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llvm-6502/lib/Target/ARM/Thumb2HazardRecognizer.cpp

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//===-- Thumb2HazardRecognizer.cpp - Thumb2 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 "ARM.h"
#include "Thumb2HazardRecognizer.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/ScheduleDAG.h"
using namespace llvm;
ScheduleHazardRecognizer::HazardType
Thumb2HazardRecognizer::getHazardType(SUnit *SU) {
if (ITBlockSize) {
MachineInstr *MI = SU->getInstr();
if (!MI->isDebugValue() && MI != ITBlockMIs[ITBlockSize-1])
return Hazard;
}
return PostRAHazardRecognizer::getHazardType(SU);
}
void Thumb2HazardRecognizer::Reset() {
ITBlockSize = 0;
PostRAHazardRecognizer::Reset();
}
void Thumb2HazardRecognizer::EmitInstruction(SUnit *SU) {
MachineInstr *MI = SU->getInstr();
unsigned Opcode = MI->getOpcode();
if (ITBlockSize) {
--ITBlockSize;
} else if (Opcode == ARM::t2IT) {
unsigned Mask = MI->getOperand(1).getImm();
unsigned NumTZ = CountTrailingZeros_32(Mask);
assert(NumTZ <= 3 && "Invalid IT mask!");
ITBlockSize = 4 - NumTZ;
MachineBasicBlock::iterator I = MI;
for (unsigned i = 0; i < ITBlockSize; ++i) {
// Advance to the next instruction, skipping any dbg_value instructions.
do {
++I;
} while (I->isDebugValue());
ITBlockMIs[ITBlockSize-1-i] = &*I;
}
}
PostRAHazardRecognizer::EmitInstruction(SU);
}