diff --git a/js/src/methodjit/FrameState.cpp b/js/src/methodjit/FrameState.cpp
index 117d83d200e..78ec209a923 100644
--- a/js/src/methodjit/FrameState.cpp
+++ b/js/src/methodjit/FrameState.cpp
@@ -278,8 +278,8 @@ FrameState::sync(Assembler &masm) const
             JS_ASSERT(backing != fe);
             JS_ASSERT(!backing->isConstant() && !fe->isConstant());
 
-            RegisterID reg;
             bool allocd = false;
+            RegisterID reg = Registers::ReturnReg;
             if (backing->type.inMemory() || backing->data.inMemory()) {
                 /* :TODO: this is not a valid assumption. */
                 JS_ASSERT(!avail.empty());
diff --git a/js/src/trace-test/tests/jaeger/fused-eq-ifeq.js b/js/src/trace-test/tests/jaeger/fused-eq-ifeq.js
index 079d29bde33..b5d2bf2f61b 100644
--- a/js/src/trace-test/tests/jaeger/fused-eq-ifeq.js
+++ b/js/src/trace-test/tests/jaeger/fused-eq-ifeq.js
@@ -3,5 +3,4 @@ function ack(m,n){
    if (n==0) { return ack(m-1,1); }
    return ack(m-1, ack(m,n-1) );
 }
-dis(ack);
 assertEq(ack(3, 3), 61);