Add SplitKit::isOriginalEndpoint and use it to force live range splitting to terminate.
An original endpoint is an instruction that killed or defined the original live
range before any live ranges were split.
When splitting global live ranges, avoid creating local live ranges without any
original endpoints. We may still create global live ranges without original
endpoints, but such a range won't be split again, and live range splitting still
terminates.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126151 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index 5663936..a97d890 100644
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -167,6 +167,20 @@
}
}
+bool SplitAnalysis::isOriginalEndpoint(SlotIndex Idx) const {
+ unsigned OrigReg = VRM.getOriginal(CurLI->reg);
+ const LiveInterval &Orig = LIS.getInterval(OrigReg);
+ assert(!Orig.empty() && "Splitting empty interval?");
+ LiveInterval::const_iterator I = Orig.find(Idx);
+
+ // Range containing Idx should begin at Idx.
+ if (I != Orig.end() && I->start <= Idx)
+ return I->start == Idx;
+
+ // Range does not contain Idx, previous must end at Idx.
+ return I != Orig.begin() && (--I)->end == Idx;
+}
+
void SplitAnalysis::print(const BlockPtrSet &B, raw_ostream &OS) const {
for (BlockPtrSet::const_iterator I = B.begin(), E = B.end(); I != E; ++I) {
unsigned count = UsingBlocks.lookup(*I);