Issue 4375 - WG21 LWG Issues
Title
`std::simd::bit_ceil` should not be `noexcept`
Status
wp
Section
[simd.bit]
Submitter
Matthias Kretz

Created on 2025-08-29.00:00:00 last changed 1 month ago

Messages

msg15646 (view)
Date: 2025-11-11.10:48:16

Proposed resolution:

This wording is relative to N5014.

  1. Modify [simd.syn], header <simd> synopsis, as indicated:

    namespace std {
  […]
  // [simd.bit], bit manipulation
  template<simd-vec-type V> constexpr V byteswap(const V& v) noexcept;
  template<simd-vec-type V> constexpr V bit_ceil(const V& v) noexcept;
  template<simd-vec-type V> constexpr V bit_floor(const V& v) noexcept;  
  […]
}

  2. Modify [simd.bit] as indicated:

    template<simd-vec-type V> constexpr V bit_ceil(const V& v) noexcept;

    -3- Constraints: The type `V::value_type` is an unsigned integer type ([basic.fundamental]).

    -4- Preconditions: […]

    […]

msg15348 (view)
Date: 2025-11-11.10:48:16

[ Kona 2025-11-08; Status changed: Voting → WP. ]
msg15066 (view)
Date: 2025-10-15.00:00:00

[ 2025-10-22; Reflector poll. ]

Set status to Tentatively Ready after six votes in favour during reflector poll.

msg15065 (view)
Date: 2025-08-29.00:00:00

`std::simd::bit_ceil` is declared 'noexcept' in [simd.syn] and [simd.bit]. But

  1. `std::bit_ceil` is not 'noexcept' ([bit.syn] and [bit.pow.two]) and

  2. `std::simd::bit_ceil` has a precondition.
History
Date User Action Args
2025-11-11 10:48:16adminsetmessages: + msg15646
2025-11-11 10:48:16adminsetstatus: voting -> wp
2025-10-30 17:45:31adminsetstatus: ready -> voting
2025-10-22 12:32:36adminsetmessages: + msg15348
2025-10-22 12:32:36adminsetstatus: new -> ready
2025-09-19 18:06:38adminsetmessages: + msg15066
2025-08-29 00:00:00admincreate