ShortenDeadCopySrcLiveRange needs to be more conservative in multi-kill situations.

llvm-svn: 75838

1 files changed, 6 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp b/llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp
index ac44c864911..94a275a21a1 100644
--- a/llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/llvm/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -861,8 +861,9 @@ bool SimpleRegisterCoalescing::ShortenDeadCopyLiveRange(LiveInterval &li,
     return false;  // Already removed by ShortenDeadCopySrcLiveRange.
   unsigned RemoveStart = MLR->start;
   unsigned RemoveEnd = MLR->end;
+  unsigned DefIdx = li_->getDefIndex(CopyIdx);
   // Remove the liverange that's defined by this.
-  if (RemoveEnd == li_->getDefIndex(CopyIdx)+1) {
+  if (RemoveStart == DefIdx && RemoveEnd == DefIdx+1) {
     removeRange(li, RemoveStart, RemoveEnd, li_, tri_);
     return removeIntervalIfEmpty(li, li_, tri_);
   }
@@ -935,6 +936,10 @@ SimpleRegisterCoalescing::ShortenDeadCopySrcLiveRange(LiveInterval &li,
   if (TrimLiveIntervalToLastUse(CopyIdx, CopyMBB, li, LR))
     return false;
 
+  // There are other kills of the val#. Nothing to do.
+  if (!li.isOnlyLROfValNo(LR))
+    return false;
+
   MachineBasicBlock *StartMBB = li_->getMBBFromIndex(RemoveStart);
   if (!isSameOrFallThroughBB(StartMBB, CopyMBB, tii_))
     // If the live range starts in another mbb and the copy mbb is not a fall