[PATCH] Builtin function roundeven folding implementation

[Joseph Myers]

On Wed, 21 Aug 2019, Martin Jambor wrote:

>   - I have listed roundeven variants in extend.texi.  If I did not find
>     the right spot, I will gladly move to a more appropriate one.

I don't think they should be documented with the __builtin_* that are 
always expanded inline.  They should be documented in the list of 
functions that *might* be expanded inline.  That is, where extend.texi 
says:

  [...]  Many of these
  functions are only optimized in certain cases; if they are not optimized in
  a particular case, a call to the library function is emitted.

  @opindex ansi
  @opindex std
  Outside strict ISO C mode (@option{-ansi}, @option{-std=c90},
  @option{-std=c99} or @option{-std=c11}), the functions
  @code{_exit}, [...]
  may be handled as built-in functions.
  All these functions have corresponding versions
  prefixed with @code{__builtin_}, which may be used even in strict C90
  mode.

(Until we enable these by default for C2X, at which point they'd be listed 
as C2X functions after the C99 ones.)

-- 
Joseph S. Myers
joseph@codesourcery.com