--- a/taskcluster/taskgraph/target_tasks.py
+++ b/taskcluster/taskgraph/target_tasks.py
@@ -49,17 +49,17 @@ def standard_filter(task, parameters):
 
 
 @_target_task('try_option_syntax')
 def target_tasks_try_option_syntax(full_task_graph, parameters):
     """Generate a list of target tasks based on try syntax in
     parameters['message'] and, for context, the full task graph."""
     options = try_option_syntax.TryOptionSyntax(parameters['message'], full_task_graph)
     target_tasks_labels = [t.label for t in full_task_graph.tasks.itervalues()
-                           if options.task_matches(t.attributes)]
+                           if options.task_matches(t)]
 
     attributes = {
         k: getattr(options, k) for k in [
             'env',
             'no_retry',
             'tag',
         ]
     }

--- a/taskcluster/taskgraph/test/test_target_tasks.py
+++ b/taskcluster/taskgraph/test/test_target_tasks.py
@@ -20,18 +20,18 @@ class FakeTryOptionSyntax(object):
         self.trigger_tests = 0
         self.talos_trigger_tests = 0
         self.notifications = None
         self.env = []
         self.profile = False
         self.tag = None
         self.no_retry = False
 
-    def task_matches(self, attributes):
-        return 'at-at' in attributes
+    def task_matches(self, task):
+        return 'at-at' in task.attributes
 
 
 class TestTargetTasks(unittest.TestCase):
 
     def default_matches(self, run_on_projects, project):
         method = target_tasks.get_method('default')
         graph = TaskGraph(tasks={
             'a': Task(kind='build', label='a',

--- a/taskcluster/taskgraph/try_option_syntax.py
+++ b/taskcluster/taskgraph/try_option_syntax.py
@@ -543,18 +543,18 @@ class TryOptionSyntax(object):
     def find_all_attribute_suffixes(self, graph, prefix):
         rv = set()
         for t in graph.tasks.itervalues():
             for a in t.attributes:
                 if a.startswith(prefix):
                     rv.add(a[len(prefix):])
         return sorted(rv)
 
-    def task_matches(self, attributes):
-        attr = attributes.get
+    def task_matches(self, task):
+        attr = task.attributes.get
 
         def check_run_on_projects():
             if attr('nightly') and not self.include_nightly:
                 return False
             return set(['try', 'all']) & set(attr('run_on_projects', []))
 
         def match_test(try_spec, attr_name):
             if attr('build_type') not in self.build_types:
@@ -569,30 +569,36 @@ class TryOptionSyntax(object):
                 return True
             # TODO: optimize this search a bit
             for test in try_spec:
                 if attr(attr_name) == test['test']:
                     break
             else:
                 return False
             if 'platforms' in test:
-                platform = attributes.get('test_platform', '').split('/')[0]
+                platform = attr('test_platform', '').split('/')[0]
                 if platform not in test['platforms']:
                     return False
             if 'only_chunks' in test and attr('test_chunk') not in test['only_chunks']:
                 return False
             return True
 
         job_try_name = attr('job_try_name')
         if job_try_name:
             # Beware the subtle distinction between [] and None for self.jobs and self.platforms.
             # They will be [] if there was no try syntax, and None if try syntax was detected but
             # they remained unspecified.
             if self.jobs and job_try_name not in self.jobs:
                 return False
+            elif not self.jobs and 'build' in task.dependencies:
+                # We exclude tasks with build dependencies from the default set of jobs because
+                # they will schedule their builds even if they end up optimized away. This means
+                # to run these tasks on try, they'll need to be explicitly specified by -j until
+                # we find a better solution (see bug 1372510).
+                return False
             elif not self.jobs and attr('build_platform'):
                 if self.platforms is None or attr('build_platform') in self.platforms:
                     return True
                 return False
             return True
         elif attr('kind') == 'test':
             return match_test(self.unittests, 'unittest_try_name') \
                  or match_test(self.talos, 'talos_try_name')