[llvm] [SVE] Don't require lookup when demangling vector function mappings (PR #72260)

[Paul Walker via llvm-commits]

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@@ -66,24 +66,26 @@ ParseRet tryParseMask(StringRef &MangledName, bool &IsMasked) {
 /// vector length. On success, the `<vlen>` token is removed from
 /// the input string `ParseString`.
 ///
-ParseRet tryParseVLEN(StringRef &ParseString, unsigned &VF, bool &IsScalable) {
+ParseRet tryParseVLEN(StringRef &ParseString,
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paulwalker-arm wrote:

I'm not too keen on `ParsedVF` being an optional return when the parsing is successful.  What about having this be a plain `ElementCount` with `x` returning `ElementCount::Scalable(0)`?

https://github.com/llvm/llvm-project/pull/72260