[PATCH] D121292: [VP] Add vp.fcmp comparison intrinsic and docs

Wed Mar 16 04:00:05 PDT 2022

simoll added a comment.

In D121292#3382065 <https://reviews.llvm.org/D121292#3382065>, @frasercrmck wrote:

> In D121292#3382023 <https://reviews.llvm.org/D121292#3382023>, @simoll wrote:
>
>> VP intrinsics aren't speculatable because they have undefined behavior if `%evl > static vector length`
>
> Hmm, this sort of goes against what was said in 9b99927618d338a2be3f13053ccf869a39eb1637 <https://reviews.llvm.org/rG9b99927618d338a2be3f13053ccf869a39eb1637>.

Right. That patch is wrong then. What we really need is something that tells us whether the replacement for the VP intrinsic is speculatable (not the VP intrinsic itself).
Something like `isSafeToSpeculativelyExecute` with just the opcode and the operands.

Repository:
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  https://reviews.llvm.org/D121292/new/

https://reviews.llvm.org/D121292