[llvm] [mlir] [Support] Accept only true, false, 1 and 0 for cl::opt<bool> (PR #224975)

[Alexis Engelke via llvm-commits]

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@@ -439,13 +439,13 @@ static 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" ||
-      Arg == "1") {
+  // A bare -flag passes a null Arg; -flag= passes an empty one.
+  if (!Arg.data() || Arg == "true" || Arg == "1") {
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aengelke wrote:

StringRef data() can be non-null for empty strings. Why change that comparison anyway?

https://github.com/llvm/llvm-project/pull/224975