[Bug analyzer/106595] New: False positive Wanalyzer-out-of-bounds warnings in yacc generated files

[tlange at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106595

            Bug ID: 106595
           Summary: False positive Wanalyzer-out-of-bounds warnings in
                    yacc generated files
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: analyzer
          Assignee: dmalcolm at gcc dot gnu.org
          Reporter: tlange at gcc dot gnu.org
  Target Milestone: ---

Created attachment 53445
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53445&action=edit
reduced httpd log with Wanalyzer-out-of-bounds false positives

The out-of-bounds checker emits some false-positives related to negative
offsets on the 'yyvsa' variable, also called 'semantic value stack'. The
analyzer isn't able to infer that the stack always has enough elements. An
exemplary log from building httpd is attached to this report.

David & I decided to leave it as is for now and merge the checker. Dependent on
how often the false-positives occur, we might auto-disable the warning on code
that looks like yacc generated code.