Add experimental half precison support

With this MR experimental half-precision support is added

pystencils/cpu/cpujit.py

@@ -50,6 +50,7 @@ import platform
 import shutil
 import subprocess
 import textwrap
+import warnings
 from collections import OrderedDict
 from sysconfig import get_paths
 from tempfile import TemporaryDirectory, NamedTemporaryFile
@@ -522,6 +523,15 @@ class ExtensionModuleCode:
         for ast in self._ast_nodes:
             for field in ast.fields_accessed:
                 if isinstance(field.dtype, BasicType) and field.dtype.is_half():
+                    if not platform.machine() in ['arm64', 'aarch64']:
+                        warnings.warn(f"The AST contains half precision data types but platform is: "
+                                      f"{platform.machine()}. Using half precision might not work properly on this "
+                                      f"platform")
+
+                    if 'clang' not in get_compiler_config()['command']:
+                        warnings.warn(f"The AST contains half precision data types but compiler is: "
+                                      f"{get_compiler_config()['command']}. Using half precision is only tested with "
+                                      f"the Clang compiler")
                     # Add the half precision header only if half precision numbers occur in the AST
                     headers.add('"half_precision.h"')
             headers.update(get_headers(ast))