[Bug rtl-optimization/51505] [4.5/4.6/4.7 Regression] ICE: in form_sum, at reload.c:5349 with -O --param max-cse-insns=1

[abel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51505

Andrey Belevantsev <abel at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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  Attachment #26353|0                           |1
        is obsolete|                            |

--- Comment #7 from Andrey Belevantsev <abel at gcc dot gnu.org> 2012-01-18 07:45:42 UTC ---
Created attachment 26359
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26359
Updated patch

How about this version then?  We need to count the number of EQ_USES to
allocate the temp vector on stack.  Unless we want a helper that would utilize
the knowledge of how df_ref_remove works.  

Is it fine that we mark bb as dirty as a result of calling df_ref_remove in the
middle of note computation?

Note also that for the testcase we find that register 68 is dead (which is
true) and that is the reason for note removal, not that register 70 is dead.