[Bug c++/101038] New: ice in vect_optimize_slp

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101038

            Bug ID: 101038
           Summary: ice in vect_optimize_slp
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

Created attachment 50988
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50988&action=edit
gzipped C++ source code

The attached C++ code, when compiled by -march=bdver2 and -O3, 
does this:

during GIMPLE pass: vect
/home/dcb34/rpmbuild/BUILD/kolourpaint-21.04.1/imagelib/effects/blitz.cpp: In
fu
nction ‘bool _Z8equalizeR6QImage.part.0(QImage&)’:
/home/dcb34/rpmbuild/BUILD/kolourpaint-21.04.1/imagelib/effects/blitz.cpp:125:6:
 internal compiler error: Segmentation fault
  125 | bool equalize(QImage &img)
      |      ^~~~~~~~
0xfcd5f9 crash_signal(int)
        ../../trunk.git/gcc/toplev.c:327
0x12a4968 vect_optimize_slp(vec_info*)
        ../../trunk.git/gcc/tree-vect-slp.c:3626

This code was fine at git hash 91349e57bbfd0101, but had gone wrong by
f8b067056ba5dd53, a few days later.