diff --git a/js/src/jsinterp.cpp b/js/src/jsinterp.cpp
index 8aa7dd920b5..eb67a6a962c 100644
--- a/js/src/jsinterp.cpp
+++ b/js/src/jsinterp.cpp
@@ -3223,8 +3223,9 @@ BEGIN_CASE(JSOP_RETSUB)
         goto error;
     }
     JS_ASSERT(rval.isInt32());
-    len = rval.toInt32();
-    regs.pc = script->code;
+
+    /* Increment the PC by this much. */
+    len = rval.toInt32() - int32_t(regs.pc - script->code);
 END_VARLEN_CASE
 }