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Optimize qt_memfill32 a little 

Benchmarking shows it took up to 3.5% of Qt Creator's initialization
cost. Optimize by modifying only one variable per loop: instead of
updating n and dst128, we only update one variable at a time.

Removing the Duff's Device also improves the code, since the compiler
won't try to update dst128 four times per loop, only once.

The moving of the epilogue close to the prologue was just to make the
code a little cleaner.

Change-Id: I5b74e27d520ca821f380aef0533c244805f003b7
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>
bb10
Thiago Macieira 2014-02-02 16:23:00 -08:00 committed by The Qt Project
parent af8c35bda4
commit ab1ec81f58
1 changed files with 19 additions and 13 deletions
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32
src/gui/painting/qdrawhelper_sse2.cpp
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@ -259,19 +259,6 @@ void qt_memfill32(quint32 *dest, quint32 value, int count)
case 12: *dest++ = value; --count;
}
int count128 = count / 4;
__m128i *dst128 = reinterpret_cast<__m128i*>(dest);
const __m128i value128 = _mm_set_epi32(value, value, value, value);
int n = (count128 + 3) / 4;
switch (count128 & 0x3) {
case 0: do { _mm_stream_si128(dst128++, value128);
case 3: _mm_stream_si128(dst128++, value128);
case 2: _mm_stream_si128(dst128++, value128);
case 1: _mm_stream_si128(dst128++, value128);
} while (--n > 0);
}
const int rest = count & 0x3;
if (rest) {
switch (rest) {
@ -280,6 +267,25 @@ void qt_memfill32(quint32 *dest, quint32 value, int count)
case 1: dest[count - 1] = value;
}
}
int count128 = count / 4;
__m128i *dst128 = reinterpret_cast<__m128i*>(dest);
__m128i *end128 = dst128 + count128;
const __m128i value128 = _mm_set_epi32(value, value, value, value);
while (dst128 + 3 < end128) {
_mm_stream_si128(dst128 + 0, value128);
_mm_stream_si128(dst128 + 1, value128);
_mm_stream_si128(dst128 + 2, value128);
_mm_stream_si128(dst128 + 3, value128);
dst128 += 4;
}
switch (count128 & 0x3) {
case 3: _mm_stream_si128(dst128++, value128);
case 2: _mm_stream_si128(dst128++, value128);
case 1: _mm_stream_si128(dst128++, value128);
}
}
void QT_FASTCALL comp_func_solid_SourceOver_sse2(uint *destPixels, int length, uint color, uint const_alpha)