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[SelectionDAGBuilder] Use address width when lowering ptrtoaddr #139423

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[SelectionDAGBuilder] Use address width when lowering ptrtoaddr #139423

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3c8c76e
[𝘀𝗽𝗿] initial version
arichardson May 11, 2025
d4520dc
remove unused variable
arichardson May 11, 2025
1222b60
rebase
arichardson Jun 11, 2025
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11 changes: 9 additions & 2 deletions llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
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The LangRef says that it's always zero extend, but DAG.getPtrExtOrTrunc's comment suggests it may decide to be another extension some day?

N = DAG.getZExtOrTrunc(N, getCurSDLoc(), TLI.getValueType(DL, I.getType()));
setValue(&I, N);
}

void SelectionDAGBuilder::visitPtrToInt(const User &I) {
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11 changes: 5 additions & 6 deletions llvm/test/CodeGen/AMDGPU/ptrtoint-ptrtoaddr-p8.ll
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Expand Up @@ -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>
Expand All @@ -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
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