llvm-project/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp

435 lines
16 KiB
C++

//===-- X86ShuffleDecode.cpp - X86 shuffle decode logic -------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Define several functions to decode x86 specific shuffle semantics into a
// generic vector mask.
//
//===----------------------------------------------------------------------===//
#include "X86ShuffleDecode.h"
#include "llvm/IR/Constants.h"
#include "llvm/CodeGen/MachineValueType.h"
//===----------------------------------------------------------------------===//
// Vector Mask Decoding
//===----------------------------------------------------------------------===//
namespace llvm {
void DecodeINSERTPSMask(unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
// Defaults the copying the dest value.
ShuffleMask.push_back(0);
ShuffleMask.push_back(1);
ShuffleMask.push_back(2);
ShuffleMask.push_back(3);
// Decode the immediate.
unsigned ZMask = Imm & 15;
unsigned CountD = (Imm >> 4) & 3;
unsigned CountS = (Imm >> 6) & 3;
// CountS selects which input element to use.
unsigned InVal = 4+CountS;
// CountD specifies which element of destination to update.
ShuffleMask[CountD] = InVal;
// ZMask zaps values, potentially overriding the CountD elt.
if (ZMask & 1) ShuffleMask[0] = SM_SentinelZero;
if (ZMask & 2) ShuffleMask[1] = SM_SentinelZero;
if (ZMask & 4) ShuffleMask[2] = SM_SentinelZero;
if (ZMask & 8) ShuffleMask[3] = SM_SentinelZero;
}
// <3,1> or <6,7,2,3>
void DecodeMOVHLPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask) {
for (unsigned i = NElts/2; i != NElts; ++i)
ShuffleMask.push_back(NElts+i);
for (unsigned i = NElts/2; i != NElts; ++i)
ShuffleMask.push_back(i);
}
// <0,2> or <0,1,4,5>
void DecodeMOVLHPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask) {
for (unsigned i = 0; i != NElts/2; ++i)
ShuffleMask.push_back(i);
for (unsigned i = 0; i != NElts/2; ++i)
ShuffleMask.push_back(NElts+i);
}
void DecodeMOVSLDUPMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
unsigned NumElts = VT.getVectorNumElements();
for (int i = 0, e = NumElts / 2; i < e; ++i) {
ShuffleMask.push_back(2 * i);
ShuffleMask.push_back(2 * i);
}
}
void DecodeMOVSHDUPMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
unsigned NumElts = VT.getVectorNumElements();
for (int i = 0, e = NumElts / 2; i < e; ++i) {
ShuffleMask.push_back(2 * i + 1);
ShuffleMask.push_back(2 * i + 1);
}
}
void DecodeMOVDDUPMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
unsigned VectorSizeInBits = VT.getSizeInBits();
unsigned ScalarSizeInBits = VT.getScalarSizeInBits();
unsigned NumElts = VT.getVectorNumElements();
unsigned NumLanes = VectorSizeInBits / 128;
unsigned NumLaneElts = NumElts / NumLanes;
unsigned NumLaneSubElts = 64 / ScalarSizeInBits;
for (unsigned l = 0; l < NumElts; l += NumLaneElts)
for (unsigned i = 0; i < NumLaneElts; i += NumLaneSubElts)
for (unsigned s = 0; s != NumLaneSubElts; s++)
ShuffleMask.push_back(l + s);
}
void DecodePSLLDQMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
unsigned VectorSizeInBits = VT.getSizeInBits();
unsigned NumElts = VectorSizeInBits / 8;
unsigned NumLanes = VectorSizeInBits / 128;
unsigned NumLaneElts = NumElts / NumLanes;
for (unsigned l = 0; l < NumElts; l += NumLaneElts)
for (unsigned i = 0; i < NumLaneElts; ++i) {
int M = SM_SentinelZero;
if (i >= Imm) M = i - Imm + l;
ShuffleMask.push_back(M);
}
}
void DecodePSRLDQMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
unsigned VectorSizeInBits = VT.getSizeInBits();
unsigned NumElts = VectorSizeInBits / 8;
unsigned NumLanes = VectorSizeInBits / 128;
unsigned NumLaneElts = NumElts / NumLanes;
for (unsigned l = 0; l < NumElts; l += NumLaneElts)
for (unsigned i = 0; i < NumLaneElts; ++i) {
unsigned Base = i + Imm;
int M = Base + l;
if (Base >= NumLaneElts) M = SM_SentinelZero;
ShuffleMask.push_back(M);
}
}
void DecodePALIGNRMask(MVT VT, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
unsigned NumElts = VT.getVectorNumElements();
unsigned Offset = Imm * (VT.getVectorElementType().getSizeInBits() / 8);
unsigned NumLanes = VT.getSizeInBits() / 128;
unsigned NumLaneElts = NumElts / NumLanes;
for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
for (unsigned i = 0; i != NumLaneElts; ++i) {
unsigned Base = i + Offset;
// if i+offset is out of this lane then we actually need the other source
if (Base >= NumLaneElts) Base += NumElts - NumLaneElts;
ShuffleMask.push_back(Base + l);
}
}
}
/// DecodePSHUFMask - This decodes the shuffle masks for pshufd, and vpermilp*.
/// VT indicates the type of the vector allowing it to handle different
/// datatypes and vector widths.
void DecodePSHUFMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
unsigned NumElts = VT.getVectorNumElements();
unsigned NumLanes = VT.getSizeInBits() / 128;
unsigned NumLaneElts = NumElts / NumLanes;
unsigned NewImm = Imm;
for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
for (unsigned i = 0; i != NumLaneElts; ++i) {
ShuffleMask.push_back(NewImm % NumLaneElts + l);
NewImm /= NumLaneElts;
}
if (NumLaneElts == 4) NewImm = Imm; // reload imm
}
}
void DecodePSHUFHWMask(MVT VT, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
unsigned NumElts = VT.getVectorNumElements();
for (unsigned l = 0; l != NumElts; l += 8) {
unsigned NewImm = Imm;
for (unsigned i = 0, e = 4; i != e; ++i) {
ShuffleMask.push_back(l + i);
}
for (unsigned i = 4, e = 8; i != e; ++i) {
ShuffleMask.push_back(l + 4 + (NewImm & 3));
NewImm >>= 2;
}
}
}
void DecodePSHUFLWMask(MVT VT, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
unsigned NumElts = VT.getVectorNumElements();
for (unsigned l = 0; l != NumElts; l += 8) {
unsigned NewImm = Imm;
for (unsigned i = 0, e = 4; i != e; ++i) {
ShuffleMask.push_back(l + (NewImm & 3));
NewImm >>= 2;
}
for (unsigned i = 4, e = 8; i != e; ++i) {
ShuffleMask.push_back(l + i);
}
}
}
/// DecodeSHUFPMask - This decodes the shuffle masks for shufp*. VT indicates
/// the type of the vector allowing it to handle different datatypes and vector
/// widths.
void DecodeSHUFPMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
unsigned NumElts = VT.getVectorNumElements();
unsigned NumLanes = VT.getSizeInBits() / 128;
unsigned NumLaneElts = NumElts / NumLanes;
unsigned NewImm = Imm;
for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
// each half of a lane comes from different source
for (unsigned s = 0; s != NumElts*2; s += NumElts) {
for (unsigned i = 0; i != NumLaneElts/2; ++i) {
ShuffleMask.push_back(NewImm % NumLaneElts + s + l);
NewImm /= NumLaneElts;
}
}
if (NumLaneElts == 4) NewImm = Imm; // reload imm
}
}
/// DecodeUNPCKHMask - This decodes the shuffle masks for unpckhps/unpckhpd
/// and punpckh*. VT indicates the type of the vector allowing it to handle
/// different datatypes and vector widths.
void DecodeUNPCKHMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
unsigned NumElts = VT.getVectorNumElements();
// Handle 128 and 256-bit vector lengths. AVX defines UNPCK* to operate
// independently on 128-bit lanes.
unsigned NumLanes = VT.getSizeInBits() / 128;
if (NumLanes == 0 ) NumLanes = 1; // Handle MMX
unsigned NumLaneElts = NumElts / NumLanes;
for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
for (unsigned i = l + NumLaneElts/2, e = l + NumLaneElts; i != e; ++i) {
ShuffleMask.push_back(i); // Reads from dest/src1
ShuffleMask.push_back(i+NumElts); // Reads from src/src2
}
}
}
/// DecodeUNPCKLMask - This decodes the shuffle masks for unpcklps/unpcklpd
/// and punpckl*. VT indicates the type of the vector allowing it to handle
/// different datatypes and vector widths.
void DecodeUNPCKLMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
unsigned NumElts = VT.getVectorNumElements();
// Handle 128 and 256-bit vector lengths. AVX defines UNPCK* to operate
// independently on 128-bit lanes.
unsigned NumLanes = VT.getSizeInBits() / 128;
if (NumLanes == 0 ) NumLanes = 1; // Handle MMX
unsigned NumLaneElts = NumElts / NumLanes;
for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
for (unsigned i = l, e = l + NumLaneElts/2; i != e; ++i) {
ShuffleMask.push_back(i); // Reads from dest/src1
ShuffleMask.push_back(i+NumElts); // Reads from src/src2
}
}
}
void DecodeVPERM2X128Mask(MVT VT, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
if (Imm & 0x88)
return; // Not a shuffle
unsigned HalfSize = VT.getVectorNumElements()/2;
for (unsigned l = 0; l != 2; ++l) {
unsigned HalfBegin = ((Imm >> (l*4)) & 0x3) * HalfSize;
for (unsigned i = HalfBegin, e = HalfBegin+HalfSize; i != e; ++i)
ShuffleMask.push_back(i);
}
}
void DecodePSHUFBMask(const Constant *C, SmallVectorImpl<int> &ShuffleMask) {
Type *MaskTy = C->getType();
// It is not an error for the PSHUFB mask to not be a vector of i8 because the
// constant pool uniques constants by their bit representation.
// e.g. the following take up the same space in the constant pool:
// i128 -170141183420855150465331762880109871104
//
// <2 x i64> <i64 -9223372034707292160, i64 -9223372034707292160>
//
// <4 x i32> <i32 -2147483648, i32 -2147483648,
// i32 -2147483648, i32 -2147483648>
unsigned MaskTySize = MaskTy->getPrimitiveSizeInBits();
if (MaskTySize != 128 && MaskTySize != 256) // FIXME: Add support for AVX-512.
return;
// This is a straightforward byte vector.
if (MaskTy->isVectorTy() && MaskTy->getVectorElementType()->isIntegerTy(8)) {
int NumElements = MaskTy->getVectorNumElements();
ShuffleMask.reserve(NumElements);
for (int i = 0; i < NumElements; ++i) {
// For AVX vectors with 32 bytes the base of the shuffle is the 16-byte
// lane of the vector we're inside.
int Base = i < 16 ? 0 : 16;
Constant *COp = C->getAggregateElement(i);
if (!COp) {
ShuffleMask.clear();
return;
} else if (isa<UndefValue>(COp)) {
ShuffleMask.push_back(SM_SentinelUndef);
continue;
}
uint64_t Element = cast<ConstantInt>(COp)->getZExtValue();
// If the high bit (7) of the byte is set, the element is zeroed.
if (Element & (1 << 7))
ShuffleMask.push_back(SM_SentinelZero);
else {
// Only the least significant 4 bits of the byte are used.
int Index = Base + (Element & 0xf);
ShuffleMask.push_back(Index);
}
}
}
// TODO: Handle funny-looking vectors too.
}
void DecodePSHUFBMask(ArrayRef<uint64_t> RawMask,
SmallVectorImpl<int> &ShuffleMask) {
for (int i = 0, e = RawMask.size(); i < e; ++i) {
uint64_t M = RawMask[i];
if (M == (uint64_t)SM_SentinelUndef) {
ShuffleMask.push_back(M);
continue;
}
// For AVX vectors with 32 bytes the base of the shuffle is the half of
// the vector we're inside.
int Base = i < 16 ? 0 : 16;
// If the high bit (7) of the byte is set, the element is zeroed.
if (M & (1 << 7))
ShuffleMask.push_back(SM_SentinelZero);
else {
// Only the least significant 4 bits of the byte are used.
int Index = Base + (M & 0xf);
ShuffleMask.push_back(Index);
}
}
}
void DecodeBLENDMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
int ElementBits = VT.getScalarSizeInBits();
int NumElements = VT.getVectorNumElements();
for (int i = 0; i < NumElements; ++i) {
// If there are more than 8 elements in the vector, then any immediate blend
// mask applies to each 128-bit lane. There can never be more than
// 8 elements in a 128-bit lane with an immediate blend.
int Bit = NumElements > 8 ? i % (128 / ElementBits) : i;
assert(Bit < 8 &&
"Immediate blends only operate over 8 elements at a time!");
ShuffleMask.push_back(((Imm >> Bit) & 1) ? NumElements + i : i);
}
}
/// DecodeVPERMMask - this decodes the shuffle masks for VPERMQ/VPERMPD.
/// No VT provided since it only works on 256-bit, 4 element vectors.
void DecodeVPERMMask(unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
for (unsigned i = 0; i != 4; ++i) {
ShuffleMask.push_back((Imm >> (2*i)) & 3);
}
}
void DecodeVPERMILPMask(const Constant *C, SmallVectorImpl<int> &ShuffleMask) {
Type *MaskTy = C->getType();
assert(MaskTy->isVectorTy() && "Expected a vector constant mask!");
assert(MaskTy->getVectorElementType()->isIntegerTy() &&
"Expected integer constant mask elements!");
int ElementBits = MaskTy->getScalarSizeInBits();
int NumElements = MaskTy->getVectorNumElements();
assert((NumElements == 2 || NumElements == 4 || NumElements == 8) &&
"Unexpected number of vector elements.");
ShuffleMask.reserve(NumElements);
if (auto *CDS = dyn_cast<ConstantDataSequential>(C)) {
assert((unsigned)NumElements == CDS->getNumElements() &&
"Constant mask has a different number of elements!");
for (int i = 0; i < NumElements; ++i) {
int Base = (i * ElementBits / 128) * (128 / ElementBits);
uint64_t Element = CDS->getElementAsInteger(i);
// Only the least significant 2 bits of the integer are used.
int Index = Base + (Element & 0x3);
ShuffleMask.push_back(Index);
}
} else if (auto *CV = dyn_cast<ConstantVector>(C)) {
assert((unsigned)NumElements == C->getNumOperands() &&
"Constant mask has a different number of elements!");
for (int i = 0; i < NumElements; ++i) {
int Base = (i * ElementBits / 128) * (128 / ElementBits);
Constant *COp = CV->getOperand(i);
if (isa<UndefValue>(COp)) {
ShuffleMask.push_back(SM_SentinelUndef);
continue;
}
uint64_t Element = cast<ConstantInt>(COp)->getZExtValue();
// Only the least significant 2 bits of the integer are used.
int Index = Base + (Element & 0x3);
ShuffleMask.push_back(Index);
}
}
}
void DecodeZeroExtendMask(MVT SrcVT, MVT DstVT, SmallVectorImpl<int> &Mask) {
unsigned NumDstElts = DstVT.getVectorNumElements();
unsigned SrcScalarBits = SrcVT.getScalarSizeInBits();
unsigned DstScalarBits = DstVT.getScalarSizeInBits();
unsigned Scale = DstScalarBits / SrcScalarBits;
assert(SrcScalarBits < DstScalarBits &&
"Expected zero extension mask to increase scalar size");
assert(SrcVT.getVectorNumElements() >= NumDstElts &&
"Too many zero extension lanes");
for (unsigned i = 0; i != NumDstElts; i++) {
Mask.push_back(i);
for (unsigned j = 1; j != Scale; j++)
Mask.push_back(SM_SentinelZero);
}
}
void DecodeZeroMoveLowMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
unsigned NumElts = VT.getVectorNumElements();
ShuffleMask.push_back(0);
for (unsigned i = 1; i < NumElts; i++)
ShuffleMask.push_back(SM_SentinelZero);
}
void DecodeScalarMoveMask(MVT VT, bool IsLoad, SmallVectorImpl<int> &Mask) {
// First element comes from the first element of second source.
// Remaining elements: Load zero extends / Move copies from first source.
unsigned NumElts = VT.getVectorNumElements();
Mask.push_back(NumElts);
for (unsigned i = 1; i < NumElts; i++)
Mask.push_back(IsLoad ? static_cast<int>(SM_SentinelZero) : i);
}
} // llvm namespace