[turbofan] First version of loop peeling.

src/compiler/opcodes.h

Index: src/compiler/opcodes.h
diff --git a/src/compiler/opcodes.h b/src/compiler/opcodes.h
index b7a2f6b51ba22c1e6bad7403407c77c3781fc91f..043333f6260dcefbd4303b3513e25e91c615553b 100644
--- a/src/compiler/opcodes.h
+++ b/src/compiler/opcodes.h
@@ -327,6 +327,10 @@ class IrOpcode {
         return false;
     }
   }
+
+  static bool IsPhiOpcode(Value val) {
+    return val == kPhi || val == kEffectPhi;
+  }
 };
 
 }  // namespace compiler