[Bug tree-optimization/25000] [4.1/4.2 Regression] ICE in coalesce_abnormal_edges, at tree-outof-ssa.c:646

[law at redhat dot com]

------- Comment #5 from law at redhat dot com  2005-11-29 00:22 -------
Subject: Re:  [4.1/4.2 Regression] ICE in
        coalesce_abnormal_edges, at tree-outof-ssa.c:646

On Mon, 2005-11-28 at 23:26 +0000, janis at gcc dot gnu dot org wrote:
> 
> ------- Comment #4 from janis at gcc dot gnu dot org  2005-11-28 23:26 -------
> A regression hunt using the reduced testcase from comment #3 identified the
> following patch:
> 
> http://gcc.gnu.org/viewcvs?view=rev&rev=98066
> 
> r98066 | law | 2005-04-13 04:29:40 +0000 (Wed, 13 Apr 2005)
Thanks.  This is clearly a problem in in the uncprop code as it
totally ignores abnormal PHIs.

We replace a constant (0) with an SSA_NAME which occurs in an abnormal
PHI.  That causes the lifetime of the SSA_NAME to be lengthened, which
is never safe if the SSA_NAME occurs in an abnormal PHI.  Eventually
this leads to the abort.

I've got a potential fix, but it'll take until tomorrow before
testing is finished.

jeff


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25000