[flang] [llvm] [flang] implement `split` for fortran 2023 (PR #161484)

[Tom Eccles via llvm-commits]

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@@ -917,6 +945,19 @@ void RTDEF(CharacterMin)(Descriptor &accumulator, const Descriptor &x,
   MaxMin<true>(accumulator, x, sourceFile, sourceLine);
 }
 
+std::size_t RTDEF(Split1)(const char *x, std::size_t xLen, const char *set,
+    std::size_t setLen, std::size_t pos, bool back) {
+  return Split<char>(x, xLen, set, setLen, pos, back);
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tblah wrote:

Please could you use `CppTypeFor<TypeCategory::Character, 1>` (here and below). Using this it might be easier to template over the numeric kind instead of over the type.

https://github.com/llvm/llvm-project/pull/161484