[Bug tree-optimization/119722] wrong code with _BitInt(), __builtin_stdc_rotate_left() at -O2 -fno-tree-forwprop -fno-tree-copy-prop -fno-tree-fre

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119722

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I think the problem is in the coalesce handling of
<bb 4> [local count: 1073741824]:
# b_17 = PHI <b_19(3), 8(2)>
g.4_13 = g;
_14 = g.4_13 >> 50;
_15 = (unsigned int) _14;
_21 = b_17;
_16 = (unsigned int) _21;
s_22 = _15 + _16;
return s_22;

bb.  We only track b_17, b_19 and _14 SSA_NAMEs there and look for conflicts
and I think the right partitioning is b_17 and b_19 coalesced together and _14
in a separate partition, as the lifetime of _14 (from _14 = g.4_13 >> 50; to
_15 = (unsigned int) _14;) overlaps with the lifetime for b_17 (from # b_17 =
PHI <b_19(3), 8(2)> to _21 = b_17;).