Keep track of how many times a live range has been dequeued, and prioritize new ranges.
When a large live range is evicted, it will usually be split when it comes
around again. By deferring evicted live ranges, the splitting happens at a time
when the interference pattern is more realistic. This prevents repeated
splitting and evictions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126282 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index 59d4fc6..0388619 100644
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -74,6 +74,7 @@
std::auto_ptr<Spiller> SpillerInstance;
std::auto_ptr<SplitAnalysis> SA;
std::priority_queue<std::pair<unsigned, unsigned> > Queue;
+ IndexedMap<unsigned, VirtReg2IndexFunctor> Generation;
// splitting state.
@@ -186,6 +187,7 @@
void RAGreedy::releaseMemory() {
SpillerInstance.reset(0);
+ Generation.clear();
RegAllocBase::releaseMemory();
}
@@ -202,6 +204,11 @@
if (TargetRegisterInfo::isPhysicalRegister(Hint))
Size |= (1u << 30);
+ // Boost ranges that we see for the first time.
+ Generation.grow(Reg);
+ if (++Generation[Reg] == 1)
+ Size |= (1u << 31);
+
Queue.push(std::make_pair(Size, Reg));
}