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From: "dcb314 at hotmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/109780] New: csmith: runtime crash with -O2 -march=znver1
Date: Mon, 08 May 2023 20:35:21 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109780

            Bug ID: 109780
           Summary: csmith: runtime crash with -O2 -march=3Dznver1
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

Created attachment 55023
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D55023&action=3Dedit
C source code

The attached C code seems to work fine with -O2:

$ ../results.20230507.asan.ubsan/bin/gcc -w -O2  bug916.c
$ ./a.out
checksum =3D 44DCF65B
$=20

But adding -march=3Dznver1 seems to cause trouble:

$ ../results.20230507.asan.ubsan/bin/gcc -w -O2 -march=3Dznver1  bug916.c
$ ./a.out
Segmentation fault (core dumped)
$=20

Adding the -fno-strict-aliasing flag doesn't seem to help:

$ ../results.20230507.asan.ubsan/bin/gcc -w -O2 -march=3Dznver1
-fno-strict-aliasing  bug916.c
$ ./a.out
Segmentation fault (core dumped)
$=20

The bug seems to have existed for a while:

$ ../results.20230417/bin/gcc -w -O2 -march=3Dznver1 -fno-strict-aliasing=20
bug916.c
$ ./a.out
Segmentation fault (core dumped)
$=