diff mbox series

[pushed] aarch64: Tweak atomic-inst-cas.c options

Message ID mpt7d9vqfco.fsf@arm.com
State Committed
Commit f31924f72a99eaa9d4d1f7e0579152d8ecc0981e
Headers
Series [pushed] aarch64: Tweak atomic-inst-cas.c options |

Commit Message

Richard Sandiford Feb. 16, 2022, 10:24 a.m. UTC 
  atomic-inst-cas.c has code to skip __atomic_compare_exchange_n
calls for invalid memory orderings, but -Winvalid-memory-model
applies before the dead code is removed (which is the right
behaviour IMO).  This patch therefore suppresses the warning
for this test.

Tested on aarch64-linux-gnu & pushed.

Richard


gcc/testsuite/
	* gcc.target/aarch64/atomic-inst-cas.c: Add
	-Wno-invalid-memory-model.
---
 gcc/testsuite/gcc.target/aarch64/atomic-inst-cas.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Andrew Pinski Feb. 16, 2022, 5:38 p.m. UTC | #1 
On Wed, Feb 16, 2022 at 2:25 AM Richard Sandiford via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> atomic-inst-cas.c has code to skip __atomic_compare_exchange_n
> calls for invalid memory orderings, but -Winvalid-memory-model
> applies before the dead code is removed (which is the right
> behaviour IMO).  This patch therefore suppresses the warning
> for this test.

It is a bit more complex than that, see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104200#c3 for the reduced
testcase.
The undefined (invalid) arguments to __atomic_compare_exchange_n are
only after constant propagation really which is not done at -O0,
though the warning does it.
So the warning does constant propagation of the arguments but not if
it was conditionally executed.
Most likely waccess should do a similar thing like it was done for the
uninitialized warnings in
https://gcc.gnu.org/pipermail/gcc-patches/2022-February/589983.html .

Thanks,
Andrew Pinski

>
> Tested on aarch64-linux-gnu & pushed.
>
> Richard
>
>
> gcc/testsuite/
>         * gcc.target/aarch64/atomic-inst-cas.c: Add
>         -Wno-invalid-memory-model.
> ---
>  gcc/testsuite/gcc.target/aarch64/atomic-inst-cas.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-inst-cas.c b/gcc/testsuite/gcc.target/aarch64/atomic-inst-cas.c
> index f6f28922319..0b4533adade 100644
> --- a/gcc/testsuite/gcc.target/aarch64/atomic-inst-cas.c
> +++ b/gcc/testsuite/gcc.target/aarch64/atomic-inst-cas.c
> @@ -1,5 +1,7 @@
>  /* { dg-do compile } */
> -/* { dg-options "-O2 -march=armv8-a+lse" } */
> +/* -Winvalid-memory-model warnings are issued before the dead invalid calls
> +   are removed.  */
> +/* { dg-options "-O2 -march=armv8-a+lse -Wno-invalid-memory-model" } */
>
>  /* Test ARMv8.1-A CAS instruction.  */
>
> --
> 2.25.1
diff mbox series

Patch

diff --git a/gcc/testsuite/gcc.target/aarch64/atomic-inst-cas.c b/gcc/testsuite/gcc.target/aarch64/atomic-inst-cas.c
index f6f28922319..0b4533adade 100644
--- a/gcc/testsuite/gcc.target/aarch64/atomic-inst-cas.c
+++ b/gcc/testsuite/gcc.target/aarch64/atomic-inst-cas.c
@@ -1,5 +1,7 @@ 
 /* { dg-do compile } */
-/* { dg-options "-O2 -march=armv8-a+lse" } */
+/* -Winvalid-memory-model warnings are issued before the dead invalid calls
+   are removed.  */
+/* { dg-options "-O2 -march=armv8-a+lse -Wno-invalid-memory-model" } */
 
 /* Test ARMv8.1-A CAS instruction.  */