266 lines
8.7 KiB
C++
266 lines
8.7 KiB
C++
//===-- X86PreTileConfig.cpp - Tile Register Configure---------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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/// \file Pass to pre-config the shape of AMX register
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/// AMX register need to be configured before use. The shape of AMX register
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/// is encoded in the 1st and 2nd machine operand of AMX pseudo instructions.
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/// The pldtilecfg is to config tile registers. It should dominator all AMX
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/// instructions. The pldtilecfg produce a virtual cfg register and the cfg
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/// register is used by all AMX instructions.
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/// This pass is to find the common dominator of all AMX instructions and
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/// insert the pldtilecfg instruction. Besides the cfg register that pldtilecfg
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/// produces is inserted as the last operand of each AMX instruction. We use
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/// this scheme to model the def-use relationship between AMX config instruction
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/// and other AMX instructions. Below is an example.
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///
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/// ----B1----
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/// / \
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/// / \
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/// B2 B3
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/// %1:tile = PTILELOADDV %2:tile = PTILELOADDV
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///
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/// is transformed to
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///
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/// B1
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/// %25:tilecfg = PLDTILECFG
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/// / \
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/// / \
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/// %1:tile = PTILELOADDV %25 %2:tile = PTILELOADDV %25
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//
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//===----------------------------------------------------------------------===//
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#include "X86.h"
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#include "X86InstrBuilder.h"
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#include "X86RegisterInfo.h"
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#include "X86Subtarget.h"
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#include "llvm/CodeGen/MachineDominators.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/CodeGen/TargetInstrInfo.h"
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#include "llvm/CodeGen/TargetRegisterInfo.h"
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#include "llvm/CodeGen/TileShapeInfo.h"
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#include "llvm/InitializePasses.h"
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using namespace llvm;
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#define DEBUG_TYPE "tile-pre-config"
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namespace {
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class X86PreTileConfig : public MachineFunctionPass {
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// context
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MachineFunction *MF = nullptr;
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const X86Subtarget *ST = nullptr;
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const TargetRegisterInfo *TRI;
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const TargetInstrInfo *TII;
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MachineDominatorTree *DomTree = nullptr;
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MachineRegisterInfo *MRI = nullptr;
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MachineInstr *getTileConfigPoint();
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public:
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X86PreTileConfig() : MachineFunctionPass(ID) {}
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/// Return the pass name.
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StringRef getPassName() const override {
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return "Tile Register Pre-configure";
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}
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/// X86PreTileConfig analysis usage.
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void getAnalysisUsage(AnalysisUsage &AU) const override;
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/// Perform register allocation.
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bool runOnMachineFunction(MachineFunction &mf) override;
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static char ID;
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};
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} // end anonymous namespace
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char X86PreTileConfig::ID = 0;
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INITIALIZE_PASS_BEGIN(X86PreTileConfig, "tilepreconfig",
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"Tile Register Configure", false, false)
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INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
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INITIALIZE_PASS_END(X86PreTileConfig, "tilepreconfig",
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"Tile Register Configure", false, false)
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void X86PreTileConfig::getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesAll();
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AU.addRequired<MachineDominatorTree>();
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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static Register buildConfigMI(MachineBasicBlock::iterator MI, int FrameIdx,
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const TargetInstrInfo *TII,
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MachineRegisterInfo *MRI,
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const X86Subtarget *ST) {
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auto *MBB = MI->getParent();
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// FIXME: AMX should assume AVX512 enabled.
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if (ST->hasAVX512()) {
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// Zero stack slot.
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Register Zmm = MRI->createVirtualRegister(&X86::VR512RegClass);
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BuildMI(*MBB, MI, DebugLoc(), TII->get(X86::VPXORDZrr), Zmm)
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.addReg(Zmm, RegState::Undef)
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.addReg(Zmm, RegState::Undef);
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addFrameReference(BuildMI(*MBB, MI, DebugLoc(), TII->get(X86::VMOVUPSZmr)),
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FrameIdx)
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.addReg(Zmm);
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}
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// build psuedo ldtilecfg
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Register VReg = MRI->createVirtualRegister(&X86::TILECFGRegClass);
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addFrameReference(
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BuildMI(*MBB, MI, DebugLoc(), TII->get(X86::PLDTILECFG), VReg), FrameIdx);
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return VReg;
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}
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static ShapeT getShape(const MachineInstr &MI, MachineRegisterInfo *MRI) {
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unsigned Opcode = MI.getOpcode();
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switch (Opcode) {
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default:
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llvm_unreachable("Unexpected machine instruction on tile");
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case X86::PTILELOADDV:
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case X86::PTDPBSSDV:
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case X86::PTILEZEROV:
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MachineOperand &MO1 = const_cast<MachineOperand &>(MI.getOperand(1));
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MachineOperand &MO2 = const_cast<MachineOperand &>(MI.getOperand(2));
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ShapeT Shape(&MO1, &MO2, MRI);
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return Shape;
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}
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}
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MachineInstr *X86PreTileConfig::getTileConfigPoint() {
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DenseMap<Register, ShapeT> PhysShapeInfo;
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MachineBasicBlock *MBB = nullptr;
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DenseSet<const MachineInstr *> MIs;
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for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
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Register VirtReg = Register::index2VirtReg(i);
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if (MRI->reg_nodbg_empty(VirtReg))
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continue;
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const TargetRegisterClass &RC = *MRI->getRegClass(VirtReg);
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if (RC.getID() != X86::TILERegClassID)
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continue;
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// Find the common dominator for all MI that define tile register.
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for (const MachineOperand &MO : MRI->def_operands(VirtReg)) {
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if (MO.isUndef())
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continue;
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const auto *MI = MO.getParent();
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// PHI or IMPLICIT_DEF instructiion.
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// There must be a input tile before PHI instruction.
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if (MI->isTransient())
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continue;
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if (!MBB)
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MBB = const_cast<MachineBasicBlock *>(MI->getParent());
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MBB = DomTree->findNearestCommonDominator(
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MBB, const_cast<MachineBasicBlock *>(MI->getParent()));
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// Collect the instructions that define shape.
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ShapeT Shape = getShape(*MI, MRI);
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std::array<MachineOperand *, 2> ShapeMOs = {Shape.getRow(),
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Shape.getCol()};
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for (auto *ShapeMO : ShapeMOs) {
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Register ShapeReg = ShapeMO->getReg();
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for (const MachineOperand &MO : MRI->def_operands(ShapeReg)) {
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const auto *ShapeMI = MO.getParent();
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MIs.insert(ShapeMI);
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}
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}
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}
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}
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if (!MBB)
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return nullptr;
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// This pass is before the pass of eliminating PHI node, so it
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// is in SSA form.
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assert(MRI->isSSA() && "Not SSA form in pre-tile config");
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// Shape def should dominate tile config MBB.
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// def s s1 s2
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// / \ \ /
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// / \ \ /
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// conf s3=phi(s1,s2)
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// |
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// c
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//
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for (const auto *MI : MIs) {
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const MachineBasicBlock *ShapeMBB = MI->getParent();
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if (DomTree->dominates(ShapeMBB, MBB))
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continue;
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if (MI->isMoveImmediate())
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continue;
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report_fatal_error(MF->getName() + ": Failed to config tile register, "
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"please define the shape earlier");
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}
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// ldtilecfg should be inserted after the MI that define the shape.
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MachineBasicBlock::reverse_instr_iterator I, E;
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for (I = MBB->instr_rbegin(), E = MBB->instr_rend(); I != E; ++I) {
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auto *MI = &*I;
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if (MIs.count(MI) && (!MI->isMoveImmediate()))
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break;
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}
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MachineBasicBlock::iterator MII;
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if (I == E)
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MII = MBB->getFirstNonPHI();
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else {
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MII = MachineBasicBlock::iterator(&*I);
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MII++;
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}
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return &*MII;
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}
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static void addTileCFGUse(MachineFunction &MF, Register CFG) {
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for (MachineBasicBlock &MBB : MF) {
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// Traverse the basic block.
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for (MachineInstr &MI : MBB) {
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unsigned Opcode = MI.getOpcode();
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switch (Opcode) {
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default:
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break;
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case X86::PTILELOADDV:
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case X86::PTILESTOREDV:
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case X86::PTDPBSSDV:
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case X86::PTILEZEROV:
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unsigned NumOperands = MI.getNumOperands();
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MI.RemoveOperand(NumOperands - 1);
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MI.addOperand(MF, MachineOperand::CreateReg(CFG, false));
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break;
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}
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}
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}
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}
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bool X86PreTileConfig::runOnMachineFunction(MachineFunction &mf) {
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MF = &mf;
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MRI = &mf.getRegInfo();
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ST = &mf.getSubtarget<X86Subtarget>();
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TRI = ST->getRegisterInfo();
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TII = mf.getSubtarget().getInstrInfo();
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DomTree = &getAnalysis<MachineDominatorTree>();
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MachineInstr *MI = getTileConfigPoint();
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if (!MI)
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return false;
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unsigned Size = ST->getTileConfigSize();
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Align Alignment = ST->getTileConfigAlignment();
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int SS = mf.getFrameInfo().CreateStackObject(Size, Alignment, false);
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Register CFG = buildConfigMI(MI, SS, TII, MRI, ST);
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addTileCFGUse(mf, CFG);
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return true;
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}
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FunctionPass *llvm::createX86PreTileConfigPass() {
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return new X86PreTileConfig();
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}
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