[PATCH] D39421: [InstCombine] Extracting common and-mask for shift operands of Or instruction

[Omer Paparo Bivas via Phabricator via llvm-commits]

opaparo created this revision.

Adding an InstCombine transformation:
((V<<C3)&C1) | ((V<<C4)&C2) --> ((V&C5)<<C3) | ((V&C5)<<C4), if C5 = C1>>C3 == C2>>C4, for both logical shifts.
When executed, this transforms five instructions into four, saving one instruction.


Repository:
  rL LLVM

https://reviews.llvm.org/D39421

Files:
  lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  test/Transforms/InstCombine/or-or-shift.ll

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