[Bug tree-optimization/48772] New: [4.7 Regression] ICE: SIGSEGV in walk_non_aliased_vuses (gimple.h:1100) with -O -fnon-call-exceptions -fno-tree-ccp -fno-tree-dce

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48772

           Summary: [4.7 Regression] ICE: SIGSEGV in
                    walk_non_aliased_vuses (gimple.h:1100) with -O
                    -fnon-call-exceptions -fno-tree-ccp -fno-tree-dce
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


Created attachment 24103
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24103
reduced testcase (from g++.dg/torture/pr44535.C)

Compiler output:
$ gcc -O -fnon-call-exceptions -fno-tree-ccp -fno-tree-dce testcase.C
==25341== Invalid read of size 1
==25341==    at 0xB0BE03: walk_non_aliased_vuses (gimple.h:1100)
==25341==    by 0xB80E8C: vn_reference_lookup (tree-ssa-sccvn.c:1697)
==25341==    by 0xB6DD99: eliminate (tree-ssa-pre.c:4341)
==25341==    by 0xB7103D: execute_pre (tree-ssa-pre.c:4921)
==25341==    by 0x984C55: execute_one_pass (passes.c:1555)
==25341==    by 0x984F34: execute_pass_list (passes.c:1610)
==25341==    by 0x984F46: execute_pass_list (passes.c:1611)
==25341==    by 0xACCBAA: tree_rest_of_compilation (tree-optimize.c:423)
==25341==    by 0xCAFB42: cgraph_expand_function (cgraphunit.c:1576)
==25341==    by 0xCB205B: cgraph_optimize (cgraphunit.c:1635)
==25341==    by 0xCB25E9: cgraph_finalize_compilation_unit (cgraphunit.c:1096)
==25341==    by 0x5BD42D: cp_write_global_declarations (decl2.c:4002)
==25341==    by 0xA71A87: toplev_main (toplev.c:591)
==25341==    by 0x644AB6C: (below main) (in /lib64/libc-2.11.3.so)
==25341==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
==25341== 
testcase.C: In function 'int main()':
testcase.C:26:1: internal compiler error: Segmentation fault
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