http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56899
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
Target Milestone|--- |4.7.3
Summary|Wrong constant folding |[4.6/4.7/4.8/4.9
| |Regression] Wrong constant
| |folding
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-04-10
08:23:00 UTC ---
I guess http://gcc.gnu.org/r152217 . Anyway, shouldn't be hard to reproduce
even with plus (say if v is negative).
I've tried
__attribute__((noinline, noclone)) void
foo (int v)
{
int x = 214748365 * (v + 1);
if (x != -1932735285)
__builtin_abort ();
}
int
main ()
{
foo (-10);
return 0;
}
but we don't miscompile it, because while we perform the distributive law in
that case too (also wrongly), it is folded back to the (v + 1) * 214748365
form (after recursing several times between the two forms).
