[AMDGPU] simplify add x, *ext (setcc) => addc|subb x, 0, setcc
This simplification allows to avoid generating v_cndmask_b32
to serialize condition code between compare and use.
Differential Revision: https://reviews.llvm.org/D34300
llvm-svn: 305962
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstrInfo.td b/llvm/lib/Target/AMDGPU/AMDGPUInstrInfo.td
index e286558..bcf89bb 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstrInfo.td
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstrInfo.td
@@ -70,6 +70,10 @@
[SDTCisVT<0, i64>, SDTCisVT<1, i64>, SDTCisVT<2, i64>]
>;
+def AMDGPUAddeSubeOp : SDTypeProfile<2, 3,
+ [SDTCisSameAs<0, 2>, SDTCisSameAs<0, 3>, SDTCisVT<0, i32>, SDTCisVT<1, i1>, SDTCisVT<4, i1>]
+>;
+
//===----------------------------------------------------------------------===//
// AMDGPU DAG Nodes
//
@@ -179,6 +183,12 @@
// out = (src1 > src0) ? 1 : 0
def AMDGPUborrow : SDNode<"AMDGPUISD::BORROW", SDTIntBinOp, []>;
+// TODO: remove AMDGPUadde/AMDGPUsube when ADDCARRY/SUBCARRY get their own
+// nodes in TargetSelectionDAG.td.
+def AMDGPUadde : SDNode<"ISD::ADDCARRY", AMDGPUAddeSubeOp, []>;
+
+def AMDGPUsube : SDNode<"ISD::SUBCARRY", AMDGPUAddeSubeOp, []>;
+
def AMDGPUSetCCOp : SDTypeProfile<1, 3, [ // setcc
SDTCisVT<0, i64>, SDTCisSameAs<1, 2>, SDTCisVT<3, OtherVT>
]>;
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
index bd307e9..325dbac 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -211,6 +211,9 @@
setOperationAction(ISD::UADDO, MVT::i32, Legal);
setOperationAction(ISD::USUBO, MVT::i32, Legal);
+ setOperationAction(ISD::ADDCARRY, MVT::i32, Legal);
+ setOperationAction(ISD::SUBCARRY, MVT::i32, Legal);
+
// We only support LOAD/STORE and vector manipulation ops for vectors
// with > 4 elements.
for (MVT VT : {MVT::v8i32, MVT::v8f32, MVT::v16i32, MVT::v16f32,
@@ -471,6 +474,7 @@
setOperationAction(ISD::SELECT, VT, Custom);
}
+ setTargetDAGCombine(ISD::ADD);
setTargetDAGCombine(ISD::FADD);
setTargetDAGCombine(ISD::FSUB);
setTargetDAGCombine(ISD::FMINNUM);
@@ -4839,6 +4843,39 @@
return 0;
}
+SDValue SITargetLowering::performAddCombine(SDNode *N,
+ DAGCombinerInfo &DCI) const {
+ SelectionDAG &DAG = DCI.DAG;
+ EVT VT = N->getValueType(0);
+
+ if (VT != MVT::i32)
+ return SDValue();
+
+ SDLoc SL(N);
+ SDValue LHS = N->getOperand(0);
+ SDValue RHS = N->getOperand(1);
+
+ // add x, zext (setcc) => addcarry x, 0, setcc
+ // add x, sext (setcc) => subcarry x, 0, setcc
+ unsigned Opc = LHS.getOpcode();
+ if (Opc == ISD::ZERO_EXTEND || Opc == ISD::SIGN_EXTEND ||
+ Opc == ISD::ANY_EXTEND)
+ std::swap(RHS, LHS);
+
+ Opc = RHS.getOpcode();
+ if (Opc == ISD::ZERO_EXTEND || Opc == ISD::SIGN_EXTEND ||
+ Opc == ISD::ANY_EXTEND) {
+ auto Cond = RHS.getOperand(0);
+ if (Cond.getOpcode() == ISD::SETCC) {
+ SDVTList VTList = DAG.getVTList(MVT::i32, MVT::i1);
+ SDValue Args[] = { LHS, DAG.getConstant(0, SL, MVT::i32), Cond };
+ Opc = (Opc == ISD::SIGN_EXTEND) ? ISD::SUBCARRY : ISD::ADDCARRY;
+ return DAG.getNode(Opc, SL, VTList, Args);
+ }
+ }
+ return SDValue();
+}
+
SDValue SITargetLowering::performFAddCombine(SDNode *N,
DAGCombinerInfo &DCI) const {
if (DCI.getDAGCombineLevel() < AfterLegalizeDAG)
@@ -5009,6 +5046,8 @@
switch (N->getOpcode()) {
default:
return AMDGPUTargetLowering::PerformDAGCombine(N, DCI);
+ case ISD::ADD:
+ return performAddCombine(N, DCI);
case ISD::FADD:
return performFAddCombine(N, DCI);
case ISD::FSUB:
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.h b/llvm/lib/Target/AMDGPU/SIISelLowering.h
index 38c4dc3..215aba8 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.h
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.h
@@ -108,6 +108,7 @@
unsigned getFusedOpcode(const SelectionDAG &DAG,
const SDNode *N0, const SDNode *N1) const;
+ SDValue performAddCombine(SDNode *N, DAGCombinerInfo &DCI) const;
SDValue performFAddCombine(SDNode *N, DAGCombinerInfo &DCI) const;
SDValue performFSubCombine(SDNode *N, DAGCombinerInfo &DCI) const;
SDValue performSetCCCombine(SDNode *N, DAGCombinerInfo &DCI) const;
diff --git a/llvm/lib/Target/AMDGPU/VOP2Instructions.td b/llvm/lib/Target/AMDGPU/VOP2Instructions.td
index 94f4274..7249d46 100644
--- a/llvm/lib/Target/AMDGPU/VOP2Instructions.td
+++ b/llvm/lib/Target/AMDGPU/VOP2Instructions.td
@@ -392,6 +392,15 @@
} // End SubtargetPredicate = isGCN
+def : Pat<
+ (AMDGPUadde i32:$src0, i32:$src1, i1:$src2),
+ (V_ADDC_U32_e64 $src0, $src1, $src2)
+>;
+
+def : Pat<
+ (AMDGPUsube i32:$src0, i32:$src1, i1:$src2),
+ (V_SUBB_U32_e64 $src0, $src1, $src2)
+>;
// These instructions only exist on SI and CI
let SubtargetPredicate = isSICI in {