[PATCH] D131672: [opt] Optimise for zero initialisation of product given finite math in Clang

[Zain Jaffal via Phabricator via llvm-commits]

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Currently, clang ignores the 0 initialisation in finite math
For example:

  double f_prod = 0;
  double arr[1000];
  for (size_t i = 0; i < 1000; i++) {
    f_prod *= arr[i];
   }

Clang will ignore that `f_prod` is set to zero and it will generate assembly to iterate over the loop.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D131672

Files:
  llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
  llvm/test/Transforms/InstCombine/remove-loop-phi-fastmul.ll

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