[Bug c++/68021] New: ice in rewrite_use_nonlinear_expr with -O3

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68021

            Bug ID: 68021
           Summary: ice in rewrite_use_nonlinear_expr with -O3
           Product: gcc
           Version: 6.0
            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 36540
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36540&action=edit
C++ source code

For today's trunk gcc on x64_64

$ ../results/bin/g++ -O3 -c bug237.cc
svga_cirrus.cc: In function ‘void bitblt_rop_bkwd_src_and_dst(Bit8u*, const
Bit8u*, int, int, int, int)’:
svga_cirrus.cc:3304:13: internal compiler error: in rewrite_use_nonlinear_expr,
at tree-ssa-loop-ivopts.c:6916
0xf044d4 rewrite_use_nonlinear_expr
        ../../src/trunk/gcc/tree-ssa-loop-ivopts.c:6916
0xf044d4 rewrite_use
        ../../src/trunk/gcc/tree-ssa-loop-ivopts.c:7177
0xf044d4 rewrite_uses
        ../../src/trunk/gcc/tree-ssa-loop-ivopts.c:7210
0xf0b190 tree_ssa_iv_optimize_loop
        ../../src/trunk/gcc/tree-ssa-loop-ivopts.c:7550
0xf0b190 tree_ssa_iv_optimize()
        ../../src/trunk/gcc/tree-ssa-loop-ivopts.c:7582
0xf24fc0 execute
        ../../src/trunk/gcc/tree-ssa-loop.c:412
Please submit a full bug report,
with preprocessed source if appropriate.
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tree-ssa-loop-ivopts.c:6916 is

  gcc_assert (comp != NULL_TREE);