maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[docs] Add an initial (non-exhaustive) list of intrinsics that can be used in constant expressions 

As suggested by @rsmith on D86398 - we should try to document the intrinsics that can be used in constexpr
This commit is contained in:
Simon Pilgrim 2020-08-23 10:55:14 +01:00
parent f8e0e5db48
commit f76adc2603
1 changed files with 73 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

73
clang/docs/LanguageExtensions.rst
View File

@ -3603,3 +3603,76 @@ and alignment as the smallest basic type that can contain them. Types that are l
than 64 bits are handled in the same way as _int128 is handled; they are conceptually
treated as struct of register size chunks. They number of chunks are the smallest
number that can contain the types which does not necessarily mean a power-of-2 size.
Intrinsics Support within Constant Expressions
==============================================
The following builtin intrinsics can be used in constant expressions:
* ``__builtin_bitreverse8``
* ``__builtin_bitreverse16``
* ``__builtin_bitreverse32``
* ``__builtin_bitreverse64``
* ``__builtin_bswap16``
* ``__builtin_bswap32``
* ``__builtin_bswap64``
* ``__builtin_clrsb``
* ``__builtin_clrsbl``
* ``__builtin_clrsbll``
* ``__builtin_clz``
* ``__builtin_clzl``
* ``__builtin_clzll``
* ``__builtin_clzs``
* ``__builtin_ctz``
* ``__builtin_ctzl``
* ``__builtin_ctzll``
* ``__builtin_ctzs``
* ``__builtin_ffs``
* ``__builtin_ffsl``
* ``__builtin_ffsll``
* ``__builtin_fpclassify``
* ``__builtin_inf``
* ``__builtin_isinf``
* ``__builtin_isinf_sign``
* ``__builtin_isfinite``
* ``__builtin_isnan``
* ``__builtin_isnormal``
* ``__builtin_nan``
* ``__builtin_nans``
* ``__builtin_parity``
* ``__builtin_parityl``
* ``__builtin_parityll``
* ``__builtin_popcount``
* ``__builtin_popcountl``
* ``__builtin_popcountll``
* ``__builtin_rotateleft8``
* ``__builtin_rotateleft16``
* ``__builtin_rotateleft32``
* ``__builtin_rotateleft64``
* ``__builtin_rotateright8``
* ``__builtin_rotateright16``
* ``__builtin_rotateright32``
* ``__builtin_rotateright64``
The following x86-specific intrinsics can be used in constant expressions:
* ``_bit_scan_forward``
* ``_bit_scan_reverse``
* ``__bsfd``
* ``__bsfq``
* ``__bsrd``
* ``__bsrq``
* ``__bswap``
* ``__bswapd``
* ``__bswap64``
* ``__bswapq``
* ``_castf32_u32``
* ``_castf64_u64``
* ``_castu32_f32``
* ``_castu64_f64``
* ``_mm_popcnt_u32``
* ``_mm_popcnt_u64``
* ``_popcnt32``
* ``_popcnt64``
* ``__popcntd``
* ``__popcntq``