#include "tm.h"
#include "tree.h"
#include "tm_p.h"
+#include "predict.h"
+#include "vec.h"
+#include "hashtab.h"
+#include "hash-set.h"
+#include "machmode.h"
+#include "hard-reg-set.h"
+#include "input.h"
+#include "function.h"
+#include "dominance.h"
+#include "cfg.h"
#include "basic-block.h"
#include "gimple-pretty-print.h"
#include "bitmap.h"
/* A helper of dse_optimize_stmt.
- Given a GIMPLE_ASSIGN in STMT, find a candidate statement *USE_STMT that
- may prove STMT to be dead.
+ Given a GIMPLE_ASSIGN in STMT that writes to REF, find a candidate
+ statement *USE_STMT that may prove STMT to be dead.
Return TRUE if the above conditions are met, otherwise FALSE. */
static bool
-dse_possible_dead_store_p (gimple stmt, gimple *use_stmt)
+dse_possible_dead_store_p (ao_ref *ref, gimple stmt, gimple *use_stmt)
{
gimple temp;
unsigned cnt = 0;
*use_stmt = NULL;
- /* Self-assignments are zombies. */
- if (operand_equal_p (gimple_assign_rhs1 (stmt), gimple_assign_lhs (stmt), 0))
- {
- *use_stmt = stmt;
- return true;
- }
-
/* Find the first dominated statement that clobbers (part of) the
memory stmt stores to with no intermediate statement that may use
part of the memory stmt stores. That is, find a store that may
temp = use_stmt;
}
/* If the statement is a use the store is not dead. */
- else if (ref_maybe_used_by_stmt_p (use_stmt,
- gimple_assign_lhs (stmt)))
+ else if (ref_maybe_used_by_stmt_p (use_stmt, ref))
{
fail = true;
BREAK_FROM_IMM_USE_STMT (ui);
just pretend the stmt makes itself dead. Otherwise fail. */
if (!temp)
{
- if (stmt_may_clobber_global_p (stmt))
+ if (ref_may_alias_global_p (ref))
return false;
temp = stmt;
break;
}
}
- /* We deliberately stop on clobbering statements and not only on
- killing ones to make walking cheaper. Otherwise we can just
- continue walking until both stores have equal reference trees. */
- while (!stmt_may_clobber_ref_p (temp, gimple_assign_lhs (stmt)));
+ /* Continue walking until we reach a kill. */
+ while (!stmt_kills_ref_p (temp, ref));
*use_stmt = temp;
if (!gimple_vdef (stmt))
return;
- /* We know we have virtual definitions. If this is a GIMPLE_ASSIGN
- that's not also a function call, then record it into our table. */
- if (is_gimple_call (stmt) && gimple_call_fndecl (stmt))
- return;
-
/* Don't return early on *this_2(D) ={v} {CLOBBER}. */
if (gimple_has_volatile_ops (stmt)
&& (!gimple_clobber_p (stmt)
|| TREE_CODE (gimple_assign_lhs (stmt)) != MEM_REF))
return;
+ /* We know we have virtual definitions. We can handle assignments and
+ some builtin calls. */
+ if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
+ {
+ switch (DECL_FUNCTION_CODE (gimple_call_fndecl (stmt)))
+ {
+ case BUILT_IN_MEMCPY:
+ case BUILT_IN_MEMMOVE:
+ case BUILT_IN_MEMSET:
+ {
+ gimple use_stmt;
+ ao_ref ref;
+ tree size = NULL_TREE;
+ if (gimple_call_num_args (stmt) == 3)
+ size = gimple_call_arg (stmt, 2);
+ tree ptr = gimple_call_arg (stmt, 0);
+ ao_ref_init_from_ptr_and_size (&ref, ptr, size);
+ if (!dse_possible_dead_store_p (&ref, stmt, &use_stmt))
+ return;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, " Deleted dead call '");
+ print_gimple_stmt (dump_file, gsi_stmt (*gsi), dump_flags, 0);
+ fprintf (dump_file, "'\n");
+ }
+
+ tree lhs = gimple_call_lhs (stmt);
+ if (lhs)
+ {
+ gimple new_stmt = gimple_build_assign (lhs, ptr);
+ unlink_stmt_vdef (stmt);
+ if (gsi_replace (gsi, new_stmt, true))
+ bitmap_set_bit (need_eh_cleanup, gimple_bb (stmt)->index);
+ }
+ else
+ {
+ /* Then we need to fix the operand of the consuming stmt. */
+ unlink_stmt_vdef (stmt);
+
+ /* Remove the dead store. */
+ if (gsi_remove (gsi, true))
+ bitmap_set_bit (need_eh_cleanup, gimple_bb (stmt)->index);
+ }
+ break;
+ }
+ default:
+ return;
+ }
+ }
+
if (is_gimple_assign (stmt))
{
gimple use_stmt;
- if (!dse_possible_dead_store_p (stmt, &use_stmt))
- return;
+ /* Self-assignments are zombies. */
+ if (operand_equal_p (gimple_assign_rhs1 (stmt),
+ gimple_assign_lhs (stmt), 0))
+ use_stmt = stmt;
+ else
+ {
+ ao_ref ref;
+ ao_ref_init (&ref, gimple_assign_lhs (stmt));
+ if (!dse_possible_dead_store_p (&ref, stmt, &use_stmt))
+ return;
+ }
+
+ /* Now we know that use_stmt kills the LHS of stmt. */
/* But only remove *this_2(D) ={v} {CLOBBER} if killed by
another clobber stmt. */
&& !gimple_clobber_p (use_stmt))
return;
- /* If we have precisely one immediate use at this point and the
- stores are to the same memory location or there is a chain of
- virtual uses from stmt and the stmt which stores to that same
- memory location, then we may have found redundant store. */
- if ((gimple_has_lhs (use_stmt)
- && (operand_equal_p (gimple_assign_lhs (stmt),
- gimple_get_lhs (use_stmt), 0)))
- || stmt_kills_ref_p (use_stmt, gimple_assign_lhs (stmt)))
+ if (dump_file && (dump_flags & TDF_DETAILS))
{
- basic_block bb;
-
- /* If use_stmt is or might be a nop assignment, e.g. for
- struct { ... } S a, b, *p; ...
- b = a; b = b;
- or
- b = a; b = *p; where p might be &b,
- or
- *p = a; *p = b; where p might be &b,
- or
- *p = *u; *p = *v; where p might be v, then USE_STMT
- acts as a use as well as definition, so store in STMT
- is not dead. */
- if (stmt != use_stmt
- && ref_maybe_used_by_stmt_p (use_stmt, gimple_assign_lhs (stmt)))
- return;
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, " Deleted dead store '");
- print_gimple_stmt (dump_file, gsi_stmt (*gsi), dump_flags, 0);
- fprintf (dump_file, "'\n");
- }
+ fprintf (dump_file, " Deleted dead store '");
+ print_gimple_stmt (dump_file, gsi_stmt (*gsi), dump_flags, 0);
+ fprintf (dump_file, "'\n");
+ }
- /* Then we need to fix the operand of the consuming stmt. */
- unlink_stmt_vdef (stmt);
+ /* Then we need to fix the operand of the consuming stmt. */
+ unlink_stmt_vdef (stmt);
- /* Remove the dead store. */
- bb = gimple_bb (stmt);
- if (gsi_remove (gsi, true))
- bitmap_set_bit (need_eh_cleanup, bb->index);
+ /* Remove the dead store. */
+ basic_block bb = gimple_bb (stmt);
+ if (gsi_remove (gsi, true))
+ bitmap_set_bit (need_eh_cleanup, bb->index);
- /* And release any SSA_NAMEs set in this statement back to the
- SSA_NAME manager. */
- release_defs (stmt);
- }
+ /* And release any SSA_NAMEs set in this statement back to the
+ SSA_NAME manager. */
+ release_defs (stmt);
}
}
GIMPLE_PASS, /* type */
"dse", /* name */
OPTGROUP_NONE, /* optinfo_flags */
- true, /* has_execute */
TV_TREE_DSE, /* tv_id */
( PROP_cfg | PROP_ssa ), /* properties_required */
0, /* properties_provided */
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