[llvm] [InferAddressSpaces] Support refinement from additional address spaces (PR #225884)

[Matt Arsenault via llvm-commits]

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@@ -54,6 +54,11 @@ class NVPTXTTIImpl final : public BasicTTIImplBase<NVPTXTTIImpl> {
     return AddressSpace::ADDRESS_SPACE_GENERIC;
   }
 
+  SmallVector<unsigned, 2> getRefinableAddressSpaces() const override {
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arsenm wrote:

Treating this as a list instead of a predicate is a little weird. I guess if you only have 1 special case, maybe this is cheaper 

https://github.com/llvm/llvm-project/pull/225884