[PATCH] D55876: [LIR] Add CTTZ support

[Yuanfang Chen via Phabricator via llvm-commits]

tabloid.adroit created this revision.
tabloid.adroit added reviewers: craig.topper, evstupac.
Herald added a subscriber: llvm-commits.

Existing LIR recognizes CTLZ where shifting input variable right until
it is zero. (Shift-Until-Zero idiom)

This commit:

1. Augments Shift-Until-Zero idiom to recognize CTTZ where input

variable is shifted left.

2. Prepare for BitScan idiom recognition.


Repository:
  rL LLVM

https://reviews.llvm.org/D55876

Files:
  lib/Transforms/Scalar/LoopIdiomRecognize.cpp
  test/Transforms/LoopIdiom/X86/cttz.ll

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