[Bug rtl-optimization/52139] [4.5/4.6/4.7 Regression] ICE: in remove_insn, at emit-rtl.c:3960 with -O -fPIC -fno-tree-dominator-opts -fno-tree-fre

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52139

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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  Attachment #26603|0                           |1
        is obsolete|                            |

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-02-07 
13:22:45 UTC ---
Created attachment 26604
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26604
gcc47-pr52139.patch

That patch didn't get too far with rtl checking, we are sometimes remove_insn a
barrier after a barrier.

So, here is the variant with the second remove_insn change removed and instead
with BB_END (a) = first; in cfg_layout_merge_blocks.  Could add there
  gcc_checking_assert (BB_END (a) == first || BARRIER_P (BB_END (a)));
before that line if requested.