transforms.iodelay_estimator: allow goto in zero-iodelay while statements.

artiq/compiler/transforms/iodelay_estimator.py

@@ -200,11 +200,15 @@ class IODelayEstimator(algorithm.Visitor):
             self.abort("{} cannot be interleaved".format(kind), node.loc)
         self.current_delay = old_delay
 
-    visit_While  = lambda self, node: self.visit_control_flow("while statement", node)
     visit_If     = lambda self, node: self.visit_control_flow("if statement",    node)
     visit_IfExpT = lambda self, node: self.visit_control_flow("if expression",   node)
     visit_Try    = lambda self, node: self.visit_control_flow("try statement",   node)
 
+    def visit_While(self, node):
+        old_goto, self.current_goto = self.current_goto, None
+        self.visit_control_flow("while statement", node)
+        self.current_goto = old_goto
+
     def visit_Return(self, node):
         self.current_return = node
 

lit-test/test/interleaving/control_flow.py

@@ -9,6 +9,7 @@ def f():
             print(2)
         while False:
             print(3)
+            break
         delay_mu(1)
     print(4)