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maths: use std::signbit instead of builtin

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This commit is contained in:
Danny Robson 2015-04-07 16:53:11 +10:00
parent 426fc1c848
commit 14cab4fb9b
1 changed files with 6 additions and 5 deletions
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11
maths.ipp
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@ -48,25 +48,26 @@ pow (T x, unsigned y)
///----------------------------------------------------------------------------
/// Return a unit type with a sign that matches the provided value
///
/// This really needs to be inline for performance as it's used in a few inner
/// loops where the possibility of a function call is a deal breaker.
/// We were using __builtin_signbit for the potential speedboost, but it causes
/// problems with constexpr under clang. If you need speed then you'll probably
/// have to handcode something.
constexpr int
sign (int v)
{
return __builtin_signbitl (v) ? -1 : 1;
return std::signbit (v) ? -1 : 1;
}
constexpr float
sign (float v)
{
return __builtin_signbitf (v) ? -1.f : 1.f;
return std::signbit (v) ? -1.f : 1.f;
}
constexpr double
sign (double v)
{
return __builtin_signbit (v) ? -1. : 1.f;
return std::signbit (v) ? -1. : 1.f;
}