[Bug middle-end/122373] New: Incorrect max size passed to movmem at -O0

[hjl.tools at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122373

            Bug ID: 122373
           Summary: Incorrect max size passed to movmem at -O0
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hjl.tools at gmail dot com
  Target Milestone: ---

While working on PR target/90262, I noticed that at -O0, the max size info
passed
to movmem is unreliable.  When the max size info was used to simplify movmem
expansion, I got

FAIL: gfortran.dg/allocate_deferred_char_scalar_1.f03   -O0  execution test
FAIL: gfortran.dg/deferred_character_23.f90   -O0  execution test