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tree-ssa-dom.c (dom_valueize): New function.

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2015-07-16  Richard Biener  <rguenther@suse.de>

	* tree-ssa-dom.c (dom_valueize): New function.
	(record_temporary_equivalences): Also record equivalences
	for dominating stmts that have uses of equivalences we are
	about to record.

From-SVN: r225860
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Richard Biener 2015-07-16 07:19:24 +00:00 • committed by Richard Biener
parent 4c3b378b5a
commit 612b9d1364
2 changed files with 56 additions and 1 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2015-07-16 Richard Biener <rguenther@suse.de>
* tree-ssa-dom.c (dom_valueize): New function.
(record_temporary_equivalences): Also record equivalences
for dominating stmts that have uses of equivalences we are
about to record.
2015-07-16 Bin Cheng <bin.cheng@arm.com>
* tree-ssa-loop-ivopts.c (add_candidate): Remove call to

50
gcc/tree-ssa-dom.c
View file

@ -1401,6 +1401,20 @@ simplify_stmt_for_jump_threading (gimple stmt,
return lookup_avail_expr (stmt, false);
}
/* Valueize hook for gimple_fold_stmt_to_constant_1. */
static tree
dom_valueize (tree t)
{
if (TREE_CODE (t) == SSA_NAME)
{
tree tem = SSA_NAME_VALUE (t);
if (tem)
return tem;
}
return t;
}
/* Record into the equivalence tables any equivalences implied by
traversing edge E (which are cached in E->aux).
@ -1428,7 +1442,6 @@ record_temporary_equivalences (edge e)
additional equivalences. */
if (lhs
&& TREE_CODE (lhs) == SSA_NAME
&& is_gimple_constant (rhs)
&& TREE_CODE (rhs) == INTEGER_CST)
{
gimple defstmt = SSA_NAME_DEF_STMT (lhs);
@ -1456,6 +1469,41 @@ record_temporary_equivalences (edge e)
}
}
/* If LHS is an SSA_NAME with a new equivalency then try if
stmts with uses of that LHS that dominate the edge destination
simplify and allow further equivalences to be recorded. */
if (lhs && TREE_CODE (lhs) == SSA_NAME)
{
use_operand_p use_p;
imm_use_iterator iter;
FOR_EACH_IMM_USE_FAST (use_p, iter, lhs)
{
gimple use_stmt = USE_STMT (use_p);
/* Only bother to record more equivalences for lhs that
can be directly used by e->dest.
??? If the code gets re-organized to a worklist to
catch more indirect opportunities and it is made to
handle PHIs then this should only consider use_stmts
in basic-blocks we have already visited. */
if (e->dest == gimple_bb (use_stmt)
|| !dominated_by_p (CDI_DOMINATORS,
e->dest, gimple_bb (use_stmt)))
continue;
tree lhs2 = gimple_get_lhs (use_stmt);
if (lhs2 && TREE_CODE (lhs2) == SSA_NAME)
{
tree res
= gimple_fold_stmt_to_constant_1 (use_stmt, dom_valueize,
no_follow_ssa_edges);
if (res
&& (TREE_CODE (res) == SSA_NAME
|| is_gimple_min_invariant (res)))
record_equality (lhs2, res);
}
}
}
/* If we have 0 = COND or 1 = COND equivalences, record them
into our expression hash tables. */
for (i = 0; edge_info->cond_equivalences.iterate (i, &eq); ++i)