LiveInterval: Fix Distribute() failing on liveranges with unused VNInfos

This fixes http://llvm.org/PR26991

llvm-svn: 264345

1 files changed, 13 insertions, 8 deletions

diff --git a/llvm/lib/CodeGen/LiveInterval.cpp b/llvm/lib/CodeGen/LiveInterval.cpp
index ab780729347..171d18aa9c4 100644
--- a/llvm/lib/CodeGen/LiveInterval.cpp
+++ b/llvm/lib/CodeGen/LiveInterval.cpp
@@ -1483,15 +1483,20 @@ void ConnectedVNInfoEqClasses::Distribute(LiveInterval &LI, LiveInterval *LIV[],
       SubRanges.resize(NumComponents-1, nullptr);
       for (unsigned I = 0; I < NumValNos; ++I) {
         const VNInfo &VNI = *SR.valnos[I];
-        const VNInfo *MainRangeVNI = LI.getVNInfoAt(VNI.def);
-        assert(MainRangeVNI != nullptr
-               && "SubRange def must have corresponding main range def");
-        unsigned ComponentNum = getEqClass(MainRangeVNI);
-        VNIMapping.push_back(ComponentNum);
-        if (ComponentNum > 0 && SubRanges[ComponentNum-1] == nullptr) {
-          SubRanges[ComponentNum-1]
-            = LIV[ComponentNum-1]->createSubRange(Allocator, SR.LaneMask);
+        unsigned ComponentNum;
+        if (VNI.isUnused()) {
+          ComponentNum = 0;
+        } else {
+          const VNInfo *MainRangeVNI = LI.getVNInfoAt(VNI.def);
+          assert(MainRangeVNI != nullptr
+                 && "SubRange def must have corresponding main range def");
+          ComponentNum = getEqClass(MainRangeVNI);
+          if (ComponentNum > 0 && SubRanges[ComponentNum-1] == nullptr) {
+            SubRanges[ComponentNum-1]
+              = LIV[ComponentNum-1]->createSubRange(Allocator, SR.LaneMask);
+          }
         }
+        VNIMapping.push_back(ComponentNum);
       }
       DistributeRange(SR, SubRanges.data(), VNIMapping);
     }