurs when a group of insns
+ must be deleted together, typically because the kept insn
+ depends on the output from the deleted insn. Deleting
+ this insns in reverse order (both at the bb level and
+ when looking at the blocks) minimizes this, but does not
+ eliminate it, since it is possible for the using insn to
+ be top of a block and the producer to be at the bottom of
+ the block. However, in most cases this will only result
+ in an uninitialized use of an insn that is dead anyway.
+
+ However, there is one rare case that will cause a
+ miscompile: deletion of non-looping pure and constant
+ calls on a machine where ACCUMULATE_OUTGOING_ARGS is true.
+ In this case it is possible to remove the call, but leave
+ the argument pushes to the stack. Because of the changes
+ to the stack pointer, this will almost always lead to a
+ miscompile. */
if (!dbg_cnt (dce))
continue;
if (dump_file)
fprintf (dump_file, "DCE: Deleting insn %d\n", INSN_UID (insn));
- /* Before we delete the insn we have to delete REG_EQUAL notes
+ /* Before we delete the insn we have to remove the REG_EQUAL notes
for the destination regs in order to avoid dangling notes. */
- delete_corresponding_reg_eq_notes (insn);
+ remove_reg_equal_equiv_notes_for_defs (insn);
/* If a pure or const call is deleted, this may make the cfg
have unreachable blocks. We rememeber this and call
if (CALL_P (insn))
must_clean = true;
- /* Now delete the insn. */
- delete_insn_and_edges (insn);
+ if (turn_into_use)
+ {
+ /* Don't remove frame related noop moves if they cary
+ REG_CFA_RESTORE note, while we don't need to emit any code,
+ we need it to emit the CFI restore note. */
+ PATTERN (insn)
+ = gen_rtx_USE (GET_MODE (turn_into_use), turn_into_use);
+ INSN_CODE (insn) = -1;
+ df_insn_rescan (insn);
+ }
+ else
+ /* Now delete the insn. */
+ delete_insn_and_edges (insn);
}
/* Deleted a pure or const call. */
prescan_insns_for_dce (bool fast)
{
basic_block bb;
- rtx insn, next;
-
+ rtx_insn *insn, *prev;
+ bitmap arg_stores = NULL;
+
if (dump_file)
fprintf (dump_file, "Finding needed instructions:\n");
-
- FOR_EACH_BB (bb)
- FOR_BB_INSNS_SAFE (bb, insn, next)
- if (INSN_P (insn))
- {
- if (deletable_insn_p (insn, fast))
- mark_nonreg_stores (PATTERN (insn), insn, fast);
- else
- mark_insn (insn, fast);
- }
+
+ if (!df_in_progress && ACCUMULATE_OUTGOING_ARGS)
+ arg_stores = BITMAP_ALLOC (NULL);
+
+ FOR_EACH_BB_FN (bb, cfun)
+ {
+ FOR_BB_INSNS_REVERSE_SAFE (bb, insn, prev)
+ if (NONDEBUG_INSN_P (insn))
+ {
+ /* Don't mark argument stores now. They will be marked
+ if needed when the associated CALL is marked. */
+ if (arg_stores && bitmap_bit_p (arg_stores, INSN_UID (insn)))
+ continue;
+ if (deletable_insn_p (insn, fast, arg_stores))
+ mark_nonreg_stores (PATTERN (insn), insn, fast);
+ else
+ mark_insn (insn, fast);
+ }
+ /* find_call_stack_args only looks at argument stores in the
+ same bb. */
+ if (arg_stores)
+ bitmap_clear (arg_stores);
+ }
+
+ if (arg_stores)
+ BITMAP_FREE (arg_stores);
if (dump_file)
fprintf (dump_file, "Finished finding needed instructions:\n");
{
basic_block bb;
struct df_link *defs;
- df_ref *use_rec;
+ df_ref use;
- FOR_ALL_BB (bb)
- {
- for (use_rec = df_get_artificial_uses (bb->index);
- *use_rec; use_rec++)
- for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next)
- if (! DF_REF_IS_ARTIFICIAL (defs->ref))
- mark_insn (DF_REF_INSN (defs->ref), false);
- }
+ FOR_ALL_BB_FN (bb, cfun)
+ FOR_EACH_ARTIFICIAL_USE (use, bb->index)
+ for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
+ if (!DF_REF_IS_ARTIFICIAL (defs->ref))
+ mark_insn (DF_REF_INSN (defs->ref), false);
}
/* Mark every instruction that defines a register value that INSN uses. */
static void
-mark_reg_dependencies (rtx insn)
+mark_reg_dependencies (rtx_insn *insn)
{
struct df_link *defs;
- df_ref *use_rec;
+ df_ref use;
- for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++)
+ if (DEBUG_INSN_P (insn))
+ return;
+
+ FOR_EACH_INSN_USE (use, insn)
{
- df_ref use = *use_rec;
if (dump_file)
{
fprintf (dump_file, "Processing use of ");
if (!df_in_progress)
{
if (!fast)
- df_chain_add_problem (DF_UD_CHAIN);
+ {
+ df_set_flags (DF_RD_PRUNE_DEAD_DEFS);
+ df_chain_add_problem (DF_UD_CHAIN);
+ }
df_analyze ();
}
{
bitmap_obstack_initialize (&dce_blocks_bitmap_obstack);
bitmap_obstack_initialize (&dce_tmp_bitmap_obstack);
+ can_alter_cfg = false;
}
+ else
+ can_alter_cfg = true;
marked = sbitmap_alloc (get_max_uid () + 1);
- sbitmap_zero (marked);
+ bitmap_clear (marked);
}
static unsigned int
rest_of_handle_ud_dce (void)
{
- rtx insn;
+ rtx_insn *insn;
init_dce (false);
prescan_insns_for_dce (false);
mark_artificial_uses ();
- while (VEC_length (rtx, worklist) > 0)
+ while (worklist.length () > 0)
{
- insn = VEC_pop (rtx, worklist);
+ insn = worklist.pop ();
mark_reg_dependencies (insn);
}
- VEC_free (rtx, heap, worklist);
+ worklist.release ();
+
+ if (MAY_HAVE_DEBUG_BIND_INSNS)
+ reset_unmarked_insns_debug_uses ();
/* Before any insns are deleted, we must remove the chains since
they are not bidirectional. */
}
-static bool
-gate_ud_dce (void)
-{
- return optimize > 1 && flag_dce
- && dbg_cnt (dce_ud);
-}
+namespace {
-struct rtl_opt_pass pass_ud_rtl_dce =
+const pass_data pass_data_ud_rtl_dce =
{
- {
- RTL_PASS,
- "dce", /* name */
- gate_ud_dce, /* gate */
- rest_of_handle_ud_dce, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_DCE, /* tv_id */
- 0, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_dump_func |
- TODO_df_finish | TODO_verify_rtl_sharing |
- TODO_ggc_collect /* todo_flags_finish */
- }
+ RTL_PASS, /* type */
+ "ud_dce", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ TV_DCE, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_df_finish, /* todo_flags_finish */
};
+class pass_ud_rtl_dce : public rtl_opt_pass
+{
+public:
+ pass_ud_rtl_dce (gcc::context *ctxt)
+ : rtl_opt_pass (pass_data_ud_rtl_dce, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ virtual bool gate (function *)
+ {
+ return optimize > 1 && flag_dce && dbg_cnt (dce_ud);
+ }
+
+ virtual unsigned int execute (function *)
+ {
+ return rest_of_handle_ud_dce ();
+ }
+
+}; // class pass_ud_rtl_dce
+
+} // anon namespace
+
+rtl_opt_pass *
+make_pass_ud_rtl_dce (gcc::context *ctxt)
+{
+ return new pass_ud_rtl_dce (ctxt);
+}
+
/* -------------------------------------------------------------------------
Fast DCE functions
/* Process basic block BB. Return true if the live_in set has
changed. REDO_OUT is true if the info at the bottom of the block
needs to be recalculated before starting. AU is the proper set of
- artificial uses. */
+ artificial uses. Track global substitution of uses of dead pseudos
+ in debug insns using GLOBAL_DEBUG. */
static bool
-byte_dce_process_block (basic_block bb, bool redo_out, bitmap au)
+word_dce_process_block (basic_block bb, bool redo_out,
+ struct dead_debug_global *global_debug)
{
bitmap local_live = BITMAP_ALLOC (&dce_tmp_bitmap_obstack);
- rtx insn;
+ rtx_insn *insn;
bool block_changed;
- df_ref *def_rec;
+ struct dead_debug_local debug;
if (redo_out)
{
set. */
edge e;
edge_iterator ei;
- df_confluence_function_n con_fun_n = df_byte_lr->problem->con_fun_n;
- bitmap_clear (DF_BYTE_LR_OUT (bb));
+ df_confluence_function_n con_fun_n = df_word_lr->problem->con_fun_n;
+ bitmap_clear (DF_WORD_LR_OUT (bb));
FOR_EACH_EDGE (e, ei, bb->succs)
(*con_fun_n) (e);
}
if (dump_file)
{
fprintf (dump_file, "processing block %d live out = ", bb->index);
- df_print_byte_regset (dump_file, DF_BYTE_LR_OUT (bb));
+ df_print_word_regset (dump_file, DF_WORD_LR_OUT (bb));
}
- bitmap_copy (local_live, DF_BYTE_LR_OUT (bb));
-
- df_byte_lr_simulate_artificial_refs_at_end (bb, local_live);
+ bitmap_copy (local_live, DF_WORD_LR_OUT (bb));
+ dead_debug_local_init (&debug, NULL, global_debug);
FOR_BB_INSNS_REVERSE (bb, insn)
- if (INSN_P (insn))
+ if (DEBUG_INSN_P (insn))
{
- /* The insn is needed if there is someone who uses the output. */
- for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
- {
- df_ref def = *def_rec;
- unsigned int last;
- unsigned int dregno = DF_REF_REGNO (def);
- unsigned int start = df_byte_lr_get_regno_start (dregno);
- unsigned int len = df_byte_lr_get_regno_len (dregno);
-
- unsigned int sb;
- unsigned int lb;
- /* This is one of the only places where DF_MM_MAY should
- be used for defs. Need to make sure that we are
- checking for all of the bits that may be used. */
-
- if (!df_compute_accessed_bytes (def, DF_MM_MAY, &sb, &lb))
- {
- start += sb;
- len = lb - sb;
- }
+ df_ref use;
+ FOR_EACH_INSN_USE (use, insn)
+ if (DF_REF_REGNO (use) >= FIRST_PSEUDO_REGISTER
+ && known_eq (GET_MODE_SIZE (GET_MODE (DF_REF_REAL_REG (use))),
+ 2 * UNITS_PER_WORD)
+ && !bitmap_bit_p (local_live, 2 * DF_REF_REGNO (use))
+ && !bitmap_bit_p (local_live, 2 * DF_REF_REGNO (use) + 1))
+ dead_debug_add (&debug, use, DF_REF_REGNO (use));
+ }
+ else if (INSN_P (insn))
+ {
+ bool any_changed;
- if (bitmap_bit_p (au, dregno))
- {
- mark_insn (insn, true);
- goto quickexit;
- }
-
- last = start + len;
- while (start < last)
- if (bitmap_bit_p (local_live, start++))
- {
- mark_insn (insn, true);
- goto quickexit;
- }
- }
-
- quickexit:
-
/* No matter if the instruction is needed or not, we remove
any regno in the defs from the live set. */
- df_byte_lr_simulate_defs (insn, local_live);
+ any_changed = df_word_lr_simulate_defs (insn, local_live);
+ if (any_changed)
+ mark_insn (insn, true);
/* On the other hand, we do not allow the dead uses to set
anything in local_live. */
if (marked_insn_p (insn))
- df_byte_lr_simulate_uses (insn, local_live);
+ df_word_lr_simulate_uses (insn, local_live);
+
+ /* Insert debug temps for dead REGs used in subsequent debug
+ insns. We may have to emit a debug temp even if the insn
+ was marked, in case the debug use was after the point of
+ death. */
+ if (debug.used && !bitmap_empty_p (debug.used))
+ {
+ df_ref def;
+
+ FOR_EACH_INSN_DEF (def, insn)
+ dead_debug_insert_temp (&debug, DF_REF_REGNO (def), insn,
+ marked_insn_p (insn)
+ && !control_flow_insn_p (insn)
+ ? DEBUG_TEMP_AFTER_WITH_REG_FORCE
+ : DEBUG_TEMP_BEFORE_WITH_VALUE);
+ }
if (dump_file)
{
- fprintf (dump_file, "finished processing insn %d live out = ",
+ fprintf (dump_file, "finished processing insn %d live out = ",
INSN_UID (insn));
- df_print_byte_regset (dump_file, local_live);
+ df_print_word_regset (dump_file, local_live);
}
}
-
- df_byte_lr_simulate_artificial_refs_at_top (bb, local_live);
- block_changed = !bitmap_equal_p (local_live, DF_BYTE_LR_IN (bb));
+ block_changed = !bitmap_equal_p (local_live, DF_WORD_LR_IN (bb));
if (block_changed)
- bitmap_copy (DF_BYTE_LR_IN (bb), local_live);
+ bitmap_copy (DF_WORD_LR_IN (bb), local_live);
+
+ dead_debug_local_finish (&debug, NULL);
BITMAP_FREE (local_live);
return block_changed;
}
/* Process basic block BB. Return true if the live_in set has
changed. REDO_OUT is true if the info at the bottom of the block
needs to be recalculated before starting. AU is the proper set of
- artificial uses. */
+ artificial uses. Track global substitution of uses of dead pseudos
+ in debug insns using GLOBAL_DEBUG. */
static bool
-dce_process_block (basic_block bb, bool redo_out, bitmap au)
+dce_process_block (basic_block bb, bool redo_out, bitmap au,
+ struct dead_debug_global *global_debug)
{
bitmap local_live = BITMAP_ALLOC (&dce_tmp_bitmap_obstack);
- rtx insn;
+ rtx_insn *insn;
bool block_changed;
- df_ref *def_rec;
+ df_ref def;
+ struct dead_debug_local debug;
if (redo_out)
{
if (dump_file)
{
- fprintf (dump_file, "processing block %d live out = ", bb->index);
+ fprintf (dump_file, "processing block %d lr out = ", bb->index);
df_print_regset (dump_file, DF_LR_OUT (bb));
}
bitmap_copy (local_live, DF_LR_OUT (bb));
- df_simulate_artificial_refs_at_end (bb, local_live);
+ df_simulate_initialize_backwards (bb, local_live);
+ dead_debug_local_init (&debug, NULL, global_debug);
FOR_BB_INSNS_REVERSE (bb, insn)
- if (INSN_P (insn))
+ if (DEBUG_INSN_P (insn))
{
- bool needed = false;
+ df_ref use;
+ FOR_EACH_INSN_USE (use, insn)
+ if (!bitmap_bit_p (local_live, DF_REF_REGNO (use))
+ && !bitmap_bit_p (au, DF_REF_REGNO (use)))
+ dead_debug_add (&debug, use, DF_REF_REGNO (use));
+ }
+ else if (INSN_P (insn))
+ {
+ bool needed = marked_insn_p (insn);
/* The insn is needed if there is someone who uses the output. */
- for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
- if (bitmap_bit_p (local_live, DF_REF_REGNO (*def_rec))
- || bitmap_bit_p (au, DF_REF_REGNO (*def_rec)))
- {
- needed = true;
- break;
- }
-
- if (needed)
- mark_insn (insn, true);
-
+ if (!needed)
+ FOR_EACH_INSN_DEF (def, insn)
+ if (bitmap_bit_p (local_live, DF_REF_REGNO (def))
+ || bitmap_bit_p (au, DF_REF_REGNO (def)))
+ {
+ needed = true;
+ mark_insn (insn, true);
+ break;
+ }
+
/* No matter if the instruction is needed or not, we remove
any regno in the defs from the live set. */
df_simulate_defs (insn, local_live);
/* On the other hand, we do not allow the dead uses to set
anything in local_live. */
- if (marked_insn_p (insn))
+ if (needed)
df_simulate_uses (insn, local_live);
+
+ /* Insert debug temps for dead REGs used in subsequent debug
+ insns. We may have to emit a debug temp even if the insn
+ was marked, in case the debug use was after the point of
+ death. */
+ if (debug.used && !bitmap_empty_p (debug.used))
+ FOR_EACH_INSN_DEF (def, insn)
+ dead_debug_insert_temp (&debug, DF_REF_REGNO (def), insn,
+ needed && !control_flow_insn_p (insn)
+ ? DEBUG_TEMP_AFTER_WITH_REG_FORCE
+ : DEBUG_TEMP_BEFORE_WITH_VALUE);
}
-
- df_simulate_artificial_refs_at_top (bb, local_live);
+
+ dead_debug_local_finish (&debug, NULL);
+ df_simulate_finalize_backwards (bb, local_live);
block_changed = !bitmap_equal_p (local_live, DF_LR_IN (bb));
if (block_changed)
}
-/* Perform fast DCE once initialization is done. If BYTE_LEVEL is
- true, use the byte level dce, otherwise do it at the pseudo
+/* Perform fast DCE once initialization is done. If WORD_LEVEL is
+ true, use the word level dce, otherwise do it at the pseudo
level. */
static void
-fast_dce (bool byte_level)
+fast_dce (bool word_level)
{
int *postorder = df_get_postorder (DF_BACKWARD);
int n_blocks = df_get_n_blocks (DF_BACKWARD);
df_simulate_fixup_sets has the disadvantage of calling
bb_has_eh_pred once per insn, so we cache the information
here. */
- bitmap au = df->regular_block_artificial_uses;
- bitmap au_eh = df->eh_block_artificial_uses;
+ bitmap au = &df->regular_block_artificial_uses;
+ bitmap au_eh = &df->eh_block_artificial_uses;
int i;
+ struct dead_debug_global global_debug;
prescan_insns_for_dce (true);
for (i = 0; i < n_blocks; i++)
bitmap_set_bit (all_blocks, postorder[i]);
+ dead_debug_global_init (&global_debug, NULL);
+
while (global_changed)
{
global_changed = false;
for (i = 0; i < n_blocks; i++)
{
int index = postorder[i];
- basic_block bb = BASIC_BLOCK (index);
+ basic_block bb = BASIC_BLOCK_FOR_FN (cfun, index);
bool local_changed;
if (index < NUM_FIXED_BLOCKS)
continue;
}
- if (byte_level)
- local_changed
- = byte_dce_process_block (bb, bitmap_bit_p (redo_out, index),
- bb_has_eh_pred (bb) ? au_eh : au);
+ if (word_level)
+ local_changed
+ = word_dce_process_block (bb, bitmap_bit_p (redo_out, index),
+ &global_debug);
else
- local_changed
+ local_changed
= dce_process_block (bb, bitmap_bit_p (redo_out, index),
- bb_has_eh_pred (bb) ? au_eh : au);
+ bb_has_eh_pred (bb) ? au_eh : au,
+ &global_debug);
bitmap_set_bit (processed, index);
-
+
if (local_changed)
{
edge e;
bitmap_set_bit (redo_out, e->src->index);
}
}
-
+
if (global_changed)
{
/* Turn off the RUN_DCE flag to prevent recursive calls to
/* So something was deleted that requires a redo. Do it on
the cheap. */
delete_unmarked_insns ();
- sbitmap_zero (marked);
+ bitmap_clear (marked);
bitmap_clear (processed);
bitmap_clear (redo_out);
-
+
/* We do not need to rescan any instructions. We only need
to redo the dataflow equations for the blocks that had a
change at the top of the block. Then we need to redo the
- iteration. */
- if (byte_level)
- df_analyze_problem (df_byte_lr, all_blocks, postorder, n_blocks);
+ iteration. */
+ if (word_level)
+ df_analyze_problem (df_word_lr, all_blocks, postorder, n_blocks);
else
df_analyze_problem (df_lr, all_blocks, postorder, n_blocks);
}
}
+ dead_debug_global_finish (&global_debug, NULL);
+
delete_unmarked_insns ();
BITMAP_FREE (processed);
/* Fast byte level DCE. */
-static unsigned int
-rest_of_handle_fast_byte_dce (void)
+void
+run_word_dce (void)
{
- df_byte_lr_add_problem ();
+ int old_flags;
+
+ if (!flag_dce)
+ return;
+
+ timevar_push (TV_DCE);
+ old_flags = df_clear_flags (DF_DEFER_INSN_RESCAN + DF_NO_INSN_RESCAN);
+ df_word_lr_add_problem ();
init_dce (true);
fast_dce (true);
fini_dce (true);
- return 0;
+ df_set_flags (old_flags);
+ timevar_pop (TV_DCE);
}
/* If dce is able to delete something, it has to happen
immediately. Otherwise there will be problems handling the
eq_notes. */
- enum df_changeable_flags old_flags
- = df_clear_flags (DF_DEFER_INSN_RESCAN + DF_NO_INSN_RESCAN);
-
+ int old_flags =
+ df_clear_flags (DF_DEFER_INSN_RESCAN + DF_NO_INSN_RESCAN);
+
df_in_progress = true;
rest_of_handle_fast_dce ();
df_in_progress = false;
}
-static bool
-gate_fast_dce (void)
-{
- return optimize > 0 && flag_dce
- && dbg_cnt (dce_fast);
-}
+namespace {
-struct rtl_opt_pass pass_fast_rtl_dce =
+const pass_data pass_data_fast_rtl_dce =
{
- {
- RTL_PASS,
- "dce", /* name */
- gate_fast_dce, /* gate */
- rest_of_handle_fast_dce, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_DCE, /* tv_id */
- 0, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_dump_func |
- TODO_df_finish | TODO_verify_rtl_sharing |
- TODO_ggc_collect /* todo_flags_finish */
- }
+ RTL_PASS, /* type */
+ "rtl_dce", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ TV_DCE, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_df_finish, /* todo_flags_finish */
};
-struct rtl_opt_pass pass_fast_rtl_byte_dce =
+class pass_fast_rtl_dce : public rtl_opt_pass
{
- {
- RTL_PASS,
- "byte-dce", /* name */
- gate_fast_dce, /* gate */
- rest_of_handle_fast_byte_dce, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_DCE, /* tv_id */
- 0, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_dump_func |
- TODO_df_finish | TODO_verify_rtl_sharing |
- TODO_ggc_collect /* todo_flags_finish */
- }
-};
+public:
+ pass_fast_rtl_dce (gcc::context *ctxt)
+ : rtl_opt_pass (pass_data_fast_rtl_dce, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ virtual bool gate (function *)
+ {
+ return optimize > 0 && flag_dce && dbg_cnt (dce_fast);
+ }
+
+ virtual unsigned int execute (function *)
+ {
+ return rest_of_handle_fast_dce ();
+ }
+
+}; // class pass_fast_rtl_dce
+
+} // anon namespace
+
+rtl_opt_pass *
+make_pass_fast_rtl_dce (gcc::context *ctxt)
+{
+ return new pass_fast_rtl_dce (ctxt);
+}
projects / gcc.git / blobdiff