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

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//===-- X86ShuffleDecode.cpp - X86 shuffle decode logic -------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Define several functions to decode x86 specific shuffle semantics into a
// generic vector mask.
//
//===----------------------------------------------------------------------===//
#include "X86ShuffleDecode.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.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;
}
void DecodeInsertElementMask(unsigned NumElts, unsigned Idx, unsigned Len,
SmallVectorImpl<int> &ShuffleMask) {
assert((Idx + Len) <= NumElts && "Insertion out of range");
for (unsigned i = 0; i != NumElts; ++i)
ShuffleMask.push_back(i);
for (unsigned i = 0; i != Len; ++i)
ShuffleMask[Idx + i] = NumElts + i;
}
// <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(unsigned NumElts, SmallVectorImpl<int> &ShuffleMask) {
for (int i = 0, e = NumElts / 2; i < e; ++i) {
ShuffleMask.push_back(2 * i);
ShuffleMask.push_back(2 * i);
}
}
void DecodeMOVSHDUPMask(unsigned NumElts, SmallVectorImpl<int> &ShuffleMask) {
for (int i = 0, e = NumElts / 2; i < e; ++i) {
ShuffleMask.push_back(2 * i + 1);
ShuffleMask.push_back(2 * i + 1);
}
}
void DecodeMOVDDUPMask(unsigned NumElts, SmallVectorImpl<int> &ShuffleMask) {
const unsigned NumLaneElts = 2;
for (unsigned l = 0; l < NumElts; l += NumLaneElts)
for (unsigned i = 0; i < NumLaneElts; ++i)
ShuffleMask.push_back(l);
}
void DecodePSLLDQMask(unsigned NumElts, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
const unsigned NumLaneElts = 16;
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(unsigned NumElts, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
const unsigned NumLaneElts = 16;
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(unsigned NumElts, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
const unsigned NumLaneElts = 16;
for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
for (unsigned i = 0; i != NumLaneElts; ++i) {
unsigned Base = i + Imm;
// if i+imm is out of this lane then we actually need the other source
if (Base >= NumLaneElts) Base += NumElts - NumLaneElts;
ShuffleMask.push_back(Base + l);
}
}
}
void DecodeVALIGNMask(unsigned NumElts, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
// Not all bits of the immediate are used so mask it.
assert(isPowerOf2_32(NumElts) && "NumElts should be power of 2");
Imm = Imm & (NumElts - 1);
for (unsigned i = 0; i != NumElts; ++i)
ShuffleMask.push_back(i + Imm);
}
void DecodePSHUFMask(unsigned NumElts, unsigned ScalarBits, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
unsigned Size = NumElts * ScalarBits;
unsigned NumLanes = Size / 128;
if (NumLanes == 0) NumLanes = 1; // Handle MMX
unsigned NumLaneElts = NumElts / NumLanes;
uint32_t SplatImm = (Imm & 0xff) * 0x01010101;
for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
for (unsigned i = 0; i != NumLaneElts; ++i) {
ShuffleMask.push_back(SplatImm % NumLaneElts + l);
SplatImm /= NumLaneElts;
}
}
}
void DecodePSHUFHWMask(unsigned NumElts, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
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(unsigned NumElts, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
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);
}
}
}
void DecodePSWAPMask(unsigned NumElts, SmallVectorImpl<int> &ShuffleMask) {
unsigned NumHalfElts = NumElts / 2;
for (unsigned l = 0; l != NumHalfElts; ++l)
ShuffleMask.push_back(l + NumHalfElts);
for (unsigned h = 0; h != NumHalfElts; ++h)
ShuffleMask.push_back(h);
}
void DecodeSHUFPMask(unsigned NumElts, unsigned ScalarBits,
unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
unsigned NumLaneElts = 128 / ScalarBits;
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
}
}
void DecodeUNPCKHMask(unsigned NumElts, unsigned ScalarBits,
SmallVectorImpl<int> &ShuffleMask) {
// Handle 128 and 256-bit vector lengths. AVX defines UNPCK* to operate
// independently on 128-bit lanes.
unsigned NumLanes = (NumElts * ScalarBits) / 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
}
}
}
void DecodeUNPCKLMask(unsigned NumElts, unsigned ScalarBits,
SmallVectorImpl<int> &ShuffleMask) {
// Handle 128 and 256-bit vector lengths. AVX defines UNPCK* to operate
// independently on 128-bit lanes.
unsigned NumLanes = (NumElts * ScalarBits) / 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 DecodeVectorBroadcast(unsigned NumElts,
SmallVectorImpl<int> &ShuffleMask) {
ShuffleMask.append(NumElts, 0);
}
void DecodeSubVectorBroadcast(unsigned DstNumElts, unsigned SrcNumElts,
SmallVectorImpl<int> &ShuffleMask) {
unsigned Scale = DstNumElts / SrcNumElts;
for (unsigned i = 0; i != Scale; ++i)
for (unsigned j = 0; j != SrcNumElts; ++j)
ShuffleMask.push_back(j);
}
void decodeVSHUF64x2FamilyMask(unsigned NumElts, unsigned ScalarSize,
unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
unsigned NumElementsInLane = 128 / ScalarSize;
unsigned NumLanes = NumElts / NumElementsInLane;
for (unsigned l = 0; l != NumElts; l += NumElementsInLane) {
unsigned Index = (Imm % NumLanes) * NumElementsInLane;
Imm /= NumLanes; // Discard the bits we just used.
// We actually need the other source.
if (l >= (NumElts / 2))
Index += NumElts;
for (unsigned i = 0; i != NumElementsInLane; ++i)
ShuffleMask.push_back(Index + i);
}
}
void DecodeVPERM2X128Mask(unsigned NumElts, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
unsigned HalfSize = NumElts / 2;
for (unsigned l = 0; l != 2; ++l) {
unsigned HalfMask = Imm >> (l * 4);
unsigned HalfBegin = (HalfMask & 0x3) * HalfSize;
for (unsigned i = HalfBegin, e = HalfBegin + HalfSize; i != e; ++i)
ShuffleMask.push_back((HalfMask & 8) ? SM_SentinelZero : (int)i);
}
}
void DecodePSHUFBMask(ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
SmallVectorImpl<int> &ShuffleMask) {
for (int i = 0, e = RawMask.size(); i < e; ++i) {
uint64_t M = RawMask[i];
if (UndefElts[i]) {
ShuffleMask.push_back(SM_SentinelUndef);
continue;
}
// For 256/512-bit vectors the base of the shuffle is the 128-bit
// subvector we're inside.
int Base = (i / 16) * 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(unsigned NumElts, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
for (unsigned i = 0; i < NumElts; ++i) {
// If there are more than 8 elements in the vector, then any immediate blend
// mask wraps around.
unsigned Bit = i % 8;
ShuffleMask.push_back(((Imm >> Bit) & 1) ? NumElts + i : i);
}
}
void DecodeVPPERMMask(ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
SmallVectorImpl<int> &ShuffleMask) {
assert(RawMask.size() == 16 && "Illegal VPPERM shuffle mask size");
// VPPERM Operation
// Bits[4:0] - Byte Index (0 - 31)
// Bits[7:5] - Permute Operation
//
// Permute Operation:
// 0 - Source byte (no logical operation).
// 1 - Invert source byte.
// 2 - Bit reverse of source byte.
// 3 - Bit reverse of inverted source byte.
// 4 - 00h (zero - fill).
// 5 - FFh (ones - fill).
// 6 - Most significant bit of source byte replicated in all bit positions.
// 7 - Invert most significant bit of source byte and replicate in all bit positions.
for (int i = 0, e = RawMask.size(); i < e; ++i) {
if (UndefElts[i]) {
ShuffleMask.push_back(SM_SentinelUndef);
continue;
}
uint64_t M = RawMask[i];
uint64_t PermuteOp = (M >> 5) & 0x7;
if (PermuteOp == 4) {
ShuffleMask.push_back(SM_SentinelZero);
continue;
}
if (PermuteOp != 0) {
ShuffleMask.clear();
return;
}
uint64_t Index = M & 0x1F;
ShuffleMask.push_back((int)Index);
}
}
void DecodeVPERMMask(unsigned NumElts, unsigned Imm,
SmallVectorImpl<int> &ShuffleMask) {
for (unsigned l = 0; l != NumElts; l += 4)
for (unsigned i = 0; i != 4; ++i)
ShuffleMask.push_back(l + ((Imm >> (2 * i)) & 3));
}
void DecodeZeroExtendMask(unsigned SrcScalarBits, unsigned DstScalarBits,
unsigned NumDstElts, bool IsAnyExtend,
SmallVectorImpl<int> &ShuffleMask) {
unsigned Scale = DstScalarBits / SrcScalarBits;
assert(SrcScalarBits < DstScalarBits &&
"Expected zero extension mask to increase scalar size");
int Sentinel = IsAnyExtend ? SM_SentinelUndef : SM_SentinelZero;
for (unsigned i = 0; i != NumDstElts; i++) {
ShuffleMask.push_back(i);
ShuffleMask.append(Scale - 1, Sentinel);
}
}
void DecodeZeroMoveLowMask(unsigned NumElts,
SmallVectorImpl<int> &ShuffleMask) {
ShuffleMask.push_back(0);
ShuffleMask.append(NumElts - 1, SM_SentinelZero);
}
void DecodeScalarMoveMask(unsigned NumElts, bool IsLoad,
SmallVectorImpl<int> &ShuffleMask) {
// First element comes from the first element of second source.
// Remaining elements: Load zero extends / Move copies from first source.
ShuffleMask.push_back(NumElts);
for (unsigned i = 1; i < NumElts; i++)
ShuffleMask.push_back(IsLoad ? static_cast<int>(SM_SentinelZero) : i);
}
void DecodeEXTRQIMask(unsigned NumElts, unsigned EltSize, int Len, int Idx,
SmallVectorImpl<int> &ShuffleMask) {
unsigned HalfElts = NumElts / 2;
// Only the bottom 6 bits are valid for each immediate.
Len &= 0x3F;
Idx &= 0x3F;
// We can only decode this bit extraction instruction as a shuffle if both the
// length and index work with whole elements.
if (0 != (Len % EltSize) || 0 != (Idx % EltSize))
return;
// A length of zero is equivalent to a bit length of 64.
if (Len == 0)
Len = 64;
// If the length + index exceeds the bottom 64 bits the result is undefined.
if ((Len + Idx) > 64) {
ShuffleMask.append(NumElts, SM_SentinelUndef);
return;
}
// Convert index and index to work with elements.
Len /= EltSize;
Idx /= EltSize;
// EXTRQ: Extract Len elements starting from Idx. Zero pad the remaining
// elements of the lower 64-bits. The upper 64-bits are undefined.
for (int i = 0; i != Len; ++i)
ShuffleMask.push_back(i + Idx);
for (int i = Len; i != (int)HalfElts; ++i)
ShuffleMask.push_back(SM_SentinelZero);
for (int i = HalfElts; i != (int)NumElts; ++i)
ShuffleMask.push_back(SM_SentinelUndef);
}
void DecodeINSERTQIMask(unsigned NumElts, unsigned EltSize, int Len, int Idx,
SmallVectorImpl<int> &ShuffleMask) {
unsigned HalfElts = NumElts / 2;
// Only the bottom 6 bits are valid for each immediate.
Len &= 0x3F;
Idx &= 0x3F;
// We can only decode this bit insertion instruction as a shuffle if both the
// length and index work with whole elements.
if (0 != (Len % EltSize) || 0 != (Idx % EltSize))
return;
// A length of zero is equivalent to a bit length of 64.
if (Len == 0)
Len = 64;
// If the length + index exceeds the bottom 64 bits the result is undefined.
if ((Len + Idx) > 64) {
ShuffleMask.append(NumElts, SM_SentinelUndef);
return;
}
// Convert index and index to work with elements.
Len /= EltSize;
Idx /= EltSize;
// INSERTQ: Extract lowest Len elements from lower half of second source and
// insert over first source starting at Idx element. The upper 64-bits are
// undefined.
for (int i = 0; i != Idx; ++i)
ShuffleMask.push_back(i);
for (int i = 0; i != Len; ++i)
ShuffleMask.push_back(i + NumElts);
for (int i = Idx + Len; i != (int)HalfElts; ++i)
ShuffleMask.push_back(i);
for (int i = HalfElts; i != (int)NumElts; ++i)
ShuffleMask.push_back(SM_SentinelUndef);
}
void DecodeVPERMILPMask(unsigned NumElts, unsigned ScalarBits,
ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
SmallVectorImpl<int> &ShuffleMask) {
unsigned VecSize = NumElts * ScalarBits;
unsigned NumLanes = VecSize / 128;
unsigned NumEltsPerLane = NumElts / NumLanes;
assert((VecSize == 128 || VecSize == 256 || VecSize == 512) &&
"Unexpected vector size");
assert((ScalarBits == 32 || ScalarBits == 64) && "Unexpected element size");
for (unsigned i = 0, e = RawMask.size(); i < e; ++i) {
if (UndefElts[i]) {
ShuffleMask.push_back(SM_SentinelUndef);
continue;
}
uint64_t M = RawMask[i];
M = (ScalarBits == 64 ? ((M >> 1) & 0x1) : (M & 0x3));
unsigned LaneOffset = i & ~(NumEltsPerLane - 1);
ShuffleMask.push_back((int)(LaneOffset + M));
}
}
void DecodeVPERMIL2PMask(unsigned NumElts, unsigned ScalarBits, unsigned M2Z,
ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
SmallVectorImpl<int> &ShuffleMask) {
unsigned VecSize = NumElts * ScalarBits;
unsigned NumLanes = VecSize / 128;
unsigned NumEltsPerLane = NumElts / NumLanes;
assert((VecSize == 128 || VecSize == 256) && "Unexpected vector size");
assert((ScalarBits == 32 || ScalarBits == 64) && "Unexpected element size");
assert((NumElts == RawMask.size()) && "Unexpected mask size");
for (unsigned i = 0, e = RawMask.size(); i < e; ++i) {
if (UndefElts[i]) {
ShuffleMask.push_back(SM_SentinelUndef);
continue;
}
// VPERMIL2 Operation.
// Bits[3] - Match Bit.
// Bits[2:1] - (Per Lane) PD Shuffle Mask.
// Bits[2:0] - (Per Lane) PS Shuffle Mask.
uint64_t Selector = RawMask[i];
unsigned MatchBit = (Selector >> 3) & 0x1;
// M2Z[0:1] MatchBit
// 0Xb X Source selected by Selector index.
// 10b 0 Source selected by Selector index.
// 10b 1 Zero.
// 11b 0 Zero.
// 11b 1 Source selected by Selector index.
if ((M2Z & 0x2) != 0 && MatchBit != (M2Z & 0x1)) {
ShuffleMask.push_back(SM_SentinelZero);
continue;
}
int Index = i & ~(NumEltsPerLane - 1);
if (ScalarBits == 64)
Index += (Selector >> 1) & 0x1;
else
Index += Selector & 0x3;
int Src = (Selector >> 2) & 0x1;
Index += Src * NumElts;
ShuffleMask.push_back(Index);
}
}
void DecodeVPERMVMask(ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
SmallVectorImpl<int> &ShuffleMask) {
uint64_t EltMaskSize = RawMask.size() - 1;
for (int i = 0, e = RawMask.size(); i != e; ++i) {
if (UndefElts[i]) {
ShuffleMask.push_back(SM_SentinelUndef);
continue;
}
uint64_t M = RawMask[i];
M &= EltMaskSize;
ShuffleMask.push_back((int)M);
}
}
void DecodeVPERMV3Mask(ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
SmallVectorImpl<int> &ShuffleMask) {
uint64_t EltMaskSize = (RawMask.size() * 2) - 1;
for (int i = 0, e = RawMask.size(); i != e; ++i) {
if (UndefElts[i]) {
ShuffleMask.push_back(SM_SentinelUndef);
continue;
}
uint64_t M = RawMask[i];
M &= EltMaskSize;
ShuffleMask.push_back((int)M);
}
}
} // llvm namespace
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