[llvm] [AMDGPU] Add alignment attr & propagate alignment through make.buffer.rsrc inst (PR #145278)

[Shilei Tian via llvm-commits]

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@@ -2042,6 +2048,19 @@ struct Attributor {
     SimplificationCallbacks[IRP].emplace_back(CB);
   }
 
+  using AlignmentCallbackTy =
+      std::function<void(const IRPosition &, const AbstractAttribute *,
+                         SmallVectorImpl<AA::ValueAndContext> &)>;
+  void registerAlignmentCallback(const IRPosition &IRP,
+                                 const AlignmentCallbackTy &CB) {
+    AlignmentCallBacks[IRP].emplace_back(CB);
+  }
+
+  SmallVector<AlignmentCallbackTy, 1>
+  getAlignmentCallback(const IRPosition &IRP) {
+    return AlignmentCallBacks.lookup(IRP);
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shiltian wrote:

What if the lookup fails? I'd prefer to do similar style as the simplification CB.

https://github.com/llvm/llvm-project/pull/145278