diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 4e96e6f4f4bd8..2411ad9ac8da2 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -3884,8 +3884,15 @@ void SelectionDAGBuilder::visitSIToFP(const User &I) {
 }
 
 void SelectionDAGBuilder::visitPtrToAddr(const User &I) {
-  // FIXME: this is not correct for pointers with addr width != pointer width
-  visitPtrToInt(I);
+  const auto &TLI = DAG.getTargetLoweringInfo();
+  const DataLayout &DL = DAG.getDataLayout();
+  // ptrtoaddr is equivalent to a truncate of ptrtoint to address/index width
+  auto Op0 = I.getOperand(0);
+  SDValue N = getValue(Op0);
+  EVT AddrVT = TLI.getValueType(DL, DL.getAddressType(Op0->getType()));
+  N = DAG.getPtrExtOrTrunc(N, getCurSDLoc(), AddrVT);
+  N = DAG.getZExtOrTrunc(N, getCurSDLoc(), TLI.getValueType(DL, I.getType()));
+  setValue(&I, N);
 }
 
 void SelectionDAGBuilder::visitPtrToInt(const User &I) {
diff --git a/llvm/test/CodeGen/AMDGPU/ptrtoint-ptrtoaddr-p8.ll b/llvm/test/CodeGen/AMDGPU/ptrtoint-ptrtoaddr-p8.ll
index 49d91e59dff2d..a230609a09eb8 100644
--- a/llvm/test/CodeGen/AMDGPU/ptrtoint-ptrtoaddr-p8.ll
+++ b/llvm/test/CodeGen/AMDGPU/ptrtoint-ptrtoaddr-p8.ll
@@ -51,9 +51,9 @@ define <2 x i64> @ptrtoaddr_vec(ptr addrspace(8) %ignored, <2 x ptr addrspace(8)
 ; CHECK-LABEL: ptrtoaddr_vec:
 ; CHECK:       ; %bb.0:
 ; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; CHECK-NEXT:    v_mov_b32_e32 v3, v9
 ; CHECK-NEXT:    v_mov_b32_e32 v2, v8
-; CHECK-NEXT:    v_mov_b32_e32 v1, v5
+; CHECK-NEXT:    v_and_b32_e32 v1, 0xffff, v5
+; CHECK-NEXT:    v_and_b32_e32 v3, 0xffff, v9
 ; CHECK-NEXT:    v_mov_b32_e32 v0, v4
 ; CHECK-NEXT:    s_setpc_b64 s[30:31]
   %ret = ptrtoaddr <2 x ptr addrspace(8)> %ptr to <2 x i64>
@@ -78,15 +78,14 @@ define zeroext i256 @ptrtoint_ext(ptr addrspace(8) %ignored, ptr addrspace(8) %p
 }
 
 ;; Check that we extend the offset to i256 instead of reinterpreting all bits.
-;; FIXME: this is wrong, we are removing the trunc to i48:
 define zeroext i256 @ptrtoaddr_ext(ptr addrspace(8) %ignored, ptr addrspace(8) %ptr) {
 ; CHECK-LABEL: ptrtoaddr_ext:
 ; CHECK:       ; %bb.0:
 ; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; CHECK-NEXT:    v_mov_b32_e32 v3, v7
-; CHECK-NEXT:    v_mov_b32_e32 v2, v6
-; CHECK-NEXT:    v_mov_b32_e32 v1, v5
 ; CHECK-NEXT:    v_mov_b32_e32 v0, v4
+; CHECK-NEXT:    v_and_b32_e32 v1, 0xffff, v5
+; CHECK-NEXT:    v_mov_b32_e32 v2, 0
+; CHECK-NEXT:    v_mov_b32_e32 v3, 0
 ; CHECK-NEXT:    v_mov_b32_e32 v4, 0
 ; CHECK-NEXT:    v_mov_b32_e32 v5, 0
 ; CHECK-NEXT:    v_mov_b32_e32 v6, 0