Evan Cheng 089751535d Avoiding overly aggressive latency scheduling. If the two nodes share an ...

operand and one of them has a single use that is a live out copy, favor the
one that is live out. Otherwise it will be difficult to eliminate the copy
if the instruction is a loop induction variable update. e.g.

BB:
sub r1, r3, #1
str r0, [r2, r3]
mov r3, r1
cmp
bne BB

=>

BB:
str r0, [r2, r3]
sub r3, r3, #1
cmp
bne BB

This fixed the recent 256.bzip2 regression.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117675 91177308-0d34-0410-b5e6-96231b3b80d8

2010-10-29 18:09:28 +00:00

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