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maths: remove const/pure attributes

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const/pure attributes are causing inconsitencies for various functions.
it's safer to just not use them until there's a more thorough
investigation of their impact.
This commit is contained in:
Danny Robson 2015-11-13 17:15:08 +11:00
parent 89fe57b65b
commit f2bd6501e2
1 changed files with 42 additions and 32 deletions
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74
maths.hpp
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@ -17,8 +17,9 @@
#ifndef __MATHS_HPP #ifndef __MATHS_HPP
#define __MATHS_HPP #define __MATHS_HPP
#include "debug.hpp" #include "./debug.hpp"
#include "types/traits.hpp" #include "./types/traits.hpp"
#include "./float.hpp"
#include <cmath> #include <cmath>
#include <cstdint> #include <cstdint>
@ -27,6 +28,13 @@
#include <utility> #include <utility>
///////////////////////////////////////////////////////////////////////////////
// NOTE: You may be tempted to add all sorts of performance enhancing
// attributes (like gnu::const or gnu::pure). DO NOT DO THIS WITHOUT EXTENSIVE
// TESTING. Just about everything will break in some way with these attributes.
//
// In particular: it is safest to apply these only to leaf functions
/////////////////////////////////////////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////
namespace util { namespace util {
@ -45,8 +53,10 @@ namespace util {
namespace util { namespace util {
template <typename T> template <typename T>
constexpr T constexpr T
pow2 [[gnu::const]] (T value) pow2 [[gnu::const]] (T value)
{ return value * value; } {
return value * value;
}
} }
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
@ -60,26 +70,26 @@ namespace util {
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
template <typename T> template <typename T>
bool bool
is_pow2 [[gnu::const]] (T value); is_pow2 (T value);
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
// Logarithms // Logarithms
template <typename T> template <typename T>
T T
log2 [[gnu::const]] (T val); log2 (T val);
template <typename T> template <typename T>
T T
log2up [[gnu::const]] (T val); log2up (T val);
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
// Roots // Roots
template <typename T> template <typename T>
double double
rootsquare [[gnu::const]] (T a, T b); rootsquare (T a, T b);
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
@ -90,7 +100,7 @@ typename std::common_type<
std::enable_if_t<std::is_integral<T>::value,T>, std::enable_if_t<std::is_integral<T>::value,T>,
std::enable_if_t<std::is_integral<U>::value,U> std::enable_if_t<std::is_integral<U>::value,U>
>::type >::type
round_to [[gnu::const]] (T value, U size) round_to (T value, U size)
{ {
if (value % size == 0) if (value % size == 0)
return value; return value;
@ -101,12 +111,12 @@ round_to [[gnu::const]] (T value, U size)
template <typename T> template <typename T>
T T
round_pow2 [[gnu::const]] (T value); round_pow2 (T value);
template <typename T, typename U> template <typename T, typename U>
constexpr T constexpr T
divup [[gnu::const]] (const T a, const U b) divup (const T a, const U b)
{ return (a + b - 1) / b; } { return (a + b - 1) / b; }
@ -114,14 +124,14 @@ divup [[gnu::const]] (const T a, const U b)
// Classification // Classification
template <typename T> template <typename T>
bool bool
is_integer [[gnu::const]] (const T& value); is_integer (const T& value);
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
// Properties // Properties
template <typename T> template <typename T>
unsigned unsigned
digits [[gnu::const]] (const T& value); digits (const T& value);
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
@ -248,7 +258,7 @@ constexpr T E = T(2.71828182845904523536028747135266250);
template <typename T> template <typename T>
constexpr T constexpr T
to_degrees [[gnu::const]] (T radians) to_degrees (T radians)
{ {
static_assert (std::is_floating_point<T>::value, "undefined for integral types"); static_assert (std::is_floating_point<T>::value, "undefined for integral types");
return radians * 180 / PI<T>; return radians * 180 / PI<T>;
@ -257,7 +267,7 @@ to_degrees [[gnu::const]] (T radians)
template <typename T> template <typename T>
constexpr T constexpr T
to_radians [[gnu::const]] (T degrees) to_radians (T degrees)
{ {
static_assert (std::is_floating_point<T>::value, "undefined for integral types"); static_assert (std::is_floating_point<T>::value, "undefined for integral types");
return degrees / 180 * PI<T>; return degrees / 180 * PI<T>;
@ -267,7 +277,7 @@ to_radians [[gnu::const]] (T degrees)
//! Normalised sinc function //! Normalised sinc function
template <typename T> template <typename T>
constexpr T constexpr T
sincn [[gnu::const]] (T x) sincn (T x)
{ {
return almost_zero (x) ? 1 : std::sin (PI<T> * x) / (PI<T> * x); return almost_zero (x) ? 1 : std::sin (PI<T> * x) / (PI<T> * x);
} }
@ -276,7 +286,7 @@ sincn [[gnu::const]] (T x)
//! Unnormalised sinc function //! Unnormalised sinc function
template <typename T> template <typename T>
constexpr T constexpr T
sincu [[gnu::const]] (T x) sincu (T x)
{ {
return almost_zero (x) ? 1 : std::sin (x) / x; return almost_zero (x) ? 1 : std::sin (x) / x;
} }
@ -284,7 +294,7 @@ sincu [[gnu::const]] (T x)
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
constexpr uintmax_t constexpr uintmax_t
factorial [[gnu::const]] (unsigned i) factorial (unsigned i)
{ {
return i <= 1 ? 0 : i * factorial (i - 1); return i <= 1 ? 0 : i * factorial (i - 1);
} }
@ -292,7 +302,7 @@ factorial [[gnu::const]] (unsigned i)
/// stirlings approximation of factorials /// stirlings approximation of factorials
constexpr uintmax_t constexpr uintmax_t
stirling [[gnu::const]] (unsigned n) stirling (unsigned n)
{ {
return static_cast<uintmax_t> ( return static_cast<uintmax_t> (
std::sqrt (2 * PI<float> * n) * std::pow (n / E<float>, n) std::sqrt (2 * PI<float> * n) * std::pow (n / E<float>, n)
@ -301,7 +311,7 @@ stirling [[gnu::const]] (unsigned n)
constexpr uintmax_t constexpr uintmax_t
combination [[gnu::const]] (unsigned n, unsigned k) combination (unsigned n, unsigned k)
{ {
return factorial (n) / (factorial (k) / (factorial (n - k))); return factorial (n) / (factorial (k) / (factorial (n - k)));
} }
@ -337,7 +347,7 @@ fsum (InputIt first, InputIt last)
namespace util { namespace util {
template <typename T> template <typename T>
constexpr T constexpr T
min [[gnu::const]] (const T a) min (const T a)
{ return a; } { return a; }
@ -347,7 +357,7 @@ namespace util {
std::is_integral<typename std::decay<T>::type>::value == std::is_integral<typename std::decay<U>::type>::value, std::is_integral<typename std::decay<T>::type>::value == std::is_integral<typename std::decay<U>::type>::value,
typename std::common_type<T,U>::type typename std::common_type<T,U>::type
>::type >::type
min [[gnu::const]] (const T a, const U b, Args ...args) min (const T a, const U b, Args ...args)
{ {
return min (a < b ? a : b, std::forward<Args> (args)...); return min (a < b ? a : b, std::forward<Args> (args)...);
} }
@ -357,7 +367,7 @@ namespace util {
/// Variadic maximum /// Variadic maximum
template <typename T> template <typename T>
constexpr T constexpr T
max [[gnu::const]] (const T a) max (const T a)
{ return a; } { return a; }
@ -367,7 +377,7 @@ namespace util {
std::is_integral<typename std::decay<T>::type>::value == std::is_integral<typename std::decay<U>::type>::value, std::is_integral<typename std::decay<T>::type>::value == std::is_integral<typename std::decay<U>::type>::value,
typename std::common_type<T,U>::type typename std::common_type<T,U>::type
>::type >::type
max [[gnu::const]] (const T a, const U b, Args ...args) max (const T a, const U b, Args ...args)
{ {
return max (a > b ? a : b, std::forward<Args> (args)...); return max (a > b ? a : b, std::forward<Args> (args)...);
} }
@ -379,7 +389,7 @@ namespace util {
// min/max clamping // min/max clamping
template <typename T, typename U, typename V> template <typename T, typename U, typename V>
constexpr T constexpr T
limit [[gnu::const]] (const T val, const U lo, const V hi) limit (const T val, const U lo, const V hi)
{ {
lo <= hi ? (void)0 : panic (); lo <= hi ? (void)0 : panic ();
@ -392,7 +402,7 @@ limit [[gnu::const]] (const T val, const U lo, const V hi)
// clamped cubic hermite interpolation // clamped cubic hermite interpolation
template <typename T> template <typename T>
T T
smoothstep [[gnu::const]] (T a, T b, T x) smoothstep (T a, T b, T x)
{ {
CHECK_LE(a, b); CHECK_LE(a, b);
x = limit ((x - a) / (b - a), T{0}, T{1}); x = limit ((x - a) / (b - a), T{0}, T{1});
@ -411,7 +421,7 @@ constexpr
typename std::enable_if< typename std::enable_if<
!std::is_floating_point<T>::value && std::is_floating_point<U>::value, U !std::is_floating_point<T>::value && std::is_floating_point<U>::value, U
>::type >::type
renormalise [[gnu::const]] (T t) renormalise (T t)
{ {
return t / static_cast<U> (std::numeric_limits<T>::max ()); return t / static_cast<U> (std::numeric_limits<T>::max ());
} }
@ -423,7 +433,7 @@ constexpr
typename std::enable_if< typename std::enable_if<
std::is_floating_point<T>::value && !std::is_floating_point<U>::value, U std::is_floating_point<T>::value && !std::is_floating_point<U>::value, U
>::type >::type
renormalise [[gnu::const]] (T t) renormalise (T t)
{ {
// Ideally std::ldexp would be involved but it complicates handing // Ideally std::ldexp would be involved but it complicates handing
// integers with greater precision than our floating point type. Also it // integers with greater precision than our floating point type. Also it
@ -458,7 +468,7 @@ typename std::enable_if<
std::is_floating_point<U>::value && std::is_floating_point<U>::value &&
!std::is_same<T,U>::value, U !std::is_same<T,U>::value, U
>::type >::type
renormalise [[gnu::const]] (T t) renormalise (T t)
{ {
return static_cast<U> (t); return static_cast<U> (t);
} }
@ -472,7 +482,7 @@ typename std::enable_if<
std::is_integral<U>::value && std::is_integral<U>::value &&
(sizeof (T) > sizeof (U)), U (sizeof (T) > sizeof (U)), U
>::type >::type
renormalise [[gnu::const]] (T t) renormalise (T t)
{ {
static_assert (sizeof (T) > sizeof (U), static_assert (sizeof (T) > sizeof (U),
"assumes right shift is sufficient"); "assumes right shift is sufficient");
@ -491,7 +501,7 @@ typename std::enable_if<
std::is_integral<U>::value && std::is_integral<U>::value &&
sizeof (T) < sizeof (U), U sizeof (T) < sizeof (U), U
>::type >::type
renormalise [[gnu::const]] (T t) renormalise (T t)
{ {
static_assert (sizeof (T) < sizeof (U), static_assert (sizeof (T) < sizeof (U),
"assumes bit creation is required to fill space"); "assumes bit creation is required to fill space");
@ -518,7 +528,7 @@ constexpr
typename std::enable_if< typename std::enable_if<
std::is_same<T,U>::value, U std::is_same<T,U>::value, U
>::type >::type
renormalise [[gnu::const]] (T t) renormalise (T t)
{ return t; } { return t; }
#include "maths.ipp" #include "maths.ipp"