Make AllocEmpty return constant-valued memory under DebugMode so that it won't trip up checks.

theano/sandbox/cuda/basic_ops.py

@@ -3682,6 +3682,13 @@ class GpuAllocEmpty(GpuOp):
         output.type.filter_checks_isfinite = False
         return Apply(self, shape, [output])
 
+    def debug_perform(self, node, inputs, out_):
+        self.perform(self, node, inputs, out_)
+        # __setitem__ is limited on CudaNdarray
+        tmp = numpy.empty(out_[0][0].shape, dtype='float32')
+        tmp.fill(-123456789)
+        out_[0][0][:] = tmp
+
     def perform(self, node, inputs, out_):
         out, = out_
         sh = tuple([int(i) for i in inputs])

theano/sandbox/gpuarray/basic_ops.py

@@ -723,6 +723,10 @@ class GpuAllocEmpty(HideC, Alloc):
         output.type.filter_checks_isfinite = False
         return Apply(self, sh, [output])
 
+    def debug_perform(self, node, inputs, out_, ctx):
+        self.perform(node, inputs, out_, ctx)
+        out_[0][0][:] = -123456789
+
     def perform(self, node, inputs, out_, ctx):
         out = out_[0]
         sh = [int(i) for i in inputs]

theano/tensor/basic.py

@@ -6240,6 +6240,10 @@ class AllocEmpty(gof.Op):
         output.type.filter_checks_isfinite = False
         return Apply(self, shape, [output])
 
+    def debug_perform(self, node, inputs, out_):
+        self.perform(node, inputs, out_)
+        out_[0][0].fill(-123456789)
+
     def perform(self, node, inputs, out_):
         out, = out_
         sh = tuple([int(i) for i in inputs])