[Bug tree-optimization/56150] New: ICE segfault in do_pre / tail_merge_optimize

[francesco.zappa.nardelli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56150

             Bug #: 56150
           Summary: ICE segfault in do_pre / tail_merge_optimize
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: francesco.zappa.narde...@gmail.com


The program below makes 

  gcc version 4.8.0 20130130 (experimental) (GCC)

crash (ICE) at optimisation level -O2 and -O3:

$ gcc -O2 5-min.c
5-min.c: In function ‘func_1’:
5-min.c:9:6: internal compiler error: Segmentation fault
 void func_1 () {
      ^
0x8e59af crash_signal
    ../../gcc-svn-src/gcc/toplev.c:332
0xa434a7 vn_valueize
    ../../gcc-svn-src/gcc/tree-ssa-sccvn.h:226
0xa434a7 gimple_equal_p
    ../../gcc-svn-src/gcc/tree-ssa-tail-merge.c:1124
0xa434a7 find_duplicate
    ../../gcc-svn-src/gcc/tree-ssa-tail-merge.c:1214
0xa434a7 find_clusters_1
    ../../gcc-svn-src/gcc/tree-ssa-tail-merge.c:1409
0xa434a7 find_clusters
    ../../gcc-svn-src/gcc/tree-ssa-tail-merge.c:1430
0xa455ec tail_merge_optimize(unsigned int)
    ../../gcc-svn-src/gcc/tree-ssa-tail-merge.c:1634
0xa0b69c do_pre
    ../../gcc-svn-src/gcc/tree-ssa-pre.c:4754

Here is the program 5-min.c:

struct {
  int f4;
} g1;

long g2;

volatile long g3;

void func_1 () {
    if (g2)
        g1 = g1;
    else
        g3;
}

void main () {
}