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[MachineLICM] Small cleanup: Constify and rangeify. 

NFC.

llvm-svn: 234018
This commit is contained in:
Daniel Jasper 2015-04-03 16:19:48 +00:00
parent f84bcf15c0
commit efece52160
1 changed files with 9 additions and 12 deletions
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21
llvm/lib/CodeGen/MachineLICM.cpp
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@ -214,7 +214,8 @@ namespace {
/// CanCauseHighRegPressure - Visit BBs from header to current BB,
/// check if hoisting an instruction of the given cost matrix can cause high
/// register pressure.
bool CanCauseHighRegPressure(DenseMap<unsigned, int> &Cost, bool Cheap);
bool CanCauseHighRegPressure(const DenseMap<unsigned, int> &Cost,
bool Cheap);
/// UpdateBackTraceRegPressure - Traverse the back trace from header to
/// the current block and update their register pressures to reflect the
@ -1125,27 +1126,23 @@ bool MachineLICM::IsCheapInstruction(MachineInstr &MI) const {
/// CanCauseHighRegPressure - Visit BBs from header to current BB, check
/// if hoisting an instruction of the given cost matrix can cause high
/// register pressure.
bool MachineLICM::CanCauseHighRegPressure(DenseMap<unsigned, int> &Cost,
bool MachineLICM::CanCauseHighRegPressure(const DenseMap<unsigned, int>& Cost,
bool CheapInstr) {
for (DenseMap<unsigned, int>::iterator CI = Cost.begin(), CE = Cost.end();
CI != CE; ++CI) {
if (CI->second <= 0)
for (const auto &ClassAndCost : Cost) {
if (ClassAndCost.second <= 0)
continue;
unsigned RCId = CI->first;
unsigned Limit = RegLimit[RCId];
int Cost = CI->second;
unsigned Class = ClassAndCost.first;
int Limit = RegLimit[Class];
// Don't hoist cheap instructions if they would increase register pressure,
// even if we're under the limit.
if (CheapInstr && !HoistCheapInsts)
return true;
for (unsigned i = BackTrace.size(); i != 0; --i) {
SmallVectorImpl<unsigned> &RP = BackTrace[i-1];
if (RP[RCId] + Cost >= Limit)
for (const auto &RP : BackTrace)
if (static_cast<int>(RP[Class]) + ClassAndCost.second >= Limit)
return true;
}
}
return false;