[llvm] [AMDGPU][LowerBufferFatPointers] Fix lack of rewrite when loading/storing null (PR #154128)

[Matt Arsenault via llvm-commits]

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@@ -223,3 +223,23 @@ define i32 @fancy_zero() {
   ptr addrspace(7) addrspacecast (ptr addrspace(8) @buf to ptr addrspace(7))
   to i32)
 }
+
+define i32 @load_null() {
+; CHECK-LABEL: define i32 @load_null
+; CHECK-SAME: () #[[ATTR0]] {
+; CHECK-NEXT:    [[X:%.*]] = call i32 @llvm.amdgcn.raw.ptr.buffer.load.i32(ptr addrspace(8) align 4 null, i32 0, i32 0, i32 0)
+; CHECK-NEXT:    ret i32 [[X]]
+;
+  %x = load i32, ptr addrspace(7) null, align 4
+  ret i32 %x
+}
+
+define void @store_null() {
+; CHECK-LABEL: define void @store_null
+; CHECK-SAME: () #[[ATTR0]] {
+; CHECK-NEXT:    call void @llvm.amdgcn.raw.ptr.buffer.store.i32(i32 0, ptr addrspace(8) align 4 null, i32 0, i32 0, i32 0)
+; CHECK-NEXT:    ret void
+;
+  store i32 0, ptr addrspace(7) null, align 4
+  ret void
+}
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arsenm wrote:

Can you also test the poison case 

https://github.com/llvm/llvm-project/pull/154128