Tim Northover 984ee65445 X86: elide comparisons after cmpxchg instructions. ...

The C++ and C semantics of the compare_and_swap operations actually
require us to return a boolean "success" value. In LLVM terms this
means a second comparison of the output of "cmpxchg" against the input
desired value.

However, x86's "cmpxchg" instruction sets all flags for the comparison
formed, so we can skip any secondary comparison. (N.b. this isn't true
for cmpxchg8b/16b, which only set ZF).

rdar://problem/13201607

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210523 91177308-0d34-0410-b5e6-96231b3b80d8

2014-06-10 10:49:07 +00:00

..

AArch64

AArch64: teach FastISel how to handle offset FrameIndices

2014-06-10 09:52:44 +00:00

ARM

Reduce verbiage of lit.local.cfg files

2014-06-09 22:42:55 +00:00

CPP

Reduce verbiage of lit.local.cfg files

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Generic

Add a new attribute called 'jumptable' that creates jump-instruction tables for functions marked with this attribute.

2014-06-05 19:29:43 +00:00

Hexagon

Reduce verbiage of lit.local.cfg files

2014-06-09 22:42:55 +00:00

Inputs

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Mips

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MSP430

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NVPTX

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PowerPC

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R600

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SPARC

Reduce verbiage of lit.local.cfg files

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SystemZ

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Thumb

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Thumb2

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X86

X86: elide comparisons after cmpxchg instructions.

2014-06-10 10:49:07 +00:00

XCore

Reduce verbiage of lit.local.cfg files

2014-06-09 22:42:55 +00:00