[llvm] ValueTracking: introduce llvm::isNotCrossLaneOperation (PR #112011)

[Nikita Popov via llvm-commits]

================
@@ -4343,13 +4343,10 @@ static Value *simplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
   if (isa<PHINode>(I))
     return nullptr;
 
-  if (Op->getType()->isVectorTy()) {
+  if (Op->getType()->isVectorTy() && !isNotCrossLaneOperation(I))
     // For vector types, the simplification must hold per-lane, so forbid
     // potentially cross-lane operations like shufflevector.
----------------
nikic wrote:

nit: Move this comment above the if.

https://github.com/llvm/llvm-project/pull/112011