[Bug lto/107936] New: #pragma GCC diagnostic ignored vs. LTO

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107936

            Bug ID: 107936
           Summary: #pragma GCC diagnostic ignored vs. LTO
           Product: gcc
           Version: 12.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

rh1948567-1.c:
void foo (char x[2]);

int
main ()
{
  char x[2];
#pragma GCC diagnostic ignored "-Wstringop-overflow"
  foo (x + 1);
}
rh1948567-2.c:
void
foo (char x[2])
{
  asm volatile ("" : : "r" (&x[0]) : "memory");
}
gcc -W -Wall -flto -o rh1948567{,-1.c,-2.c}
rh1948567-1.c: In function ‘main’:
rh1948567-1.c:8:3: warning: ‘foo’ accessing 2 bytes in a region of size 1
[-Wstringop-overflow=]
    8 |   foo (x + 1);
      |   ^
rh1948567-1.c:8:3: note: referencing argument 1 of type ‘char[2]’
rh1948567-2.c:2:1: note: in a call to function ‘foo’
    2 | foo (char x[2])
      | ^

Shouldn't the diagnostic pragma prevent the warning even in the LTO case?