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Be more strict about the first/last interference-free use.

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If the interference overlaps the instruction, we cannot separate it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124918 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2011-02-05 01:06:39 +00:00
parent de71095a1a
commit fe3f99f95c
1 changed files with 25 additions and 4 deletions
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29
lib/CodeGen/RegAllocGreedy.cpp
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@ -716,6 +716,15 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
// Block has interference.
DEBUG(dbgs() << ", interference to " << IP.second);
if (!BI.LiveThrough && IP.second <= BI.Def) {
// The interference doesn't reach the outgoing segment.
DEBUG(dbgs() << " doesn't affect def from " << BI.Def << '\n');
SE.useIntv(BI.Def, Stop);
continue;
}
if (!BI.Uses) {
// No uses in block, avoid interference by reloading as late as possible.
DEBUG(dbgs() << ", no uses.\n");
@ -723,11 +732,14 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
assert(SegStart >= IP.second && "Couldn't avoid interference");
continue;
}
if (IP.second < BI.LastUse && IP.second <= BI.LastSplitPoint) {
if (IP.second.getBoundaryIndex() < BI.LastUse &&
IP.second.getBoundaryIndex() <= BI.LastSplitPoint) {
// There are interference-free uses at the end of the block.
// Find the first use that can get the live-out register.
SmallVectorImpl<SlotIndex>::const_iterator UI =
std::lower_bound(SA->UseSlots.begin(), SA->UseSlots.end(), IP.second);
std::lower_bound(SA->UseSlots.begin(), SA->UseSlots.end(),
IP.second.getBoundaryIndex());
assert(UI != SA->UseSlots.end() && "Couldn't find last use");
SlotIndex Use = *UI;
DEBUG(dbgs() << ", free use at " << Use << ".\n");
@ -798,6 +810,14 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
// Block has interference.
DEBUG(dbgs() << ", interference from " << IP.first);
if (!BI.LiveThrough && IP.first >= BI.Kill) {
// The interference doesn't reach the outgoing segment.
DEBUG(dbgs() << " doesn't affect kill at " << BI.Kill << '\n');
SE.useIntv(Start, BI.Kill);
continue;
}
if (!BI.Uses) {
// No uses in block, avoid interference by spilling as soon as possible.
DEBUG(dbgs() << ", no uses.\n");
@ -805,11 +825,12 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
assert(SegEnd <= IP.first && "Couldn't avoid interference");
continue;
}
if (IP.first > BI.FirstUse) {
if (IP.first.getBaseIndex() > BI.FirstUse) {
// There are interference-free uses at the beginning of the block.
// Find the last use that can get the register.
SmallVectorImpl<SlotIndex>::const_iterator UI =
std::lower_bound(SA->UseSlots.begin(), SA->UseSlots.end(), IP.first);
std::lower_bound(SA->UseSlots.begin(), SA->UseSlots.end(),
IP.first.getBaseIndex());
assert(UI != SA->UseSlots.begin() && "Couldn't find first use");
SlotIndex Use = (--UI)->getBoundaryIndex();
DEBUG(dbgs() << ", free use at " << *UI << ".\n");