Q.seenAllInterferences() must be called after Q.collectInterferingVRegs().

llvm-svn: 121774

1 files changed, 4 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/RegAllocGreedy.cpp b/llvm/lib/CodeGen/RegAllocGreedy.cpp
index 943da11ad37..46cfbe7234b 100644
--- a/llvm/lib/CodeGen/RegAllocGreedy.cpp
+++ b/llvm/lib/CodeGen/RegAllocGreedy.cpp
@@ -175,9 +175,9 @@ LiveInterval *RAGreedy::getSingleInterference(LiveInterval &VirtReg,
   // Check direct interferences.
   LiveIntervalUnion::Query &Q = query(VirtReg, PhysReg);
   if (Q.checkInterference()) {
+    Q.collectInterferingVRegs(1);
     if (!Q.seenAllInterferences())
       return 0;
-    Q.collectInterferingVRegs(1);
     Interference = Q.interferingVRegs().front();
   }
 
@@ -185,9 +185,11 @@ LiveInterval *RAGreedy::getSingleInterference(LiveInterval &VirtReg,
   for (const unsigned *AliasI = TRI->getAliasSet(PhysReg); *AliasI; ++AliasI) {
     LiveIntervalUnion::Query &Q = query(VirtReg, *AliasI);
     if (Q.checkInterference()) {
-      if (Interference || !Q.seenAllInterferences())
+      if (Interference)
         return 0;
       Q.collectInterferingVRegs(1);
+      if (!Q.seenAllInterferences())
+        return 0;
       Interference = Q.interferingVRegs().front();
     }
   }