US 31-071 15.11p1.12 [cpp.predefined] Overbroad definition of __STDCPP_BFLOAT16_T__

[wg21bot]

The wording for the predefined macro __STDCPP_BFLOAT16_T__ added by P1467 can be interpreted more broadly than was intended. See this GitHub issue on the working draft.

Proposed change:

Modify 15.11 [cpp.predefined] paragraph 1 sentence 12 as follows:
Defined as the integer literal 1 if and only if the implementation supports an extended floating-point type with the properties of the typedef-name std::bfloat16_t as described in 6.8.3 [basic.extended.fp].

[jensmaurer]

CWG2652

[jensmaurer]

CWG 2022-11-08: Accepted.