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