Merge pull request #1266 from nouiz/march

theano/gof/cmodule.py

@@ -1474,6 +1474,37 @@ def gcc_version():
     return gcc_version_str
 
 
+def gcc_llvm():
+    """ Detect if the g++ version used is the llvm one or not.
+
+    It don't support all g++ parameters even if it support many of them.
+    """
+    if gcc_llvm.is_llvm is None:
+        pass
+        dummy_in = open(os.devnull)
+        p = None
+        try:
+            p = call_subprocess_Popen(['g++', '--version'],
+                                      stdout=subprocess.PIPE,
+                                      stdin=dummy_in.fileno(),
+                                      stderr=subprocess.PIPE)
+            p.wait()
+            output = p.stdout.read() + p.stderr.read()
+        except OSError:
+            # Typically means g++ cannot be found.
+            # So it is not an llvm compiler.
+
+            # Normally this should not happen as we should not try to
+            # compile when g++ is not available. If this happen, it
+            # will crash later so supposing it is not llvm is "safe".
+            output = ''
+        del p
+        del dummy_in
+        gcc_llvm.is_llvm = "llvm" in output
+    return gcc_llvm.is_llvm
+gcc_llvm.is_llvm = None
+
+
 class GCC_compiler(object):
     # The equivalent flags of --march=native used by g++.
     march_flags = None
@@ -1495,6 +1526,9 @@ class GCC_compiler(object):
         # http://en.gentoo-wiki.com/wiki/Safe_Cflags#-march.3Dnative
         # http://en.gentoo-wiki.com/wiki/Hardware_CFLAGS
         detect_march = GCC_compiler.march_flags is None
+        if detect_march and gcc_llvm():
+            detect_march = False
+            GCC_compiler.march_flags = []
 
         if detect_march:
             for f in cxxflags: