https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118558

            Bug ID: 118558
           Summary: csmith: another runtime error with march=znver3
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

Created attachment 60207
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=60207&action=edit
C source code

The attached C source code, generated by csmith, does this:

foundBugs $ ~/gcc/results/bin/gcc -w bug1076.c
foundBugs $ ./a.out 1 | grep g_256
...checksum after hashing g_256[i] : 991033EB
...checksum after hashing g_256[i] : 79991091
...checksum after hashing g_256[i] : AB373C07
foundBugs $ ~/gcc/results/bin/gcc -w -O1 bug1076.c
foundBugs $ ./a.out 1 | grep g_256
...checksum after hashing g_256[i] : 991033EB
...checksum after hashing g_256[i] : 79991091
...checksum after hashing g_256[i] : AB373C07
foundBugs $ ~/gcc/results/bin/gcc -w -O2 bug1076.c
foundBugs $ ./a.out 1 | grep g_256
...checksum after hashing g_256[i] : 991033EB
...checksum after hashing g_256[i] : 79991091
...checksum after hashing g_256[i] : AB373C07
foundBugs $ ~/gcc/results/bin/gcc -w -O3 bug1076.c
foundBugs $ ./a.out 1 | grep g_256
...checksum after hashing g_256[i] : 991033EB
...checksum after hashing g_256[i] : 79991091
...checksum after hashing g_256[i] : AB373C07
foundBugs $ ~/gcc/results/bin/gcc -w -O3 -march=znver3 bug1076.c
foundBugs $ ./a.out 1 | grep g_256
...checksum after hashing g_256[i] : D02808C8
...checksum after hashing g_256[i] : 19CE3B74
...checksum after hashing g_256[i] : 25043566
foundBugs $ 

Adding -march=znver3 seems to cause problems.
I have a reduction running. 

The problem first seems to appear sometime before 20241218:

foundBugs $ ~/gcc/results.20241218.asan.ubsan/bin/gcc -w -O3 bug1076.c
foundBugs $ ./a.out 1 | grep g_256
...checksum after hashing g_256[i] : 991033EB
...checksum after hashing g_256[i] : 79991091
...checksum after hashing g_256[i] : AB373C07
foundBugs $ ~/gcc/results.20241218.asan.ubsan/bin/gcc -w -O3 -march=znver3
bug1076.c
foundBugs $ ./a.out 1 | grep g_256
...checksum after hashing g_256[i] : D02808C8
...checksum after hashing g_256[i] : 19CE3B74
...checksum after hashing g_256[i] : 25043566
foundBugs $

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