[Bug lto/95533] New: Spurious(?) warning "writing 2 bytes into a region of size 0" with -O(2|3) -fwhole-program -flto

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95533

            Bug ID: 95533
           Summary: Spurious(?) warning "writing 2 bytes into a region of
                    size 0" with -O(2|3) -fwhole-program -flto
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dominiq at lps dot ens.fr
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

% gfc /opt/gcc/work/gcc/testsuite/gfortran.dg/deferred_character_8.f90 -O3
-fwhole-program -flto
In function 'g',
    inlined from 'MAIN__' at
/opt/gcc/work/gcc/testsuite/gfortran.dg/deferred_character_8.f90:73:0:
/opt/gcc/work/gcc/testsuite/gfortran.dg/deferred_character_8.f90:28: warning:
writing 4 bytes into a region of size 0 [-Wstringop-overflow=]
   28 |   res = [a, b]
      | 
% gfc /opt/gcc/work/gcc/testsuite/gfortran.dg/deferred_character_8.f90 -O2
-fwhole-program -flto
In function 'g',
    inlined from 'MAIN__' at
/opt/gcc/work/gcc/testsuite/gfortran.dg/deferred_character_8.f90:73:0:
/opt/gcc/work/gcc/testsuite/gfortran.dg/deferred_character_8.f90:28: warning:
writing 2 bytes into a region of size 0 [-Wstringop-overflow=]
   28 |   res = [a, b]
      | 
/opt/gcc/work/gcc/testsuite/gfortran.dg/deferred_character_8.f90:28: warning:
writing 4 bytes into a region of size 0 [-Wstringop-overflow=]
   28 |   res = [a, b]
      |