[PATCH] D73832: Ignore/Drop droppable uses for code-sinking in InstCombine

[Johannes Doerfert via Phabricator via llvm-commits]

jdoerfert added inline comments.


================
Comment at: llvm/lib/Transforms/Utils/KnowledgeRetention.cpp:263
+      Assume.bundle_op_infos(), [&Assume](const CallBase::BundleOpInfo &BOI) {
+        return BOI.Begin == BOI.End ||
+               getValueFromBundleOpInfo(Assume, BOI, BOIE_WasOn) != nullptr;
----------------
Tyker wrote:
> jdoerfert wrote:
> > We do we disallow empty BundleOpInfo here?
> i am not sure i understood the question.
> 
> we will return true for empty bundles.
> 
> this is a simple utility to check if the operand bundle of an llvm.assume still holds any information. it is used in a few places because instcombine was removing instructions like `call void @llvm.assume(i1 true) ["nonnull"(%p)]` because the argument to the call is known to be true so the assume was considered useless which is not true anymore.
> 
> 
Oh, empty bundles like `call void @llvm.assume(i1 true) ["cold"()]` ?
Maybe we should put a comment here because I will forget again.

Nit: no `!= nullptr`


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D73832/new/

https://reviews.llvm.org/D73832