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image: Fix strict-aliasing compiler warnings #159

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image: Fix strict-aliasing compiler warnings #159

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22 changes: 13 additions & 9 deletions src/image/p_scharr3x3.c
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Original file line number Diff line number Diff line change
Expand Up @@ -81,14 +81,18 @@ void p_scharr3x3_f32(const float *x, float *r, int rows, int cols)
* @return The length of the hypotenuse
*/

static __inline __attribute((__always_inline__)) float my_hypot( float a, float b )
static __inline __attribute((__always_inline__)) float my_hypot(float a, float b)
{
float s2 = __builtin_fmaf(a,a,b * b);
float x = s2 * -0.5f;
long i = * ( long * ) &s2;
i = 0x5f375a86 - ( i >> 1 );
float y = * ( float * ) &i;
y = y * __builtin_fmaf(x, y*y, 1.5f); // 1st Newton iteration
y = y * __builtin_fmaf(x, y*y, 1.5f); // 2nd iteration, this can be removed
return s2 * y;
union fl {
float f;
long l;
};
union fl s2 = { .l = 0 };
s2.f = __builtin_fmaf(a,a,b * b);
float x = s2.f * -0.5f;
union fl i = { .l = 0x5f375a86 - ( s2.l >> 1 ) } ;
float y = i.f;
y = y * __builtin_fmaf(x, y*y, 1.5f); // 1st Newton iteration
y = y * __builtin_fmaf(x, y*y, 1.5f); // 2nd iteration, this can be removed
return s2.f * y;
}
22 changes: 13 additions & 9 deletions src/image/p_sobel3x3.c
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Original file line number Diff line number Diff line change
Expand Up @@ -116,14 +116,18 @@ void p_sobel3x3_f32(const float *x, float *r, int rows, int cols)
* @return The length of the hypotenuse
*/

static __inline __attribute((__always_inline__)) float my_hypot( float a, float b )
static __inline __attribute((__always_inline__)) float my_hypot(float a, float b)
{
float s2 = __builtin_fmaf(a,a,b * b);
float x = s2 * -0.5f;
long i = * ( long * ) &s2;
i = 0x5f375a86 - ( i >> 1 );
float y = * ( float * ) &i;
y = y * __builtin_fmaf(x, y*y, 1.5f); // 1st Newton iteration
y = y * __builtin_fmaf(x, y*y, 1.5f); // 2nd iteration, this can be removed
return s2 * y;
union fl {
float f;
long l;
};
union fl s2 = { .l = 0 };
s2.f = __builtin_fmaf(a,a,b * b);
float x = s2.f * -0.5f;
union fl i = { .l = 0x5f375a86 - ( s2.l >> 1 ) } ;
float y = i.f;
y = y * __builtin_fmaf(x, y*y, 1.5f); // 1st Newton iteration
y = y * __builtin_fmaf(x, y*y, 1.5f); // 2nd iteration, this can be removed
return s2.f * y;
}