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CPSR can be livein; transfer predicate operands correctly; tMUL is two-address. 

llvm-svn: 78559
This commit is contained in:
Evan Cheng 2009-08-10 06:57:42 +00:00
parent 092b701a2c
commit 1f5bee14a1
1 changed files with 57 additions and 19 deletions
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76
llvm/lib/Target/ARM/Thumb2SizeReduction.cpp
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@ -21,8 +21,8 @@
#include "llvm/ADT/Statistic.h"
using namespace llvm;
STATISTIC(NumNarrows, "Number of 32-bit instructions reduced to 16-bit ones");
STATISTIC(Num2Addrs, "Number of 32-bit instructions reduced to 2-address");
STATISTIC(NumNarrows, "Number of 32-bit instrs reduced to 16-bit ones");
STATISTIC(Num2Addrs, "Number of 32-bit instrs reduced to 2addr 16-bit ones");
namespace {
/// ReduceTable - A static table with information on mapping from wide
@ -63,8 +63,9 @@ namespace {
{ ARM::t2LSRrr, ARM::tLSRrr, 0, 0, 0, 1, 0, 0,0, 0 },
{ ARM::t2MOVi, ARM::tMOVi8, 0, 8, 0, 1, 0, 0,0, 0 },
// FIXME: Do we need the 16-bit 'S' variant?
// FIXME: t2MOVcc
{ ARM::t2MOVr,ARM::tMOVgpr2gpr,0, 0, 0, 0, 0, 1,0, 0 },
{ ARM::t2MUL, ARM::tMUL, 0, 0, 0, 1, 0, 0,0, 0 },
{ ARM::t2MUL, 0, ARM::tMUL, 0, 0, 1, 0, 0,0, 0 },
{ ARM::t2MVNr, ARM::tMVN, 0, 0, 0, 1, 0, 0,0, 0 },
{ ARM::t2ORRrr, ARM::tORR, 0, 0, 0, 1, 0, 0,0, 0 },
{ ARM::t2REV, ARM::tREV, 0, 0, 0, 1, 0, 0,0, 0 },
@ -126,10 +127,8 @@ Thumb2SizeReduce::Thumb2SizeReduce() : MachineFunctionPass(&ID) {
}
static bool VerifyPredAndCC(MachineInstr *MI, const ReduceEntry &Entry,
bool is2Addr, bool LiveCPSR,
bool &HasCC, bool &CCDead) {
unsigned PredReg = 0;
ARMCC::CondCodes Pred = getInstrPredicate(MI, PredReg);
bool is2Addr, ARMCC::CondCodes Pred,
bool LiveCPSR, bool &HasCC, bool &CCDead) {
if ((is2Addr && Entry.PredCC2 == 0) ||
(!is2Addr && Entry.PredCC1 == 0)) {
if (Pred == ARMCC::AL) {
@ -181,6 +180,19 @@ Thumb2SizeReduce::ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI,
return false;
}
// Check if it's possible / necessary to transfer the predicate.
const TargetInstrDesc &NewTID = TII->get(Entry.NarrowOpc2);
unsigned PredReg = 0;
ARMCC::CondCodes Pred = getInstrPredicate(MI, PredReg);
bool SkipPred = false;
if (Pred != ARMCC::AL) {
if (!NewTID.isPredicable())
// Can't transfer predicate, fail.
return false;
} else {
SkipPred = !NewTID.isPredicable();
}
bool HasCC = false;
bool CCDead = false;
if (TID.hasOptionalDef()) {
@ -189,7 +201,7 @@ Thumb2SizeReduce::ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI,
if (HasCC && MI->getOperand(NumOps-1).isDead())
CCDead = true;
}
if (!VerifyPredAndCC(MI, Entry, true, LiveCPSR, HasCC, CCDead))
if (!VerifyPredAndCC(MI, Entry, true, Pred, LiveCPSR, HasCC, CCDead))
return false;
// Add the 16-bit instruction.
@ -201,15 +213,18 @@ Thumb2SizeReduce::ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI,
// Transfer the rest of operands.
unsigned NumOps = TID.getNumOperands();
for (unsigned i = 1, e = MI->getNumOperands(); i != e; ++i)
if (!(i < NumOps && TID.OpInfo[i].isOptionalDef()))
MIB.addOperand(MI->getOperand(i));
for (unsigned i = 1, e = MI->getNumOperands(); i != e; ++i) {
if (i < NumOps && TID.OpInfo[i].isOptionalDef())
continue;
if (SkipPred && TID.OpInfo[i].isPredicate())
continue;
MIB.addOperand(MI->getOperand(i));
}
DOUT << "Converted 32-bit: " << *MI << " to 16-bit: " << *MIB;
MBB.erase(MI);
++Num2Addrs;
++NumNarrows;
return true;
}
@ -238,6 +253,19 @@ Thumb2SizeReduce::ReduceToNarrow(MachineBasicBlock &MBB, MachineInstr *MI,
}
}
// Check if it's possible / necessary to transfer the predicate.
const TargetInstrDesc &NewTID = TII->get(Entry.NarrowOpc1);
unsigned PredReg = 0;
ARMCC::CondCodes Pred = getInstrPredicate(MI, PredReg);
bool SkipPred = false;
if (Pred != ARMCC::AL) {
if (!NewTID.isPredicable())
// Can't transfer predicate, fail.
return false;
} else {
SkipPred = !NewTID.isPredicable();
}
bool HasCC = false;
bool CCDead = false;
if (TID.hasOptionalDef()) {
@ -246,7 +274,7 @@ Thumb2SizeReduce::ReduceToNarrow(MachineBasicBlock &MBB, MachineInstr *MI,
if (HasCC && MI->getOperand(NumOps-1).isDead())
CCDead = true;
}
if (!VerifyPredAndCC(MI, Entry, false, LiveCPSR, HasCC, CCDead))
if (!VerifyPredAndCC(MI, Entry, false, Pred, LiveCPSR, HasCC, CCDead))
return false;
// Add the 16-bit instruction.
@ -258,15 +286,18 @@ Thumb2SizeReduce::ReduceToNarrow(MachineBasicBlock &MBB, MachineInstr *MI,
// Transfer the rest of operands.
unsigned NumOps = TID.getNumOperands();
for (unsigned i = 1, e = MI->getNumOperands(); i != e; ++i)
if (!(i < NumOps && TID.OpInfo[i].isOptionalDef()))
MIB.addOperand(MI->getOperand(i));
for (unsigned i = 1, e = MI->getNumOperands(); i != e; ++i) {
if (i < NumOps && TID.OpInfo[i].isOptionalDef())
continue;
if (SkipPred && TID.OpInfo[i].isPredicate())
continue;
MIB.addOperand(MI->getOperand(i));
}
DOUT << "Converted 32-bit: " << *MI << " to 16-bit: " << *MIB;
MBB.erase(MI);
++Num2Addrs;
++NumNarrows;
return true;
}
@ -298,9 +329,16 @@ static bool UpdateCPSRLiveness(MachineInstr &MI, bool LiveCPSR) {
bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) {
bool Modified = false;
// FIXME: Track whether CPSR is live. If not, then it's possible to convert
// one that doesn't set CPSR to one that does.
bool LiveCPSR = false;
// Yes, CPSR could be livein.
for (MachineBasicBlock::const_livein_iterator I = MBB.livein_begin(),
E = MBB.livein_end(); I != E; ++I) {
if (*I == ARM::CPSR) {
LiveCPSR = true;
break;
}
}
MachineBasicBlock::iterator MII = MBB.begin(), E = MBB.end();
MachineBasicBlock::iterator NextMII = next(MII);
for (; MII != E; MII = NextMII) {