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Clang support for __is_assignable intrinsic
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Authored by DaveBartolomeo on May 20 2016, 2:21 PM.

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Summary

MSVC now supports the __is_assignable type trait intrinsic, to enable easier and more efficient implementation of the Standard Library's is_assignable trait. As of Visual Studio 2015 Update 3, the VC Standard Library implementation uses the new intrinsic unconditionally. We had already implemented this trait for Clang/C2, so we're upstreaming the change so that mainline Clang can handle the new intrinsic as well.

The implementation is pretty straightforward, due to the previously existing is_nothrow_assignable and is_trivially_assignable. We handle __is_assignable via the same code as the other two, except that we skip the extra checks for nothrow or triviality.

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rL LLVM

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DaveBartolomeo retitled this revision from to Clang support for __is_assignable intrinsic.
DaveBartolomeo updated this object.
DaveBartolomeo added a reviewer: rnk.
DaveBartolomeo added a subscriber: cfe-commits.
majnemer added inline comments.
lib/Sema/SemaExprCXX.cpp
4523–4525 ↗(On Diff #57987)

I'd remove the braces and sort it above the BTT_IsNothrowAssignable case.

Removed unnecessary braces.
Moved BTT_IsAssignable case to a more clear location.

EricWF added a subscriber: EricWF.May 20 2016, 8:10 PM

Should this have a test in test/Lexer/has_feature_type_traits.cpp?

This revision was automatically updated to reflect the committed changes.