[PATCH] D132412: [InstCombine] reassociate/factor add+mul with common operand

[Sanjay Patel via Phabricator via llvm-commits]

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(X * Y) + (X + Z) --> ((Y + 1) * X) + Z

https://alive2.llvm.org/ce/z/CvBvyz

This is one of the IR transforms suggested in issue #57255 <https://github.com/llvm/llvm-project/issues/57255>.

In examples like the motivating report with a constant operand, we eliminate an instruction, but this should be better in IR even with all variables because it removes a use of a variable operand. The backend should be able to re-distribute the multiply if that's better for the target.


https://reviews.llvm.org/D132412

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
  llvm/test/Transforms/InstCombine/add.ll
  llvm/test/Transforms/PGOProfile/chr.ll

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