Add a safe-guard against repeated splitting for some rare cases.
The number of blocks covered by a live range must be strictly decreasing when
splitting, otherwise we can't allow repeated splitting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130249 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index c6e1bd5..427ef94 100644
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -221,6 +221,29 @@
return true;
}
+unsigned SplitAnalysis::countLiveBlocks(const LiveInterval *cli) const {
+ if (cli->empty())
+ return 0;
+ LiveInterval *li = const_cast<LiveInterval*>(cli);
+ LiveInterval::iterator LVI = li->begin();
+ LiveInterval::iterator LVE = li->end();
+ unsigned Count = 0;
+
+ // Loop over basic blocks where li is live.
+ MachineFunction::const_iterator MFI = LIS.getMBBFromIndex(LVI->start);
+ SlotIndex Stop = LIS.getMBBEndIdx(MFI);
+ for (;;) {
+ ++Count;
+ LVI = li->advanceTo(LVI, Stop);
+ if (LVI == LVE)
+ return Count;
+ do {
+ ++MFI;
+ Stop = LIS.getMBBEndIdx(MFI);
+ } while (Stop <= LVI->start);
+ }
+}
+
bool SplitAnalysis::isOriginalEndpoint(SlotIndex Idx) const {
unsigned OrigReg = VRM.getOriginal(CurLI->reg);
const LiveInterval &Orig = LIS.getInterval(OrigReg);