https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65244
--- Comment #17 from Richard Biener <rguenth at gcc dot gnu.org> ---
OK, so the "optimization" is needed on the DEF side as
extern void __attribute__((noreturn)) abort (void);
int foo (int flag, int val)
{
int tem;
if (flag)
{
if (val == 0)
abort ();
tem = val;
}
/* large - prevent jump threading */
__asm__ volatile ("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n");
if (flag)
return tem;
return 0;
}
shows (I'll add that testcase). Otherwise we pick up
((NOT (val_5(D) == 0)) AND (flag_3(D) != 0))
as the condition on which 'tem' is well-defined and the guard of the use is
just
((flag_3(D) != 0))
