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3c101973b3
The vperm2f128/vperm2i128 shuffle mask decoding was not attempting to deal with shuffles that give zero lanes. This patch fixes this so that the assembly printer can provide shuffle comments. As this decoder is also used in X86ISelLowering for shuffle combining, I've added an early-out to match existing behaviour. The hope is that we can add zero support in the future, this would allow other ops' decodes (e.g. insertps) to be combined as well. Differential Revision: http://reviews.llvm.org/D10593 llvm-svn: 241516
507 lines
18 KiB
C++
507 lines
18 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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unsigned HalfSize = VT.getVectorNumElements() / 2;
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for (unsigned l = 0; l != 2; ++l) {
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unsigned HalfMask = Imm >> (l * 4);
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unsigned HalfBegin = (HalfMask & 0x3) * HalfSize;
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for (unsigned i = HalfBegin, e = HalfBegin + HalfSize; i != e; ++i)
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ShuffleMask.push_back(HalfMask & 8 ? SM_SentinelZero : 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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void DecodeZeroExtendMask(MVT SrcVT, MVT DstVT, SmallVectorImpl<int> &Mask) {
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unsigned NumDstElts = DstVT.getVectorNumElements();
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unsigned SrcScalarBits = SrcVT.getScalarSizeInBits();
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unsigned DstScalarBits = DstVT.getScalarSizeInBits();
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unsigned Scale = DstScalarBits / SrcScalarBits;
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assert(SrcScalarBits < DstScalarBits &&
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"Expected zero extension mask to increase scalar size");
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assert(SrcVT.getVectorNumElements() >= NumDstElts &&
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"Too many zero extension lanes");
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for (unsigned i = 0; i != NumDstElts; i++) {
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Mask.push_back(i);
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for (unsigned j = 1; j != Scale; j++)
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Mask.push_back(SM_SentinelZero);
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}
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}
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void DecodeZeroMoveLowMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
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unsigned NumElts = VT.getVectorNumElements();
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ShuffleMask.push_back(0);
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for (unsigned i = 1; i < NumElts; i++)
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ShuffleMask.push_back(SM_SentinelZero);
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}
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void DecodeScalarMoveMask(MVT VT, bool IsLoad, SmallVectorImpl<int> &Mask) {
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// First element comes from the first element of second source.
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// Remaining elements: Load zero extends / Move copies from first source.
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unsigned NumElts = VT.getVectorNumElements();
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Mask.push_back(NumElts);
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for (unsigned i = 1; i < NumElts; i++)
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Mask.push_back(IsLoad ? static_cast<int>(SM_SentinelZero) : i);
|
|
}
|
|
|
|
void DecodeEXTRQIMask(int Len, int Idx,
|
|
SmallVectorImpl<int> &ShuffleMask) {
|
|
// 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 bytes.
|
|
if (0 != (Len % 8) || 0 != (Idx % 8))
|
|
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(16, SM_SentinelUndef);
|
|
return;
|
|
}
|
|
|
|
// Convert index and index to work with bytes.
|
|
Len /= 8;
|
|
Idx /= 8;
|
|
|
|
// EXTRQ: Extract Len bytes starting from Idx. Zero pad the remaining bytes
|
|
// 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 != 8; ++i)
|
|
ShuffleMask.push_back(SM_SentinelZero);
|
|
for (int i = 8; i != 16; ++i)
|
|
ShuffleMask.push_back(SM_SentinelUndef);
|
|
}
|
|
|
|
void DecodeINSERTQIMask(int Len, int Idx,
|
|
SmallVectorImpl<int> &ShuffleMask) {
|
|
// 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 bytes.
|
|
if (0 != (Len % 8) || 0 != (Idx % 8))
|
|
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(16, SM_SentinelUndef);
|
|
return;
|
|
}
|
|
|
|
// Convert index and index to work with bytes.
|
|
Len /= 8;
|
|
Idx /= 8;
|
|
|
|
// INSERTQ: Extract lowest Len bytes from lower half of second source and
|
|
// insert over first source starting at Idx byte. 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 + 16);
|
|
for (int i = Idx + Len; i != 8; ++i)
|
|
ShuffleMask.push_back(i);
|
|
for (int i = 8; i != 16; ++i)
|
|
ShuffleMask.push_back(SM_SentinelUndef);
|
|
}
|
|
|
|
} // llvm namespace
|