[Bug analyzer/108666] New: -Wanalyzer-use-of-uninitialized-value false positives seen in coreutils's sum.c: bsd_sum_stream

[dmalcolm at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108666

            Bug ID: 108666
           Summary: -Wanalyzer-use-of-uninitialized-value false positives
                    seen in coreutils's sum.c: bsd_sum_stream
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: analyzer
          Assignee: dmalcolm at gcc dot gnu.org
          Reporter: dmalcolm at gcc dot gnu.org
  Target Milestone: ---

Created attachment 54408
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54408&action=edit
Reproducer

Trunk emits false positives: https://godbolt.org/z/coeesxxP4
Similar to bug 108664, but also emits:

<source>:90:3: warning: use of uninitialized value '*(unsigned int *)&checksum'
[CWE-457] [-Wanalyzer-use-of-uninitialized-value]
   90 |   memcpy(resstream, &checksum, sizeof checksum);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

despite this initialization:
  int checksum = 0;