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Restructure code to allow renaming of multiple-register groups for anti-dep breaking. 

llvm-svn: 89511
This commit is contained in:
David Goodwin 2009-11-20 23:33:54 +00:00
parent 73f9a9e2c8
commit 5305dc0be1
2 changed files with 75 additions and 46 deletions
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2
llvm/include/llvm/Target/TargetRegisterInfo.h
View File

@ -465,7 +465,7 @@ public:
virtual unsigned getSubReg(unsigned RegNo, unsigned Index) const = 0;
/// getSubRegIndex - For a given register pair, return the sub-register index
/// if they are second register is a sub-register of the second. Return zero
/// if the are second register is a sub-register of the first. Return zero
/// otherwise.
virtual unsigned getSubRegIndex(unsigned RegNo, unsigned SubRegNo) const = 0;

119
llvm/lib/CodeGen/AggressiveAntiDepBreaker.cpp
View File

@ -587,79 +587,108 @@ bool AggressiveAntiDepBreaker::FindSuitableFreeRegisters(
return false;
}
#ifndef NDEBUG
// If DebugDiv > 0 then only rename (renamecnt % DebugDiv) == DebugMod
if (DebugDiv > 0) {
static int renamecnt = 0;
if (renamecnt++ % DebugDiv != DebugMod)
return false;
errs() << "*** Performing rename " << TRI->getName(SuperReg) <<
" for debug ***\n";
}
#endif
// Check each possible rename register for SuperReg in round-robin
// order. If that register is available, and the corresponding
// registers are available for the other group subregisters, then we
// can use those registers to rename.
BitVector SuperBV = RenameRegisterMap[SuperReg];
const TargetRegisterClass *SuperRC =
TRI->getPhysicalRegisterRegClass(SuperReg, MVT::Other);
const TargetRegisterClass::iterator RB = SuperRC->allocation_order_begin(MF);
const TargetRegisterClass::iterator RE = SuperRC->allocation_order_end(MF);
if (RB == RE) {
DEBUG(errs() << "\tEmpty Regclass!!\n");
DEBUG(errs() << "\tEmpty Super Regclass!!\n");
return false;
}
#ifndef NDEBUG
// If DebugDiv > 0 then only rename (renamecnt % DebugDiv) == DebugMod
if (DebugDiv > 0) {
static int renamecnt = 0;
if (renamecnt++ % DebugDiv != DebugMod)
return false;
errs() << "*** Performing rename " << TRI->getName(SuperReg) <<
" for debug ***\n";
}
#endif
DEBUG(errs() << "\tFind Registers:");
if (RenameOrder.count(SuperRC) == 0)
RenameOrder.insert(RenameOrderType::value_type(SuperRC, RE));
DEBUG(errs() << "\tFind Register:");
const TargetRegisterClass::iterator OrigR = RenameOrder[SuperRC];
const TargetRegisterClass::iterator EndR = ((OrigR == RE) ? RB : OrigR);
TargetRegisterClass::iterator R = OrigR;
do {
if (R == RB) R = RE;
--R;
const unsigned Reg = *R;
const unsigned NewSuperReg = *R;
// Don't replace a register with itself.
if (Reg == SuperReg) continue;
if (NewSuperReg == SuperReg) continue;
DEBUG(errs() << " " << TRI->getName(Reg));
// If Reg is dead and Reg's most recent def is not before
// SuperRegs's kill, it's safe to replace SuperReg with Reg. We
// must also check all aliases of Reg. because we can't define a
// register when any sub or super is already live.
if (State->IsLive(Reg) || (KillIndices[SuperReg] > DefIndices[Reg])) {
DEBUG(errs() << "(live)");
continue;
} else {
bool found = false;
for (const unsigned *Alias = TRI->getAliasSet(Reg);
*Alias; ++Alias) {
unsigned AliasReg = *Alias;
if (State->IsLive(AliasReg) || (KillIndices[SuperReg] > DefIndices[AliasReg])) {
DEBUG(errs() << "(alias " << TRI->getName(AliasReg) << " live)");
found = true;
break;
}
DEBUG(errs() << " [" << TRI->getName(NewSuperReg) << ':');
RenameMap.clear();
// For each referenced group register (which must be a SuperReg or
// a subregister of SuperReg), find the corresponding subregister
// of NewSuperReg and make sure it is free to be renamed.
for (unsigned i = 0, e = Regs.size(); i != e; ++i) {
unsigned Reg = Regs[i];
unsigned NewReg = 0;
if (Reg == SuperReg) {
NewReg = NewSuperReg;
} else {
unsigned NewSubRegIdx = TRI->getSubRegIndex(SuperReg, Reg);
if (NewSubRegIdx != 0)
NewReg = TRI->getSubReg(NewSuperReg, NewSubRegIdx);
}
if (found)
continue;
DEBUG(errs() << " " << TRI->getName(NewReg));
// Check if Reg can be renamed to NewReg.
BitVector BV = RenameRegisterMap[Reg];
if (!BV.test(NewReg)) {
DEBUG(errs() << "(no rename)");
goto next_super_reg;
}
// If NewReg is dead and NewReg's most recent def is not before
// Regs's kill, it's safe to replace Reg with NewReg. We
// must also check all aliases of NewReg, because we can't define a
// register when any sub or super is already live.
if (State->IsLive(NewReg) || (KillIndices[Reg] > DefIndices[NewReg])) {
DEBUG(errs() << "(live)");
goto next_super_reg;
} else {
bool found = false;
for (const unsigned *Alias = TRI->getAliasSet(NewReg);
*Alias; ++Alias) {
unsigned AliasReg = *Alias;
if (State->IsLive(AliasReg) || (KillIndices[Reg] > DefIndices[AliasReg])) {
DEBUG(errs() << "(alias " << TRI->getName(AliasReg) << " live)");
found = true;
break;
}
}
if (found)
goto next_super_reg;
}
// Record that 'Reg' can be renamed to 'NewReg'.
RenameMap.insert(std::pair<unsigned, unsigned>(Reg, NewReg));
}
if (Reg != 0) {
DEBUG(errs() << '\n');
RenameOrder.erase(SuperRC);
RenameOrder.insert(RenameOrderType::value_type(SuperRC, R));
RenameMap.insert(std::pair<unsigned, unsigned>(SuperReg, Reg));
return true;
}
// If we fall-out here, then every register in the group can be
// renamed, as recorded in RenameMap.
RenameOrder.erase(SuperRC);
RenameOrder.insert(RenameOrderType::value_type(SuperRC, R));
DEBUG(errs() << "]\n");
return true;
next_super_reg:
DEBUG(errs() << ']');
} while (R != EndR);
DEBUG(errs() << '\n');