[Bug tree-optimization/42917] [4.5 Regression] "-fcompare-debug failure" with -ftree-loop-linear

jakub at gcc dot gnu dot org gcc-bugzilla@gcc.gnu.org
Wed Feb 17 13:56:00 GMT 2010



------- Comment #2 from jakub at gcc dot gnu dot org  2010-02-17 13:56 -------
I guess lambda-code.c needs to be taught about debug stmts.
This is actually more important than usual -fcompare-debug differences, here
debug stmt actually prevent the optimization altogether.
Without -g the loops are perfectly nested (perfect_nest_p succeeds), without it
the debug stmt cause both perfect_nest_p and can_convert_to_perfect_nest to
fail.

I guess best would be to ignore debug stmts in these functions, and do
something about them in perfect_nestify and in lambda_loopnest_to_gcc_loopnest,
but am not sure it will actually possible.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42917



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