[Bug tree-optimization/26806] [4.2 Regression] ICE at gcc/tree-gimple.c:269

["law at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #9 from law at redhat dot com  2006-03-23 09:48 -------
Subject: Re:  [4.2 Regression] ICE at
        gcc/tree-gimple.c:269

On Thu, 2006-03-23 at 00:09 +0000, pinskia at gcc dot gnu dot org wrote:
> 
> ------- Comment #5 from pinskia at gcc dot gnu dot org  2006-03-23 00:09 -------
> I see a similar failure in galgel on Diego's testers:
> /home/cygnus/dnovillo/perf/sbox/gcc/local.i686/inst.tobiano/bin/gfortran -c -o
> bifgel.o  -ffixed-form -ffloat-store          -O2 -march=pentium4
> -mtune=generic    bifgel.f90
> Error from make 'specmake  build 2> make.err | tee make.out':
> bifgel.f90: In function 'bifgel':
> bifgel.f90:1: internal compiler error: Segmentation fault
> Please submit a full bug report,
> with preprocessed source if appropriate.
> See <URL:http://gcc.gnu.org/bugs.html> for instructions.
> 
> But I cannot reduce that or debug that because I don't have the source to SPEC.
This is arguably a bug in the code to walk immediate uses; if a
statement has multiple uses of the same SSA_NAME and you modify
the statement during the imm-uses walk, there are cases where
the imm-uses walk will miss the second use within the statement.

The net result in this particular case is we fail to propagate
away a use (because it wasn't visited due to the bug noted above),
we then proceed to remove the SSA_NAME (as all its uses should have
been removed).

Andrew is aware of the problem and we kicked around some ideas
for how to resolve it long term.  I've got a couple of short-term
workarounds that I'm testing.

jeff


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26806