Index: llvm/lib/Transforms/Scalar/GVN.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/GVN.cpp
+++ llvm/lib/Transforms/Scalar/GVN.cpp
@@ -1892,7 +1892,8 @@
       continue;
 
     // Prefer a constant on the right-hand side, or an Argument if no constants.
-    if (isa<Constant>(LHS) || (isa<Argument>(LHS) && !isa<Constant>(RHS)))
+    if (isa<Constant>(LHS)
+        || (isa<Argument>(LHS) && !isa<Argument>(RHS) && !isa<Constant>(RHS)))
       std::swap(LHS, RHS);
     assert((isa<Argument>(LHS) || isa<Instruction>(LHS)) && "Unexpected value!");