[clang] [clang] Deduce _BitInt(N) template parameter as size_t (PR #195534)

[Corentin Jabot via cfe-commits]

================
@@ -2511,11 +2521,14 @@ static TemplateDeductionResult DeduceTemplateArgumentsByTypeMatch(
         if (!NTTP)
           return TemplateDeductionResult::Success;
 
-        llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false);
+        // P3666 suggested wording for [temp.deduct.type]:
+        //   The type of N in the type _BitInt(N) is std::size_t.
----------------
cor3ntin wrote:

```suggestion
        // Deduce the size parameter of _BitInt as std::size_t
```

https://github.com/llvm/llvm-project/pull/195534