Re: [PATCH] [testsuite] Remove undefined behavior from gcc.dg/tree-ssa/pr44306.c

[Richard Biener <richard.guenther@gmail.com>]

> Am 25.09.2023 um 14:18 schrieb Aldy Hernandez <aldyh@redhat.com>:
> 
> In auditing the DOM code to see what the scoped tables catch that
> ranger doesn't, I've run accross this test, which seems to
> have uninitialized reads from both j and present[].
> 
> From the original PR, it looks like this came from a reduction of a
> failing test in SPEC's 464.h264ref.  A google search of the
> CalculateQuant8Param() in the test yields:
> 
> https://github.com/microsoft/test-suite/blob/master/MultiSource/Applications/JM/lencod/q_matrix.c
> 
> Assuming the above source is similar to the original testcase, it looks
> like both "j" and "present" were initialized before use, so our testcase
> just got reduced a bit too far.
> 
> I tried to build the offending commit to see if my adjustments to the
> test still caused it to fail:
> 
> commit e1449456c0a88f5b3122db5452f7e91f5a9535f6 (HEAD -> master)
> Author: Sebastian Pop <sebastian.pop@amd.com>
> Date:   Wed May 26 16:46:59 2010 +0000
> 
>    Reorganize the analysis of basic block predication.
> 
> ...but alas it no longer builds with a recent compiler.  Perhaps
> someone has a ./cc1 of that revision around to verify?
> 
> OK?

Ok


> gcc/testsuite/ChangeLog:
> 
>    * gcc.dg/tree-ssa/pr44306.c: Remove undefined behavior.
> ---
> gcc/testsuite/gcc.dg/tree-ssa/pr44306.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr44306.c b/gcc/testsuite/gcc.dg/tree-ssa/pr44306.c
> index 1ea04ce3a98..d322fe048b5 100644
> --- a/gcc/testsuite/gcc.dg/tree-ssa/pr44306.c
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr44306.c
> @@ -8,10 +8,10 @@ int LevelScale8x8Luma_Inter[6][8][8];
> int InvLevelScale8x8Luma_Intra[6][8][8];
> int InvLevelScale8x8Luma_Inter[6][8][8];
> short UseDefaultScalingMatrix8x8Flag[2];
> -void CalculateQuant8Param()
> +int present[2];
> +void CalculateQuant8Param(int j)
> {
> - int i, j, k, temp;
> - int present[2];
> + int i, k, temp;
>  for(k=0; j<8; j++)
>    for(i=0; i<8; i++)
>      {
> -- 
> 2.41.0
>