On Sat, Mar 28, 2026 at 10:05 PM Alexandre Oliva <[email protected]> wrote:
>
>
> gcc.dg/fstack-protector-strong.c used to expect one stack_chk_fail per
> function. When vectorizer improvements caused foo2 to get vectorized
> to the point of enabling the loop and the automatic array-containing
> data structure to be optimized away entirely, it no longer required
> stack protection, and the expected pattern count was decreased.
>
> However, on platforms that don't or can't vectorize the loop, it isn't
> optimized away, and then we find the wrong pattern count.
>
> Reverse the decrease and disable optimizations of the loop that could
> cause it to be optimized out, so that we get the originally-expected
> stack protection everywhere.
Ok for trunk and 15.
Thanks,
Andrew
>
>
> for gcc/testsuite/ChangeLog
>
> * gcc.dg/fstack-protector-strong.c (foo2): Prevent loop
> optimizations. Expect stack protection again.
> ---
> gcc/testsuite/gcc.dg/fstack-protector-strong.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/testsuite/gcc.dg/fstack-protector-strong.c
> b/gcc/testsuite/gcc.dg/fstack-protector-strong.c
> index b9f63966b7ccc..52485b5252ddb 100644
> --- a/gcc/testsuite/gcc.dg/fstack-protector-strong.c
> +++ b/gcc/testsuite/gcc.dg/fstack-protector-strong.c
> @@ -43,6 +43,8 @@ foo2 ()
> {
> struct AA aa;
> int i;
> +#pragma GCC novector
> +#pragma GCC unroll 0
> for (i = 0; i < 10; ++i)
> {
> aa.as.array[i] = i * (i-1) + i / 2;
> @@ -154,4 +156,4 @@ void foo12 ()
> global3 ();
> }
>
> -/* { dg-final { scan-assembler-times "stack_chk_fail" 11 } } */
> +/* { dg-final { scan-assembler-times "stack_chk_fail" 12 } } */
>
> --
> Alexandre Oliva, happy hacker https://blog.lx.oliva.nom.br/
> Free Software Activist FSFLA co-founder GNU Toolchain Engineer
> More tolerance and less prejudice are key for inclusion and diversity.
> Excluding neuro-others for not behaving ""normal"" is *not* inclusive!
