[Bug tree-optimization/103800] [12 Regression] ICE in vectorizable_phi, at tree-vect-loop.c:7861 with -O3 since r12-5626-g0194d92c35ca8b3a

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103800

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
So in this case we have an SLP tree for a merge PHI with scalar bools where
we do

t.c:10:12: note:   using boolean precision 32 for iftmp.1_168 = pretmp_175 !=
0;
t.c:10:12: note:   using boolean precision 16 for _177 = _176 != 0;
t.c:10:12: note:   using boolean precision 16 for iftmp.1_173 = PHI
<iftmp.1_168(6), _177(7)>

but pattern detection doesn't have any code to insert compensation on PHI
edges.

We now detect the mismatch but I fell foul of thinking it can only happen for
non-bool vs. bool context ...