[PATCH] D80433: [clang-tblgen][CommandLine][ManagedStatic] Fix build errors with clang-tblgen in Debug mode using MSVC 2019 v16.6

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


================
Comment at: llvm/include/llvm/Support/ManagedStatic.h:47
+// (https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros?redirectedfrom=MSDN&view=vs-2019).
+#if (defined(_MSC_VER) && (_MSC_VER >= 1925)) || defined(__clang__)
 #define LLVM_USE_CONSTEXPR_CTOR
----------------
aganea wrote:
> ASDenysPetrov wrote:
> > RKSimon wrote:
> > > Won't this no longer fire on gcc builds? Maybe this:
> > > ```
> > > #if !defined(_MSC_VER) || defined(__clang__) || (defined(_MSC_VER) && (_MSC_VER >= 1925))
> > > ```
> > Thank you. I somehow missed this case.
> > It'd be even better this:
> > ```
> > #if !defined(_MSC_VER) || (_MSC_VER >= 1925)
> > ```
> @ASDenysPetrov You need the `defined(__clang__)` part because users can set `_MSC_VER` with `-fmsc-version=` or through auto-detection (so you could have `_MSC_VER < 1925`), and yet that should use the `LLVM_USE_CONSTEXPR_CTOR` codepath.
You need the clang case to support clang-cl builds.
```
#if !defined(_MSC_VER) || (_MSC_VER >= 1925) || defined(__clang__)
```


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https://reviews.llvm.org/D80433