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Only safe to use a call-clobbered or spilled callee-saved register as scratch register.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35010 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2007-03-07 20:30:36 +00:00
parent c32a7f98ab
commit 603b83ebcd
1 changed files with 8 additions and 2 deletions
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10
lib/Target/ARM/ARMLoadStoreOptimizer.cpp
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@ -15,6 +15,7 @@
#define DEBUG_TYPE "arm-ldst-opt"
#include "ARM.h"
#include "ARMAddressingModes.h"
#include "ARMMachineFunctionInfo.h"
#include "ARMRegisterInfo.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
@ -39,6 +40,7 @@ namespace {
struct VISIBILITY_HIDDEN ARMLoadStoreOpt : public MachineFunctionPass {
const TargetInstrInfo *TII;
const MRegisterInfo *MRI;
ARMFunctionInfo *AFI;
RegScavenger *RS;
MachineBasicBlock::iterator RSI;
@ -587,8 +589,11 @@ bool ARMLoadStoreOpt::LoadStoreMultipleOpti(MachineBasicBlock &MBB) {
// First advance to the instruction just before the start of the chain.
if (RSI != MBB.begin())
RS->forward(prior(RSI));
// Find a scratch register.
Scratch = RS->FindUnusedReg(&ARM::GPRRegClass);
// Find a scratch register. Make sure it's a call clobbered register or
// a spilled callee-saved register.
Scratch = RS->FindUnusedReg(&ARM::GPRRegClass, true);
if (!Scratch)
RS->FindUnusedReg(&ARM::GPRRegClass, AFI->getSpilledCSRegisters());
// Process the load / store instructions.
RS->forward(prior(MBBI));
@ -661,6 +666,7 @@ bool ARMLoadStoreOpt::MergeReturnIntoLDM(MachineBasicBlock &MBB) {
bool ARMLoadStoreOpt::runOnMachineFunction(MachineFunction &Fn) {
const TargetMachine &TM = Fn.getTarget();
AFI = Fn.getInfo<ARMFunctionInfo>();
TII = TM.getInstrInfo();
MRI = TM.getRegisterInfo();
RS = new RegScavenger();