Fix a typo 'iff' => 'if'

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164767 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index 40605af..81be243 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -1202,7 +1202,7 @@
   }
 
   case ISD::OR:
-    // Handle "X | C" as "X + C" iff X is known to have C bits clear.
+    // Handle "X | C" as "X + C" if X is known to have C bits clear.
     if (CurDAG->isBaseWithConstantOffset(N)) {
       X86ISelAddressMode Backup = AM;
       ConstantSDNode *CN = cast<ConstantSDNode>(N.getOperand(1));