[clang] Perf/lexer faster slow get char and size (PR #70543)

[via cfe-commits]

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@@ -1964,11 +1969,14 @@ bool Lexer::LexIdentifierContinue(Token &Result, const char *CurPtr) {
 /// isHexaLiteral - Return true if Start points to a hex constant.
 /// in microsoft mode (where this is supposed to be several different tokens).
 bool Lexer::isHexaLiteral(const char *Start, const LangOptions &LangOpts) {
-  unsigned Size;
-  char C1 = Lexer::getCharAndSizeNoWarn(Start, Size, LangOpts);
+  auto CharAndSize1 = Lexer::getCharAndSizeNoWarn(Start, LangOpts);
+  char C1 = CharAndSize1.Char;
   if (C1 != '0')
     return false;
-  char C2 = Lexer::getCharAndSizeNoWarn(Start + Size, Size, LangOpts);
+
+  auto CharAndSize2 =
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cor3ntin wrote:

I won't insist!

https://github.com/llvm/llvm-project/pull/70543