[PATCH] D28158: [SCEV] limit recursion depth and operands number in getAddExpr

[Daniil Fukalov via Phabricator via llvm-commits]

dfukalov created this revision.
dfukalov added a reviewer: sanjoy.
dfukalov added a subscriber: llvm-commits.
Herald added a subscriber: mzolotukhin.

for a quite big function with source like

  %add = add nsw i32 %mul, %conv
  %mul1 = mul nsw i32 %add, %conv
  %add2 = add nsw i32 %mul1, %add
  %mul3 = mul nsw i32 %add2, %add
  ; repeat couple of thousands times

that can be produced by loop unroll, getAddExpr() tries to recursively construct SCEV and runs almost infinite time.

1. implemented recursion depth restriction parameter
2. added threshold for inlining addition operands (the same way as it's already implemented for multiplication operands inlining)


https://reviews.llvm.org/D28158

Files:
  include/llvm/Analysis/ScalarEvolution.h
  lib/Analysis/ScalarEvolution.cpp
  unittests/Analysis/ScalarEvolutionTest.cpp

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