[Bug tree-optimization/77514] New: [7 Regression] ICE in VN_INFO_GET, at tree-ssa-sccvn.c:406 w/ -O2 (and above)

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77514

            Bug ID: 77514
           Summary: [7 Regression] ICE in VN_INFO_GET, at
                    tree-ssa-sccvn.c:406 w/ -O2 (and above)
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---

gcc-7.0.0-alpha20160904 ICEs when compiling the following reduces snippet at
-O2 (-O3, -Ofast):

void
m1 (char l0, char e8, int hw)
{
  char *rs = &l0;

 yu:
  l0 = 1;
  while (l0 != 0)
    {
      l0 = -l0;
      l0 += (*rs ^ (l0 &= 1));
    }
  for (;;)
    {
      if (hw != 0)
        goto yu;
      rs = &e8;
    }
}


% gcc-7.0.0-alpha20160904 -O2 -c nhbgsfda.c -Wall -Wextra -Wpedantic            
nhbgsfda.c: In function 'm1':
nhbgsfda.c:11:10: warning: operation on 'l0' may be undefined
[-Wsequence-point]
       l0 += (*rs ^ (l0 &= 1));
          ^~
nhbgsfda.c:2:1: internal compiler error: in VN_INFO_GET, at
tree-ssa-sccvn.c:406
 m1 (char l0, char e8, int hw)
 ^~