Don't hoist or sink instructions with physreg uses if the physreg is

allocatable. Even if it doesn't appear to have any defs, it may latter
on after register allocation.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82834 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2009-09-26 02:34:00 +00:00
parent 22cb6579b3
commit 45094e34bc
2 changed files with 24 additions and 6 deletions

View File

@ -44,6 +44,7 @@ namespace {
const TargetMachine *TM;
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
BitVector AllocatableSet;
// Various analyses that we use...
MachineLoopInfo *LI; // Current MachineLoopInfo
@ -138,6 +139,7 @@ bool MachineLICM::runOnMachineFunction(MachineFunction &MF) {
TII = TM->getInstrInfo();
TRI = TM->getRegisterInfo();
RegInfo = &MF.getRegInfo();
AllocatableSet = TRI->getAllocatableSet(MF);
// Get our Loop information...
LI = &getAnalysis<MachineLoopInfo>();
@ -261,13 +263,20 @@ bool MachineLICM::IsLoopInvariantInst(MachineInstr &I) {
// we can move it, but only if the def is dead.
if (MO.isUse()) {
// If the physreg has no defs anywhere, it's just an ambient register
// and we can freely move its uses.
// and we can freely move its uses. Alternatively, if it's allocatable,
// it could get allocated to something with a def during allocation.
if (!RegInfo->def_empty(Reg))
return false;
// Check for a def among the register's aliases too.
for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias)
if (!RegInfo->def_empty(*Alias))
if (AllocatableSet.test(Reg))
return false;
// Check for a def among the register's aliases too.
for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) {
unsigned AliasReg = *Alias;
if (!RegInfo->def_empty(AliasReg))
return false;
if (AllocatableSet.test(AliasReg))
return false;
}
// Otherwise it's safe to move.
continue;
} else if (!MO.isDead()) {

View File

@ -39,6 +39,7 @@ namespace {
MachineFunction *CurMF; // Current MachineFunction
MachineRegisterInfo *RegInfo; // Machine register information
MachineDominatorTree *DT; // Machine dominator tree
BitVector AllocatableSet; // Which physregs are allocatable?
public:
static char ID; // Pass identification
@ -99,6 +100,7 @@ bool MachineSinking::runOnMachineFunction(MachineFunction &MF) {
TRI = TM->getRegisterInfo();
RegInfo = &CurMF->getRegInfo();
DT = &getAnalysis<MachineDominatorTree>();
AllocatableSet = TRI->getAllocatableSet(*CurMF);
bool EverMadeChange = false;
@ -180,13 +182,20 @@ bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) {
// we can move it, but only if the def is dead.
if (MO.isUse()) {
// If the physreg has no defs anywhere, it's just an ambient register
// and we can freely move its uses.
// and we can freely move its uses. Alternatively, if it's allocatable,
// it could get allocated to something with a def during allocation.
if (!RegInfo->def_empty(Reg))
return false;
// Check for a def among the register's aliases too.
for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias)
if (!RegInfo->def_empty(*Alias))
if (AllocatableSet.test(Reg))
return false;
// Check for a def among the register's aliases too.
for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) {
unsigned AliasReg = *Alias;
if (!RegInfo->def_empty(AliasReg))
return false;
if (AllocatableSet.test(AliasReg))
return false;
}
} else if (!MO.isDead()) {
// A def that isn't dead. We can't move it.
return false;