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Code Issues 4 Releases Wiki Activity

[smooth] Remove SSE2. 

Benchmarking shows that rendering curves is faster without SSE2. This is
understandable because we deal with 2D space and simple calculations.
See !314 for testing results.

* src/smooth/ftgrays.c (gray_render_conic): Remove SSE2 code.
This commit is contained in:
Alexei Podtelezhnikov (Алексей Подтележников) 2024-01-11 06:40:38 -05:00 committed by Alexei Podtelezhnikov
parent 6d9147263b
commit c381aaa3d1
1 changed files with 6 additions and 98 deletions
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104
src/smooth/ftgrays.c
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@ -997,49 +997,12 @@ typedef ptrdiff_t FT_PtrDist;
#endif
/*
* Benchmarking shows that using DDA to flatten the quadratic Bézier arcs
* is slightly faster in the following cases:
*
* - When the host CPU is 64-bit.
* - When SSE2 SIMD registers and instructions are available (even on
* x86).
*
* For other cases, using binary splits is actually slightly faster.
* For now, the code that uses DDA to render conic curves requires
* `FT_Int64` to be defined. See for example
* https://gitlab.freedesktop.org/freetype/freetype/-/issues/1071.
*/
#if ( defined( __SSE2__ ) || \
defined( __x86_64__ ) || \
defined( _M_AMD64 ) || \
( defined( _M_IX86_FP ) && _M_IX86_FP >= 2 ) ) && \
!defined( __VMS )
# define FT_SSE2 1
#else
# define FT_SSE2 0
#endif
#if FT_SSE2 || \
defined( __aarch64__ ) || \
defined( _M_ARM64 )
# define BEZIER_USE_DDA 1
#else
# define BEZIER_USE_DDA 0
#endif
/*
* For now, the code that depends on `BEZIER_USE_DDA` requires `FT_Int64`
* to be defined. If `FT_INT64` is not defined, meaning there is no
* 64-bit type available, disable it to avoid compilation errors. See for
* example https://gitlab.freedesktop.org/freetype/freetype/-/issues/1071.
*/
#if !defined( FT_INT64 )
# undef BEZIER_USE_DDA
# define BEZIER_USE_DDA 0
#endif
#if BEZIER_USE_DDA
#if FT_SSE2
# include <emmintrin.h>
#endif
#ifdef FT_INT64
#define LEFT_SHIFT( a, b ) (FT_Int64)( (FT_UInt64)(a) << (b) )
@ -1151,61 +1114,6 @@ typedef ptrdiff_t FT_PtrDist;
* = (B << (33 - N)) + (A << (32 - 2*N))
*/
#if FT_SSE2
/* Experience shows that for small counts, SSE2 is actually slower. */
if ( count > 4 )
{
union
{
struct { FT_Int64 ax, ay, bx, by; } i;
struct { __m128i a, b; } vec;
} u;
union
{
struct { FT_Int32 px_lo, px_hi, py_lo, py_hi; } i;
__m128i vec;
} v;
__m128i p, q, r;
u.i.ax = ax;
u.i.ay = ay;
u.i.bx = bx;
u.i.by = by;
q = _mm_load_si128( &u.vec.b );
r = _mm_load_si128( &u.vec.a );
q = _mm_slli_epi64( q, shift + 17);
r = _mm_slli_epi64( r, shift + shift );
q = _mm_add_epi64( q, r );
r = _mm_add_epi64( r, r );
v.i.px_lo = 0;
v.i.px_hi = p0.x;
v.i.py_lo = 0;
v.i.py_hi = p0.y;
p = _mm_load_si128( &v.vec );
do
{
p = _mm_add_epi64( p, q );
q = _mm_add_epi64( q, r );
_mm_store_si128( &v.vec, p );
gray_render_line( RAS_VAR_ v.i.px_hi, v.i.py_hi );
} while ( --count );
return;
}
#endif /* FT_SSE2 */
rx = LEFT_SHIFT( ax, shift + shift );
ry = LEFT_SHIFT( ay, shift + shift );
@ -1230,7 +1138,7 @@ typedef ptrdiff_t FT_PtrDist;
} while ( --count );
}
#else /* !BEZIER_USE_DDA */
#else /* !FT_INT64 */
/*
* Note that multiple attempts to speed up the function below
@ -1324,7 +1232,7 @@ typedef ptrdiff_t FT_PtrDist;
} while ( --draw );
}
#endif /* !BEZIER_USE_DDA */
#endif /* !FT_INT64 */
/*