misched: fix LiveInterval update for bottom-up scheduling

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153162 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 13 insertions, 3 deletions

diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 1019ad2594..3ade66097c 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -1049,9 +1049,19 @@ public:
     bool hasRegMaskOp = false;
     collectRanges(MI, Entering, Internal, Exiting, hasRegMaskOp, OldIdx);
 
-    moveAllEnteringFrom(OldIdx, Entering);
-    moveAllInternalFrom(OldIdx, Internal);
-    moveAllExitingFrom(OldIdx, Exiting);
+    // To keep the LiveRanges valid within an interval, move the ranges closest
+    // to the destination first. This prevents ranges from overlapping, to that
+    // APIs like removeRange still work.
+    if (NewIdx < OldIdx) {
+      moveAllEnteringFrom(OldIdx, Entering);
+      moveAllInternalFrom(OldIdx, Internal);
+      moveAllExitingFrom(OldIdx, Exiting);
+    }
+    else {
+      moveAllExitingFrom(OldIdx, Exiting);
+      moveAllInternalFrom(OldIdx, Internal);
+      moveAllEnteringFrom(OldIdx, Entering);
+    }
 
     if (hasRegMaskOp)
       updateRegMaskSlots(OldIdx);