https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117239
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |law at gcc dot gnu.org
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So, the problem is in cselib.
cselib_process_insn for calls does:
/* Since it is not clear how cselib is going to be used, be
conservative here and treat looping pure or const functions
as if they were regular functions. */
if (RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)
|| !(RTL_CONST_OR_PURE_CALL_P (insn)))
cselib_invalidate_mem (callmem);
else
/* For const/pure calls, invalidate any argument slots because
they are owned by the callee. */
for (x = CALL_INSN_FUNCTION_USAGE (insn); x; x = XEXP (x, 1))
if (GET_CODE (XEXP (x, 0)) == USE
&& MEM_P (XEXP (XEXP (x, 0), 0)))
cselib_invalidate_mem (XEXP (XEXP (x, 0), 0));
For non-pure/const calls callmem is gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH
(VOIDmode))
and so it invalidates everything, but here we have const/pure calls and
invalidating just the argument slot isn't enough.
