[llvm] r243264 - [X86] Reordered lowerVectorShuffleAsBitMask before lowerVectorShuffleAsBlend. NFCI.
Simon Pilgrim
llvm-dev at redking.me.uk
Mon Jul 27 05:37:20 PDT 2015
Author: rksimon
Date: Mon Jul 27 07:37:19 2015
New Revision: 243264
URL: http://llvm.org/viewvc/llvm-project?rev=243264&view=rev
Log:
[X86] Reordered lowerVectorShuffleAsBitMask before lowerVectorShuffleAsBlend. NFCI.
Allows us to show diffs for D11518 more clearly
Modified:
llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=243264&r1=243263&r2=243264&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Mon Jul 27 07:37:19 2015
@@ -6471,6 +6471,92 @@ static SDValue getV4X86ShuffleImm8ForMas
return DAG.getConstant(Imm, DL, MVT::i8);
}
+/// \brief Compute whether each element of a shuffle is zeroable.
+///
+/// A "zeroable" vector shuffle element is one which can be lowered to zero.
+/// Either it is an undef element in the shuffle mask, the element of the input
+/// referenced is undef, or the element of the input referenced is known to be
+/// zero. Many x86 shuffles can zero lanes cheaply and we often want to handle
+/// as many lanes with this technique as possible to simplify the remaining
+/// shuffle.
+static SmallBitVector computeZeroableShuffleElements(ArrayRef<int> Mask,
+ SDValue V1, SDValue V2) {
+ SmallBitVector Zeroable(Mask.size(), false);
+
+ while (V1.getOpcode() == ISD::BITCAST)
+ V1 = V1->getOperand(0);
+ while (V2.getOpcode() == ISD::BITCAST)
+ V2 = V2->getOperand(0);
+
+ bool V1IsZero = ISD::isBuildVectorAllZeros(V1.getNode());
+ bool V2IsZero = ISD::isBuildVectorAllZeros(V2.getNode());
+
+ for (int i = 0, Size = Mask.size(); i < Size; ++i) {
+ int M = Mask[i];
+ // Handle the easy cases.
+ if (M < 0 || (M >= 0 && M < Size && V1IsZero) || (M >= Size && V2IsZero)) {
+ Zeroable[i] = true;
+ continue;
+ }
+
+ // If this is an index into a build_vector node (which has the same number
+ // of elements), dig out the input value and use it.
+ SDValue V = M < Size ? V1 : V2;
+ if (V.getOpcode() != ISD::BUILD_VECTOR || Size != (int)V.getNumOperands())
+ continue;
+
+ SDValue Input = V.getOperand(M % Size);
+ // The UNDEF opcode check really should be dead code here, but not quite
+ // worth asserting on (it isn't invalid, just unexpected).
+ if (Input.getOpcode() == ISD::UNDEF || X86::isZeroNode(Input))
+ Zeroable[i] = true;
+ }
+
+ return Zeroable;
+}
+
+/// \brief Try to emit a bitmask instruction for a shuffle.
+///
+/// This handles cases where we can model a blend exactly as a bitmask due to
+/// one of the inputs being zeroable.
+static SDValue lowerVectorShuffleAsBitMask(SDLoc DL, MVT VT, SDValue V1,
+ SDValue V2, ArrayRef<int> Mask,
+ SelectionDAG &DAG) {
+ MVT EltVT = VT.getScalarType();
+ int NumEltBits = EltVT.getSizeInBits();
+ MVT IntEltVT = MVT::getIntegerVT(NumEltBits);
+ SDValue Zero = DAG.getConstant(0, DL, IntEltVT);
+ SDValue AllOnes = DAG.getConstant(APInt::getAllOnesValue(NumEltBits), DL,
+ IntEltVT);
+ if (EltVT.isFloatingPoint()) {
+ Zero = DAG.getBitcast(EltVT, Zero);
+ AllOnes = DAG.getBitcast(EltVT, AllOnes);
+ }
+ SmallVector<SDValue, 16> VMaskOps(Mask.size(), Zero);
+ SmallBitVector Zeroable = computeZeroableShuffleElements(Mask, V1, V2);
+ SDValue V;
+ for (int i = 0, Size = Mask.size(); i < Size; ++i) {
+ if (Zeroable[i])
+ continue;
+ if (Mask[i] % Size != i)
+ return SDValue(); // Not a blend.
+ if (!V)
+ V = Mask[i] < Size ? V1 : V2;
+ else if (V != (Mask[i] < Size ? V1 : V2))
+ return SDValue(); // Can only let one input through the mask.
+
+ VMaskOps[i] = AllOnes;
+ }
+ if (!V)
+ return SDValue(); // No non-zeroable elements!
+
+ SDValue VMask = DAG.getNode(ISD::BUILD_VECTOR, DL, VT, VMaskOps);
+ V = DAG.getNode(VT.isFloatingPoint()
+ ? (unsigned) X86ISD::FAND : (unsigned) ISD::AND,
+ DL, VT, V, VMask);
+ return V;
+}
+
/// \brief Try to emit a blend instruction for a shuffle using bit math.
///
/// This is used as a fallback approach when first class blend instructions are
@@ -6834,92 +6920,6 @@ static SDValue lowerVectorShuffleAsByteR
DAG.getNode(ISD::OR, DL, MVT::v2i64, LoShift, HiShift));
}
-/// \brief Compute whether each element of a shuffle is zeroable.
-///
-/// A "zeroable" vector shuffle element is one which can be lowered to zero.
-/// Either it is an undef element in the shuffle mask, the element of the input
-/// referenced is undef, or the element of the input referenced is known to be
-/// zero. Many x86 shuffles can zero lanes cheaply and we often want to handle
-/// as many lanes with this technique as possible to simplify the remaining
-/// shuffle.
-static SmallBitVector computeZeroableShuffleElements(ArrayRef<int> Mask,
- SDValue V1, SDValue V2) {
- SmallBitVector Zeroable(Mask.size(), false);
-
- while (V1.getOpcode() == ISD::BITCAST)
- V1 = V1->getOperand(0);
- while (V2.getOpcode() == ISD::BITCAST)
- V2 = V2->getOperand(0);
-
- bool V1IsZero = ISD::isBuildVectorAllZeros(V1.getNode());
- bool V2IsZero = ISD::isBuildVectorAllZeros(V2.getNode());
-
- for (int i = 0, Size = Mask.size(); i < Size; ++i) {
- int M = Mask[i];
- // Handle the easy cases.
- if (M < 0 || (M >= 0 && M < Size && V1IsZero) || (M >= Size && V2IsZero)) {
- Zeroable[i] = true;
- continue;
- }
-
- // If this is an index into a build_vector node (which has the same number
- // of elements), dig out the input value and use it.
- SDValue V = M < Size ? V1 : V2;
- if (V.getOpcode() != ISD::BUILD_VECTOR || Size != (int)V.getNumOperands())
- continue;
-
- SDValue Input = V.getOperand(M % Size);
- // The UNDEF opcode check really should be dead code here, but not quite
- // worth asserting on (it isn't invalid, just unexpected).
- if (Input.getOpcode() == ISD::UNDEF || X86::isZeroNode(Input))
- Zeroable[i] = true;
- }
-
- return Zeroable;
-}
-
-/// \brief Try to emit a bitmask instruction for a shuffle.
-///
-/// This handles cases where we can model a blend exactly as a bitmask due to
-/// one of the inputs being zeroable.
-static SDValue lowerVectorShuffleAsBitMask(SDLoc DL, MVT VT, SDValue V1,
- SDValue V2, ArrayRef<int> Mask,
- SelectionDAG &DAG) {
- MVT EltVT = VT.getScalarType();
- int NumEltBits = EltVT.getSizeInBits();
- MVT IntEltVT = MVT::getIntegerVT(NumEltBits);
- SDValue Zero = DAG.getConstant(0, DL, IntEltVT);
- SDValue AllOnes = DAG.getConstant(APInt::getAllOnesValue(NumEltBits), DL,
- IntEltVT);
- if (EltVT.isFloatingPoint()) {
- Zero = DAG.getBitcast(EltVT, Zero);
- AllOnes = DAG.getBitcast(EltVT, AllOnes);
- }
- SmallVector<SDValue, 16> VMaskOps(Mask.size(), Zero);
- SmallBitVector Zeroable = computeZeroableShuffleElements(Mask, V1, V2);
- SDValue V;
- for (int i = 0, Size = Mask.size(); i < Size; ++i) {
- if (Zeroable[i])
- continue;
- if (Mask[i] % Size != i)
- return SDValue(); // Not a blend.
- if (!V)
- V = Mask[i] < Size ? V1 : V2;
- else if (V != (Mask[i] < Size ? V1 : V2))
- return SDValue(); // Can only let one input through the mask.
-
- VMaskOps[i] = AllOnes;
- }
- if (!V)
- return SDValue(); // No non-zeroable elements!
-
- SDValue VMask = DAG.getNode(ISD::BUILD_VECTOR, DL, VT, VMaskOps);
- V = DAG.getNode(VT.isFloatingPoint()
- ? (unsigned) X86ISD::FAND : (unsigned) ISD::AND,
- DL, VT, V, VMask);
- return V;
-}
-
/// \brief Try to lower a vector shuffle as a bit shift (shifts in zeros).
///
/// Attempts to match a shuffle mask against the PSLL(W/D/Q/DQ) and
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