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Allow compiler to vectorise vips_shrinkh 

Reduce for-loop count in shrinkh macros
Don't access loop variable outside loop
Remove unnecessary use of ceil from integer
This commit is contained in:
Lovell Fuller 2016-01-21 20:18:56 +00:00
parent 16b76b2cfd
commit 572354b793
1 changed files with 9 additions and 15 deletions
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24
libvips/resample/shrinkh.c
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@ -111,18 +111,15 @@ vips_shrinkh_start( VipsImage *out, void *a, void *b )
TYPE * restrict q = (TYPE *) out; \
\
for( x = 0; x < width; x++ ) { \
for( b = 0; b < bands; b++ ) \
for( b = 0; b < bands; b++ ) { \
sum[b] = 0; \
\
for( b = 0; b < bands; b++ ) \
for( x1 = b; x1 < ne; x1 += bands ) \
sum[b] += p[x1]; \
p += ne; \
\
for( b = 0; b < bands; b++ ) \
q[b] = (sum[b] + shrink->xshrink / 2) / \
shrink->xshrink; \
q += b; \
} \
p += ne; \
q += bands; \
} \
}
@ -134,17 +131,14 @@ vips_shrinkh_start( VipsImage *out, void *a, void *b )
TYPE * restrict q = (TYPE *) out; \
\
for( x = 0; x < width; x++ ) { \
for( b = 0; b < bands; b++ ) \
for( b = 0; b < bands; b++ ) { \
sum[b] = 0.0; \
\
for( b = 0; b < bands; b++ ) \
for( x1 = b; x1 < ne; x1 += bands ) \
sum[b] += p[x1]; \
p += ne; \
\
for( b = 0; b < bands; b++ ) \
q[b] = sum[b] / shrink->xshrink; \
q += b; \
} \
p += ne; \
q += bands; \
} \
}
@ -227,7 +221,7 @@ vips_shrinkh_gen( VipsRegion *or, void *vseq,
s.left = r->left * shrink->xshrink;
s.top = r->top + y;
s.width = ceil( r->width * shrink->xshrink );
s.width = r->width * shrink->xshrink;
s.height = 1;
#ifdef DEBUG
printf( "shrinkh_gen: requesting line %d\n", s.top );