[PATCH] D29385: Clzero intrinsic and its addition under znver1

[Andrea Di Biagio via Phabricator via llvm-commits]

andreadb added a comment.

In https://reviews.llvm.org/D29385#670375, @craig.topper wrote:

> The instruction will default to having MCID::UnmodeledSideEffects set. Is that sufficient to protect the scheduling?


Yes, that would work.
An instruction with unmodeled side effects is basically treated as a scheduling barrier. So we are safe.

@craig.topper, is it fair to say that flag `UnmodeledSideEffects` is conservatively implicitly set because the tablegen definition for CLZEROr does not provide a primary instruction pattern, and flag hasSideEffects_Unset is `true` (i.e. hasSideEffects is not explicitly mentioned)?


Repository:
  rL LLVM

https://reviews.llvm.org/D29385