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861986401e
This patch takes pain to ensure all the PEI lowering code does the right thing when lowering frame indices, insert code to manipulate stack pointers, etc. It's also custom lowering dynamic stack alloc into pseudo instructions so we can insert the right instructions at scheduling time. This fixes PR4659 and PR4682. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78361 91177308-0d34-0410-b5e6-96231b3b80d8
479 lines
15 KiB
C++
479 lines
15 KiB
C++
//===- Thumb2InstrInfo.cpp - Thumb-2 Instruction Information --------*- C++ -*-===//
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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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// This file contains the Thumb-2 implementation of the TargetInstrInfo class.
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//
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//===----------------------------------------------------------------------===//
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#include "ARMInstrInfo.h"
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#include "ARM.h"
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#include "ARMAddressingModes.h"
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#include "ARMGenInstrInfo.inc"
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#include "ARMMachineFunctionInfo.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/ADT/SmallVector.h"
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#include "Thumb2InstrInfo.h"
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using namespace llvm;
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Thumb2InstrInfo::Thumb2InstrInfo(const ARMSubtarget &STI) : RI(*this, STI) {
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}
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unsigned Thumb2InstrInfo::getUnindexedOpcode(unsigned Opc) const {
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// FIXME
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return 0;
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}
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bool
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Thumb2InstrInfo::BlockHasNoFallThrough(const MachineBasicBlock &MBB) const {
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if (MBB.empty()) return false;
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switch (MBB.back().getOpcode()) {
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case ARM::t2LDM_RET:
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case ARM::t2B: // Uncond branch.
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case ARM::t2BR_JT: // Jumptable branch.
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case ARM::t2TBB: // Table branch byte.
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case ARM::t2TBH: // Table branch halfword.
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case ARM::tBR_JTr: // Jumptable branch (16-bit version).
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case ARM::tBX_RET:
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case ARM::tBX_RET_vararg:
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case ARM::tPOP_RET:
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case ARM::tB:
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return true;
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default:
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break;
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}
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return false;
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}
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bool
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Thumb2InstrInfo::copyRegToReg(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator I,
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unsigned DestReg, unsigned SrcReg,
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const TargetRegisterClass *DestRC,
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const TargetRegisterClass *SrcRC) const {
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DebugLoc DL = DebugLoc::getUnknownLoc();
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if (I != MBB.end()) DL = I->getDebugLoc();
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if (DestRC == ARM::GPRRegisterClass &&
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SrcRC == ARM::GPRRegisterClass) {
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// FIXME: Just use tMOVgpr2gpr since it's shorter?
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if (SrcReg == ARM::SP || DestReg == ARM::SP)
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BuildMI(MBB, I, DL, get(ARM::tMOVgpr2gpr), DestReg).addReg(SrcReg);
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else
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AddDefaultCC(AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::t2MOVr),
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DestReg).addReg(SrcReg)));
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return true;
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} else if (DestRC == ARM::GPRRegisterClass &&
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SrcRC == ARM::tGPRRegisterClass) {
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BuildMI(MBB, I, DL, get(ARM::tMOVtgpr2gpr), DestReg).addReg(SrcReg);
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return true;
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} else if (DestRC == ARM::tGPRRegisterClass &&
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SrcRC == ARM::GPRRegisterClass) {
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BuildMI(MBB, I, DL, get(ARM::tMOVgpr2tgpr), DestReg).addReg(SrcReg);
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return true;
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}
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// Handle SPR, DPR, and QPR copies.
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return ARMBaseInstrInfo::copyRegToReg(MBB, I, DestReg, SrcReg, DestRC, SrcRC);
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}
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void Thumb2InstrInfo::
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storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
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unsigned SrcReg, bool isKill, int FI,
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const TargetRegisterClass *RC) const {
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DebugLoc DL = DebugLoc::getUnknownLoc();
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if (I != MBB.end()) DL = I->getDebugLoc();
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if (RC == ARM::GPRRegisterClass) {
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AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::t2STRi12))
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.addReg(SrcReg, getKillRegState(isKill))
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.addFrameIndex(FI).addImm(0));
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return;
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}
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ARMBaseInstrInfo::storeRegToStackSlot(MBB, I, SrcReg, isKill, FI, RC);
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}
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void Thumb2InstrInfo::
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loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
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unsigned DestReg, int FI,
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const TargetRegisterClass *RC) const {
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DebugLoc DL = DebugLoc::getUnknownLoc();
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if (I != MBB.end()) DL = I->getDebugLoc();
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if (RC == ARM::GPRRegisterClass) {
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AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::t2LDRi12), DestReg)
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.addFrameIndex(FI).addImm(0));
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return;
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}
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ARMBaseInstrInfo::loadRegFromStackSlot(MBB, I, DestReg, FI, RC);
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}
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void llvm::emitT2RegPlusImmediate(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator &MBBI, DebugLoc dl,
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unsigned DestReg, unsigned BaseReg, int NumBytes,
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ARMCC::CondCodes Pred, unsigned PredReg,
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const ARMBaseInstrInfo &TII) {
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bool isSub = NumBytes < 0;
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if (isSub) NumBytes = -NumBytes;
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// If profitable, use a movw or movt to materialize the offset.
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// FIXME: Use the scavenger to grab a scratch register.
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if (DestReg != ARM::SP && DestReg != BaseReg &&
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NumBytes >= 4096 &&
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ARM_AM::getT2SOImmVal(NumBytes) == -1) {
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bool Fits = false;
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if (NumBytes < 65536) {
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// Use a movw to materialize the 16-bit constant.
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BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVi16), DestReg)
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.addImm(NumBytes)
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.addImm((unsigned)Pred).addReg(PredReg).addReg(0);
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Fits = true;
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} else if ((NumBytes & 0xffff) == 0) {
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// Use a movt to materialize the 32-bit constant.
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BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVTi16), DestReg)
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.addReg(DestReg)
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.addImm(NumBytes >> 16)
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.addImm((unsigned)Pred).addReg(PredReg).addReg(0);
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Fits = true;
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}
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if (Fits) {
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if (isSub) {
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BuildMI(MBB, MBBI, dl, TII.get(ARM::t2SUBrr), DestReg)
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.addReg(BaseReg, RegState::Kill)
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.addReg(DestReg, RegState::Kill)
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.addImm((unsigned)Pred).addReg(PredReg).addReg(0);
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} else {
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BuildMI(MBB, MBBI, dl, TII.get(ARM::t2ADDrr), DestReg)
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.addReg(DestReg, RegState::Kill)
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.addReg(BaseReg, RegState::Kill)
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.addImm((unsigned)Pred).addReg(PredReg).addReg(0);
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}
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return;
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}
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}
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while (NumBytes) {
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unsigned ThisVal = NumBytes;
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unsigned Opc = 0;
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if (DestReg == ARM::SP && BaseReg != ARM::SP) {
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// mov sp, rn. Note t2MOVr cannot be used.
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BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr),DestReg).addReg(BaseReg);
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BaseReg = ARM::SP;
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continue;
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}
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if (BaseReg == ARM::SP) {
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// sub sp, sp, #imm7
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if (DestReg == ARM::SP && (ThisVal < ((1 << 7)-1) * 4)) {
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assert((ThisVal & 3) == 0 && "Stack update is not multiple of 4?");
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Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
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// FIXME: Fix Thumb1 immediate encoding.
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BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
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.addReg(BaseReg).addImm(ThisVal/4);
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NumBytes = 0;
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continue;
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}
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// sub rd, sp, so_imm
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Opc = isSub ? ARM::t2SUBrSPi : ARM::t2ADDrSPi;
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if (ARM_AM::getT2SOImmVal(NumBytes) != -1) {
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NumBytes = 0;
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} else {
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// FIXME: Move this to ARMAddressingModes.h?
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unsigned RotAmt = CountLeadingZeros_32(ThisVal);
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ThisVal = ThisVal & ARM_AM::rotr32(0xff000000U, RotAmt);
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NumBytes &= ~ThisVal;
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assert(ARM_AM::getT2SOImmVal(ThisVal) != -1 &&
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"Bit extraction didn't work?");
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}
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} else {
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assert(DestReg != ARM::SP && BaseReg != ARM::SP);
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Opc = isSub ? ARM::t2SUBri : ARM::t2ADDri;
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if (ARM_AM::getT2SOImmVal(NumBytes) != -1) {
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NumBytes = 0;
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} else if (ThisVal < 4096) {
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Opc = isSub ? ARM::t2SUBri12 : ARM::t2ADDri12;
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NumBytes = 0;
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} else {
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// FIXME: Move this to ARMAddressingModes.h?
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unsigned RotAmt = CountLeadingZeros_32(ThisVal);
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ThisVal = ThisVal & ARM_AM::rotr32(0xff000000U, RotAmt);
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NumBytes &= ~ThisVal;
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assert(ARM_AM::getT2SOImmVal(ThisVal) != -1 &&
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"Bit extraction didn't work?");
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}
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}
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// Build the new ADD / SUB.
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AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
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.addReg(BaseReg, RegState::Kill)
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.addImm(ThisVal)));
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BaseReg = DestReg;
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}
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}
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static unsigned
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negativeOffsetOpcode(unsigned opcode)
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{
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switch (opcode) {
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case ARM::t2LDRi12: return ARM::t2LDRi8;
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case ARM::t2LDRHi12: return ARM::t2LDRHi8;
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case ARM::t2LDRBi12: return ARM::t2LDRBi8;
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case ARM::t2LDRSHi12: return ARM::t2LDRSHi8;
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case ARM::t2LDRSBi12: return ARM::t2LDRSBi8;
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case ARM::t2STRi12: return ARM::t2STRi8;
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case ARM::t2STRBi12: return ARM::t2STRBi8;
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case ARM::t2STRHi12: return ARM::t2STRHi8;
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case ARM::t2LDRi8:
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case ARM::t2LDRHi8:
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case ARM::t2LDRBi8:
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case ARM::t2LDRSHi8:
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case ARM::t2LDRSBi8:
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case ARM::t2STRi8:
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case ARM::t2STRBi8:
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case ARM::t2STRHi8:
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return opcode;
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default:
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break;
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}
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return 0;
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}
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static unsigned
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positiveOffsetOpcode(unsigned opcode)
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{
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switch (opcode) {
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case ARM::t2LDRi8: return ARM::t2LDRi12;
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case ARM::t2LDRHi8: return ARM::t2LDRHi12;
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case ARM::t2LDRBi8: return ARM::t2LDRBi12;
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case ARM::t2LDRSHi8: return ARM::t2LDRSHi12;
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case ARM::t2LDRSBi8: return ARM::t2LDRSBi12;
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case ARM::t2STRi8: return ARM::t2STRi12;
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case ARM::t2STRBi8: return ARM::t2STRBi12;
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case ARM::t2STRHi8: return ARM::t2STRHi12;
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case ARM::t2LDRi12:
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case ARM::t2LDRHi12:
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case ARM::t2LDRBi12:
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case ARM::t2LDRSHi12:
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case ARM::t2LDRSBi12:
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case ARM::t2STRi12:
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case ARM::t2STRBi12:
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case ARM::t2STRHi12:
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return opcode;
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default:
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break;
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}
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return 0;
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}
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static unsigned
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immediateOffsetOpcode(unsigned opcode)
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{
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switch (opcode) {
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case ARM::t2LDRs: return ARM::t2LDRi12;
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case ARM::t2LDRHs: return ARM::t2LDRHi12;
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case ARM::t2LDRBs: return ARM::t2LDRBi12;
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case ARM::t2LDRSHs: return ARM::t2LDRSHi12;
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case ARM::t2LDRSBs: return ARM::t2LDRSBi12;
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case ARM::t2STRs: return ARM::t2STRi12;
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case ARM::t2STRBs: return ARM::t2STRBi12;
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case ARM::t2STRHs: return ARM::t2STRHi12;
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case ARM::t2LDRi12:
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case ARM::t2LDRHi12:
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case ARM::t2LDRBi12:
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case ARM::t2LDRSHi12:
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case ARM::t2LDRSBi12:
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case ARM::t2STRi12:
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case ARM::t2STRBi12:
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case ARM::t2STRHi12:
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case ARM::t2LDRi8:
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case ARM::t2LDRHi8:
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case ARM::t2LDRBi8:
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case ARM::t2LDRSHi8:
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case ARM::t2LDRSBi8:
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case ARM::t2STRi8:
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case ARM::t2STRBi8:
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case ARM::t2STRHi8:
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return opcode;
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default:
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break;
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}
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return 0;
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}
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int llvm::rewriteT2FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
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unsigned FrameReg, int Offset,
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const ARMBaseInstrInfo &TII) {
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unsigned Opcode = MI.getOpcode();
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const TargetInstrDesc &Desc = MI.getDesc();
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unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
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bool isSub = false;
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// Memory operands in inline assembly always use AddrModeT2_i12.
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if (Opcode == ARM::INLINEASM)
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AddrMode = ARMII::AddrModeT2_i12; // FIXME. mode for thumb2?
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if (Opcode == ARM::t2ADDri || Opcode == ARM::t2ADDri12) {
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Offset += MI.getOperand(FrameRegIdx+1).getImm();
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bool isSP = FrameReg == ARM::SP;
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if (Offset == 0) {
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// Turn it into a move.
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unsigned NewOpc = isSP ? ARM::tMOVgpr2gpr : ARM::t2MOVr;
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MI.setDesc(TII.get(NewOpc));
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MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
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MI.RemoveOperand(FrameRegIdx+1);
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return 0;
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}
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if (Offset < 0) {
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Offset = -Offset;
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isSub = true;
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MI.setDesc(TII.get(isSP ? ARM::t2SUBrSPi : ARM::t2SUBri));
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} else {
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MI.setDesc(TII.get(isSP ? ARM::t2ADDrSPi : ARM::t2ADDri));
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}
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// Common case: small offset, fits into instruction.
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if (ARM_AM::getT2SOImmVal(Offset) != -1) {
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MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
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MI.getOperand(FrameRegIdx+1).ChangeToImmediate(Offset);
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return 0;
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}
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// Another common case: imm12.
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if (Offset < 4096) {
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unsigned NewOpc = isSP
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? (isSub ? ARM::t2SUBrSPi12 : ARM::t2ADDrSPi12)
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: (isSub ? ARM::t2SUBri12 : ARM::t2ADDri12);
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MI.setDesc(TII.get(NewOpc));
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MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
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MI.getOperand(FrameRegIdx+1).ChangeToImmediate(Offset);
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return 0;
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}
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// Otherwise, extract 8 adjacent bits from the immediate into this
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// t2ADDri/t2SUBri.
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unsigned RotAmt = CountLeadingZeros_32(Offset);
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unsigned ThisImmVal = Offset & ARM_AM::rotr32(0xff000000U, RotAmt);
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// We will handle these bits from offset, clear them.
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Offset &= ~ThisImmVal;
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assert(ARM_AM::getT2SOImmVal(ThisImmVal) != -1 &&
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"Bit extraction didn't work?");
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MI.getOperand(FrameRegIdx+1).ChangeToImmediate(ThisImmVal);
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} else {
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// AddrModeT2_so cannot handle any offset. If there is no offset
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// register then we change to an immediate version.
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unsigned NewOpc = Opcode;
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if (AddrMode == ARMII::AddrModeT2_so) {
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unsigned OffsetReg = MI.getOperand(FrameRegIdx+1).getReg();
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if (OffsetReg != 0) {
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MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
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return Offset;
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}
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MI.RemoveOperand(FrameRegIdx+1);
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MI.getOperand(FrameRegIdx+1).ChangeToImmediate(0);
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NewOpc = immediateOffsetOpcode(Opcode);
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AddrMode = ARMII::AddrModeT2_i12;
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}
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unsigned NumBits = 0;
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unsigned Scale = 1;
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if (AddrMode == ARMII::AddrModeT2_i8 || AddrMode == ARMII::AddrModeT2_i12) {
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// i8 supports only negative, and i12 supports only positive, so
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// based on Offset sign convert Opcode to the appropriate
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// instruction
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Offset += MI.getOperand(FrameRegIdx+1).getImm();
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if (Offset < 0) {
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NewOpc = negativeOffsetOpcode(Opcode);
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NumBits = 8;
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isSub = true;
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Offset = -Offset;
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} else {
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NewOpc = positiveOffsetOpcode(Opcode);
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NumBits = 12;
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}
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} else {
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// VFP address modes.
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assert(AddrMode == ARMII::AddrMode5);
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int InstrOffs=ARM_AM::getAM5Offset(MI.getOperand(FrameRegIdx+1).getImm());
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if (ARM_AM::getAM5Op(MI.getOperand(FrameRegIdx+1).getImm()) ==ARM_AM::sub)
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InstrOffs *= -1;
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NumBits = 8;
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Scale = 4;
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Offset += InstrOffs * 4;
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assert((Offset & (Scale-1)) == 0 && "Can't encode this offset!");
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if (Offset < 0) {
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Offset = -Offset;
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isSub = true;
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}
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}
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if (NewOpc != Opcode)
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MI.setDesc(TII.get(NewOpc));
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MachineOperand &ImmOp = MI.getOperand(FrameRegIdx+1);
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// Attempt to fold address computation
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// Common case: small offset, fits into instruction.
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int ImmedOffset = Offset / Scale;
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unsigned Mask = (1 << NumBits) - 1;
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if ((unsigned)Offset <= Mask * Scale) {
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// Replace the FrameIndex with fp/sp
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MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);
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if (isSub) {
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if (AddrMode == ARMII::AddrMode5)
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// FIXME: Not consistent.
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ImmedOffset |= 1 << NumBits;
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else
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ImmedOffset = -ImmedOffset;
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}
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ImmOp.ChangeToImmediate(ImmedOffset);
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|
return 0;
|
|
}
|
|
|
|
// Otherwise, offset doesn't fit. Pull in what we can to simplify
|
|
ImmedOffset = ImmedOffset & Mask;
|
|
if (isSub) {
|
|
if (AddrMode == ARMII::AddrMode5)
|
|
// FIXME: Not consistent.
|
|
ImmedOffset |= 1 << NumBits;
|
|
else {
|
|
ImmedOffset = -ImmedOffset;
|
|
if (ImmedOffset == 0)
|
|
// Change the opcode back if the encoded offset is zero.
|
|
MI.setDesc(TII.get(positiveOffsetOpcode(NewOpc)));
|
|
}
|
|
}
|
|
ImmOp.ChangeToImmediate(ImmedOffset);
|
|
Offset &= ~(Mask*Scale);
|
|
}
|
|
|
|
return (isSub) ? -Offset : Offset;
|
|
}
|