[PATCH] D85709: [InstSimplify] Implement Instruction simplification for X/sqrt(X) to sqrt(X).

[Cameron McInally via Phabricator via llvm-commits]

cameron.mcinally added a comment.

I'm fairly sure this transform is a performance loss. For a target like Skylake Server, a SQRT(x) can take up to 20 cycles. But a RSQRT(x) is about 6 cycles and a MUL(y) is 4 cycles. We'd be better off with a X*RSQRT(X).


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D85709/new/

https://reviews.llvm.org/D85709