[PATCH] D50556: [InstCombine] Improve strncpy to memcpy optimization

[Dávid Bolvanský via Phabricator via llvm-commits]

xbolva00 created this revision.
xbolva00 added a reviewer: efriedma.
Herald added a subscriber: llvm-commits.

We optimize

  char buf[20];
  strncpy(buf, "hi", 3);
  puts(buf);

}

to memcpy, but we bail out in the following case:

int f1(void) {

  char buf[20];
  strncpy(buf, "hi", 4);
  puts(buf);

}

Godbolt: https://godbolt.org/g/ganpSH


Repository:
  rL LLVM

https://reviews.llvm.org/D50556

Files:
  lib/Transforms/Utils/SimplifyLibCalls.cpp
  test/Transforms/InstCombine/strncpy-1.ll

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