[llvm] [NFC][Support] Create helper function to parse bool. (PR #102818)

[Alexandre Ganea via llvm-commits]

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@@ -404,6 +404,22 @@ class CommandLineParser {
 
 static ManagedStatic<CommandLineParser> GlobalParser;
 
+template <typename T, T TrueVal, T FalseVal>
+static bool parseBool(Option &O, StringRef ArgName, StringRef Arg, T &Value) {
+  if (Arg == "" || Arg == "true" || Arg == "TRUE" || Arg == "True" ||
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aganea wrote:

We could use `Arg.equals_insensitive("true") here. Same below for `false`

https://github.com/llvm/llvm-project/pull/102818