[Bug target/48380] [gcc-4.7 regression] ICE in postreload.c while building trunk

[vmakarov at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48380

Vladimir Makarov <vmakarov at redhat dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |vmakarov at redhat dot com

--- Comment #4 from Vladimir Makarov <vmakarov at redhat dot com> 2011-04-01 20:47:39 UTC ---
We have the following situation:
  - a pseudo has equivalent constant.
  - a loop allocno corresponding to the pseudo got hard reg and
    the subloop allocno got memory.
  - the load generated by IRA on the loop/subloop border is not removed.
  - the loop allocno is spilled in reload transforming the load into mem-mem
move.
  - reload skip processing the move because it sets up regno with equiv
constant.
  - gcc dies in the post=reload.

There are several possible solutions but the most optimal would be removing the
load transformed into mem-mem move in the reload.  We need to add the load to
equiv init insn.

I'll submit a patch solving the problem soon.