in the theano flags, compiledir_format, allow the g++ version.

theano/gof/cmodule.py

@@ -25,6 +25,7 @@ from theano.gof.cc import hash_from_code
 
 # we will abuse the lockfile mechanism when reading and writing the registry
 import compilelock
+from compiledir import gcc_version_str
 
 from theano.configparser import AddConfigVar, BoolParam
 
@@ -1407,25 +1408,6 @@ def std_lib_dirs():
     return std_lib_dirs_and_libs()[1]
 
 
-# Using the dummy file descriptors below is a workaround for a crash
-# experienced in an unusual Python 2.4.4 Windows environment with the default
-# None values.
-dummy_in = open(os.devnull)
-dummy_err = open(os.devnull, 'w')
-p = None
-try:
-    p = subprocess.Popen(['g++', '-dumpversion'], stdout=subprocess.PIPE,
-                         stdin=dummy_in.fileno(), stderr=dummy_err.fileno())
-    p.wait()
-    gcc_version_str = p.stdout.readline().strip()
-except OSError:
-    # Typically means gcc cannot be found.
-    gcc_version_str = 'GCC_NOT_FOUND'
-del p
-del dummy_in
-del dummy_err
-
-
 def gcc_version():
     return gcc_version_str
 

theano/gof/compiledir.py

@@ -3,6 +3,7 @@ import errno
 import os
 import platform
 import re
+import subprocess
 import shutil
 import sys
 import textwrap
@@ -13,11 +14,30 @@ import theano
 from theano.configparser import config, AddConfigVar, ConfigParam, StrParam
 from theano.gof.utils import flatten
 
+# Using the dummy file descriptors below is a workaround for a crash
+# experienced in an unusual Python 2.4.4 Windows environment with the default
+# None values.
+dummy_in = open(os.devnull)
+dummy_err = open(os.devnull, 'w')
+p = None
+try:
+    p = subprocess.Popen(['g++', '-dumpversion'], stdout=subprocess.PIPE,
+                         stdin=dummy_in.fileno(), stderr=dummy_err.fileno())
+    p.wait()
+    gcc_version_str = p.stdout.readline().strip()
+except OSError:
+    # Typically means gcc cannot be found.
+    gcc_version_str = 'GCC_NOT_FOUND'
+del p
+del dummy_in
+del dummy_err
+
 compiledir_format_dict = {"platform": platform.platform(),
                           "processor": platform.processor(),
                           "python_version": platform.python_version(),
                           "theano_version": theano.__version__,
                           "numpy_version": numpy.__version__,
+                          "g++": gcc_version_str.replace(" ", "_"),
                          }
 compiledir_format_keys = ", ".join(compiledir_format_dict.keys())
 default_compiledir_format =\