--- a/js/src/devtools/automation/cgc-jittest-timeouts.txt
+++ b/js/src/devtools/automation/cgc-jittest-timeouts.txt
@@ -15,16 +15,18 @@ basic/testManyVars.js
 basic/testTypedArrayInit.js
 debug/DebuggeeWouldRun-01.js
 debug/DebuggeeWouldRun-02.js
 gc/bug-1014972.js
 gc/bug-1246593.js
 gc/bug-906236.js
 gc/bug-906241.js
 ion/bug787921.js
+ion/bug977966.js
 parallel/alloc-many-objs.js
 parallel/alloc-too-many-objs.js
 saved-stacks/bug-1006876-too-much-recursion.js
 self-test/assertDeepEq.js
+sunspider/check-string-unpack-code.js
 v8-v5/check-earley-boyer.js
 v8-v5/check-raytrace.js
 v8-v5/check-regexp.js
 v8-v5/check-splay.js

--- a/js/src/jit-test/tests/basic/bug754150.js
+++ b/js/src/jit-test/tests/basic/bug754150.js
@@ -1,9 +1,18 @@
 // |jit-test| error: TypeError;
+
+// String.prototype.replace takes too long time with gczeal(4) if
+// --no-baseline --no-ion options.
+if (typeof inJit == "function" && typeof inJit() == "string") {
+  assertEq(inJit(), "Baseline is disabled.");
+  // This test expects TypeError.
+  toPrinted(null);
+}
+
 function printStatus (msg) {}
 function toPrinted(value) {
   value = value.replace(/\\n/g, 'NL')
 }
 function reportCompare (expected, actual, description) {
     printStatus ("Expected value '" + toPrinted(expected) +  "' matched actual value '" + toPrinted(actual) + "'");
 }
 var UBound = 0;