[llvm] [llvm][Tablegen][llvm-tblgen] Added keyword #undef to llvm-tblgen and fixed a small b… (PR #69135)

[Qiu Chaofan via llvm-commits]

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@@ -664,7 +660,7 @@ tgtok::TokKind TGLexer::prepIsDirective() const {
           // It looks like TableGen does not support '\r' as the actual
           // carriage return, e.g. getNextChar() treats a single '\r'
           // as '\n'.  So we do the same here.
-          NextChar == '\r')
+          NextChar == '\r' || NextChar == '\0')
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ecnelises wrote:

Wouldn't that make any case fail? I guess if a reproducible case is given, this deserves a dedicated PR

https://github.com/llvm/llvm-project/pull/69135