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//===-- ARMMul.cpp - Define TargetMachine for A5CRM -----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the "Instituto Nokia de Tecnologia" and
// is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Modify the ARM multiplication instructions so that Rd{Hi,Lo} and Rm are distinct
//
//===----------------------------------------------------------------------===//
#include "ARM.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/Support/Compiler.h"
using namespace llvm;
namespace {
class VISIBILITY_HIDDEN FixMul : public MachineFunctionPass {
virtual bool runOnMachineFunction(MachineFunction &MF);
};
}
FunctionPass *llvm::createARMFixMulPass() { return new FixMul(); }
bool FixMul::runOnMachineFunction(MachineFunction &MF) {
bool Changed = false;
for (MachineFunction::iterator BB = MF.begin(), E = MF.end();
BB != E; ++BB) {
MachineBasicBlock &MBB = *BB;
for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end();
I != E; ++I) {
MachineInstr *MI = I;
int Op = MI->getOpcode();
if (Op == ARM::MUL ||
Op == ARM::SMULL ||
Op == ARM::UMULL) {
MachineOperand &RdOp = MI->getOperand(0);
MachineOperand &RmOp = MI->getOperand(1);
MachineOperand &RsOp = MI->getOperand(2);
unsigned Rd = RdOp.getReg();
unsigned Rm = RmOp.getReg();
unsigned Rs = RsOp.getReg();
if (Rd == Rm) {
Changed = true;
if (Rd != Rs) {
//Rd and Rm must be distinct, but Rd can be equal to Rs.
//Swap Rs and Rm
RmOp.setReg(Rs);
RsOp.setReg(Rm);
} else {
unsigned scratch = Op == ARM::MUL ? ARM::R12 : ARM::R0;
BuildMI(MBB, I, ARM::MOV, 3, scratch).addReg(Rm).addImm(0)
.addImm(ARMShift::LSL);
RmOp.setReg(scratch);
}
}
}
}
}
return Changed;
}
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