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re PR tree-optimization/71947 (x ^ y not folded to 0 if x == y by DOM)

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PR tree-optimization/71947
	* tree-ssa-dom.c (cprop_into_stmt): Avoid replacing A with B, then
	B with A within a single statement.

	PR tree-optimization/71947
	* gcc.dg/tree-ssa/pr71947-1.c: New test.
	* gcc.dg/tree-ssa/pr71947-2.c: New test.
	* gcc.dg/tree-ssa/pr71947-3.c: New test.
	* gcc.dg/tree-ssa/pr71947-4.c: New test.
	* gcc.dg/tree-ssa/pr71947-5.c: New test.
	* gcc.dg/tree-ssa/pr71947-6.c: New test.

From-SVN: r240947
This commit is contained in:
Jeff Law 2016-10-10 14:40:59 -06:00 • committed by Jeff Law
parent db62593447
commit d30078b8e7
9 changed files with 140 additions and 1 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2016-10-10 Jeff Law <law@redhat.com>
PR tree-optimization/71947
* tree-ssa-dom.c (cprop_into_stmt): Avoid replacing A with B, then
B with A within a single statement.
2016-10-10 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
PR tree-optimization/77824

10
gcc/testsuite/ChangeLog
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@ -1,3 +1,13 @@
2016-10-10 Jeff Law <law@redhat.com>
PR tree-optimization/71947
* gcc.dg/tree-ssa/pr71947-1.c: New test.
* gcc.dg/tree-ssa/pr71947-2.c: New test.
* gcc.dg/tree-ssa/pr71947-3.c: New test.
* gcc.dg/tree-ssa/pr71947-4.c: New test.
* gcc.dg/tree-ssa/pr71947-5.c: New test.
* gcc.dg/tree-ssa/pr71947-6.c: New test.
2016-10-10 Thomas Koenig <tkoenig@gcc.gnu.org>
PR fortran/77915

19
gcc/testsuite/gcc.dg/tree-ssa/pr71947-1.c Normal file
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@ -0,0 +1,19 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fno-tree-vrp -fdump-tree-dom-details" } */
int f(int x, int y)
{
int ret;
if (x == y)
ret = x ^ y;
else
ret = 1;
return ret;
}
/* { dg-final { scan-tree-dump "Folded to: ret_\[0-9\]+ = 0;" "dom2" } } */

16
gcc/testsuite/gcc.dg/tree-ssa/pr71947-2.c Normal file
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@ -0,0 +1,16 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fno-tree-vrp -fdump-tree-dom-details" } */
int f(int x, int y)
{
int ret;
if (x == y)
ret = x - y;
else
ret = 1;
return ret;
}
/* { dg-final { scan-tree-dump "Folded to: ret_\[0-9\]+ = 0;" "dom2" } } */

12
gcc/testsuite/gcc.dg/tree-ssa/pr71947-3.c Normal file
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@ -0,0 +1,12 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fno-tree-vrp -fdump-tree-dom-details" } */
int f(int x, int y)
{
int ret = 10;
if (x == y)
ret = x - y;
return ret;
}
/* { dg-final { scan-tree-dump "Folded to: ret_\[0-9\]+ = 0;" "dom2" } } */

22
gcc/testsuite/gcc.dg/tree-ssa/pr71947-4.c Normal file
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@ -0,0 +1,22 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fno-tree-vrp -fdump-tree-dom-details" } */
static inline long load(long *p)
{
long ret;
asm ("movq %1,%0\n\t" : "=r" (ret) : "m" (*p));
if (ret != *p)
__builtin_unreachable();
return ret;
}
long foo(long *mem)
{
long ret;
ret = load(mem);
return ret + *mem;
}
/* { dg-final { scan-tree-dump "Folded to: _\[0-9\]+ = _\[0-9\]+ \\* 2" "dom2" } } */

21
gcc/testsuite/gcc.dg/tree-ssa/pr71947-5.c Normal file
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@ -0,0 +1,21 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fno-tree-vrp -fdump-tree-dom-details" } */
static inline long load(long *p)
{
long ret;
asm ("movq %1,%0\n\t" : "=r" (ret) : "m" (*p));
if (ret != *p)
__builtin_unreachable();
return ret;
}
long foo(long *mem)
{
long ret;
ret = load(mem);
return ret - *mem;
}
/* { dg-final { scan-tree-dump "Folded to: _\[0-9\]+ = 0;" "dom2" } } */

16
gcc/testsuite/gcc.dg/tree-ssa/pr71947-6.c Normal file
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@ -0,0 +1,16 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fno-tree-vrp -fdump-tree-dom-details" } */
int f(int x, int y, int a, int b)
{
int ret = 10;
if (a == x
&& b == y
&& a == b)
ret = x - y;
return ret;
}
/* { dg-final { scan-tree-dump "Folded to: ret_\[0-9\]+ = 0;" "dom2" { xfail *-*-* } } } */

19
gcc/tree-ssa-dom.c
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@ -1731,9 +1731,26 @@ cprop_into_stmt (gimple *stmt)
{
use_operand_p op_p;
ssa_op_iter iter;
tree last_copy_propagated_op = NULL;
FOR_EACH_SSA_USE_OPERAND (op_p, stmt, iter, SSA_OP_USE)
cprop_operand (stmt, op_p);
{
tree old_op = USE_FROM_PTR (op_p);
/* If we have A = B and B = A in the copy propagation tables
(due to an equality comparison), avoid substituting B for A
then A for B in the trivially discovered cases. This allows
optimization of statements were A and B appear as input
operands. */
if (old_op != last_copy_propagated_op)
{
cprop_operand (stmt, op_p);
tree new_op = USE_FROM_PTR (op_p);
if (new_op != old_op && TREE_CODE (new_op) == SSA_NAME)
last_copy_propagated_op = new_op;
}
}
}
/* Optimize the statement in block BB pointed to by iterator SI