https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105835
Roger Sayle <roger at nextmovesoftware dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2022-06-03
Ever confirmed|0 |1
--- Comment #1 from Roger Sayle <roger at nextmovesoftware dot com> ---
Hmm. There might be something missing in CCP (with -O1)...
# RANGE [0, 1] NONZERO 1
_3 = (intD.6) _2;
# RANGE [0, 65535] NONZERO 65535
_10 = _3 * 65535;
d_11 = (short unsigned intD.18) _10;
if (d_11 != 1)
goto <bb 3>; [67.00%]
else
goto <bb 4>; [33.00%]
So it knows _10 is either 0 or 65535, so if it knew d_11 had the
range {0 or -1}, i.e. [-1,0] it would know d_11 != 1, and hence
goto <bb 3>.
