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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14719 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Alkis Evlogimenos 2004-07-09 11:10:00 +00:00
parent 4f12399fb8
commit 607baea7d2
1 changed files with 11 additions and 5 deletions
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16
lib/CodeGen/LiveIntervalAnalysis.cpp
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@ -286,9 +286,9 @@ void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock* mbb,
DEBUG(std::cerr << "\t\tregister: "; printRegName(interval.reg)); DEBUG(std::cerr << "\t\tregister: "; printRegName(interval.reg));
LiveVariables::VarInfo& vi = lv_->getVarInfo(interval.reg); LiveVariables::VarInfo& vi = lv_->getVarInfo(interval.reg);
// iterate over all of the blocks that the variable is completely // Iterate over all of the blocks that the variable is completely
// live in, adding them to the live interval. obviously we only // live in, adding [insrtIndex(begin), instrIndex(end)+4) to the
// need to do this once. // live interval. Obviously we only need to do this once.
if (interval.empty()) { if (interval.empty()) {
for (unsigned i = 0, e = vi.AliveBlocks.size(); i != e; ++i) { for (unsigned i = 0, e = vi.AliveBlocks.size(); i != e; ++i) {
if (vi.AliveBlocks[i]) { if (vi.AliveBlocks[i]) {
@ -337,6 +337,8 @@ void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock* mbb,
MachineBasicBlock::iterator mi, MachineBasicBlock::iterator mi,
LiveInterval& interval) LiveInterval& interval)
{ {
// A physical register cannot be live across basic block, so its
// lifetime must end somewhere in its defining basic block.
DEBUG(std::cerr << "\t\tregister: "; printRegName(interval.reg)); DEBUG(std::cerr << "\t\tregister: "; printRegName(interval.reg));
typedef LiveVariables::killed_iterator KillIter; typedef LiveVariables::killed_iterator KillIter;
@ -345,7 +347,9 @@ void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock* mbb,
unsigned start = getDefIndex(baseIndex); unsigned start = getDefIndex(baseIndex);
unsigned end = start; unsigned end = start;
// a variable can be dead by the instruction defining it // If it is not used after definition, it is considered dead at
// the instruction defining it. Hence its interval is:
// [defSlot(def), defSlot(def)+1)
for (KillIter ki = lv_->dead_begin(mi), ke = lv_->dead_end(mi); for (KillIter ki = lv_->dead_begin(mi), ke = lv_->dead_end(mi);
ki != ke; ++ki) { ki != ke; ++ki) {
if (interval.reg == ki->second) { if (interval.reg == ki->second) {
@ -355,7 +359,9 @@ void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock* mbb,
} }
} }
// a variable can only be killed by subsequent instructions // If it is not dead on definition, it must be killed by a
// subsequent instruction. Hence its interval is:
// [defSlot(def), useSlot(def)+1)
do { do {
++mi; ++mi;
baseIndex += InstrSlots::NUM; baseIndex += InstrSlots::NUM;