[PATCH] D31968: Remove all allocation and divisions from GreatestCommonDivisor

[Richard Smith via Phabricator via llvm-commits]

rsmith created this revision.

Switch from Euclid's algorithm to Stein's algorithm for computing GCD. This avoids the (expensive) APInt division operation in favour of bit operations. Remove all memory allocation from within the GCD loop by tweaking our `lshr` implementation so it can operate in-place.


Repository:
  rL LLVM

https://reviews.llvm.org/D31968

Files:
  include/llvm/ADT/APInt.h
  lib/Support/APInt.cpp
  unittests/ADT/APIntTest.cpp

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