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Diffstat (limited to 'llvm/lib/Target/RISCV/RISCVISelLowering.cpp')
-rw-r--r--llvm/lib/Target/RISCV/RISCVISelLowering.cpp134
1 files changed, 71 insertions, 63 deletions
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 6234714..a3a4cf2 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -16498,43 +16498,60 @@ static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
SDValue X = N->getOperand(0);
if (Subtarget.hasShlAdd(3)) {
- for (uint64_t Divisor : {3, 5, 9}) {
- if (MulAmt % Divisor != 0)
- continue;
- uint64_t MulAmt2 = MulAmt / Divisor;
- // 3/5/9 * 2^N -> shl (shXadd X, X), N
- if (isPowerOf2_64(MulAmt2)) {
- 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)) &&
- X.getConstantOperandVal(1) == UINT64_C(0xffffffff)) {
- SDValue Shl = DAG.getNode(ISD::SHL, DL, VT, X,
- DAG.getConstant(Log2_64(MulAmt2), DL, VT));
- return DAG.getNode(RISCVISD::SHL_ADD, DL, VT, Shl,
- DAG.getConstant(Log2_64(Divisor - 1), DL, VT),
- Shl);
- }
- // Otherwise, put rhe 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(Log2_64(Divisor - 1), DL, VT), X);
- return DAG.getNode(ISD::SHL, DL, VT, Mul359,
- DAG.getConstant(Log2_64(MulAmt2), DL, VT));
- }
-
- // 3/5/9 * 3/5/9 -> shXadd (shYadd X, X), (shYadd X, X)
- if (MulAmt2 == 3 || MulAmt2 == 5 || MulAmt2 == 9) {
- SDLoc DL(N);
- SDValue Mul359 =
- DAG.getNode(RISCVISD::SHL_ADD, DL, VT, X,
- DAG.getConstant(Log2_64(Divisor - 1), DL, VT), X);
- return DAG.getNode(RISCVISD::SHL_ADD, DL, VT, Mul359,
- DAG.getConstant(Log2_64(MulAmt2 - 1), DL, VT),
- Mul359);
+ 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)) &&
+ X.getConstantOperandVal(1) == UINT64_C(0xffffffff)) {
+ 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);
}
+ // 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);
+ 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) {
+ 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);
}
// If this is a power 2 + 2/4/8, we can use a shift followed by a single
@@ -16557,18 +16574,14 @@ static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
// variants we could implement. e.g.
// (2^(1,2,3) * 3,5,9 + 1) << C2
// 2^(C1>3) * 3,5,9 +/- 1
- for (uint64_t Divisor : {3, 5, 9}) {
- uint64_t C = MulAmt - 1;
- if (C <= Divisor)
- continue;
- unsigned TZ = llvm::countr_zero(C);
- if ((C >> TZ) == Divisor && (TZ == 1 || TZ == 2 || TZ == 3)) {
+ 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(Log2_64(Divisor - 1), DL, VT), X);
+ 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(TZ, DL, VT), X);
+ DAG.getConstant(Shift, DL, VT), X);
}
}
@@ -16576,7 +16589,7 @@ static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
if (MulAmt > 2 && isPowerOf2_64((MulAmt - 1) & (MulAmt - 2))) {
unsigned ScaleShift = llvm::countr_zero(MulAmt - 1);
if (ScaleShift >= 1 && ScaleShift < 4) {
- unsigned ShiftAmt = Log2_64(((MulAmt - 1) & (MulAmt - 2)));
+ unsigned ShiftAmt = llvm::countr_zero((MulAmt - 1) & (MulAmt - 2));
SDLoc DL(N);
SDValue Shift1 =
DAG.getNode(ISD::SHL, DL, VT, X, DAG.getConstant(ShiftAmt, DL, VT));
@@ -16589,7 +16602,7 @@ static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
// 2^N - 3/5/9 --> (sub (shl X, C1), (shXadd X, x))
for (uint64_t Offset : {3, 5, 9}) {
if (isPowerOf2_64(MulAmt + Offset)) {
- unsigned ShAmt = Log2_64(MulAmt + Offset);
+ unsigned ShAmt = llvm::countr_zero(MulAmt + Offset);
if (ShAmt >= VT.getSizeInBits())
continue;
SDLoc DL(N);
@@ -16608,21 +16621,16 @@ static SDValue expandMul(SDNode *N, SelectionDAG &DAG,
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.
- for (uint64_t Divisor2 : {3, 5, 9}) {
- if (MulAmt2 % Divisor2 != 0)
- continue;
- uint64_t MulAmt3 = MulAmt2 / Divisor2;
- if (isPowerOf2_64(MulAmt3)) {
- 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(Log2_64(Divisor2 - 1), DL, VT), Mul359A);
- return DAG.getNode(ISD::SHL, DL, VT, Mul359B,
- DAG.getConstant(Log2_64(MulAmt3), DL, VT));
- }
+ 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));
}
}
}
generated by cgit v1.1 at 2025-10-07 14:46:19 +0000