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Diffstat (limited to 'llvm/lib/Target/RISCV/RISCVISelLowering.cpp')
-rw-r--r--llvm/lib/Target/RISCV/RISCVISelLowering.cpp216
1 files changed, 109 insertions, 107 deletions
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index e0cf739..3b69eda 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -9186,7 +9186,7 @@ static SDValue lowerSelectToBinOp(SDNode *N, SelectionDAG &DAG,
unsigned ShAmount = Log2_64(TrueM1);
if (Subtarget.hasShlAdd(ShAmount))
return DAG.getNode(RISCVISD::SHL_ADD, DL, VT, CondV,
- DAG.getConstant(ShAmount, DL, VT), CondV);
+ DAG.getTargetConstant(ShAmount, DL, VT), CondV);
}
}
// (select c, y, 0) -> -c & y
@@ -15463,7 +15463,7 @@ static SDValue transformAddShlImm(SDNode *N, SelectionDAG &DAG,
SDValue NS = (C0 < C1) ? N0->getOperand(0) : N1->getOperand(0);
SDValue NL = (C0 > C1) ? N0->getOperand(0) : N1->getOperand(0);
SDValue SHADD = DAG.getNode(RISCVISD::SHL_ADD, DL, VT, NL,
- DAG.getConstant(Diff, DL, VT), NS);
+ DAG.getTargetConstant(Diff, DL, VT), NS);
return DAG.getNode(ISD::SHL, DL, VT, SHADD, DAG.getConstant(Bits, DL, VT));
}
@@ -15501,7 +15501,7 @@ static SDValue combineShlAddIAddImpl(SDNode *N, SDValue AddI, SDValue Other,
int64_t AddConst = AddVal.getSExtValue();
SDValue SHADD = DAG.getNode(RISCVISD::SHL_ADD, DL, VT, SHLVal->getOperand(0),
- DAG.getConstant(ShlConst, DL, VT), Other);
+ DAG.getTargetConstant(ShlConst, DL, VT), Other);
return DAG.getNode(ISD::ADD, DL, VT, SHADD,
DAG.getSignedConstant(AddConst, DL, VT));
}
@@ -16495,6 +16495,45 @@ static SDValue expandMulToAddOrSubOfShl(SDNode *N, SelectionDAG &DAG,
return DAG.getNode(Op, DL, VT, Shift1, Shift2);
}
+static SDValue getShlAddShlAdd(SDNode *N, SelectionDAG &DAG, unsigned ShX,
+ unsigned ShY, bool AddX) {
+ SDLoc DL(N);
+ EVT VT = N->getValueType(0);
+ SDValue X = N->getOperand(0);
+ SDValue Mul359 = DAG.getNode(RISCVISD::SHL_ADD, DL, VT, X,
+ DAG.getTargetConstant(ShY, DL, VT), X);
+ return DAG.getNode(RISCVISD::SHL_ADD, DL, VT, Mul359,
+ DAG.getTargetConstant(ShX, DL, VT), AddX ? X : Mul359);
+}
+
+static SDValue expandMulToShlAddShlAdd(SDNode *N, SelectionDAG &DAG,
+ uint64_t MulAmt) {
+ // 3/5/9 * 3/5/9 -> (shXadd (shYadd X, X), (shYadd X, X))
+ switch (MulAmt) {
+ case 5 * 3:
+ return getShlAddShlAdd(N, DAG, 2, 1, /*AddX=*/false);
+ case 9 * 3:
+ return getShlAddShlAdd(N, DAG, 3, 1, /*AddX=*/false);
+ case 5 * 5:
+ return getShlAddShlAdd(N, DAG, 2, 2, /*AddX=*/false);
+ case 9 * 5:
+ return getShlAddShlAdd(N, DAG, 3, 2, /*AddX=*/false);
+ case 9 * 9:
+ return getShlAddShlAdd(N, DAG, 3, 3, /*AddX=*/false);
+ default:
+ break;
+ }
+
+ // 2/4/8 * 3/5/9 + 1 -> (shXadd (shYadd X, X), X)
+ int ShX;
+ if (int ShY = isShifted359(MulAmt - 1, ShX)) {
+ assert(ShX != 0 && "MulAmt=4,6,10 handled before");
+ if (ShX <= 3)
+ return getShlAddShlAdd(N, DAG, ShX, ShY, /*AddX=*/true);
+ }
+ return SDValue();
+}
+
// Try to expand a scalar multiply to a faster sequence.
static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
TargetLowering::DAGCombinerInfo &DCI,
@@ -16524,18 +16563,17 @@ static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
if (Subtarget.hasVendorXqciac() && isInt<12>(CNode->getSExtValue()))
return SDValue();
- // WARNING: The code below is knowingly incorrect with regards to undef semantics.
- // We're adding additional uses of X here, and in principle, we should be freezing
- // X before doing so. However, adding freeze here causes real regressions, and no
- // other target properly freezes X in these cases either.
- SDValue X = N->getOperand(0);
-
+ // WARNING: The code below is knowingly incorrect with regards to undef
+ // semantics. We're adding additional uses of X here, and in principle, we
+ // should be freezing X before doing so. However, adding freeze here causes
+ // real regressions, and no other target properly freezes X in these cases
+ // either.
if (Subtarget.hasShlAdd(3)) {
+ SDValue X = N->getOperand(0);
int Shift;
if (int ShXAmount = isShifted359(MulAmt, Shift)) {
// 3/5/9 * 2^N -> shl (shXadd X, X), N
SDLoc DL(N);
- SDValue X = N->getOperand(0);
// Put the shift first if we can fold a zext into the shift forming
// a slli.uw.
if (X.getOpcode() == ISD::AND && isa<ConstantSDNode>(X.getOperand(1)) &&
@@ -16543,80 +16581,40 @@ static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
SDValue Shl =
DAG.getNode(ISD::SHL, DL, VT, X, DAG.getConstant(Shift, DL, VT));
return DAG.getNode(RISCVISD::SHL_ADD, DL, VT, Shl,
- DAG.getConstant(ShXAmount, DL, VT), Shl);
+ DAG.getTargetConstant(ShXAmount, DL, VT), Shl);
}
// Otherwise, put the shl second so that it can fold with following
// instructions (e.g. sext or add).
SDValue Mul359 = DAG.getNode(RISCVISD::SHL_ADD, DL, VT, X,
- DAG.getConstant(ShXAmount, DL, VT), X);
+ DAG.getTargetConstant(ShXAmount, DL, VT), X);
return DAG.getNode(ISD::SHL, DL, VT, Mul359,
DAG.getConstant(Shift, DL, VT));
}
- // 3/5/9 * 3/5/9 -> shXadd (shYadd X, X), (shYadd X, X)
- int ShX;
- int ShY;
- switch (MulAmt) {
- case 3 * 5:
- ShY = 1;
- ShX = 2;
- break;
- case 3 * 9:
- ShY = 1;
- ShX = 3;
- break;
- case 5 * 5:
- ShX = ShY = 2;
- break;
- case 5 * 9:
- ShY = 2;
- ShX = 3;
- break;
- case 9 * 9:
- ShX = ShY = 3;
- break;
- default:
- ShX = ShY = 0;
- break;
- }
- if (ShX) {
+ // 3/5/9 * 3/5/9 * 2^N - In particular, this covers multiples
+ // of 25 which happen to be quite common.
+ // (2/4/8 * 3/5/9 + 1) * 2^N
+ Shift = llvm::countr_zero(MulAmt);
+ if (SDValue V = expandMulToShlAddShlAdd(N, DAG, MulAmt >> Shift)) {
+ if (Shift == 0)
+ return V;
SDLoc DL(N);
- SDValue Mul359 = DAG.getNode(RISCVISD::SHL_ADD, DL, VT, X,
- DAG.getConstant(ShY, DL, VT), X);
- return DAG.getNode(RISCVISD::SHL_ADD, DL, VT, Mul359,
- DAG.getConstant(ShX, DL, VT), Mul359);
+ return DAG.getNode(ISD::SHL, DL, VT, V, DAG.getConstant(Shift, DL, VT));
}
// If this is a power 2 + 2/4/8, we can use a shift followed by a single
// shXadd. First check if this a sum of two power of 2s because that's
// easy. Then count how many zeros are up to the first bit.
- if (isPowerOf2_64(MulAmt & (MulAmt - 1))) {
- unsigned ScaleShift = llvm::countr_zero(MulAmt);
- if (ScaleShift >= 1 && ScaleShift < 4) {
- unsigned ShiftAmt = Log2_64((MulAmt & (MulAmt - 1)));
- SDLoc DL(N);
- SDValue Shift1 =
- DAG.getNode(ISD::SHL, DL, VT, X, DAG.getConstant(ShiftAmt, DL, VT));
- return DAG.getNode(RISCVISD::SHL_ADD, DL, VT, X,
- DAG.getConstant(ScaleShift, DL, VT), Shift1);
- }
+ if (Shift >= 1 && Shift <= 3 && isPowerOf2_64(MulAmt & (MulAmt - 1))) {
+ unsigned ShiftAmt = llvm::countr_zero((MulAmt & (MulAmt - 1)));
+ SDLoc DL(N);
+ SDValue Shift1 =
+ DAG.getNode(ISD::SHL, DL, VT, X, DAG.getConstant(ShiftAmt, DL, VT));
+ return DAG.getNode(RISCVISD::SHL_ADD, DL, VT, X,
+ DAG.getTargetConstant(Shift, DL, VT), Shift1);
}
- // 2^(1,2,3) * 3,5,9 + 1 -> (shXadd (shYadd x, x), x)
- // This is the two instruction form, there are also three instruction
- // variants we could implement. e.g.
- // (2^(1,2,3) * 3,5,9 + 1) << C2
- // 2^(C1>3) * 3,5,9 +/- 1
- if (int ShXAmount = isShifted359(MulAmt - 1, Shift)) {
- assert(Shift != 0 && "MulAmt=4,6,10 handled before");
- if (Shift <= 3) {
- SDLoc DL(N);
- SDValue Mul359 = DAG.getNode(RISCVISD::SHL_ADD, DL, VT, X,
- DAG.getConstant(ShXAmount, DL, VT), X);
- return DAG.getNode(RISCVISD::SHL_ADD, DL, VT, Mul359,
- DAG.getConstant(Shift, DL, VT), X);
- }
- }
+ // TODO: 2^(C1>3) * 3,5,9 +/- 1
// 2^n + 2/4/8 + 1 -> (add (shl X, C1), (shXadd X, X))
if (MulAmt > 2 && isPowerOf2_64((MulAmt - 1) & (MulAmt - 2))) {
@@ -16626,9 +16624,10 @@ static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
SDLoc DL(N);
SDValue Shift1 =
DAG.getNode(ISD::SHL, DL, VT, X, DAG.getConstant(ShiftAmt, DL, VT));
- return DAG.getNode(ISD::ADD, DL, VT, Shift1,
- DAG.getNode(RISCVISD::SHL_ADD, DL, VT, X,
- DAG.getConstant(ScaleShift, DL, VT), X));
+ return DAG.getNode(
+ ISD::ADD, DL, VT, Shift1,
+ DAG.getNode(RISCVISD::SHL_ADD, DL, VT, X,
+ DAG.getTargetConstant(ScaleShift, DL, VT), X));
}
}
@@ -16643,29 +16642,10 @@ static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
DAG.getNode(ISD::SHL, DL, VT, X, DAG.getConstant(ShAmt, DL, VT));
SDValue Mul359 =
DAG.getNode(RISCVISD::SHL_ADD, DL, VT, X,
- DAG.getConstant(Log2_64(Offset - 1), DL, VT), X);
+ DAG.getTargetConstant(Log2_64(Offset - 1), DL, VT), X);
return DAG.getNode(ISD::SUB, DL, VT, Shift1, Mul359);
}
}
-
- for (uint64_t Divisor : {3, 5, 9}) {
- if (MulAmt % Divisor != 0)
- continue;
- uint64_t MulAmt2 = MulAmt / Divisor;
- // 3/5/9 * 3/5/9 * 2^N - In particular, this covers multiples
- // of 25 which happen to be quite common.
- if (int ShBAmount = isShifted359(MulAmt2, Shift)) {
- SDLoc DL(N);
- SDValue Mul359A =
- DAG.getNode(RISCVISD::SHL_ADD, DL, VT, X,
- DAG.getConstant(Log2_64(Divisor - 1), DL, VT), X);
- SDValue Mul359B =
- DAG.getNode(RISCVISD::SHL_ADD, DL, VT, Mul359A,
- DAG.getConstant(ShBAmount, DL, VT), Mul359A);
- return DAG.getNode(ISD::SHL, DL, VT, Mul359B,
- DAG.getConstant(Shift, DL, VT));
- }
- }
}
if (SDValue V = expandMulToAddOrSubOfShl(N, DAG, MulAmt))
@@ -17887,6 +17867,7 @@ static SDValue combineOp_VLToVWOp_VL(SDNode *N,
SmallVector<SDNode *> Worklist;
SmallPtrSet<SDNode *, 8> Inserted;
+ SmallPtrSet<SDNode *, 8> ExtensionsToRemove;
Worklist.push_back(N);
Inserted.insert(N);
SmallVector<CombineResult> CombinesToApply;
@@ -17896,22 +17877,25 @@ static SDValue combineOp_VLToVWOp_VL(SDNode *N,
NodeExtensionHelper LHS(Root, 0, DAG, Subtarget);
NodeExtensionHelper RHS(Root, 1, DAG, Subtarget);
- auto AppendUsersIfNeeded = [&Worklist, &Subtarget,
- &Inserted](const NodeExtensionHelper &Op) {
- if (Op.needToPromoteOtherUsers()) {
- for (SDUse &Use : Op.OrigOperand->uses()) {
- SDNode *TheUser = Use.getUser();
- if (!NodeExtensionHelper::isSupportedRoot(TheUser, Subtarget))
- return false;
- // We only support the first 2 operands of FMA.
- if (Use.getOperandNo() >= 2)
- return false;
- if (Inserted.insert(TheUser).second)
- Worklist.push_back(TheUser);
- }
- }
- return true;
- };
+ auto AppendUsersIfNeeded =
+ [&Worklist, &Subtarget, &Inserted,
+ &ExtensionsToRemove](const NodeExtensionHelper &Op) {
+ if (Op.needToPromoteOtherUsers()) {
+ // Remember that we're supposed to remove this extension.
+ ExtensionsToRemove.insert(Op.OrigOperand.getNode());
+ for (SDUse &Use : Op.OrigOperand->uses()) {
+ SDNode *TheUser = Use.getUser();
+ if (!NodeExtensionHelper::isSupportedRoot(TheUser, Subtarget))
+ return false;
+ // We only support the first 2 operands of FMA.
+ if (Use.getOperandNo() >= 2)
+ return false;
+ if (Inserted.insert(TheUser).second)
+ Worklist.push_back(TheUser);
+ }
+ }
+ return true;
+ };
// Control the compile time by limiting the number of node we look at in
// total.
@@ -17932,6 +17916,15 @@ static SDValue combineOp_VLToVWOp_VL(SDNode *N,
std::optional<CombineResult> Res =
FoldingStrategy(Root, LHS, RHS, DAG, Subtarget);
if (Res) {
+ // If this strategy wouldn't remove an extension we're supposed to
+ // remove, reject it.
+ if (!Res->LHSExt.has_value() &&
+ ExtensionsToRemove.contains(LHS.OrigOperand.getNode()))
+ continue;
+ if (!Res->RHSExt.has_value() &&
+ ExtensionsToRemove.contains(RHS.OrigOperand.getNode()))
+ continue;
+
Matched = true;
CombinesToApply.push_back(*Res);
// All the inputs that are extended need to be folded, otherwise
@@ -25320,3 +25313,12 @@ ArrayRef<MCPhysReg> RISCVTargetLowering::getRoundingControlRegisters() const {
}
return {};
}
+
+bool RISCVTargetLowering::shouldFoldMaskToVariableShiftPair(SDValue Y) const {
+ EVT VT = Y.getValueType();
+
+ if (VT.isVector())
+ return false;
+
+ return VT.getSizeInBits() <= Subtarget.getXLen();
+}
generated by cgit v1.1 at 2025-11-07 00:09:56 +0000