[llvm] AMDGPU: Propagate amdgpu-max-num-workgroups attribute (PR #113018)

[Shilei Tian via llvm-commits]

================
@@ -821,6 +826,146 @@ AAAMDFlatWorkGroupSize::createForPosition(const IRPosition &IRP,
       "AAAMDFlatWorkGroupSize is only valid for function position");
 }
 
+struct TupleDecIntegerRangeState : public AbstractState {
+  DecIntegerState<uint32_t> X, Y, Z;
+
+  bool isValidState() const override {
+    return X.isValidState() && Y.isValidState() && Z.isValidState();
+  }
+
+  bool isAtFixpoint() const override {
+    return X.isAtFixpoint() && Y.isAtFixpoint() && Z.isAtFixpoint();
+  }
+
+  ChangeStatus indicateOptimisticFixpoint() override {
+    return X.indicateOptimisticFixpoint() | Y.indicateOptimisticFixpoint() |
+           Z.indicateOptimisticFixpoint();
+  }
+
+  ChangeStatus indicatePessimisticFixpoint() override {
+    return X.indicatePessimisticFixpoint() | Y.indicatePessimisticFixpoint() |
+           Z.indicatePessimisticFixpoint();
+  }
+
+  TupleDecIntegerRangeState operator^=(const TupleDecIntegerRangeState &Other) {
+    X ^= Other.X;
+    Y ^= Other.Y;
+    Z ^= Other.Z;
+    return *this;
+  }
+
+  bool operator==(const TupleDecIntegerRangeState &Other) const {
+    return X == Other.X && Y == Other.Y && Z == Other.Z;
+  }
+
+  TupleDecIntegerRangeState &getAssumed() { return *this; }
+  const TupleDecIntegerRangeState &getAssumed() const { return *this; }
+};
+
+using AAAMDMaxNumWorkgroupsState =
+    StateWrapper<TupleDecIntegerRangeState, AbstractAttribute, uint32_t>;
+
+/// Propagate amdgpu-max-num-workgroups attribute.
+struct AAAMDMaxNumWorkgroups
+    : public StateWrapper<TupleDecIntegerRangeState, AbstractAttribute> {
+  using Base = StateWrapper<TupleDecIntegerRangeState, AbstractAttribute>;
+
+  AAAMDMaxNumWorkgroups(const IRPosition &IRP, Attributor &A) : Base(IRP) {}
+
+  void initialize(Attributor &A) override {
+    Function *F = getAssociatedFunction();
+    auto &InfoCache = static_cast<AMDGPUInformationCache &>(A.getInfoCache());
----------------
shiltian wrote:

I'm not sure how this attribute is gonna be used in the future, but it can get convoluted and go south if the moving direction of this AA is different from its depending AA (if there is any in the future).

https://github.com/llvm/llvm-project/pull/113018