[Bug target/104723] [12 regression] Redundant usage of stack

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104723

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-03-01
             Status|UNCONFIRMED                 |NEW
           Keywords|                            |missed-optimization,
                   |                            |needs-bisection
   Target Milestone|---                         |12.0

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed with -O2 -march=skylake-avx512.  On the high-level side we fail to
promote write-once vars to static storage:

bool f256 (char * a)
{
  char t[49];

  <bb 2> [local count: 1073741824]:
  t = "012345678901234567890123456789012345678901234567";
  __builtin_memcpy (a_3(D), &t[0], 49);
  t ={v} {CLOBBER};
  return 0;

}