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re PR tree-optimization/72772 (Missed SCEV after pass reordering@236440)

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PR tree-optimization/72772
	* tree-ssa-loop-niter.c (loop_exits_before_overflow): Check equality
	for expanded base.

	gcc/testsuite
	PR tree-optimization/pr72772
	* gcc.dg/tree-ssa/pr72772.c: New test.

From-SVN: r239291
This commit is contained in:
Bin Cheng 2016-08-09 15:08:02 +00:00 • committed by Bin Cheng
parent 8aa46dd2d5
commit 42970a179d
4 changed files with 47 additions and 8 deletions
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6
gcc/ChangeLog
View file

@ -1,3 +1,9 @@
2016-08-09 Bin Cheng <bin.cheng@arm.com>
PR tree-optimization/72772
* tree-ssa-loop-niter.c (loop_exits_before_overflow): Check equality
for expanded base.
2016-08-09 Bin Cheng <bin.cheng@arm.com>
PR tree-optimization/72772

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2016-08-09 Bin Cheng <bin.cheng@arm.com>
PR tree-optimization/pr72772
* gcc.dg/tree-ssa/pr72772.c: New test.
2016-08-09 Matthew Fortune <matthew.fortune@imgtec.com>
PR rtl-optimization/66669

21
gcc/testsuite/gcc.dg/tree-ssa/pr72772.c Normal file
View file

@ -0,0 +1,21 @@
/* { dg-do compile } */
/* { dg-options "-O2 -ftree-loop-distribution -fdump-tree-ldist-details" } */
int foo (int flag, char *a)
{
short i, j;
short l = 0;
if (flag == 1)
l = 3;
for (i = 0; i < 4; i++)
{
for (j = l - 1; j > 0; j--)
a[j] = a[j - 1];
a[0] = i;
}
}
/* Addresses of array reference a[j] and a[j - 1] are SCEVs. */
/* { dg-final { scan-tree-dump-not "failed: evolution of base is not affine." "ldist" } } */

23
gcc/tree-ssa-loop-niter.c
View file

@ -4214,7 +4214,7 @@ loop_exits_before_overflow (tree base, tree step,
for (civ = loop->control_ivs; civ; civ = civ->next)
{
enum tree_code code;
tree stepped, extreme, civ_type = TREE_TYPE (civ->step);
tree civ_type = TREE_TYPE (civ->step);
/* Have to consider type difference because operand_equal_p ignores
that for constants. */
@ -4227,11 +4227,13 @@ loop_exits_before_overflow (tree base, tree step,
continue;
/* Done proving if this is a no-overflow control IV. */
if (operand_equal_p (base, civ->base, 0)
/* Control IV is recorded after expanding simple operations,
Here we compare it against expanded base too. */
|| operand_equal_p (expand_simple_operations (base),
civ->base, 0))
if (operand_equal_p (base, civ->base, 0))
return true;
/* Control IV is recorded after expanding simple operations,
Here we expand base and compare it too. */
tree expanded_base = expand_simple_operations (base);
if (operand_equal_p (expanded_base, civ->base, 0))
return true;
/* If this is a before stepping control IV, in other words, we have
@ -4253,9 +4255,14 @@ loop_exits_before_overflow (tree base, tree step,
else
code = PLUS_EXPR;
stepped = fold_build2 (code, TREE_TYPE (base), base, step);
if (operand_equal_p (stepped, civ->base, 0))
tree stepped = fold_build2 (code, TREE_TYPE (base), base, step);
tree expanded_stepped = fold_build2 (code, TREE_TYPE (base),
expanded_base, step);
if (operand_equal_p (stepped, civ->base, 0)
|| operand_equal_p (expanded_stepped, civ->base, 0))
{
tree extreme;
if (tree_int_cst_sign_bit (step))
{
code = LT_EXPR;