[clang] [clang][utils] Add auto mode to reduction script (PR #163282)

[Arthur Eubanks via cfe-commits]

================
@@ -70,6 +80,44 @@ def write_to_script(text, filename):
     os.chmod(filename, os.stat(filename).st_mode | stat.S_IEXEC)
 
 
+def extract_opt_level(args_list: List[str]) -> Optional[str]:
+    """
+    Finds the last optimization flag (-O...) from a list of arguments.
+
+    Args:
+      args_list: A list of string arguments passed to the compiler.
+
+    Returns:
+      The last matching optimization flag string if found, otherwise None.
+    """
+    valid_opt_flags = {"-O0", "-O1", "-O2", "-O3", "-Os", "-Oz", "-Og", "-Ofast"}
----------------
aeubanks wrote:

llc/opt won't recognize -Og/-Ofast

https://github.com/llvm/llvm-project/pull/163282