Also handle the situation where an indirect branch is the first (and last)
instruction in a basic block.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125116 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index 4713da8..d5d76ca 100644
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -808,16 +808,18 @@
DEBUG(dbgs() << ", uses at " << BI.LastUse << " after split point "
<< BI.LastSplitPoint << ", stack-out.\n");
SlotIndex SegEnd;
- if (BI.LastSplitPoint == Start)
+ // Find the last real instruction before the split point.
+ MachineBasicBlock::iterator SplitI =
+ LIS->getInstructionFromIndex(BI.LastSplitPoint);
+ MachineBasicBlock::iterator I = SplitI, B = BI.MBB->begin();
+ while (I != B && (--I)->isDebugValue())
+ ;
+ if (I == SplitI)
SegEnd = SE.leaveIntvAtTop(*BI.MBB);
else {
- MachineBasicBlock::iterator I =
- LIS->getInstructionFromIndex(BI.LastSplitPoint);
- do assert(I != BI.MBB->begin() && "Expected instruction");
- while ((--I)->isDebugValue());
SegEnd = SE.leaveIntvAfter(LIS->getInstructionIndex(I));
+ SE.useIntv(Start, SegEnd);
}
- SE.useIntv(Start, SegEnd);
// Run a double interval from the split to the last use.
// This makes it possible to spill the complement without affecting the
// indirect branch.