[PATCH] D13686: [SCEV] Teach SCEV some axioms about non-wrapping arithmetic

[Sanjoy Das via llvm-commits]

sanjoy created this revision.
sanjoy added reviewers: atrick, hfinkel, reames, nlewycky.
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 - A s<  (A + C)<nsw> if C >  0
 - A s<= (A + C)<nsw> if C >= 0
 - (A + C)<nsw> s<  A if C <  0
 - (A + C)<nsw> s<= A if C <= 0

Right now `C` needs to be a constant, but we can later generalize it to
be a non-constant if needed.

http://reviews.llvm.org/D13686

Files:
  include/llvm/Analysis/ScalarEvolution.h
  lib/Analysis/ScalarEvolution.cpp
  test/Transforms/IndVarSimplify/eliminate-comparison.ll

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