It's possible to commute instrctions with more than 3 operands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43256 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index 53b08d6..277257b 100644
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -143,7 +143,7 @@
             // so, swap the B and C operands.  This makes the live ranges of A
             // and C joinable.
             // FIXME: This code also works for A := B op C instructions.
-            if ((TID->Flags & M_COMMUTABLE) && mi->getNumOperands() == 3) {
+            if ((TID->Flags & M_COMMUTABLE) && mi->getNumOperands() >= 3) {
               assert(mi->getOperand(3-si).isRegister() &&
                      "Not a proper commutative instruction!");
               unsigned regC = mi->getOperand(3-si).getReg();