Quentin Colombet 2c6ef1c433 [InstCombiner] Expose opportunities to merge subtract and comparison. ...

Several architectures use the same instruction to perform both a comparison and
a subtract. The instruction selection framework does not allow to consider
different basic blocks to expose such fusion opportunities.

Therefore, these instructions are “merged” by CSE at MI IR level.

To increase the likelihood of CSE to apply in such situation, we reorder the
operands of the comparison, when they have the same complexity, so that they
matches the order of the most frequent subtract.
E.g.,

icmp A, B
...
sub B, A

<rdar://problem/14514580>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190352 91177308-0d34-0410-b5e6-96231b3b80d8

2013-09-09 20:56:48 +00:00

..

CMakeLists.txt

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InstCombine.h

Consistently use dbgs() in debug printing

2013-09-05 19:48:28 +00:00

InstCombineAddSub.cpp

Preserve fast-math flags when folding (fsub x, (fneg y)) to (fadd x, y).

2013-07-30 23:53:17 +00:00

InstCombineAndOrXor.cpp

InstCombine: allow unmasked icmps to be combined with logical ops

2013-09-04 11:57:17 +00:00

InstCombineCalls.cpp

Change behavior of calling bitcasted alias functions.

2013-07-30 20:45:05 +00:00

InstCombineCasts.cpp

Teach InstCombine about address spaces

2013-08-21 19:53:10 +00:00

InstCombineCompares.cpp

[InstCombiner] Expose opportunities to merge subtract and comparison.

2013-09-09 20:56:48 +00:00

InstCombineLoadStoreAlloca.cpp

Teach InstCombineLoadCast about address spaces.

2013-09-03 21:05:48 +00:00

InstCombineMulDivRem.cpp

Correct case of m_UIToFp to m_UIToFP to match instruction name, add m_SIToFP for consistency.

2013-07-26 17:55:00 +00:00

InstCombinePHI.cpp

Consistently use dbgs() in debug printing

2013-09-05 19:48:28 +00:00

InstCombineSelect.cpp

InstCombine: Also turn selects fed by an and into arithmetic when the types don't match.

2013-06-29 21:17:04 +00:00

InstCombineShifts.cpp

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InstCombineSimplifyDemanded.cpp

InstCombine: Check for zero shift amounts before subtracting one causing integer overflow.

2013-08-30 14:35:35 +00:00

InstCombineVectorOps.cpp

Use type helper functions.

2013-09-06 00:37:24 +00:00

InstCombineWorklist.h

Consistently use dbgs() in debug printing

2013-09-05 19:48:28 +00:00

InstructionCombining.cpp

Consistently use dbgs() in debug printing

2013-09-05 19:48:28 +00:00

LLVMBuild.txt

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Makefile

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