[Bug rtl-optimization/42839] [4.5 Regression] gcc.target/mips/octeon-bbit-2.c failing for -mabi=64

[pinskia at gcc dot gnu dot org]

------- Comment #6 from pinskia at gcc dot gnu dot org  2010-02-12 23:14 -------
(In reply to comment #5)
> Can you explain how? It's not clear from the code of your comment #2 how a
> simplification would cause the extra basic block.

sorry if I was not clear here but there are two different issues with this
testcase.  the extra basic block is there for 4.4 still; just it uses the
branch likely instruction which is what the testcase is trying to test for. 
(for those who don't know the MIPS ISA, branch likely says the delay slot is
only executed if the branch is taken).

The extra simplification is causing the branch likely instruction not to used
as there is a way to combine the sign extend with the addition.  So there is an
extra instruction introduced early on.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42839