[Bug c/108718] New: csmith: possible bad code with -O2

[dcb314 at hotmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108718

            Bug ID: 108718
           Summary: csmith: possible bad code with -O2
           Product: gcc
           Version: 13.0
            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 54432
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54432&action=edit
C source code

The attached C code, produced by csmith, does this:

$ ../results/bin/gcc -w -O1 bug883.c && ./a.out
checksum = 7A94E377
$ ../results/bin/gcc -w -O2 bug883.c && ./a.out
checksum = 842F1622
$ 

The bug seems to exist since sometime before 20220703

$ ../results.20220703/bin/gcc -w -O2 bug883.c && ./a.out
checksum = 842F1622
$ 

I will have a go at a reduction.