--- a/js/src/jit-test/README
+++ b/js/src/jit-test/README
@@ -66,14 +66,15 @@ to be placed inside any kind of comment.
 The meaning of the items:
 
     slow         Test runs slowly. Do not run if the --no-slow option is given.
     allow-oom    If the test runs out of memory, it counts as passing.
     valgrind     Run test under valgrind.
     tz-pacific   Always run test with the Pacific time zone (TZ=PST8PDT).
     mjitalways   Run js with -a, whether --jitflags says to or not
     debug        Run js with -d, whether --jitflags says to or not
+    dump-bytecode Run js with -D, whether --jitflags says to or not
 
     error        The test should be considered to pass iff it throws the
                  given JS exception.
     exitstatus   The test should exit with the given status value (an integer).
 
 * END

--- a/js/src/jit-test/jit_test.py
+++ b/js/src/jit-test/jit_test.py
@@ -106,16 +106,18 @@ class Test:
                     elif name == 'tz-pacific':
                         test.tz_pacific = True
                     elif name == 'mjitalways':
                         test.jitflags.append('-a')
                     elif name == 'debug':
                         test.jitflags.append('-d')
                     elif name == 'mjit':
                         test.jitflags.append('-m')
+                    elif name == 'dump-bytecode':
+                        test.jitflags.append('-D')
                     else:
                         print('warning: unrecognized |jit-test| attribute %s'%part)
 
         if options.valgrind_all:
             test.valgrind = True
 
         return test
 

new file mode 100644
--- /dev/null
+++ b/js/src/jit-test/tests/jaeger/bug768313.js
@@ -0,0 +1,6 @@
+// |jit-test| mjit; mjitalways; dump-bytecode
+
+function f() { }
+evaluate('function g() { f(); }', {newContext: true});
+for (var i = 0; i < 2; i++)
+    g(0);

--- a/js/src/methodjit/Compiler.cpp
+++ b/js/src/methodjit/Compiler.cpp
@@ -277,16 +277,22 @@ mjit::Compiler::scanInlineCalls(uint32_t
              * doing so can change type information we have queried already
              * in making inlining decisions.
              */
             if (!script->hasAnalysis() || !script->analysis()->ranInference()) {
                 okay = false;
                 break;
             }
 
+            /* See bug 768313. */
+            if (script->hasScriptCounts != outerScript->hasScriptCounts) {
+                okay = false;
+                break;
+            }
+
             /*
              * The outer and inner scripts must have the same scope. This only
              * allows us to inline calls between non-inner functions. Also
              * check for consistent strictness between the functions.
              */
             if (!globalObj ||
                 fun->getParent() != globalObj ||
                 outerScript->strictModeCode != script->strictModeCode) {