/* Dead code elimination pass for the GNU compiler.
- Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
- Free Software Foundation, Inc.
+ Copyright (C) 2002-2015 Free Software Foundation, Inc.
Contributed by Ben Elliston <bje@redhat.com>
and Andrew MacLeod <amacleod@redhat.com>
Adapted to use control dependence by Steven Bosscher, SUSE Labs.
#include "system.h"
#include "coretypes.h"
#include "tm.h"
-
+#include "alias.h"
+#include "symtab.h"
#include "tree.h"
-#include "tree-pretty-print.h"
+#include "fold-const.h"
+#include "calls.h"
#include "gimple-pretty-print.h"
+#include "predict.h"
+#include "hard-reg-set.h"
+#include "function.h"
+#include "dominance.h"
+#include "cfg.h"
+#include "cfganal.h"
#include "basic-block.h"
-#include "tree-flow.h"
+#include "tree-ssa-alias.h"
+#include "internal-fn.h"
+#include "tree-eh.h"
+#include "gimple-expr.h"
#include "gimple.h"
-#include "tree-dump.h"
-#include "tree-pass.h"
-#include "timevar.h"
+#include "gimplify.h"
+#include "gimple-iterator.h"
+#include "gimple-ssa.h"
+#include "tree-cfg.h"
+#include "tree-phinodes.h"
+#include "ssa-iterators.h"
+#include "stringpool.h"
+#include "tree-ssanames.h"
+#include "tree-ssa-loop-niter.h"
+#include "tree-into-ssa.h"
+#include "rtl.h"
#include "flags.h"
+#include "insn-config.h"
+#include "expmed.h"
+#include "dojump.h"
+#include "explow.h"
+#include "emit-rtl.h"
+#include "varasm.h"
+#include "stmt.h"
+#include "expr.h"
+#include "tree-dfa.h"
+#include "tree-pass.h"
#include "cfgloop.h"
#include "tree-scalar-evolution.h"
+#include "tree-chkp.h"
+#include "tree-ssa-propagate.h"
+#include "gimple-fold.h"
static struct stmt_stats
{
#define STMT_NECESSARY GF_PLF_1
-static VEC(gimple,heap) *worklist;
+static vec<gimple> worklist;
/* Vector indicating an SSA name has already been processed and marked
as necessary. */
use a bitmap for each block recording its edges. An array holds the
bitmap. The Ith bit in the bitmap is set if that block is dependent
on the Ith edge. */
-static bitmap *control_dependence_map;
+static control_dependences *cd;
/* Vector indicating that a basic block has already had all the edges
processed that it is control dependent on. */
to be recomputed. */
static bool cfg_altered;
-/* Execute code that follows the macro for each edge (given number
- EDGE_NUMBER within the CODE) for which the block with index N is
- control dependent. */
-#define EXECUTE_IF_CONTROL_DEPENDENT(BI, N, EDGE_NUMBER) \
- EXECUTE_IF_SET_IN_BITMAP (control_dependence_map[(N)], 0, \
- (EDGE_NUMBER), (BI))
-
-
-/* Indicate block BB is control dependent on an edge with index EDGE_INDEX. */
-static inline void
-set_control_dependence_map_bit (basic_block bb, int edge_index)
-{
- if (bb == ENTRY_BLOCK_PTR)
- return;
- gcc_assert (bb != EXIT_BLOCK_PTR);
- bitmap_set_bit (control_dependence_map[bb->index], edge_index);
-}
-
-/* Clear all control dependences for block BB. */
-static inline void
-clear_control_dependence_bitmap (basic_block bb)
-{
- bitmap_clear (control_dependence_map[bb->index]);
-}
-
-
-/* Find the immediate postdominator PDOM of the specified basic block BLOCK.
- This function is necessary because some blocks have negative numbers. */
-
-static inline basic_block
-find_pdom (basic_block block)
-{
- gcc_assert (block != ENTRY_BLOCK_PTR);
-
- if (block == EXIT_BLOCK_PTR)
- return EXIT_BLOCK_PTR;
- else
- {
- basic_block bb = get_immediate_dominator (CDI_POST_DOMINATORS, block);
- if (! bb)
- return EXIT_BLOCK_PTR;
- return bb;
- }
-}
-
-
-/* Determine all blocks' control dependences on the given edge with edge_list
- EL index EDGE_INDEX, ala Morgan, Section 3.6. */
-
-static void
-find_control_dependence (struct edge_list *el, int edge_index)
-{
- basic_block current_block;
- basic_block ending_block;
-
- gcc_assert (INDEX_EDGE_PRED_BB (el, edge_index) != EXIT_BLOCK_PTR);
-
- if (INDEX_EDGE_PRED_BB (el, edge_index) == ENTRY_BLOCK_PTR)
- ending_block = single_succ (ENTRY_BLOCK_PTR);
- else
- ending_block = find_pdom (INDEX_EDGE_PRED_BB (el, edge_index));
-
- for (current_block = INDEX_EDGE_SUCC_BB (el, edge_index);
- current_block != ending_block && current_block != EXIT_BLOCK_PTR;
- current_block = find_pdom (current_block))
- {
- edge e = INDEX_EDGE (el, edge_index);
-
- /* For abnormal edges, we don't make current_block control
- dependent because instructions that throw are always necessary
- anyway. */
- if (e->flags & EDGE_ABNORMAL)
- continue;
-
- set_control_dependence_map_bit (current_block, edge_index);
- }
-}
-
-
-/* Record all blocks' control dependences on all edges in the edge
- list EL, ala Morgan, Section 3.6. */
-
-static void
-find_all_control_dependences (struct edge_list *el)
-{
- int i;
-
- for (i = 0; i < NUM_EDGES (el); ++i)
- find_control_dependence (el, i);
-}
/* If STMT is not already marked necessary, mark it, and add it to the
worklist if ADD_TO_WORKLIST is true. */
gimple_set_plf (stmt, STMT_NECESSARY, true);
if (add_to_worklist)
- VEC_safe_push (gimple, heap, worklist, stmt);
+ worklist.safe_push (stmt);
if (bb_contains_live_stmts && !is_gimple_debug (stmt))
- SET_BIT (bb_contains_live_stmts, gimple_bb (stmt)->index);
+ bitmap_set_bit (bb_contains_live_stmts, gimple_bb (stmt)->index);
}
gcc_assert (op);
ver = SSA_NAME_VERSION (op);
- if (TEST_BIT (processed, ver))
+ if (bitmap_bit_p (processed, ver))
{
stmt = SSA_NAME_DEF_STMT (op);
gcc_assert (gimple_nop_p (stmt)
|| gimple_plf (stmt, STMT_NECESSARY));
return;
}
- SET_BIT (processed, ver);
+ bitmap_set_bit (processed, ver);
stmt = SSA_NAME_DEF_STMT (op);
gcc_assert (stmt);
gimple_set_plf (stmt, STMT_NECESSARY, true);
if (bb_contains_live_stmts)
- SET_BIT (bb_contains_live_stmts, gimple_bb (stmt)->index);
- VEC_safe_push (gimple, heap, worklist, stmt);
+ bitmap_set_bit (bb_contains_live_stmts, gimple_bb (stmt)->index);
+ worklist.safe_push (stmt);
}
mark_stmt_if_obviously_necessary (gimple stmt, bool aggressive)
{
/* With non-call exceptions, we have to assume that all statements could
- throw. If a statement may throw, it is inherently necessary. */
- if (cfun->can_throw_non_call_exceptions && stmt_could_throw_p (stmt))
+ throw. If a statement could throw, it can be deemed necessary. */
+ if (cfun->can_throw_non_call_exceptions
+ && !cfun->can_delete_dead_exceptions
+ && stmt_could_throw_p (stmt))
{
mark_stmt_necessary (stmt, true);
return;
return;
case GIMPLE_CALL:
- /* Most, but not all function calls are required. Function calls that
- produce no result and have no side effects (i.e. const pure
- functions) are unnecessary. */
- if (gimple_has_side_effects (stmt))
- {
- mark_stmt_necessary (stmt, true);
+ {
+ tree callee = gimple_call_fndecl (stmt);
+ if (callee != NULL_TREE
+ && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
+ switch (DECL_FUNCTION_CODE (callee))
+ {
+ case BUILT_IN_MALLOC:
+ case BUILT_IN_ALIGNED_ALLOC:
+ case BUILT_IN_CALLOC:
+ case BUILT_IN_ALLOCA:
+ case BUILT_IN_ALLOCA_WITH_ALIGN:
+ return;
+
+ default:;
+ }
+ /* Most, but not all function calls are required. Function calls that
+ produce no result and have no side effects (i.e. const pure
+ functions) are unnecessary. */
+ if (gimple_has_side_effects (stmt))
+ {
+ mark_stmt_necessary (stmt, true);
+ return;
+ }
+ if (!gimple_call_lhs (stmt))
return;
- }
- if (!gimple_call_lhs (stmt))
- return;
- break;
+ break;
+ }
case GIMPLE_DEBUG:
/* Debug temps without a value are not useful. ??? If we could
mark_stmt_necessary (stmt, true);
break;
+ case GIMPLE_ASSIGN:
+ if (gimple_clobber_p (stmt))
+ return;
+ break;
+
default:
break;
}
return;
}
- if (is_hidden_global_store (stmt))
+ if (stmt_may_clobber_global_p (stmt))
{
mark_stmt_necessary (stmt, true);
return;
{
gimple stmt = last_stmt (bb);
- SET_BIT (last_stmt_necessary, bb->index);
- SET_BIT (bb_contains_live_stmts, bb->index);
+ bitmap_set_bit (last_stmt_necessary, bb->index);
+ bitmap_set_bit (bb_contains_live_stmts, bb->index);
/* We actually mark the statement only if it is a control statement. */
if (stmt && is_ctrl_stmt (stmt))
When IGNORE_SELF is true, ignore BB in the list of control dependences. */
static void
-mark_control_dependent_edges_necessary (basic_block bb, struct edge_list *el,
- bool ignore_self)
+mark_control_dependent_edges_necessary (basic_block bb, bool ignore_self)
{
bitmap_iterator bi;
unsigned edge_number;
bool skipped = false;
- gcc_assert (bb != EXIT_BLOCK_PTR);
+ gcc_assert (bb != EXIT_BLOCK_PTR_FOR_FN (cfun));
- if (bb == ENTRY_BLOCK_PTR)
+ if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun))
return;
- EXECUTE_IF_CONTROL_DEPENDENT (bi, bb->index, edge_number)
+ EXECUTE_IF_SET_IN_BITMAP (cd->get_edges_dependent_on (bb->index),
+ 0, edge_number, bi)
{
- basic_block cd_bb = INDEX_EDGE_PRED_BB (el, edge_number);
+ basic_block cd_bb = cd->get_edge (edge_number)->src;
if (ignore_self && cd_bb == bb)
{
continue;
}
- if (!TEST_BIT (last_stmt_necessary, cd_bb->index))
+ if (!bitmap_bit_p (last_stmt_necessary, cd_bb->index))
mark_last_stmt_necessary (cd_bb);
}
if (!skipped)
- SET_BIT (visited_control_parents, bb->index);
+ bitmap_set_bit (visited_control_parents, bb->index);
}
dependence analysis. */
static void
-find_obviously_necessary_stmts (struct edge_list *el)
+find_obviously_necessary_stmts (bool aggressive)
{
basic_block bb;
gimple_stmt_iterator gsi;
gimple phi, stmt;
int flags;
- FOR_EACH_BB (bb)
+ FOR_EACH_BB_FN (bb, cfun)
{
/* PHI nodes are never inherently necessary. */
for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
stmt = gsi_stmt (gsi);
gimple_set_plf (stmt, STMT_NECESSARY, false);
- mark_stmt_if_obviously_necessary (stmt, el != NULL);
+ mark_stmt_if_obviously_necessary (stmt, aggressive);
}
}
return;
/* Prevent the empty possibly infinite loops from being removed. */
- if (el)
+ if (aggressive)
{
- loop_iterator li;
struct loop *loop;
scev_initialize ();
if (mark_irreducible_loops ())
- FOR_EACH_BB (bb)
+ FOR_EACH_BB_FN (bb, cfun)
{
edge_iterator ei;
FOR_EACH_EDGE (e, ei, bb->succs)
if (dump_file)
fprintf (dump_file, "Marking back edge of irreducible loop %i->%i\n",
e->src->index, e->dest->index);
- mark_control_dependent_edges_necessary (e->dest, el, false);
+ mark_control_dependent_edges_necessary (e->dest, false);
}
}
- FOR_EACH_LOOP (li, loop, 0)
+ FOR_EACH_LOOP (loop, 0)
if (!finite_loop_p (loop))
{
if (dump_file)
fprintf (dump_file, "can not prove finiteness of loop %i\n", loop->num);
- mark_control_dependent_edges_necessary (loop->latch, el, false);
+ mark_control_dependent_edges_necessary (loop->latch, false);
}
scev_finalize ();
}
in the references (gcc.c-torture/execute/pr42142.c).
The simplest way is to check if the kill dominates
the use. */
+ /* But when both are in the same block we cannot
+ easily tell whether we came from a backedge
+ unless we decide to compute stmt UIDs
+ (see PR58246). */
+ && (basic_block) data != gimple_bb (def_stmt)
&& dominated_by_p (CDI_DOMINATORS, (basic_block) data,
gimple_bb (def_stmt))
&& operand_equal_p (ref->ref, lhs, 0))
/* We have to skip already visited (and thus necessary) statements
to make the chaining work after we dropped back to simple mode. */
if (chain_ovfl
- && TEST_BIT (processed, SSA_NAME_VERSION (vdef)))
+ && bitmap_bit_p (processed, SSA_NAME_VERSION (vdef)))
{
gcc_assert (gimple_nop_p (def_stmt)
|| gimple_plf (def_stmt, STMT_NECESSARY));
return false;
}
+ /* We want to skip statments that do not constitute stores but have
+ a virtual definition. */
+ if (is_gimple_call (def_stmt))
+ {
+ tree callee = gimple_call_fndecl (def_stmt);
+ if (callee != NULL_TREE
+ && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
+ switch (DECL_FUNCTION_CODE (callee))
+ {
+ case BUILT_IN_MALLOC:
+ case BUILT_IN_ALIGNED_ALLOC:
+ case BUILT_IN_CALLOC:
+ case BUILT_IN_ALLOCA:
+ case BUILT_IN_ALLOCA_WITH_ALIGN:
+ case BUILT_IN_FREE:
+ return false;
+
+ default:;
+ }
+ }
+
mark_operand_necessary (vdef);
return false;
In conservative mode, EL is NULL. */
static void
-propagate_necessity (struct edge_list *el)
+propagate_necessity (bool aggressive)
{
gimple stmt;
- bool aggressive = (el ? true : false);
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "\nProcessing worklist:\n");
- while (VEC_length (gimple, worklist) > 0)
+ while (worklist.length () > 0)
{
/* Take STMT from worklist. */
- stmt = VEC_pop (gimple, worklist);
+ stmt = worklist.pop ();
if (dump_file && (dump_flags & TDF_DETAILS))
{
containing STMT is control dependent, but only if we haven't
already done so. */
basic_block bb = gimple_bb (stmt);
- if (bb != ENTRY_BLOCK_PTR
- && !TEST_BIT (visited_control_parents, bb->index))
- mark_control_dependent_edges_necessary (bb, el, false);
+ if (bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)
+ && !bitmap_bit_p (visited_control_parents, bb->index))
+ mark_control_dependent_edges_necessary (bb, false);
}
if (gimple_code (stmt) == GIMPLE_PHI
/* We do not process virtual PHI nodes nor do we track their
necessity. */
- && is_gimple_reg (gimple_phi_result (stmt)))
+ && !virtual_operand_p (gimple_phi_result (stmt)))
{
/* PHI nodes are somewhat special in that each PHI alternative has
data and control dependencies. All the statements feeding the
we also consider the control dependent edges leading to the
predecessor block associated with each PHI alternative as
necessary. */
+ gphi *phi = as_a <gphi *> (stmt);
size_t k;
for (k = 0; k < gimple_phi_num_args (stmt); k++)
{
for (k = 0; k < gimple_phi_num_args (stmt); k++)
{
- basic_block arg_bb = gimple_phi_arg_edge (stmt, k)->src;
+ basic_block arg_bb = gimple_phi_arg_edge (phi, k)->src;
if (gimple_bb (stmt)
!= get_immediate_dominator (CDI_POST_DOMINATORS, arg_bb))
{
- if (!TEST_BIT (last_stmt_necessary, arg_bb->index))
+ if (!bitmap_bit_p (last_stmt_necessary, arg_bb->index))
mark_last_stmt_necessary (arg_bb);
}
- else if (arg_bb != ENTRY_BLOCK_PTR
- && !TEST_BIT (visited_control_parents,
+ else if (arg_bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)
+ && !bitmap_bit_p (visited_control_parents,
arg_bb->index))
- mark_control_dependent_edges_necessary (arg_bb, el, true);
+ mark_control_dependent_edges_necessary (arg_bb, true);
}
}
}
ssa_op_iter iter;
tree use;
+ /* If this is a call to free which is directly fed by an
+ allocation function do not mark that necessary through
+ processing the argument. */
+ if (gimple_call_builtin_p (stmt, BUILT_IN_FREE))
+ {
+ tree ptr = gimple_call_arg (stmt, 0);
+ gimple def_stmt;
+ tree def_callee;
+ /* If the pointer we free is defined by an allocation
+ function do not add the call to the worklist. */
+ if (TREE_CODE (ptr) == SSA_NAME
+ && is_gimple_call (def_stmt = SSA_NAME_DEF_STMT (ptr))
+ && (def_callee = gimple_call_fndecl (def_stmt))
+ && DECL_BUILT_IN_CLASS (def_callee) == BUILT_IN_NORMAL
+ && (DECL_FUNCTION_CODE (def_callee) == BUILT_IN_ALIGNED_ALLOC
+ || DECL_FUNCTION_CODE (def_callee) == BUILT_IN_MALLOC
+ || DECL_FUNCTION_CODE (def_callee) == BUILT_IN_CALLOC))
+ {
+ gimple bounds_def_stmt;
+ tree bounds;
+
+ /* For instrumented calls we should also check used
+ bounds are returned by the same allocation call. */
+ if (!gimple_call_with_bounds_p (stmt)
+ || ((bounds = gimple_call_arg (stmt, 1))
+ && TREE_CODE (bounds) == SSA_NAME
+ && (bounds_def_stmt = SSA_NAME_DEF_STMT (bounds))
+ && chkp_gimple_call_builtin_p (bounds_def_stmt,
+ BUILT_IN_CHKP_BNDRET)
+ && gimple_call_arg (bounds_def_stmt, 0) == ptr))
+ continue;
+ }
+ }
+
FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)
mark_operand_necessary (use);
&& (DECL_FUNCTION_CODE (callee) == BUILT_IN_MEMSET
|| DECL_FUNCTION_CODE (callee) == BUILT_IN_MEMSET_CHK
|| DECL_FUNCTION_CODE (callee) == BUILT_IN_MALLOC
+ || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALIGNED_ALLOC
|| DECL_FUNCTION_CODE (callee) == BUILT_IN_CALLOC
|| DECL_FUNCTION_CODE (callee) == BUILT_IN_FREE
|| DECL_FUNCTION_CODE (callee) == BUILT_IN_VA_END
|| DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA
+ || (DECL_FUNCTION_CODE (callee)
+ == BUILT_IN_ALLOCA_WITH_ALIGN)
|| DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_SAVE
|| DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE
|| DECL_FUNCTION_CODE (callee) == BUILT_IN_ASSUME_ALIGNED))
else if (gimple_assign_single_p (stmt))
{
tree rhs;
- bool rhs_aliased = false;
/* If this is a load mark things necessary. */
rhs = gimple_assign_rhs1 (stmt);
if (TREE_CODE (rhs) != SSA_NAME
- && !is_gimple_min_invariant (rhs))
+ && !is_gimple_min_invariant (rhs)
+ && TREE_CODE (rhs) != CONSTRUCTOR)
{
if (!ref_may_be_aliased (rhs))
mark_aliased_reaching_defs_necessary (stmt, rhs);
else
- rhs_aliased = true;
+ mark_all_reaching_defs_necessary (stmt);
}
- if (rhs_aliased)
- mark_all_reaching_defs_necessary (stmt);
}
- else if (gimple_code (stmt) == GIMPLE_RETURN)
+ else if (greturn *return_stmt = dyn_cast <greturn *> (stmt))
{
- tree rhs = gimple_return_retval (stmt);
+ tree rhs = gimple_return_retval (return_stmt);
/* A return statement may perform a load. */
if (rhs
&& TREE_CODE (rhs) != SSA_NAME
- && !is_gimple_min_invariant (rhs))
+ && !is_gimple_min_invariant (rhs)
+ && TREE_CODE (rhs) != CONSTRUCTOR)
{
if (!ref_may_be_aliased (rhs))
mark_aliased_reaching_defs_necessary (stmt, rhs);
mark_all_reaching_defs_necessary (stmt);
}
}
- else if (gimple_code (stmt) == GIMPLE_ASM)
+ else if (gasm *asm_stmt = dyn_cast <gasm *> (stmt))
{
unsigned i;
mark_all_reaching_defs_necessary (stmt);
/* Inputs may perform loads. */
- for (i = 0; i < gimple_asm_ninputs (stmt); ++i)
+ for (i = 0; i < gimple_asm_ninputs (asm_stmt); ++i)
{
- tree op = TREE_VALUE (gimple_asm_input_op (stmt, i));
+ tree op = TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
if (TREE_CODE (op) != SSA_NAME
&& !is_gimple_min_invariant (op)
+ && TREE_CODE (op) != CONSTRUCTOR
&& !ref_may_be_aliased (op))
mark_aliased_reaching_defs_necessary (stmt, op);
}
}
+ else if (gimple_code (stmt) == GIMPLE_TRANSACTION)
+ {
+ /* The beginning of a transaction is a memory barrier. */
+ /* ??? If we were really cool, we'd only be a barrier
+ for the memories touched within the transaction. */
+ mark_all_reaching_defs_necessary (stmt);
+ }
else
gcc_unreachable ();
}
}
-/* Replace all uses of result of PHI by underlying variable and mark it
- for renaming. */
-
-void
-mark_virtual_phi_result_for_renaming (gimple phi)
-{
- bool used = false;
- imm_use_iterator iter;
- use_operand_p use_p;
- gimple stmt;
- tree result_ssa, result_var;
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Marking result for renaming : ");
- print_gimple_stmt (dump_file, phi, 0, TDF_SLIM);
- fprintf (dump_file, "\n");
- }
-
- result_ssa = gimple_phi_result (phi);
- result_var = SSA_NAME_VAR (result_ssa);
- FOR_EACH_IMM_USE_STMT (stmt, iter, result_ssa)
- {
- FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
- SET_USE (use_p, result_var);
- update_stmt (stmt);
- used = true;
- }
- if (used)
- mark_sym_for_renaming (result_var);
-}
-
/* Remove dead PHI nodes from block BB. */
static bool
remove_dead_phis (basic_block bb)
{
bool something_changed = false;
- gimple_seq phis;
- gimple phi;
- gimple_stmt_iterator gsi;
- phis = phi_nodes (bb);
+ gphi *phi;
+ gphi_iterator gsi;
- for (gsi = gsi_start (phis); !gsi_end_p (gsi);)
+ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);)
{
stats.total_phis++;
- phi = gsi_stmt (gsi);
+ phi = gsi.phi ();
/* We do not track necessity of virtual PHI nodes. Instead do
very simple dead PHI removal here. */
- if (!is_gimple_reg (gimple_phi_result (phi)))
+ if (virtual_operand_p (gimple_phi_result (phi)))
{
/* Virtual PHI nodes with one or identical arguments
can be removed. */
static edge
forward_edge_to_pdom (edge e, basic_block post_dom_bb)
{
- gimple_stmt_iterator gsi;
+ gphi_iterator gsi;
edge e2 = NULL;
edge_iterator ei;
e2 = redirect_edge_and_branch (e, post_dom_bb);
cfg_altered = true;
- /* If edge was already around, no updating is neccesary. */
+ /* If edge was already around, no updating is necessary. */
if (e2 != e)
return e2;
break;
for (gsi = gsi_start_phis (post_dom_bb); !gsi_end_p (gsi);)
{
- gimple phi = gsi_stmt (gsi);
+ gphi *phi = gsi.phi ();
tree op;
source_location locus;
/* PHIs for virtuals have no control dependency relation on them.
We are lost here and must force renaming of the symbol. */
- if (!is_gimple_reg (gimple_phi_result (phi)))
+ if (virtual_operand_p (gimple_phi_result (phi)))
{
mark_virtual_phi_result_for_renaming (phi);
remove_phi_node (&gsi, true);
fake edges in the dominator tree. */
if (e)
;
- else if (! post_dom_bb || post_dom_bb == EXIT_BLOCK_PTR)
+ else if (! post_dom_bb || post_dom_bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
e = EDGE_SUCC (bb, 0);
else
e = forward_edge_to_pdom (EDGE_SUCC (bb, 0), post_dom_bb);
if (e != e2)
{
cfg_altered = true;
- remove_edge (e2);
+ /* If we made a BB unconditionally exit a loop then this
+ transform alters the set of BBs in the loop. Schedule
+ a fixup. */
+ if (loop_exit_edge_p (bb->loop_father, e))
+ loops_state_set (LOOPS_NEED_FIXUP);
+ remove_edge (e2);
}
else
ei_next (&ei);
}
+ /* If this is a store into a variable that is being optimized away,
+ add a debug bind stmt if possible. */
+ if (MAY_HAVE_DEBUG_STMTS
+ && gimple_assign_single_p (stmt)
+ && is_gimple_val (gimple_assign_rhs1 (stmt)))
+ {
+ tree lhs = gimple_assign_lhs (stmt);
+ if ((TREE_CODE (lhs) == VAR_DECL || TREE_CODE (lhs) == PARM_DECL)
+ && !DECL_IGNORED_P (lhs)
+ && is_gimple_reg_type (TREE_TYPE (lhs))
+ && !is_global_var (lhs)
+ && !DECL_HAS_VALUE_EXPR_P (lhs))
+ {
+ tree rhs = gimple_assign_rhs1 (stmt);
+ gdebug *note
+ = gimple_build_debug_bind (lhs, unshare_expr (rhs), stmt);
+ gsi_insert_after (i, note, GSI_SAME_STMT);
+ }
+ }
+
unlink_stmt_vdef (stmt);
gsi_remove (i, true);
release_defs (stmt);
}
+/* Helper for maybe_optimize_arith_overflow. Find in *TP if there are any
+ uses of data (SSA_NAME) other than REALPART_EXPR referencing it. */
+
+static tree
+find_non_realpart_uses (tree *tp, int *walk_subtrees, void *data)
+{
+ if (TYPE_P (*tp) || TREE_CODE (*tp) == REALPART_EXPR)
+ *walk_subtrees = 0;
+ if (*tp == (tree) data)
+ return *tp;
+ return NULL_TREE;
+}
+
+/* If the IMAGPART_EXPR of the {ADD,SUB,MUL}_OVERFLOW result is never used,
+ but REALPART_EXPR is, optimize the {ADD,SUB,MUL}_OVERFLOW internal calls
+ into plain unsigned {PLUS,MINUS,MULT}_EXPR, and if needed reset debug
+ uses. */
+
+static void
+maybe_optimize_arith_overflow (gimple_stmt_iterator *gsi,
+ enum tree_code subcode)
+{
+ gimple stmt = gsi_stmt (*gsi);
+ tree lhs = gimple_call_lhs (stmt);
+
+ if (lhs == NULL || TREE_CODE (lhs) != SSA_NAME)
+ return;
+
+ imm_use_iterator imm_iter;
+ use_operand_p use_p;
+ bool has_debug_uses = false;
+ bool has_realpart_uses = false;
+ bool has_other_uses = false;
+ FOR_EACH_IMM_USE_FAST (use_p, imm_iter, lhs)
+ {
+ gimple use_stmt = USE_STMT (use_p);
+ if (is_gimple_debug (use_stmt))
+ has_debug_uses = true;
+ else if (is_gimple_assign (use_stmt)
+ && gimple_assign_rhs_code (use_stmt) == REALPART_EXPR
+ && TREE_OPERAND (gimple_assign_rhs1 (use_stmt), 0) == lhs)
+ has_realpart_uses = true;
+ else
+ {
+ has_other_uses = true;
+ break;
+ }
+ }
+
+ if (!has_realpart_uses || has_other_uses)
+ return;
+
+ tree arg0 = gimple_call_arg (stmt, 0);
+ tree arg1 = gimple_call_arg (stmt, 1);
+ location_t loc = gimple_location (stmt);
+ tree type = TREE_TYPE (TREE_TYPE (lhs));
+ tree utype = type;
+ if (!TYPE_UNSIGNED (type))
+ utype = build_nonstandard_integer_type (TYPE_PRECISION (type), 1);
+ tree result = fold_build2_loc (loc, subcode, utype,
+ fold_convert_loc (loc, utype, arg0),
+ fold_convert_loc (loc, utype, arg1));
+ result = fold_convert_loc (loc, type, result);
+
+ if (has_debug_uses)
+ {
+ gimple use_stmt;
+ FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, lhs)
+ {
+ if (!gimple_debug_bind_p (use_stmt))
+ continue;
+ tree v = gimple_debug_bind_get_value (use_stmt);
+ if (walk_tree (&v, find_non_realpart_uses, lhs, NULL))
+ {
+ gimple_debug_bind_reset_value (use_stmt);
+ update_stmt (use_stmt);
+ }
+ }
+ }
+
+ if (TREE_CODE (result) == INTEGER_CST && TREE_OVERFLOW (result))
+ result = drop_tree_overflow (result);
+ tree overflow = build_zero_cst (type);
+ tree ctype = build_complex_type (type);
+ if (TREE_CODE (result) == INTEGER_CST)
+ result = build_complex (ctype, result, overflow);
+ else
+ result = build2_loc (gimple_location (stmt), COMPLEX_EXPR,
+ ctype, result, overflow);
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Transforming call: ");
+ print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
+ fprintf (dump_file, "because the overflow result is never used into: ");
+ print_generic_stmt (dump_file, result, TDF_SLIM);
+ fprintf (dump_file, "\n");
+ }
+
+ if (!update_call_from_tree (gsi, result))
+ gimplify_and_update_call_from_tree (gsi, result);
+}
+
/* Eliminate unnecessary statements. Any instruction not marked as necessary
contributes nothing to the program, and can be deleted. */
gimple_stmt_iterator gsi, psi;
gimple stmt;
tree call;
- VEC (basic_block, heap) *h;
+ vec<basic_block> h;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "\nEliminating unnecessary statements:\n");
as desired. */
gcc_assert (dom_info_available_p (CDI_DOMINATORS));
- h = get_all_dominated_blocks (CDI_DOMINATORS, single_succ (ENTRY_BLOCK_PTR));
+ h = get_all_dominated_blocks (CDI_DOMINATORS,
+ single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)));
- while (VEC_length (basic_block, h))
+ while (h.length ())
{
- bb = VEC_pop (basic_block, h);
+ bb = h.pop ();
/* Remove dead statements. */
for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi = psi)
stats.total++;
+ /* We can mark a call to free as not necessary if the
+ defining statement of its argument is not necessary
+ (and thus is getting removed). */
+ if (gimple_plf (stmt, STMT_NECESSARY)
+ && gimple_call_builtin_p (stmt, BUILT_IN_FREE))
+ {
+ tree ptr = gimple_call_arg (stmt, 0);
+ if (TREE_CODE (ptr) == SSA_NAME)
+ {
+ gimple def_stmt = SSA_NAME_DEF_STMT (ptr);
+ if (!gimple_nop_p (def_stmt)
+ && !gimple_plf (def_stmt, STMT_NECESSARY))
+ gimple_set_plf (stmt, STMT_NECESSARY, false);
+ }
+ /* We did not propagate necessity for free calls fed
+ by allocation function to allow unnecessary
+ alloc-free sequence elimination. For instrumented
+ calls it also means we did not mark bounds producer
+ as necessary and it is time to do it in case free
+ call is not removed. */
+ if (gimple_call_with_bounds_p (stmt))
+ {
+ gimple bounds_def_stmt;
+ tree bounds = gimple_call_arg (stmt, 1);
+ gcc_assert (TREE_CODE (bounds) == SSA_NAME);
+ bounds_def_stmt = SSA_NAME_DEF_STMT (bounds);
+ if (bounds_def_stmt
+ && !gimple_plf (bounds_def_stmt, STMT_NECESSARY))
+ gimple_set_plf (bounds_def_stmt, STMT_NECESSARY,
+ gimple_plf (stmt, STMT_NECESSARY));
+ }
+ }
+
/* If GSI is not necessary then remove it. */
if (!gimple_plf (stmt, STMT_NECESSARY))
{
+ /* Keep clobbers that we can keep live live. */
+ if (gimple_clobber_p (stmt))
+ {
+ ssa_op_iter iter;
+ use_operand_p use_p;
+ bool dead = false;
+ FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
+ {
+ tree name = USE_FROM_PTR (use_p);
+ if (!SSA_NAME_IS_DEFAULT_DEF (name)
+ && !bitmap_bit_p (processed, SSA_NAME_VERSION (name)))
+ {
+ dead = true;
+ break;
+ }
+ }
+ if (!dead)
+ continue;
+ }
if (!is_gimple_debug (stmt))
something_changed = true;
remove_dead_stmt (&gsi, bb);
}
else if (is_gimple_call (stmt))
{
- call = gimple_call_fndecl (stmt);
- if (call)
+ tree name = gimple_call_lhs (stmt);
+
+ notice_special_calls (as_a <gcall *> (stmt));
+
+ /* When LHS of var = call (); is dead, simplify it into
+ call (); saving one operand. */
+ if (name
+ && TREE_CODE (name) == SSA_NAME
+ && !bitmap_bit_p (processed, SSA_NAME_VERSION (name))
+ /* Avoid doing so for allocation calls which we
+ did not mark as necessary, it will confuse the
+ special logic we apply to malloc/free pair removal. */
+ && (!(call = gimple_call_fndecl (stmt))
+ || DECL_BUILT_IN_CLASS (call) != BUILT_IN_NORMAL
+ || (DECL_FUNCTION_CODE (call) != BUILT_IN_ALIGNED_ALLOC
+ && DECL_FUNCTION_CODE (call) != BUILT_IN_MALLOC
+ && DECL_FUNCTION_CODE (call) != BUILT_IN_CALLOC
+ && DECL_FUNCTION_CODE (call) != BUILT_IN_ALLOCA
+ && (DECL_FUNCTION_CODE (call)
+ != BUILT_IN_ALLOCA_WITH_ALIGN)))
+ /* Avoid doing so for bndret calls for the same reason. */
+ && !chkp_gimple_call_builtin_p (stmt, BUILT_IN_CHKP_BNDRET))
{
- tree name;
-
- /* When LHS of var = call (); is dead, simplify it into
- call (); saving one operand. */
- name = gimple_call_lhs (stmt);
- if (name && TREE_CODE (name) == SSA_NAME
- && !TEST_BIT (processed, SSA_NAME_VERSION (name)))
+ something_changed = true;
+ if (dump_file && (dump_flags & TDF_DETAILS))
{
- something_changed = true;
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Deleting LHS of call: ");
- print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
- fprintf (dump_file, "\n");
- }
-
- gimple_call_set_lhs (stmt, NULL_TREE);
- maybe_clean_or_replace_eh_stmt (stmt, stmt);
- update_stmt (stmt);
- release_ssa_name (name);
+ fprintf (dump_file, "Deleting LHS of call: ");
+ print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
+ fprintf (dump_file, "\n");
}
- notice_special_calls (stmt);
+
+ gimple_call_set_lhs (stmt, NULL_TREE);
+ maybe_clean_or_replace_eh_stmt (stmt, stmt);
+ update_stmt (stmt);
+ release_ssa_name (name);
+
+ /* GOMP_SIMD_LANE without lhs is not needed. */
+ if (gimple_call_internal_p (stmt)
+ && gimple_call_internal_fn (stmt) == IFN_GOMP_SIMD_LANE)
+ remove_dead_stmt (&gsi, bb);
}
+ else if (gimple_call_internal_p (stmt))
+ switch (gimple_call_internal_fn (stmt))
+ {
+ case IFN_ADD_OVERFLOW:
+ maybe_optimize_arith_overflow (&gsi, PLUS_EXPR);
+ break;
+ case IFN_SUB_OVERFLOW:
+ maybe_optimize_arith_overflow (&gsi, MINUS_EXPR);
+ break;
+ case IFN_MUL_OVERFLOW:
+ maybe_optimize_arith_overflow (&gsi, MULT_EXPR);
+ break;
+ default:
+ break;
+ }
}
}
}
- VEC_free (basic_block, heap, h);
+ h.release ();
/* Since we don't track liveness of virtual PHI nodes, it is possible that we
rendered some PHI nodes unreachable while they are still in use.
find_unreachable_blocks ();
/* Delete all unreachable basic blocks in reverse dominator order. */
- for (bb = EXIT_BLOCK_PTR->prev_bb; bb != ENTRY_BLOCK_PTR; bb = prev_bb)
+ for (bb = EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb;
+ bb != ENTRY_BLOCK_PTR_FOR_FN (cfun); bb = prev_bb)
{
prev_bb = bb->prev_bb;
- if (!TEST_BIT (bb_contains_live_stmts, bb->index)
+ if (!bitmap_bit_p (bb_contains_live_stmts, bb->index)
|| !(bb->flags & BB_REACHABLE))
{
- for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
- if (!is_gimple_reg (gimple_phi_result (gsi_stmt (gsi))))
+ for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
+ gsi_next (&gsi))
+ if (virtual_operand_p (gimple_phi_result (gsi.phi ())))
{
bool found = false;
imm_use_iterator iter;
- FOR_EACH_IMM_USE_STMT (stmt, iter, gimple_phi_result (gsi_stmt (gsi)))
+ FOR_EACH_IMM_USE_STMT (stmt, iter,
+ gimple_phi_result (gsi.phi ()))
{
if (!(gimple_bb (stmt)->flags & BB_REACHABLE))
continue;
}
}
if (found)
- mark_virtual_phi_result_for_renaming (gsi_stmt (gsi));
+ mark_virtual_phi_result_for_renaming (gsi.phi ());
}
if (!(bb->flags & BB_REACHABLE))
{
h = get_all_dominated_blocks (CDI_DOMINATORS, bb);
- while (VEC_length (basic_block, h))
+ while (h.length ())
{
- bb = VEC_pop (basic_block, h);
+ bb = h.pop ();
prev_bb = bb->prev_bb;
/* Rearrangements to the CFG may have failed
to update the dominators tree, so that
delete_basic_block (bb);
}
- VEC_free (basic_block, heap, h);
+ h.release ();
}
}
}
}
}
- FOR_EACH_BB (bb)
+ FOR_EACH_BB_FN (bb, cfun)
{
/* Remove dead PHI nodes. */
something_changed |= remove_dead_phis (bb);
if (aggressive)
{
- int i;
-
- control_dependence_map = XNEWVEC (bitmap, last_basic_block);
- for (i = 0; i < last_basic_block; ++i)
- control_dependence_map[i] = BITMAP_ALLOC (NULL);
-
- last_stmt_necessary = sbitmap_alloc (last_basic_block);
- sbitmap_zero (last_stmt_necessary);
- bb_contains_live_stmts = sbitmap_alloc (last_basic_block);
- sbitmap_zero (bb_contains_live_stmts);
+ last_stmt_necessary = sbitmap_alloc (last_basic_block_for_fn (cfun));
+ bitmap_clear (last_stmt_necessary);
+ bb_contains_live_stmts = sbitmap_alloc (last_basic_block_for_fn (cfun));
+ bitmap_clear (bb_contains_live_stmts);
}
processed = sbitmap_alloc (num_ssa_names + 1);
- sbitmap_zero (processed);
+ bitmap_clear (processed);
- worklist = VEC_alloc (gimple, heap, 64);
+ worklist.create (64);
cfg_altered = false;
}
{
if (aggressive)
{
- int i;
-
- for (i = 0; i < last_basic_block; ++i)
- BITMAP_FREE (control_dependence_map[i]);
- free (control_dependence_map);
-
+ delete cd;
sbitmap_free (visited_control_parents);
sbitmap_free (last_stmt_necessary);
sbitmap_free (bb_contains_live_stmts);
sbitmap_free (processed);
- VEC_free (gimple, heap, worklist);
+ worklist.release ();
}
/* Main routine to eliminate dead code.
static unsigned int
perform_tree_ssa_dce (bool aggressive)
{
- struct edge_list *el = NULL;
bool something_changed = 0;
calculate_dominance_info (CDI_DOMINATORS);
if (aggressive)
{
/* Compute control dependence. */
- timevar_push (TV_CONTROL_DEPENDENCES);
calculate_dominance_info (CDI_POST_DOMINATORS);
- el = create_edge_list ();
- find_all_control_dependences (el);
- timevar_pop (TV_CONTROL_DEPENDENCES);
+ cd = new control_dependences (create_edge_list ());
- visited_control_parents = sbitmap_alloc (last_basic_block);
- sbitmap_zero (visited_control_parents);
+ visited_control_parents =
+ sbitmap_alloc (last_basic_block_for_fn (cfun));
+ bitmap_clear (visited_control_parents);
mark_dfs_back_edges ();
}
- find_obviously_necessary_stmts (el);
+ find_obviously_necessary_stmts (aggressive);
if (aggressive)
loop_optimizer_finalize ();
nr_walks = 0;
chain_ovfl = false;
visited = BITMAP_ALLOC (NULL);
- propagate_necessity (el);
+ propagate_necessity (aggressive);
BITMAP_FREE (visited);
something_changed |= eliminate_unnecessary_stmts ();
tree_dce_done (aggressive);
- free_edge_list (el);
-
if (something_changed)
- return (TODO_update_ssa | TODO_cleanup_cfg | TODO_ggc_collect
- | TODO_remove_unused_locals);
- else
- return 0;
+ {
+ free_numbers_of_iterations_estimates ();
+ if (scev_initialized_p ())
+ scev_reset ();
+ return TODO_update_ssa | TODO_cleanup_cfg;
+ }
+ return 0;
}
/* Pass entry points. */
return perform_tree_ssa_dce (/*aggressive=*/false);
}
-static unsigned int
-tree_ssa_dce_loop (void)
-{
- unsigned int todo;
- todo = perform_tree_ssa_dce (/*aggressive=*/false);
- if (todo)
- {
- free_numbers_of_iterations_estimates ();
- scev_reset ();
- }
- return todo;
-}
-
static unsigned int
tree_ssa_cd_dce (void)
{
return perform_tree_ssa_dce (/*aggressive=*/optimize >= 2);
}
-static bool
-gate_dce (void)
+namespace {
+
+const pass_data pass_data_dce =
+{
+ GIMPLE_PASS, /* type */
+ "dce", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ TV_TREE_DCE, /* tv_id */
+ ( PROP_cfg | PROP_ssa ), /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ 0, /* todo_flags_finish */
+};
+
+class pass_dce : public gimple_opt_pass
+{
+public:
+ pass_dce (gcc::context *ctxt)
+ : gimple_opt_pass (pass_data_dce, ctxt)
+ {}
+
+ /* opt_pass methods: */
+ opt_pass * clone () { return new pass_dce (m_ctxt); }
+ virtual bool gate (function *) { return flag_tree_dce != 0; }
+ virtual unsigned int execute (function *) { return tree_ssa_dce (); }
+
+}; // class pass_dce
+
+} // anon namespace
+
+gimple_opt_pass *
+make_pass_dce (gcc::context *ctxt)
{
- return flag_tree_dce != 0;
+ return new pass_dce (ctxt);
}
-struct gimple_opt_pass pass_dce =
+namespace {
+
+const pass_data pass_data_cd_dce =
{
- {
- GIMPLE_PASS,
- "dce", /* name */
- gate_dce, /* gate */
- tree_ssa_dce, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_TREE_DCE, /* tv_id */
- PROP_cfg | PROP_ssa, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_verify_ssa /* todo_flags_finish */
- }
+ GIMPLE_PASS, /* type */
+ "cddce", /* name */
+ OPTGROUP_NONE, /* optinfo_flags */
+ TV_TREE_CD_DCE, /* tv_id */
+ ( PROP_cfg | PROP_ssa ), /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ 0, /* todo_flags_finish */
};
-struct gimple_opt_pass pass_dce_loop =
+class pass_cd_dce : public gimple_opt_pass
{
- {
- GIMPLE_PASS,
- "dceloop", /* name */
- gate_dce, /* gate */
- tree_ssa_dce_loop, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_TREE_DCE, /* tv_id */
- PROP_cfg | PROP_ssa, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_verify_ssa /* todo_flags_finish */
- }
-};
+public:
+ pass_cd_dce (gcc::context *ctxt)
+ : gimple_opt_pass (pass_data_cd_dce, ctxt)
+ {}
-struct gimple_opt_pass pass_cd_dce =
+ /* opt_pass methods: */
+ opt_pass * clone () { return new pass_cd_dce (m_ctxt); }
+ virtual bool gate (function *) { return flag_tree_dce != 0; }
+ virtual unsigned int execute (function *) { return tree_ssa_cd_dce (); }
+
+}; // class pass_cd_dce
+
+} // anon namespace
+
+gimple_opt_pass *
+make_pass_cd_dce (gcc::context *ctxt)
{
- {
- GIMPLE_PASS,
- "cddce", /* name */
- gate_dce, /* gate */
- tree_ssa_cd_dce, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_TREE_CD_DCE, /* tv_id */
- PROP_cfg | PROP_ssa, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_verify_ssa
- | TODO_verify_flow /* todo_flags_finish */
- }
-};
+ return new pass_cd_dce (ctxt);
+}
projects / gcc.git / blobdiff