[Attributor] Take the address space from addrspacecast directly

If the value to be analyzed is directly from addrspacecast, we take the source
address space directly. This is to improve the case where in
`AMDGPUPromoteKernelArgumentsPass`, the kernel argument is promoted by
insertting an addrspacecast directly from a generic pointer. However, during the
analysis, the underlying object will be the generic pointer, instead of the
addrspacecast, thus the inferred address space is the generic one, which is not
ideal.

Author: shiltian

llvm/include/llvm/Transforms/IPO/Attributor.h

@@ -6249,7 +6249,7 @@ struct AAAddressSpace : public StateWrapper<BooleanState, AbstractAttribute> {
   /// Return the address space of the associated value. \p NoAddressSpace is
   /// returned if the associated value is dead. This functions is not supposed
   /// to be called if the AA is invalid.
-  virtual int32_t getAddressSpace() const = 0;
+  virtual uint32_t getAddressSpace() const = 0;
 
   /// Create an abstract attribute view for the position \p IRP.
   static AAAddressSpace &createForPosition(const IRPosition &IRP,
@@ -6268,7 +6268,7 @@ struct AAAddressSpace : public StateWrapper<BooleanState, AbstractAttribute> {
   }
 
   // No address space which indicates the associated value is dead.
-  static const int32_t NoAddressSpace = -1;
+  static const uint32_t NoAddressSpace = ~0U;
 
   /// Unique ID (due to the unique address)
   static const char ID;

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

@@ -12562,7 +12562,7 @@ struct AAAddressSpaceImpl : public AAAddressSpace {
   AAAddressSpaceImpl(const IRPosition &IRP, Attributor &A)
       : AAAddressSpace(IRP, A) {}
 
-  int32_t getAddressSpace() const override {
+  uint32_t getAddressSpace() const override {
     assert(isValidState() && "the AA is invalid");
     return AssumedAddressSpace;
   }
@@ -12571,12 +12571,37 @@ struct AAAddressSpaceImpl : public AAAddressSpace {
   void initialize(Attributor &A) override {
     assert(getAssociatedType()->isPtrOrPtrVectorTy() &&
            "Associated value is not a pointer");
-    if (getAssociatedType()->getPointerAddressSpace())
+    // If the pointer already has non-generic address space, we assume it is the
+    // correct one.
+    if (getAssociatedType()->getPointerAddressSpace()) {
+      [[maybe_unused]] bool R =
+          takeAddressSpace(getAssociatedType()->getPointerAddressSpace());
+      assert(R && "the take should happen");
       indicateOptimisticFixpoint();
+      return;
+    }
+    // If the pointer is an addrspacecast, we assume the source address space is
+    // the correct one.
+    Value *V = &getAssociatedValue();
+    if (auto *ASC = dyn_cast<AddrSpaceCastInst>(V)) {
+      [[maybe_unused]] bool R = takeAddressSpace(ASC->getSrcAddressSpace());
+      assert(R && "the take should happen");
+      indicateOptimisticFixpoint();
+      return;
+    }
+    if (auto *C = dyn_cast<ConstantExpr>(V)) {
+      if (C->getOpcode() == Instruction::AddrSpaceCast) {
+        [[maybe_unused]] bool R = takeAddressSpace(
+            C->getOperand(0)->getType()->getPointerAddressSpace());
+        assert(R && "the take should happen");
+        indicateOptimisticFixpoint();
+        return;
+      }
+    }
   }
 
   ChangeStatus updateImpl(Attributor &A) override {
-    int32_t OldAddressSpace = AssumedAddressSpace;
+    uint32_t OldAddressSpace = AssumedAddressSpace;
     auto *AUO = A.getOrCreateAAFor<AAUnderlyingObjects>(getIRPosition(), this,
                                                         DepClassTy::REQUIRED);
     auto Pred = [&](Value &Obj) {
@@ -12594,19 +12619,17 @@ struct AAAddressSpaceImpl : public AAAddressSpace {
 
   /// See AbstractAttribute::manifest(...).
   ChangeStatus manifest(Attributor &A) override {
-    Value *AssociatedValue = &getAssociatedValue();
-    Value *OriginalValue = peelAddrspacecast(AssociatedValue);
-    if (getAddressSpace() == NoAddressSpace ||
-        static_cast<uint32_t>(getAddressSpace()) ==
-            getAssociatedType()->getPointerAddressSpace())
+    unsigned NewAS = getAddressSpace();
+    if (NewAS == NoAddressSpace ||
+        NewAS == getAssociatedType()->getPointerAddressSpace())
       return ChangeStatus::UNCHANGED;
 
-    PointerType *NewPtrTy =
-        PointerType::get(getAssociatedType()->getContext(),
-                         static_cast<uint32_t>(getAddressSpace()));
+    Value *AssociatedValue = &getAssociatedValue();
+    Value *OriginalValue = peelAddrspacecast(AssociatedValue);
     bool UseOriginalValue =
-        OriginalValue->getType()->getPointerAddressSpace() ==
-        static_cast<uint32_t>(getAddressSpace());
+        OriginalValue->getType()->getPointerAddressSpace() == NewAS;
+    PointerType *NewPtrTy =
+        PointerType::get(getAssociatedType()->getContext(), NewAS);
 
     bool Changed = false;
 
@@ -12656,9 +12679,9 @@ struct AAAddressSpaceImpl : public AAAddressSpace {
   }
 
 private:
-  int32_t AssumedAddressSpace = NoAddressSpace;
+  uint32_t AssumedAddressSpace = NoAddressSpace;
 
-  bool takeAddressSpace(int32_t AS) {
+  bool takeAddressSpace(uint32_t AS) {
     if (AssumedAddressSpace == NoAddressSpace) {
       AssumedAddressSpace = AS;
       return true;
@@ -12667,11 +12690,16 @@ struct AAAddressSpaceImpl : public AAAddressSpace {
   }
 
   static Value *peelAddrspacecast(Value *V) {
-    if (auto *I = dyn_cast<AddrSpaceCastInst>(V))
-      return peelAddrspacecast(I->getPointerOperand());
+    if (auto *I = dyn_cast<AddrSpaceCastInst>(V)) {
+      assert(I->getSrcAddressSpace() && "there should not be AS 0 -> AS X");
+      return I->getPointerOperand();
+    }
     if (auto *C = dyn_cast<ConstantExpr>(V))
-      if (C->getOpcode() == Instruction::AddrSpaceCast)
-        return peelAddrspacecast(C->getOperand(0));
+      if (C->getOpcode() == Instruction::AddrSpaceCast) {
+        assert(C->getOperand(0)->getType()->getPointerAddressSpace() &&
+               "there should not be AS 0 -> AS X");
+        return C->getOperand(0);
+      }
     return V;
   }
 };

llvm/test/CodeGen/AMDGPU/aa-as-infer.ll

@@ -243,3 +243,15 @@ define void @foo(ptr addrspace(3) %val) {
   ret void
 }
 
+define void @kernel_argument_promotion_pattern(ptr %p, i32 %val) {
+; CHECK-LABEL: define void @kernel_argument_promotion_pattern(
+; CHECK-SAME: ptr [[P:%.*]], i32 [[VAL:%.*]]) #[[ATTR0]] {
+; CHECK-NEXT:    [[P_CAST_0:%.*]] = addrspacecast ptr [[P]] to ptr addrspace(1)
+; CHECK-NEXT:    store i32 [[VAL]], ptr addrspace(1) [[P_CAST_0]], align 4
+; CHECK-NEXT:    ret void
+;
+  %p.cast.0 = addrspacecast ptr %p to ptr addrspace(1)
+  %p.cast.1 = addrspacecast ptr addrspace(1) %p.cast.0 to ptr
+  store i32 %val, ptr %p.cast.1
+  ret void
+}

llvm/test/CodeGen/AMDGPU/addrspacecast.ll

@@ -215,11 +215,14 @@ define amdgpu_kernel void @use_flat_to_constant_addrspacecast(ptr %ptr) #0 {
 }
 
 ; HSA-LABEL: {{^}}cast_0_group_to_flat_addrspacecast:
+; CI: s_load_dword [[APERTURE:s[0-9]+]], s[4:5], 0x10
+; CI-DAG: v_mov_b32_e32 v[[HI:[0-9]+]], [[APERTURE]]
+
+; GFX9-DAG: s_mov_b64 s[{{[0-9]+}}:[[HI:[0-9]+]]], src_shared_base
 
 ; HSA-DAG: v_mov_b32_e32 v[[LO:[0-9]+]], 0{{$}}
-; HSA-DAG: v_mov_b32_e32 v[[HI:[0-9]+]], 0{{$}}
 ; HSA-DAG: v_mov_b32_e32 v[[K:[0-9]+]], 7{{$}}
-; HSA: flat_store_dword v[[[LO]]:[[HI]]], v[[K]]
+; HSA: {{flat|global}}_store_dword v[[[LO]]:[[HI]]], v[[K]]
 define amdgpu_kernel void @cast_0_group_to_flat_addrspacecast() #0 {
   %cast = addrspacecast ptr addrspace(3) null to ptr
   store volatile i32 7, ptr %cast
@@ -259,10 +262,14 @@ define amdgpu_kernel void @cast_neg1_flat_to_group_addrspacecast() #0 {
 
 ; FIXME: Shouldn't need to enable queue ptr
 ; HSA-LABEL: {{^}}cast_0_private_to_flat_addrspacecast:
+; CI: s_load_dword [[APERTURE:s[0-9]+]], s[4:5], 0x11
+; CI-DAG: v_mov_b32_e32 v[[HI:[0-9]+]], [[APERTURE]]
+
+; GFX9-DAG: s_mov_b64 s[{{[0-9]+}}:[[HI:[0-9]+]]], src_private_base
+
 ; HSA-DAG: v_mov_b32_e32 v[[LO:[0-9]+]], 0{{$}}
-; HSA-DAG: v_mov_b32_e32 v[[HI:[0-9]+]], 0{{$}}
 ; HSA-DAG: v_mov_b32_e32 v[[K:[0-9]+]], 7{{$}}
-; HSA: flat_store_dword v[[[LO]]:[[HI]]], v[[K]]
+; HSA: {{flat|global}}_store_dword v[[[LO]]:[[HI]]], v[[K]]
 define amdgpu_kernel void @cast_0_private_to_flat_addrspacecast() #0 {
   %cast = addrspacecast ptr addrspace(5) null to ptr
   store volatile i32 7, ptr %cast