Fix for PR1279. Dead def has a live interval of length 1. Copy coalescing should
not violate that.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35396 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 38ada30..eb3ac31 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -935,9 +935,9 @@
// The instruction which defines the src is only truly dead if there are
// no intermediate uses and there isn't a use beyond the copy.
// FIXME: find the last use, mark is kill and shorten the live range.
- if (SrcEnd > getDefIndex(CopyIdx))
+ if (SrcEnd > getDefIndex(CopyIdx)) {
isDead = false;
- else {
+ } else {
MachineOperand *MOU;
MachineInstr *LastUse= lastRegisterUse(repSrcReg, SrcStart, CopyIdx, MOU);
if (LastUse) {
@@ -947,7 +947,9 @@
isShorten = true;
RemoveStart = getDefIndex(getInstructionIndex(LastUse));
RemoveEnd = SrcEnd;
- }
+ } else if (RemoveStart > 0)
+ // A dead def should have a single cycle interval.
+ ++RemoveStart;
}
}