Remove the unnecessary `is_nothrow_swappable` condition in `swap`.
Thanks to @lewissbaker who pointed out the unnecessary condition in
https://reviews.llvm.org/D81954#inline-756872. Since this codepath does not
make use of `swap` anyway (that codepath is a different branch), we can safely
remove this condition and produce better codegen when all types are nothrow
movable but are potentially-throwing swappable.
See codegen in https://gcc.godbolt.org/z/uDFZjz
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D83274
Cr-Mirrored-From: https://chromium.googlesource.com/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 6ab3208d779ffb3b32744b0190d7035d4b369173
diff --git a/include/variant b/include/variant
index 502d8d8..0355723 100644
--- a/include/variant
+++ b/include/variant
@@ -1063,8 +1063,7 @@
}
__impl __tmp(_VSTD::move(*__rhs));
#ifndef _LIBCPP_NO_EXCEPTIONS
- if constexpr (__all<(is_nothrow_move_constructible_v<_Types> &&
- is_nothrow_swappable_v<_Types>)...>::value) {
+ if constexpr (__all<is_nothrow_move_constructible_v<_Types>...>::value) {
this->__generic_construct(*__rhs, _VSTD::move(*__lhs));
} else {
// EXTENSION: When the move construction of `__lhs` into `__rhs` throws