InferAddressSpaces: Fix mishandling stores of pointers to themselves (llvm#101877)

Author: arsenm

llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp

@@ -1233,7 +1233,7 @@ bool InferAddressSpacesImpl::rewriteWithNewAddressSpaces(
         // If V is used as the pointer operand of a compatible memory operation,
         // sets the pointer operand to NewV. This replacement does not change
         // the element type, so the resultant load/store is still valid.
-        CurUser->replaceUsesOfWith(V, NewV);
+        U.set(NewV);
         continue;
       }
 

llvm/test/Transforms/InferAddressSpaces/AMDGPU/store-pointer-to-self.ll

@@ -0,0 +1,71 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S -mtriple=amdgcn-amd-amdhsa -passes=infer-address-spaces %s | FileCheck %s
+
+; Make sure memory instructions where the pointer appears in both a
+; pointer and value operand work correctly.
+
+declare void @user(ptr)
+
+; Make sure only the pointer operand use of the store is replaced
+define void @store_flat_pointer_to_self() {
+; CHECK-LABEL: define void @store_flat_pointer_to_self() {
+; CHECK-NEXT:    [[ALLOCA:%.*]] = alloca ptr, align 8, addrspace(5)
+; CHECK-NEXT:    [[FLAT:%.*]] = addrspacecast ptr addrspace(5) [[ALLOCA]] to ptr
+; CHECK-NEXT:    store ptr [[FLAT]], ptr addrspace(5) [[ALLOCA]], align 8
+; CHECK-NEXT:    call void @user(ptr [[FLAT]])
+; CHECK-NEXT:    ret void
+;
+  %alloca = alloca ptr, align 8, addrspace(5)
+  %flat = addrspacecast ptr addrspace(5) %alloca to ptr
+  store ptr %flat, ptr %flat, align 8
+  call void @user(ptr %flat)
+  ret void
+}
+
+; FIXME: Should be able to optimize the pointer operand to flat.
+define ptr @atomicrmw_xchg_flat_pointer_to_self() {
+; CHECK-LABEL: define ptr @atomicrmw_xchg_flat_pointer_to_self() {
+; CHECK-NEXT:    [[ALLOCA:%.*]] = alloca ptr, align 8, addrspace(5)
+; CHECK-NEXT:    [[FLAT:%.*]] = addrspacecast ptr addrspace(5) [[ALLOCA]] to ptr
+; CHECK-NEXT:    [[XCHG:%.*]] = atomicrmw xchg ptr [[FLAT]], ptr [[FLAT]] seq_cst, align 8
+; CHECK-NEXT:    call void @user(ptr [[FLAT]])
+; CHECK-NEXT:    ret ptr [[XCHG]]
+;
+  %alloca = alloca ptr, align 8, addrspace(5)
+  %flat = addrspacecast ptr addrspace(5) %alloca to ptr
+  %xchg = atomicrmw xchg ptr %flat, ptr %flat seq_cst, align 8
+  call void @user(ptr %flat)
+  ret ptr %xchg
+}
+
+define { ptr, i1 } @cmpxchg_flat_pointer_new_to_self(ptr %cmp) {
+; CHECK-LABEL: define { ptr, i1 } @cmpxchg_flat_pointer_new_to_self(
+; CHECK-SAME: ptr [[CMP:%.*]]) {
+; CHECK-NEXT:    [[ALLOCA:%.*]] = alloca ptr, align 8, addrspace(5)
+; CHECK-NEXT:    [[FLAT:%.*]] = addrspacecast ptr addrspace(5) [[ALLOCA]] to ptr
+; CHECK-NEXT:    [[CMPX:%.*]] = cmpxchg ptr [[FLAT]], ptr [[CMP]], ptr [[FLAT]] seq_cst seq_cst, align 8
+; CHECK-NEXT:    call void @user(ptr [[FLAT]])
+; CHECK-NEXT:    ret { ptr, i1 } [[CMPX]]
+;
+  %alloca = alloca ptr, align 8, addrspace(5)
+  %flat = addrspacecast ptr addrspace(5) %alloca to ptr
+  %cmpx = cmpxchg ptr %flat, ptr %cmp, ptr %flat seq_cst seq_cst, align 8
+  call void @user(ptr %flat)
+  ret { ptr, i1 } %cmpx
+}
+
+define { ptr, i1 } @cmpxchg_flat_pointer_cmp_to_self(ptr %new) {
+; CHECK-LABEL: define { ptr, i1 } @cmpxchg_flat_pointer_cmp_to_self(
+; CHECK-SAME: ptr [[NEW:%.*]]) {
+; CHECK-NEXT:    [[ALLOCA:%.*]] = alloca ptr, align 8, addrspace(5)
+; CHECK-NEXT:    [[FLAT:%.*]] = addrspacecast ptr addrspace(5) [[ALLOCA]] to ptr
+; CHECK-NEXT:    [[CMPX:%.*]] = cmpxchg ptr [[FLAT]], ptr [[FLAT]], ptr [[NEW]] seq_cst seq_cst, align 8
+; CHECK-NEXT:    call void @user(ptr [[FLAT]])
+; CHECK-NEXT:    ret { ptr, i1 } [[CMPX]]
+;
+  %alloca = alloca ptr, align 8, addrspace(5)
+  %flat = addrspacecast ptr addrspace(5) %alloca to ptr
+  %cmpx = cmpxchg ptr %flat, ptr %flat, ptr %new seq_cst seq_cst, align 8
+  call void @user(ptr %flat)
+  ret { ptr, i1 } %cmpx
+}