diff --git a/js/src/frontend/BytecodeEmitter.cpp b/js/src/frontend/BytecodeEmitter.cpp
index 4ef098dcd0b3..b1b4befeb5ea 100644
--- a/js/src/frontend/BytecodeEmitter.cpp
+++ b/js/src/frontend/BytecodeEmitter.cpp
@@ -278,8 +278,8 @@ frontend::Emit3(JSContext *cx, BytecodeEmitter *bce, JSOp op, jsbytecode op1,
                     jsbytecode op2)
 {
     /* These should filter through EmitVarOp. */
-    JS_ASSERT(JOF_OPTYPE(op) != JOF_QARG);
-    JS_ASSERT(JOF_OPTYPE(op) != JOF_LOCAL);
+    JS_ASSERT(!IsArgOp(op));
+    JS_ASSERT(!IsLocalOp(op));
 
     ptrdiff_t offset = EmitCheck(cx, bce, 3);
 
@@ -917,11 +917,11 @@ EmitAliasedVarOp(JSContext *cx, JSOp op, ParseNode *pn, BytecodeEmitter *bce)
     }
 
     ScopeCoordinate sc;
-    if (JOF_OPTYPE(pn->getOp()) == JOF_QARG) {
+    if (IsArgOp(pn->getOp())) {
         sc.hops = skippedScopes + ClonedBlockDepth(bceOfDef);
         sc.slot = bceOfDef->sc->bindings.formalIndexToSlot(pn->pn_cookie.slot());
     } else {
-        JS_ASSERT(JOF_OPTYPE(pn->getOp()) == JOF_LOCAL || pn->isKind(PNK_FUNCTION));
+        JS_ASSERT(IsLocalOp(pn->getOp()) || pn->isKind(PNK_FUNCTION));
         unsigned local = pn->pn_cookie.slot();
         if (local < bceOfDef->sc->bindings.numVars()) {
             sc.hops = skippedScopes + ClonedBlockDepth(bceOfDef);
@@ -946,7 +946,7 @@ static bool
 EmitVarOp(JSContext *cx, ParseNode *pn, JSOp op, BytecodeEmitter *bce)
 {
     JS_ASSERT(pn->isKind(PNK_FUNCTION) || pn->isKind(PNK_NAME));
-    JS_ASSERT_IF(pn->isKind(PNK_NAME), JOF_OPTYPE(op) == JOF_QARG || JOF_OPTYPE(op) == JOF_LOCAL);
+    JS_ASSERT_IF(pn->isKind(PNK_NAME), IsArgOp(op) || IsLocalOp(op));
     JS_ASSERT(!pn->pn_cookie.isFree());
 
     if (!bce->isAliasedName(pn)) {
@@ -970,7 +970,7 @@ static bool
 EmitVarIncDec(JSContext *cx, ParseNode *pn, JSOp op, BytecodeEmitter *bce)
 {
     JS_ASSERT(pn->isKind(PNK_NAME));
-    JS_ASSERT(JOF_OPTYPE(op) == JOF_QARG || JOF_OPTYPE(op) == JOF_LOCAL);
+    JS_ASSERT(IsArgOp(op) || IsLocalOp(op));
     JS_ASSERT(js_CodeSpec[op].format & (JOF_INC | JOF_DEC));
     JS_ASSERT(!pn->pn_cookie.isFree());
 
@@ -2697,7 +2697,7 @@ MaybeEmitVarDecl(JSContext *cx, BytecodeEmitter *bce, JSOp prologOp, ParseNode *
     }
 
     if (bce->sc->inFunction() &&
-        JOF_OPTYPE(pn->getOp()) == JOF_LOCAL &&
+        IsLocalOp(pn->getOp()) &&
         !pn->isLet() &&
         bce->shouldNoteClosedName(pn))
     {
@@ -6130,7 +6130,7 @@ frontend::EmitTree(JSContext *cx, BytecodeEmitter *bce, ParseNode *pn)
                 continue;
             if (!BindNameToSlot(cx, bce, pn2))
                 return false;
-            if (JOF_OPTYPE(pn2->getOp()) == JOF_QARG && bce->shouldNoteClosedName(pn2)) {
+            if (IsArgOp(pn2->getOp()) && bce->shouldNoteClosedName(pn2)) {
                 if (!bce->noteClosedArg(pn2))
                     return false;
             }
diff --git a/js/src/jsopcode.h b/js/src/jsopcode.h
index c14c3aa9ecb4..3491fe260d6b 100644
--- a/js/src/jsopcode.h
+++ b/js/src/jsopcode.h
@@ -486,6 +486,18 @@ FlowsIntoNext(JSOp op)
            op != JSOP_GOTO && op != JSOP_RETSUB;
 }
 
+inline bool
+IsArgOp(JSOp op)
+{
+    return JOF_OPTYPE(op) == JOF_QARG;
+}
+
+inline bool
+IsLocalOp(JSOp op)
+{
+    return JOF_OPTYPE(op) == JOF_LOCAL;
+}
+
 /*
  * Counts accumulated for a single opcode in a script. The counts tracked vary
  * between opcodes, and this structure ensures that counts are accessed in a