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llvm-mirror/lib/Target/ARM/ARMHazardRecognizer.cpp
David Blaikie e01dc73ad2 Fix a bunch more layering of CodeGen headers that are in Target
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).

llvm-svn: 318490
2017-11-17 01:07:10 +00:00

102 lines
3.4 KiB
C++

//===-- ARMHazardRecognizer.cpp - ARM postra hazard recognizer ------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "ARMHazardRecognizer.h"
#include "ARMBaseInstrInfo.h"
#include "ARMBaseRegisterInfo.h"
#include "ARMSubtarget.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/ScheduleDAG.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
using namespace llvm;
static bool hasRAWHazard(MachineInstr *DefMI, MachineInstr *MI,
const TargetRegisterInfo &TRI) {
// FIXME: Detect integer instructions properly.
const MCInstrDesc &MCID = MI->getDesc();
unsigned Domain = MCID.TSFlags & ARMII::DomainMask;
if (MI->mayStore())
return false;
unsigned Opcode = MCID.getOpcode();
if (Opcode == ARM::VMOVRS || Opcode == ARM::VMOVRRD)
return false;
if ((Domain & ARMII::DomainVFP) || (Domain & ARMII::DomainNEON))
return MI->readsRegister(DefMI->getOperand(0).getReg(), &TRI);
return false;
}
ScheduleHazardRecognizer::HazardType
ARMHazardRecognizer::getHazardType(SUnit *SU, int Stalls) {
assert(Stalls == 0 && "ARM hazards don't support scoreboard lookahead");
MachineInstr *MI = SU->getInstr();
if (!MI->isDebugValue()) {
// Look for special VMLA / VMLS hazards. A VMUL / VADD / VSUB following
// a VMLA / VMLS will cause 4 cycle stall.
const MCInstrDesc &MCID = MI->getDesc();
if (LastMI && (MCID.TSFlags & ARMII::DomainMask) != ARMII::DomainGeneral) {
MachineInstr *DefMI = LastMI;
const MCInstrDesc &LastMCID = LastMI->getDesc();
const MachineFunction *MF = MI->getParent()->getParent();
const ARMBaseInstrInfo &TII = *static_cast<const ARMBaseInstrInfo *>(
MF->getSubtarget().getInstrInfo());
// Skip over one non-VFP / NEON instruction.
if (!LastMI->isBarrier() &&
!(TII.getSubtarget().hasMuxedUnits() && LastMI->mayLoadOrStore()) &&
(LastMCID.TSFlags & ARMII::DomainMask) == ARMII::DomainGeneral) {
MachineBasicBlock::iterator I = LastMI;
if (I != LastMI->getParent()->begin()) {
I = std::prev(I);
DefMI = &*I;
}
}
if (TII.isFpMLxInstruction(DefMI->getOpcode()) &&
(TII.canCauseFpMLxStall(MI->getOpcode()) ||
hasRAWHazard(DefMI, MI, TII.getRegisterInfo()))) {
// Try to schedule another instruction for the next 4 cycles.
if (FpMLxStalls == 0)
FpMLxStalls = 4;
return Hazard;
}
}
}
return ScoreboardHazardRecognizer::getHazardType(SU, Stalls);
}
void ARMHazardRecognizer::Reset() {
LastMI = nullptr;
FpMLxStalls = 0;
ScoreboardHazardRecognizer::Reset();
}
void ARMHazardRecognizer::EmitInstruction(SUnit *SU) {
MachineInstr *MI = SU->getInstr();
if (!MI->isDebugValue()) {
LastMI = MI;
FpMLxStalls = 0;
}
ScoreboardHazardRecognizer::EmitInstruction(SU);
}
void ARMHazardRecognizer::AdvanceCycle() {
if (FpMLxStalls && --FpMLxStalls == 0)
// Stalled for 4 cycles but still can't schedule any other instructions.
LastMI = nullptr;
ScoreboardHazardRecognizer::AdvanceCycle();
}
void ARMHazardRecognizer::RecedeCycle() {
llvm_unreachable("reverse ARM hazard checking unsupported");
}