* [PATCH] Fix neg overflow expansion (PR middle-end/77594)
@ 2016-09-15 23:10 Jakub Jelinek
2016-09-16 5:59 ` Richard Biener
0 siblings, 1 reply; 2+ messages in thread
From: Jakub Jelinek @ 2016-09-15 23:10 UTC (permalink / raw)
To: Richard Biener; +Cc: gcc-patches
Hi!
As mentioned in the PR, during expand_arith_overflow expansion
expand_neg_overflow falls through into expand_addsub_overflow, so expands
roughly the same code twice and keeps perhaps the less efficient version
around.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?
2016-09-16 Jakub Jelinek <jakub@redhat.com>
Eric Botcazou <ebotcazou@adacore.com>
PR middle-end/77594
* internal-fn.c (expand_arith_overflow) <case MINUS_EXPR>: Don't fall
through into expand_addsub_overflow after expand_neg_overflow.
* gcc.target/i386/pr77594.c: New test.
--- gcc/internal-fn.c.jj 2016-08-29 12:17:14.000000000 +0200
+++ gcc/internal-fn.c 2016-09-15 09:42:09.693980531 +0200
@@ -1833,7 +1833,10 @@ expand_arith_overflow (enum tree_code co
{
case MINUS_EXPR:
if (integer_zerop (arg0) && !unsr_p)
- expand_neg_overflow (loc, lhs, arg1, false);
+ {
+ expand_neg_overflow (loc, lhs, arg1, false);
+ return;
+ }
/* FALLTHRU */
case PLUS_EXPR:
expand_addsub_overflow (loc, code, lhs, arg0, arg1,
--- gcc/testsuite/gcc.target/i386/pr77594.c.jj 2016-09-15 09:44:51.879910346 +0200
+++ gcc/testsuite/gcc.target/i386/pr77594.c 2016-09-15 09:44:43.000000000 +0200
@@ -0,0 +1,11 @@
+/* PR middle-end/77594 */
+/* { dg-do compile } */
+/* { dg-options "-O0" } */
+
+int
+foo (int a, int *b)
+{
+ return __builtin_sub_overflow (0, a, b);
+}
+
+/* { dg-final { scan-assembler-times "\tjn?o\t" 1 } } */
Jakub
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] Fix neg overflow expansion (PR middle-end/77594)
2016-09-15 23:10 [PATCH] Fix neg overflow expansion (PR middle-end/77594) Jakub Jelinek
@ 2016-09-16 5:59 ` Richard Biener
0 siblings, 0 replies; 2+ messages in thread
From: Richard Biener @ 2016-09-16 5:59 UTC (permalink / raw)
To: Jakub Jelinek; +Cc: gcc-patches
On September 16, 2016 12:48:04 AM GMT+02:00, Jakub Jelinek <jakub@redhat.com> wrote:
>Hi!
>
>As mentioned in the PR, during expand_arith_overflow expansion
>expand_neg_overflow falls through into expand_addsub_overflow, so
>expands
>roughly the same code twice and keeps perhaps the less efficient
>version
>around.
>
>Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok
>for
>trunk?
OK (really obvious).
Thanks,
Richard.
>2016-09-16 Jakub Jelinek <jakub@redhat.com>
> Eric Botcazou <ebotcazou@adacore.com>
>
> PR middle-end/77594
> * internal-fn.c (expand_arith_overflow) <case MINUS_EXPR>: Don't fall
> through into expand_addsub_overflow after expand_neg_overflow.
>
> * gcc.target/i386/pr77594.c: New test.
>
>--- gcc/internal-fn.c.jj 2016-08-29 12:17:14.000000000 +0200
>+++ gcc/internal-fn.c 2016-09-15 09:42:09.693980531 +0200
>@@ -1833,7 +1833,10 @@ expand_arith_overflow (enum tree_code co
> {
> case MINUS_EXPR:
> if (integer_zerop (arg0) && !unsr_p)
>- expand_neg_overflow (loc, lhs, arg1, false);
>+ {
>+ expand_neg_overflow (loc, lhs, arg1, false);
>+ return;
>+ }
> /* FALLTHRU */
> case PLUS_EXPR:
> expand_addsub_overflow (loc, code, lhs, arg0, arg1,
>--- gcc/testsuite/gcc.target/i386/pr77594.c.jj 2016-09-15
>09:44:51.879910346 +0200
>+++ gcc/testsuite/gcc.target/i386/pr77594.c 2016-09-15
>09:44:43.000000000 +0200
>@@ -0,0 +1,11 @@
>+/* PR middle-end/77594 */
>+/* { dg-do compile } */
>+/* { dg-options "-O0" } */
>+
>+int
>+foo (int a, int *b)
>+{
>+ return __builtin_sub_overflow (0, a, b);
>+}
>+
>+/* { dg-final { scan-assembler-times "\tjn?o\t" 1 } } */
>
> Jakub
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