[llvm] [IR] Add new CreateVectorInterleave interface and constant fold (PR #150931)

[Luke Lau via llvm-commits]

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@@ -189,6 +189,24 @@ class LLVM_ABI TargetFolder final : public IRBuilderFolder {
     return nullptr;
   }
 
+  Value *FoldVectorInterleave(ArrayRef<Value *> Ops) const override {
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lukel97 wrote:

I guess we need a `llvm::ConstantFoldBinaryIntrinsic` in ConstantFolding.cpp, and call that from both ConstantFolder.h and InstructionSimplify.cpp's `ConstantFoldInstOperandsImpl`? That would bring it inline with the other the other instruction types.

And we probably need to rename that to just ConstantFoldIntrinsic?

https://github.com/llvm/llvm-project/pull/150931