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Use reverse iterators when updating the vector, since scanning from 

the end will reduce erase() runtimes.

llvm-svn: 15093
This commit is contained in:
Alkis Evlogimenos 2004-07-22 02:16:53 +00:00
parent 6ff6021712
commit 120187935d
1 changed files with 14 additions and 11 deletions
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25
llvm/lib/CodeGen/RegAllocIterativeScan.cpp
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@ -230,20 +230,21 @@ bool RA::linearScan()
}
// expire any remaining active intervals
for (IntervalPtrs::iterator i = active_.begin(); i != active_.end(); ) {
for (IntervalPtrs::reverse_iterator
i = active_.rbegin(); i != active_.rend(); ) {
unsigned reg = (*i)->reg;
DEBUG(std::cerr << "\tinterval " << **i << " expired\n");
if (MRegisterInfo::isVirtualRegister(reg))
reg = vrm_->getPhys(reg);
prt_->delRegUse(reg);
i = active_.erase(i);
i = IntervalPtrs::reverse_iterator(active_.erase(i.base()-1));
}
// expire any remaining inactive intervals
for (IntervalPtrs::iterator
i = inactive_.begin(); i != inactive_.end(); ) {
for (IntervalPtrs::reverse_iterator
i = inactive_.rbegin(); i != inactive_.rend(); ) {
DEBUG(std::cerr << "\tinterval " << **i << " expired\n");
i = inactive_.erase(i);
i = IntervalPtrs::reverse_iterator(inactive_.erase(i.base()-1));
}
// return true if we spilled anything
@ -267,7 +268,8 @@ void RA::initIntervalSets(LiveIntervals::Intervals& li)
void RA::processActiveIntervals(IntervalPtrs::value_type cur)
{
DEBUG(std::cerr << "\tprocessing active intervals:\n");
for (IntervalPtrs::iterator i = active_.begin(); i != active_.end();) {
for (IntervalPtrs::reverse_iterator
i = active_.rbegin(); i != active_.rend();) {
unsigned reg = (*i)->reg;
// remove expired intervals
if ((*i)->expiredAt(cur->start())) {
@ -276,7 +278,7 @@ void RA::processActiveIntervals(IntervalPtrs::value_type cur)
reg = vrm_->getPhys(reg);
prt_->delRegUse(reg);
// remove from active
i = active_.erase(i);
i = IntervalPtrs::reverse_iterator(active_.erase(i.base()-1));
}
// move inactive intervals to inactive list
else if (!(*i)->liveAt(cur->start())) {
@ -287,7 +289,7 @@ void RA::processActiveIntervals(IntervalPtrs::value_type cur)
// add to inactive
inactive_.push_back(*i);
// remove from active
i = active_.erase(i);
i = IntervalPtrs::reverse_iterator(active_.erase(i.base()-1));
}
else {
++i;
@ -298,14 +300,15 @@ void RA::processActiveIntervals(IntervalPtrs::value_type cur)
void RA::processInactiveIntervals(IntervalPtrs::value_type cur)
{
DEBUG(std::cerr << "\tprocessing inactive intervals:\n");
for (IntervalPtrs::iterator i = inactive_.begin(); i != inactive_.end();) {
for (IntervalPtrs::reverse_iterator
i = inactive_.rbegin(); i != inactive_.rend();) {
unsigned reg = (*i)->reg;
// remove expired intervals
if ((*i)->expiredAt(cur->start())) {
DEBUG(std::cerr << "\t\tinterval " << **i << " expired\n");
// remove from inactive
i = inactive_.erase(i);
i = IntervalPtrs::reverse_iterator(inactive_.erase(i.base()-1));
}
// move re-activated intervals in active list
else if ((*i)->liveAt(cur->start())) {
@ -316,7 +319,7 @@ void RA::processInactiveIntervals(IntervalPtrs::value_type cur)
// add to active
active_.push_back(*i);
// remove from inactive
i = inactive_.erase(i);
i = IntervalPtrs::reverse_iterator(inactive_.erase(i.base()-1));
}
else {
++i;