[PATCH] D27245: Integer division expansion should handle constant divisors intelligently

[Dmitri Shtilman via Phabricator via llvm-commits]

dshtilman created this revision.
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The following patch improves integer division sw expansion.
Namely - the case of division by a constant, which would be expanded to a simple multiplication by a magic number rather than a full division loop.
Implementation follows the DAG code in TargetLowering::BuildSDIV().
Ref: "Hacker's Delight" or "The PowerPC Compiler Writer's Guide”.

Please review.
Dmitri


Repository:
  rL LLVM

https://reviews.llvm.org/D27245

Files:
  lib/Transforms/Utils/IntegerDivision.cpp
  unittests/Transforms/Utils/IntegerDivision.cpp

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