[Bug tree-optimization/92704] New: [8/9/10 Regression] ICE: Segmentation fault (in process_bb)

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92704

            Bug ID: 92704
           Summary: [8/9/10 Regression] ICE: Segmentation fault (in
                    process_bb)
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Keywords: ice-on-invalid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---
            Target: x86_64-pc-linux-gnu

gcc-10.0.0-alpha20191124 snapshot (r278660) and 9.2.0 ICE when compiling the
following testcase w/ -O3 -fexceptions -fnon-call-exceptions -fno-tree-dce:

int zr, yx;

void __attribute__ ((simd))
oj (int rd, int q7)
{
  int wo = &rd;

  while (q7 < 1)
    {
      int kv;
      short int v3;

      for (v3 = 0; v3 < 82; v3 += 3)
        {
        }

      kv = zr ? 0 : v3;
      yx = kv < rd;
      zr = zr && yx;
      ++q7;
    }
}

% x86_64-pc-linux-gnu-gcc-10.0.0-alpha20191124 -O3 -fexceptions
-fnon-call-exceptions -fno-tree-dce -w -c xmnlq6pk.c
during GIMPLE pass: ifcvt
xmnlq6pk.c: In function 'oj.simdclone.0':
xmnlq6pk.c:4:1: internal compiler error: Segmentation fault
    4 | oj (int rd, int q7)
      | ^~
0xd11940 crash_signal
       
/var/tmp/portage/sys-devel/gcc-10.0.0_alpha20191124/work/gcc-10-20191124/gcc/toplev.c:328
0xec0494 process_bb
       
/var/tmp/portage/sys-devel/gcc-10.0.0_alpha20191124/work/gcc-10-20191124/gcc/tree-ssa-sccvn.c:6705
0xec1818 do_rpo_vn
       
/var/tmp/portage/sys-devel/gcc-10.0.0_alpha20191124/work/gcc-10-20191124/gcc/tree-ssa-sccvn.c:7168
0xec2e63 do_rpo_vn(function*, edge_def*, bitmap_head*)
       
/var/tmp/portage/sys-devel/gcc-10.0.0_alpha20191124/work/gcc-10-20191124/gcc/tree-ssa-sccvn.c:7265
0xd8071f tree_if_conversion(loop*, vec<gimple*, va_heap, vl_ptr>*)
       
/var/tmp/portage/sys-devel/gcc-10.0.0_alpha20191124/work/gcc-10-20191124/gcc/tree-if-conv.c:3090
0xd822e6 execute
       
/var/tmp/portage/sys-devel/gcc-10.0.0_alpha20191124/work/gcc-10-20191124/gcc/tree-if-conv.c:3170
0xd822e6 execute
       
/var/tmp/portage/sys-devel/gcc-10.0.0_alpha20191124/work/gcc-10-20191124/gcc/tree-if-conv.c:3157

gcc 8.3.0 fails differently (via godbolt):

<source>: In function 'oj.simdclone.0':
<source>:4:1: error: missing PHI def
 oj (int rd, int q7)
 ^~
.MEM_110 = PHI <(5), .MEM_103(50)>
<source>:4: confused by earlier errors, bailing out