diff options
Diffstat (limited to 'lib/CodeGen')
| -rw-r--r-- | lib/CodeGen/CriticalAntiDepBreaker.cpp | 32 | ||||
| -rw-r--r-- | lib/CodeGen/CriticalAntiDepBreaker.h | 3 |
2 files changed, 26 insertions, 9 deletions
diff --git a/lib/CodeGen/CriticalAntiDepBreaker.cpp b/lib/CodeGen/CriticalAntiDepBreaker.cpp index 48105d9aa8..ee31dde638 100644 --- a/lib/CodeGen/CriticalAntiDepBreaker.cpp +++ b/lib/CodeGen/CriticalAntiDepBreaker.cpp @@ -371,12 +371,13 @@ CriticalAntiDepBreaker::isNewRegClobberedByRefs(RegRefIter RegRefBegin, return false; } -unsigned -CriticalAntiDepBreaker::findSuitableFreeRegister(RegRefIter RegRefBegin, - RegRefIter RegRefEnd, - unsigned AntiDepReg, - unsigned LastNewReg, - const TargetRegisterClass *RC) +unsigned CriticalAntiDepBreaker:: +findSuitableFreeRegister(RegRefIter RegRefBegin, + RegRefIter RegRefEnd, + unsigned AntiDepReg, + unsigned LastNewReg, + const TargetRegisterClass *RC, + SmallVector<unsigned, 2> &Forbid) { ArrayRef<MCPhysReg> Order = RegClassInfo.getOrder(RC); for (unsigned i = 0; i != Order.size(); ++i) { @@ -401,6 +402,15 @@ CriticalAntiDepBreaker::findSuitableFreeRegister(RegRefIter RegRefBegin, Classes[NewReg] == reinterpret_cast<TargetRegisterClass *>(-1) || KillIndices[AntiDepReg] > DefIndices[NewReg]) continue; + // If NewReg overlaps any of the forbidden registers, we can't use it. + bool Forbidden = false; + for (SmallVector<unsigned, 2>::iterator it = Forbid.begin(), + ite = Forbid.end(); it != ite; ++it) + if (TRI->regsOverlap(NewReg, *it)) { + Forbidden = true; + break; + } + if (Forbidden) continue; return NewReg; } @@ -564,6 +574,8 @@ BreakAntiDependencies(const std::vector<SUnit>& SUnits, PrescanInstruction(MI); + SmallVector<unsigned, 2> ForbidRegs; + // If MI's defs have a special allocation requirement, don't allow // any def registers to be changed. Also assume all registers // defined in a call must not be changed (ABI). @@ -574,7 +586,9 @@ BreakAntiDependencies(const std::vector<SUnit>& SUnits, AntiDepReg = 0; else if (AntiDepReg) { // If this instruction has a use of AntiDepReg, breaking it - // is invalid. + // is invalid. If the instruction defines other registers, + // save a list of them so that we don't pick a new register + // that overlaps any of them. for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { MachineOperand &MO = MI->getOperand(i); if (!MO.isReg()) continue; @@ -584,6 +598,8 @@ BreakAntiDependencies(const std::vector<SUnit>& SUnits, AntiDepReg = 0; break; } + if (MO.isDef() && Reg != AntiDepReg) + ForbidRegs.push_back(Reg); } } @@ -606,7 +622,7 @@ BreakAntiDependencies(const std::vector<SUnit>& SUnits, if (unsigned NewReg = findSuitableFreeRegister(Range.first, Range.second, AntiDepReg, LastNewReg[AntiDepReg], - RC)) { + RC, ForbidRegs)) { DEBUG(dbgs() << "Breaking anti-dependence edge on " << TRI->getName(AntiDepReg) << " with " << RegRefs.count(AntiDepReg) << " references" diff --git a/lib/CodeGen/CriticalAntiDepBreaker.h b/lib/CodeGen/CriticalAntiDepBreaker.h index 8fb2b0eced..df13dd31f6 100644 --- a/lib/CodeGen/CriticalAntiDepBreaker.h +++ b/lib/CodeGen/CriticalAntiDepBreaker.h @@ -102,7 +102,8 @@ class TargetRegisterInfo; RegRefIter RegRefEnd, unsigned AntiDepReg, unsigned LastNewReg, - const TargetRegisterClass *RC); + const TargetRegisterClass *RC, + SmallVector<unsigned, 2> &Forbid); }; } |