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Re: [wwwdocs] Typo in description of __builtin_expect_with_probability
On Tue, 30 Oct 2018 at 09:54, Jonathan Wakely <jwakely.gcc@gmail.com> wrote:
>
> On Tue, 30 Oct 2018 at 09:18, Rasmus Villemoes <rv@rasmusvillemoes.dk> wrote:
> >
> > On 2018-10-30 09:29, Martin Liška wrote:
> > > On 10/30/18 3:56 AM, Alexander Oblovatniy wrote:
> > >> Hello,
> > >>
> > >> I'd like to report a typo in description of
> > >> «__builtin_expect_with_probability»:
> > >> https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other-Builtins
> > >>
> > >> The description starts with "The built-in has same semantics as
> > >> *__builtin_expect_with_probability*", but it seems like *__builtin_expect*
> > >> should be there.
> > >
> > > Thanks for reporting the issue. It's fixed as r265615.
> >
> > Other issues around the same place: "expected probability (in percent)"
> > seems to contradict "valid values are in inclusive range 0.0f and 1.0f".
> > The prototype is listed as
> >
> > (long exp, long c, long probability)
>
> The testcases added alongside the new built-in use float arguments,
> but the actual definition of the built-in seems to use a long double.
>
> What does "user can provide expected probability (in percent) for
> value of @var{exp}" mean? What is the probability of the value of exp?
> Don't you mean the probability that exp==c?
>
> Also the grammar in the text needs several fixes.
Maybe something like:
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -12025,12 +12025,12 @@ when testing pointer or floating-point values.
@end deftypefn
@deftypefn {Built-in Function} long __builtin_expect_with_probability
-(long @var{exp}, long @var{c}, long @var{probability})
+(long @var{exp}, long @var{c}, long double @var{probability})
-The built-in has same semantics as @code{__builtin_expect},
-but user can provide expected probability (in percent) for value of @var{exp}.
-Last argument @var{probability} is of float type and valid values
-are in inclusive range 0.0f and 1.0f.
+This function has the same semantics as @code{__builtin_expect},
+but the caller provides the expected probability that @var{exp} == @var{c}.
+The last argument, @var{probability}, is a floating point value in the
+range 0.0 to 1.0, inclusive.
@end deftypefn
@deftypefn {Built-in Function} void __builtin_trap (void)