[PATCH] D131757: [instcombine] Check for zero initialisation optimisation of a product given fast flags are enabled in clang.

[Zain Jaffal via Phabricator via llvm-commits]

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Given a zero initialised variable iterating through an array and multiplying its elements, the optimiser should be able to remove the loop safely and return the initial value because fast math flags are enabled.

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

The loop here can be deleted and we can return `f_prod` instead


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D131757

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

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