Fix coloring bug when mapping values in the middle of a live-through block.

If the found value is not live-through the block, we should only add liveness up
to the requested slot index. When the value is live-through, the whole block
should be colored.

Bug found by SSA verification in the machine code verifier.

llvm-svn: 124812

1 files changed, 7 insertions, 7 deletions

diff --git a/llvm/lib/CodeGen/SplitKit.cpp b/llvm/lib/CodeGen/SplitKit.cpp
index a1c9ced332c..8bd62800e02 100644
--- a/llvm/lib/CodeGen/SplitKit.cpp
+++ b/llvm/lib/CodeGen/SplitKit.cpp
@@ -607,14 +607,14 @@ VNInfo *LiveIntervalMap::mapValue(const VNInfo *ParentVNI, SlotIndex Idx,
   for (unsigned i = 0, e = LiveIn.size(); i != e; ++i) {
     MachineBasicBlock *MBB = LiveIn[i]->getBlock();
     SlotIndex Start = LIS.getMBBStartIdx(MBB);
-    if (MBB == IdxMBB) {
-      LI->addRange(LiveRange(Start, Idx.getNextSlot(), IdxVNI));
-      continue;
-    }
-    // Anything in LiveIn other than IdxMBB is live-through.
     VNInfo *VNI = LiveOutCache.lookup(MBB).first;
-    assert(VNI && "Missing block value");
-    LI->addRange(LiveRange(Start, LIS.getMBBEndIdx(MBB), VNI));
+
+    // Anything in LiveIn other than IdxMBB is live-through.
+    // In IdxMBB, we should stop at Idx unless the same value is live-out.
+    if (MBB == IdxMBB && IdxVNI != VNI)
+      LI->addRange(LiveRange(Start, Idx.getNextSlot(), IdxVNI));
+    else
+      LI->addRange(LiveRange(Start, LIS.getMBBEndIdx(MBB), VNI));
   }
 
   return IdxVNI;