[llvm] [VPlan] Manage instruction medata in VPlan. (PR #135272)

[via llvm-commits]

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@@ -1646,7 +1654,7 @@ void VPWidenRecipe::execute(VPTransformState &State) {
 
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ayalz wrote:

Here setFlags() is already applied under dyn_cast to Instruction. Place setMetadata() here as well, or rather applyMetadata(Instruction*)?

https://github.com/llvm/llvm-project/pull/135272