From 4d18300560b18b1e100880f48e1c5f86f45f4d9a Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Tue, 26 Jan 2016 12:26:21 +0000
Subject: [PATCH] add VIPS_FABS/MAX/MIN/CLIP

macros which use the gcc __builtin_fabs() etc. functions when they can
---
 ChangeLog                       |  2 +
 README.md                       |  6 +--
 TODO                            |  2 +
 libvips/arithmetic/abs.c        |  6 +--
 libvips/arithmetic/deviate.c    |  2 +-
 libvips/arithmetic/divide.c     |  2 +-
 libvips/arithmetic/linear.c     |  6 +--
 libvips/arithmetic/measure.c    |  3 +-
 libvips/arithmetic/stats.c      |  4 +-
 libvips/arithmetic/unaryconst.c |  2 +-
 libvips/colour/HSV2sRGB.c       | 67 ++++++++++++++++++---------------
 libvips/colour/LCh2UCS.c        |  2 +-
 libvips/colour/Lab2LabQ.c       | 15 ++++----
 libvips/colour/LabS2LabQ.c      |  5 ++-
 libvips/colour/XYZ2Lab.c        |  6 +--
 libvips/colour/dE00.c           |  6 +--
 libvips/colour/sRGB2HSV.c       | 66 ++++++++++++++++++--------------
 libvips/colour/scRGB2BW.c       |  2 +-
 libvips/colour/scRGB2sRGB.c     |  2 +-
 libvips/create/buildlut.c       |  2 +-
 libvips/create/logmat.c         |  2 +-
 libvips/foreign/ppm.c           |  2 +-
 libvips/foreign/vips2jpeg.c     |  4 +-
 libvips/foreign/vips2tiff.c     |  4 +-
 libvips/include/vips/util.h     | 42 ++++++++++++---------
 25 files changed, 147 insertions(+), 115 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 4f119364..d44b4cdf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -11,6 +11,8 @@
 - add VIPS_FLOOR()/VIPS_CEIL(), much faster [Lovell Fuller]
 - use g_assert_not_reached();
 - better vips-from-C docs
+- add VIPS_FMIN() / VIPS_FMAX() / VIPS_FABS() / VIPS_FCLIP() ... use builtins 
+  when available
 
 1/1/16 started 8.2.1
 - add a compat stub [Benjamin Gilbert]
diff --git a/README.md b/README.md
index 2dd3da05..9e2aa96d 100644
--- a/README.md
+++ b/README.md
@@ -112,7 +112,7 @@ Clang dynamic analysis:
 	$ FLAGS="$FLAGS -fno-omit-frame-pointer -fno-optimize-sibling-calls"
 	$ CC=clang CXX=clang++ LD=clang \
 		CFLAGS="$FLAGS" CXXFLAGS="$FLAGS" LDFLAGS=-fsanitize=address \
-		./configure --prefix=/home/john/vips --disable-introspection
+		./configure --prefix=/home/john/vips 
 
 	$ FLAGS="-O1 -g -fsanitize=thread"
 	$ FLAGS="$FLAGS -fPIC -pie"
@@ -120,14 +120,14 @@ Clang dynamic analysis:
 	$ CC=clang CXX=clang++ LD=clang \
 		CFLAGS="$FLAGS" CXXFLAGS="$FLAGS" \
 		LDFLAGS="-fsanitize=thread -fPIC -pie" \
-		./configure --prefix=/home/john/vips --disable-introspection
+		./configure --prefix=/home/john/vips 
 
 Build with the GCC auto-vectorizer and diagnostics (or just -O3):
 
 	$ FLAGS="-O2 -msse4.2 -ffast-math"
 	$ FLAGS="$FLAGS -ftree-vectorize -fdump-tree-vect-details"
 	$ CFLAGS="$FLAGS" CXXFLAGS="$FLAGS" \
-		./configure --prefix=/home/john/vips --disable-introspection 
+		./configure --prefix=/home/john/vips 
 
 Static analysis with:
 
diff --git a/TODO b/TODO
index 1b15b9a5..dc3d76a2 100644
--- a/TODO
+++ b/TODO
@@ -1,3 +1,5 @@
+- look for FCLIP / FABS use ... VIPS_ABS() on float type
+
 - write a shrinker that does two 1D shrinks, vertical and horizontal, with
   bicubic interpolation
 
diff --git a/libvips/arithmetic/abs.c b/libvips/arithmetic/abs.c
index 0d414dd3..8574688c 100644
--- a/libvips/arithmetic/abs.c
+++ b/libvips/arithmetic/abs.c
@@ -112,7 +112,7 @@ vips_abs_build( VipsObject *object )
 	int x; \
 	\
 	for( x = 0; x < sz; x++ ) \
-		q[x] = fabs( p[x] ); \
+		q[x] = VIPS_FABS( p[x] ); \
 }
 
 /* Complex abs operation: calculate modulus.
@@ -141,8 +141,8 @@ vips_abs_build( VipsObject *object )
 	for( x = 0; x < sz; x++ ) { \
 		double rp = p[0]; \
 		double ip = p[1]; \
-		double abs_rp = fabs( rp ); \
-		double abs_ip = fabs( ip ); \
+		double abs_rp = VIPS_FABS( rp ); \
+		double abs_ip = VIPS_FABS( ip ); \
 		\
 		if( abs_rp > abs_ip ) { \
 			double temp = ip / rp; \
diff --git a/libvips/arithmetic/deviate.c b/libvips/arithmetic/deviate.c
index 1b4b9019..3c62e3d8 100644
--- a/libvips/arithmetic/deviate.c
+++ b/libvips/arithmetic/deviate.c
@@ -121,7 +121,7 @@ vips_deviate_build( VipsObject *object )
 	s2 = deviate->sum2;
 
 	g_object_set( object, 
-		"out", sqrt( fabs( s2 - (s * s / vals) ) / (vals - 1) ),
+		"out", sqrt( VIPS_FABS( s2 - (s * s / vals) ) / (vals - 1) ),
 		NULL );
 
 	return( 0 );
diff --git a/libvips/arithmetic/divide.c b/libvips/arithmetic/divide.c
index 60b59e56..000fbcf4 100644
--- a/libvips/arithmetic/divide.c
+++ b/libvips/arithmetic/divide.c
@@ -131,7 +131,7 @@ G_DEFINE_TYPE( VipsDivide, vips_divide, VIPS_TYPE_BINARY );
 			q[0] = 0.0; \
 			q[1] = 0.0; \
 		} \
-		else if( fabs( right[0] ) > fabs( right[1] ) ) { \
+		else if( VIPS_FABS( right[0] ) > VIPS_FABS( right[1] ) ) { \
 			double a = right[1] / right[0]; \
 			double b = right[0] + right[1] * a; \
 			\
diff --git a/libvips/arithmetic/linear.c b/libvips/arithmetic/linear.c
index d113c97f..9aba5054 100644
--- a/libvips/arithmetic/linear.c
+++ b/libvips/arithmetic/linear.c
@@ -241,7 +241,7 @@ vips_linear_build( VipsObject *object )
 	for( x = 0; x < sz; x++ ) { \
 		float t = a1 * p[x] + b1; \
 		\
-		q[x] = VIPS_CLIP( 0, t, 255 ); \
+		q[x] = VIPS_FCLIP( 0, t, 255 ); \
 	} \
 }
 
@@ -255,7 +255,7 @@ vips_linear_build( VipsObject *object )
 		for( k = 0; k < nb; k++, i++ ) { \
 			double t = a[k] * p[i] + b[k]; \
 			\
-			q[i] = VIPS_CLIP( 0, t, 255 ); \
+			q[i] = VIPS_FCLIP( 0, t, 255 ); \
 		} \
 }
 
@@ -278,7 +278,7 @@ vips_linear_build( VipsObject *object )
 		for( k = 0; k < nb; k++, i++ ) { \
 			double t = a[k] * p[0] + b[k]; \
 			\
-			q[i] = VIPS_CLIP( 0, t, 255 ); \
+			q[i] = VIPS_FCLIP( 0, t, 255 ); \
 			p += 2; \
 		} \
 }
diff --git a/libvips/arithmetic/measure.c b/libvips/arithmetic/measure.c
index 9497799c..67d6feb6 100644
--- a/libvips/arithmetic/measure.c
+++ b/libvips/arithmetic/measure.c
@@ -163,7 +163,8 @@ vips_measure_build( VipsObject *object )
 				 * averages near zero (can get these if use
 				 * measure on IM_TYPE_LAB images).
 				 */
-				if( dev * 5 > fabs( avg ) && fabs( avg ) > 3 )
+				if( dev * 5 > VIPS_FABS( avg ) && 
+					VIPS_FABS( avg ) > 3 )
 					vips_warn( class->nickname,
 						_( "patch %d x %d, band %d: " 
 						   "avg = %g, sdev = %g" ), 
diff --git a/libvips/arithmetic/stats.c b/libvips/arithmetic/stats.c
index 345275ca..2e170a06 100644
--- a/libvips/arithmetic/stats.c
+++ b/libvips/arithmetic/stats.c
@@ -159,12 +159,12 @@ vips_stats_build( VipsObject *object )
 		double *row = VIPS_MATRIX( stats->out, 0, y ); 
 
 		row[COL_AVG] = row[COL_SUM] / pels;
-		row[COL_SD] = sqrt( fabs( row[COL_SUM2] - 
+		row[COL_SD] = sqrt( VIPS_FABS( row[COL_SUM2] - 
 			(row[COL_SUM] * row[COL_SUM] / pels) ) / (pels - 1) );
 	}
 
 	row0[COL_AVG] = row0[COL_SUM] / vals;
-	row0[COL_SD] = sqrt( fabs( row0[COL_SUM2] - 
+	row0[COL_SD] = sqrt( VIPS_FABS( row0[COL_SUM2] - 
 		(row0[COL_SUM] * row0[COL_SUM] / vals) ) / (vals - 1) );
 
 	return( 0 );
diff --git a/libvips/arithmetic/unaryconst.c b/libvips/arithmetic/unaryconst.c
index 679987e1..e95dc78e 100644
--- a/libvips/arithmetic/unaryconst.c
+++ b/libvips/arithmetic/unaryconst.c
@@ -57,7 +57,7 @@ G_DEFINE_ABSTRACT_TYPE( VipsUnaryConst, vips_unary_const, VIPS_TYPE_UNARY );
 	for( i = 0; i < m; i++ ) { \
 		double v = p[VIPS_MIN( n - 1, i )]; \
 		\
-		tq[i] = (TYPE) VIPS_CLIP( N, v, X ); \
+		tq[i] = (TYPE) VIPS_FCLIP( N, v, X ); \
 	} \
 }
 
diff --git a/libvips/colour/HSV2sRGB.c b/libvips/colour/HSV2sRGB.c
index 519e9a60..e9835234 100644
--- a/libvips/colour/HSV2sRGB.c
+++ b/libvips/colour/HSV2sRGB.c
@@ -52,43 +52,50 @@ typedef VipsColourCodeClass VipsHSV2sRGBClass;
 
 G_DEFINE_TYPE( VipsHSV2sRGB, vips_HSV2sRGB, VIPS_TYPE_COLOUR_CODE );
 
-static void vips_HSV2sRGB_line(VipsColour *colour, VipsPel *out, VipsPel **in,
-		int width) {
+static void 
+vips_HSV2sRGB_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width ) 
+{
 	unsigned char *p = (unsigned char *) in[0];
 	unsigned char *q = (unsigned char *) out;
+
 	int i;
 
-	float c, x, m;
-	for (i = 0; i < width; i++) {
+	for( i = 0; i < width; i++ ) {
+		float c, x, m;
 
-		c = p[2] * p[1] / 255.0f;
-		x = c * (1 - fabs(fmod(p[0] / SIXTH_OF_CHAR, 2) - 1));
+		c = p[2] * p[1] / 255.0;
+		x = c * (1 - VIPS_FABS( fmod( p[0] / SIXTH_OF_CHAR, 2 ) - 1 ));
 		m = p[2] - c;
 
-		if (p[0] < SIXTH_OF_CHAR) {
-			q[0]= (c+m);
-			q[1]= (x+m);
-			q[2]= (0+m);
-		} else if (p[0] < 2*SIXTH_OF_CHAR) {
-			q[0]= (x+m);
-			q[1]= (c+m);
-			q[2]= (0+m);
-		} else if (p[0] < 3*SIXTH_OF_CHAR) {
-			q[0]= (0+m);
-			q[1]= (c+m);
-			q[2]= (x+m);
-		} else if (p[0] < 4*SIXTH_OF_CHAR) {
-			q[0]= (0+m);
-			q[1]= (x+m);
-			q[2]= (c+m);
-		} else if (p[0] < 5*SIXTH_OF_CHAR) {
-			q[0]= (x+m);
-			q[1]= (0+m);
-			q[2]= (c+m);
-		} else {
-			q[0]= (c+m);
-			q[1]= (0+m);
-			q[2]= (x+m);
+		if( p[0] < SIXTH_OF_CHAR ) {
+			q[0] = c + m;
+			q[1] = x + m;
+			q[2] = 0 + m;
+		} 
+		else if( p[0] < 2 * SIXTH_OF_CHAR ) {
+			q[0] = x + m;
+			q[1] = c + m;
+			q[2] = 0 + m;
+		} 
+		else if( p[0] < 3 * SIXTH_OF_CHAR ) {
+			q[0] = 0 + m;
+			q[1] = c + m;
+			q[2] = x + m;
+		} 
+		else if( p[0] < 4 * SIXTH_OF_CHAR ) {
+			q[0] = 0 + m;
+			q[1] = x + m;
+			q[2] = c + m;
+		} 
+		else if( p[0] < 5 * SIXTH_OF_CHAR ) {
+			q[0] = x + m;
+			q[1] = 0 + m;
+			q[2] = c + m;
+		} 
+		else {
+			q[0] = c + m;
+			q[1] = 0 + m;
+			q[2] = x + m;
 		}
 
 		p += 3;
diff --git a/libvips/colour/LCh2UCS.c b/libvips/colour/LCh2UCS.c
index da09512b..ffd11511 100644
--- a/libvips/colour/LCh2UCS.c
+++ b/libvips/colour/LCh2UCS.c
@@ -165,7 +165,7 @@ vips_col_Ch2hcmc( float C, float h )
 	}
 
 	P = cos( VIPS_RAD( k7 * h + k8 ) );
-	D = k4 + k5 * P * pow( fabs( P ), k6 );
+	D = k4 + k5 * P * pow( VIPS_FABS( P ), k6 );
 	g = C * C * C * C;
 	f = sqrt( g / (g + 1900.0) );
 	hcmc = h + D * f;
diff --git a/libvips/colour/Lab2LabQ.c b/libvips/colour/Lab2LabQ.c
index d522c737..01d250c4 100644
--- a/libvips/colour/Lab2LabQ.c
+++ b/libvips/colour/Lab2LabQ.c
@@ -88,12 +88,13 @@ vips_Lab2LabQ_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 	float * restrict p = (float *) in[0];
 	VipsPel * restrict q = out; 
 
-	float fval;
-	int lsbs;
-	int intv;
 	int i;
 
-	for( i = 0; i < width; i++) {
+	for( i = 0; i < width; i++ ) {
+		float fval;
+		int lsbs;
+		int intv;
+
 		/* Scale L up to 10 bits. Add 0.5 rather than call VIPS_RINT 
 		 * for speed. This will not round negatives correctly! But 
 		 * this does not matter, since L is >0. L*=100.0 -> 1023.
@@ -101,19 +102,19 @@ vips_Lab2LabQ_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 		intv = 10.23 * p[0] + 0.5;	/* scale L up to 10 bits */
 		intv = VIPS_CLIP( 0, intv, 1023 );
 		lsbs = (intv & 0x3) << 6;       /* 00000011 -> 11000000 */
-		q[0] = (intv >> 2); 		/* drop bot 2 bits and store */
+		q[0] = intv >> 2; 		/* drop bot 2 bits and store */
 
 		fval = 8.0 * p[1];              /* do a */
 		intv = VIPS_RINT( fval );
 		intv = VIPS_CLIP( -1024, intv, 1023 );
 		lsbs |= (intv & 0x7) << 3;      /* 00000111 -> 00111000 */
-		q[1] = (intv >> 3);   		/* drop bot 3 bits & store */
+		q[1] = intv >> 3;   		/* drop bot 3 bits & store */
 
 		fval = 8.0 * p[2];              /* do b */
 		intv = VIPS_RINT( fval );
 		intv = VIPS_CLIP( -1024, intv, 1023 );
 		lsbs |= (intv & 0x7);
-		q[2] = (intv >> 3);
+		q[2] = intv >> 3;
 
 		q[3] = lsbs;                	/* store lsb band */
 
diff --git a/libvips/colour/LabS2LabQ.c b/libvips/colour/LabS2LabQ.c
index f15090e5..368514a0 100644
--- a/libvips/colour/LabS2LabQ.c
+++ b/libvips/colour/LabS2LabQ.c
@@ -69,10 +69,11 @@ vips_LabS2LabQ_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 	unsigned char *q = (unsigned char *) out;
 
 	int i;
-	int l, a, b;
-	unsigned char ext;
 
 	for( i = 0; i < width; i++ ) {
+		int l, a, b;
+		unsigned char ext;
+
 		/* Get LAB, rounding to 10, 11, 11. 
 		 */
 		l = p[0] + 16;
diff --git a/libvips/colour/XYZ2Lab.c b/libvips/colour/XYZ2Lab.c
index 9b86ce66..97d9af1d 100644
--- a/libvips/colour/XYZ2Lab.c
+++ b/libvips/colour/XYZ2Lab.c
@@ -133,15 +133,15 @@ vips_XYZ2Lab_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 		nZ = QUANT_ELEMENTS * p[2] / XYZ2Lab->Z0;
 		p += 3;
 
-		i = VIPS_CLIP( 0, (int) nX, QUANT_ELEMENTS - 2 );
+		i = VIPS_FCLIP( 0, nX, QUANT_ELEMENTS - 2 );
 		f = nX - i;
 		cbx = cbrt_table[i] + f * (cbrt_table[i + 1] - cbrt_table[i]);
 
-		i = VIPS_CLIP( 0, (int) nY, QUANT_ELEMENTS - 2 );
+		i = VIPS_FCLIP( 0, nY, QUANT_ELEMENTS - 2 );
 		f = nY - i;
 		cby = cbrt_table[i] + f * (cbrt_table[i + 1] - cbrt_table[i]);
 
-		i = VIPS_CLIP( 0, (int) nZ, QUANT_ELEMENTS - 2 );
+		i = VIPS_FCLIP( 0, nZ, QUANT_ELEMENTS - 2 );
 		f = nZ - i;
 		cbz = cbrt_table[i] + f * (cbrt_table[i + 1] - cbrt_table[i]);
 
diff --git a/libvips/colour/dE00.c b/libvips/colour/dE00.c
index 3dfb304f..6c2d203d 100644
--- a/libvips/colour/dE00.c
+++ b/libvips/colour/dE00.c
@@ -132,9 +132,9 @@ vips_col_dE00( float L1, float a1, float b1,
 	 */
 	double Ldb = (L1d + L2d) / 2;
 	double Cdb = (C1d + C2d) / 2;
-	double hdb = fabs( h1d - h2d ) < 180 ?
+	double hdb = VIPS_FABS( h1d - h2d ) < 180 ?
 	 	(h1d + h2d) / 2 :
-	 	fabs( h1d + h2d - 360 ) / 2;
+	 	VIPS_FABS( h1d + h2d - 360 ) / 2;
 
 	/* dtheta, RC
 	 */
@@ -161,7 +161,7 @@ vips_col_dE00( float L1, float a1, float b1,
 
 	/* hue difference ... careful!
 	 */
-	double dhd = fabs( h1d - h2d ) < 180 ?
+	double dhd = VIPS_FABS( h1d - h2d ) < 180 ?
 		h1d - h2d :
 		360 - (h1d - h2d);
 
diff --git a/libvips/colour/sRGB2HSV.c b/libvips/colour/sRGB2HSV.c
index e74634e8..5dca321c 100644
--- a/libvips/colour/sRGB2HSV.c
+++ b/libvips/colour/sRGB2HSV.c
@@ -52,61 +52,71 @@ vips_sRGB2HSV_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
 {
 	unsigned char *p = (unsigned char *) in[0];
 	unsigned char *q = (unsigned char *) out;
+
 	int i;
 
-	unsigned char c_max,c_min,delta;
-
-	float wrap_around_hue, secondary_diff;
-
-
 	for( i = 0; i < width; i++ ) {
+		unsigned char c_max;
+		unsigned char c_min;
+		float secondary_diff;
+		float wrap_around_hue;
 
-		if (p[1] < p[2]) {
-			if (p[2] < p[0]) {
-				// Center red (at top)
+		if( p[1] < p[2] ) {
+			if( p[2] < p[0] ) {
+				/* Center red (at top).
+				 */
 				c_max = p[0];
 				c_min = p[1];
 				secondary_diff = p[1] - p[2];
-				wrap_around_hue = 255.0f;
-			} else {
-				// Center blue
+				wrap_around_hue = 255.0;
+			} 
+			else {
+				/* Center blue.
+				 */
 				c_max = p[2];
-				c_min = VIPS_MIN(p[1], p[0]);
+				c_min = VIPS_MIN( p[1], p[0] );
 				secondary_diff = p[0] - p[1];
-				wrap_around_hue = 170.0f;
+				wrap_around_hue = 170.0;
 			}
-		} else {
-			if (p[1] < p[0]) {
-				// Center red (at bottom)
+		} 
+		else {
+			if( p[1] < p[0] ) {
+				/* Center red (at bottom)
+				 */
 				c_max = p[0];
 				c_min = p[2];
 				secondary_diff = p[1] - p[2];
-				wrap_around_hue = 0.0f;
-			} else {
-				// Center green
+				wrap_around_hue = 0.0;
+			} 
+			else {
+				/* Center green
+				 */
 				c_max = p[1];
-				c_min = VIPS_MIN(p[2], p[0]);
+				c_min = VIPS_MIN( p[2], p[0] );
 				secondary_diff = p[2] - p[0];
-				wrap_around_hue = 85.0f;
+				wrap_around_hue = 85.0;
 			}
 		}
 
 
-		if (c_max == 0) {
+		if( c_max == 0 ) {
 			q[0] = 0;
 			q[1] = 0;
 			q[2] = 0;
-		} else {
+		} 
+		else {
+			unsigned char delta;
+
 			q[2] = c_max;
 			delta = c_max - c_min;
 
-			if (delta == 0) {
+			if( delta == 0 ) 
 				q[0] = 0;
-			} else {
-				q[0] = (42.5f*(secondary_diff / (float) delta) + wrap_around_hue);
-			}
+			else 
+				q[0] = 42.5 * (secondary_diff / (float) delta) +
+				       	wrap_around_hue;
 
-			q[1] = (( delta*255.0f / (float) c_max));
+			q[1] = delta * 255.0 / (float) c_max;
 		}
 
 		p += 3;
diff --git a/libvips/colour/scRGB2BW.c b/libvips/colour/scRGB2BW.c
index f961f1a2..3d5803a7 100644
--- a/libvips/colour/scRGB2BW.c
+++ b/libvips/colour/scRGB2BW.c
@@ -113,7 +113,7 @@ vips_scRGB2BW_line_16( unsigned short * restrict q, float * restrict p,
 		q += 1;
 
 		for( j = 0; j < extra_bands; j++ ) 
-			q[j] = VIPS_CLIP( 0, p[j] * 256.0, USHRT_MAX ); 
+			q[j] = VIPS_FCLIP( 0, p[j] * 256.0, USHRT_MAX ); 
 		p += extra_bands;
 		q += extra_bands;
 	}
diff --git a/libvips/colour/scRGB2sRGB.c b/libvips/colour/scRGB2sRGB.c
index 1102d117..6e3f2a78 100644
--- a/libvips/colour/scRGB2sRGB.c
+++ b/libvips/colour/scRGB2sRGB.c
@@ -142,7 +142,7 @@ vips_scRGB2sRGB_line_16( unsigned short * restrict q, float * restrict p,
 		q += 3;
 
 		for( j = 0; j < extra_bands; j++ ) 
-			q[j] = VIPS_CLIP( 0, p[j] * 256.0, USHRT_MAX ); 
+			q[j] = VIPS_FCLIP( 0, p[j] * 256.0, USHRT_MAX ); 
 		p += extra_bands;
 		q += extra_bands;
 	}
diff --git a/libvips/create/buildlut.c b/libvips/create/buildlut.c
index 42881e06..48bfa0f7 100644
--- a/libvips/create/buildlut.c
+++ b/libvips/create/buildlut.c
@@ -129,7 +129,7 @@ vips_buildlut_build_init( VipsBuildlut *lut )
 			
 		/* Allow for being a bit off.
 		 */
-		if( fabs( v - VIPS_RINT( v ) ) > 0.001 ) {
+		if( VIPS_FABS( v - VIPS_RINT( v ) ) > 0.001 ) {
 			vips_error( class->nickname,
 				_( "x value row %d not an int" ), y );
 			return( -1 );
diff --git a/libvips/create/logmat.c b/libvips/create/logmat.c
index 5b3a480b..64520504 100644
--- a/libvips/create/logmat.c
+++ b/libvips/create/logmat.c
@@ -138,7 +138,7 @@ vips_logmat_build( VipsObject *object )
 		 * is less than the min.
 		 */
 		if( val - last >= 0 &&
-			fabs( val ) < logmat->min_ampl )
+			VIPS_FABS( val ) < logmat->min_ampl )
 			break;
 
 		last = val;
diff --git a/libvips/foreign/ppm.c b/libvips/foreign/ppm.c
index 8b70cb16..bc5334ca 100644
--- a/libvips/foreign/ppm.c
+++ b/libvips/foreign/ppm.c
@@ -204,7 +204,7 @@ read_header( FILE *fp, VipsImage *out, int *bits, int *ascii, int *msb_first )
 			 */
 			*msb_first = scale > 0;
 			vips_image_set_double( out, 
-				"pfm-scale", fabs( scale ) );
+				"pfm-scale", VIPS_FABS( scale ) );
 		}
 		else {
 			int max_value;
diff --git a/libvips/foreign/vips2jpeg.c b/libvips/foreign/vips2jpeg.c
index dc153732..71b71ae2 100644
--- a/libvips/foreign/vips2jpeg.c
+++ b/libvips/foreign/vips2jpeg.c
@@ -398,7 +398,7 @@ vips_exif_set_double( ExifData *ed,
 
 		rv = exif_get_rational( entry->data + offset, bo );
 		old_value = (double) rv.numerator / rv.denominator;
-		if( fabs( old_value - value ) > 0.0001 ) {
+		if( VIPS_FABS( old_value - value ) > 0.0001 ) {
 			vips_exif_double_to_rational( value, &rv ); 
 
 			VIPS_DEBUG_MSG( "vips_exif_set_double: %u / %u\n", 
@@ -413,7 +413,7 @@ vips_exif_set_double( ExifData *ed,
 
 		srv = exif_get_srational( entry->data + offset, bo );
 		old_value = (double) srv.numerator / srv.denominator;
-		if( fabs( old_value - value ) > 0.0001 ) {
+		if( VIPS_FABS( old_value - value ) > 0.0001 ) {
 			vips_exif_double_to_srational( value, &srv ); 
 
 			VIPS_DEBUG_MSG( "vips_exif_set_double: %d / %d\n", 
diff --git a/libvips/foreign/vips2tiff.c b/libvips/foreign/vips2tiff.c
index cb6c3bbd..32c14998 100644
--- a/libvips/foreign/vips2tiff.c
+++ b/libvips/foreign/vips2tiff.c
@@ -573,9 +573,9 @@ write_tiff_header( Write *write, Layer *layer )
 	 */
 	TIFFSetField( tif, TIFFTAG_RESOLUTIONUNIT, write->resunit );
 	TIFFSetField( tif, TIFFTAG_XRESOLUTION, 
-		VIPS_CLIP( 0.01, write->xres, 1000000 ) );
+		VIPS_FCLIP( 0.01, write->xres, 1000000 ) );
 	TIFFSetField( tif, TIFFTAG_YRESOLUTION, 
-		VIPS_CLIP( 0.01, write->yres, 1000000 ) );
+		VIPS_FCLIP( 0.01, write->yres, 1000000 ) );
 
 	if( write_embed_profile( write, tif ) ||
 		write_embed_xmp( write, tif ) ||
diff --git a/libvips/include/vips/util.h b/libvips/include/vips/util.h
index d67b89a0..20288d6e 100644
--- a/libvips/include/vips/util.h
+++ b/libvips/include/vips/util.h
@@ -58,6 +58,31 @@ extern "C" {
 #define VIPS_CLIP( A, V, B ) VIPS_MAX( (A), VIPS_MIN( (B), (V) ) )
 #define VIPS_NUMBER( R ) ((int) (sizeof(R) / sizeof(R[0])))
 
+/* The built-in isnan and isinf functions provided by gcc 4+ and clang are
+ * up to 7x faster than their libc equivalent included from <math.h>.
+ */
+#if defined(__clang__) || (__GNUC__ >= 4)
+#define VIPS_ISNAN( V ) __builtin_isnan( V )
+#define VIPS_ISINF( V ) __builtin_isinf( V )
+#define VIPS_FLOOR( V ) __builtin_floor( V )
+#define VIPS_CEIL( V ) __builtin_ceil( V )
+#define VIPS_RINT( V ) __builtin_rint( V )
+#define VIPS_FABS( V ) __builtin_fabs( V )
+#define VIPS_FMAX( A, B ) __builtin_fmax( A, B )
+#define VIPS_FMIN( A, B ) __builtin_fmin( A, B )
+#else
+#define VIPS_ISNAN( V ) isnan( V )
+#define VIPS_ISINF( V ) isinf( V )
+#define VIPS_FLOOR( V ) floor( V )
+#define VIPS_CEIL( V ) ceil( V )
+#define VIPS_RINT( R ) ((int) ((R) > 0 ? ((R) + 0.5) : ((R) - 0.5)))
+#define VIPS_FABS( V ) VIPS_FABS( V )
+#define VIPS_FMAX( A, B ) VIPS_MAX( A, B )
+#define VIPS_FMIN( A, B ) VIPS_MIN( A, B )
+#endif
+
+#define VIPS_FCLIP( A, V, B ) VIPS_FMAX( (A), VIPS_FMIN( (B), (V) ) )
+
 #define VIPS_SWAP( TYPE, A, B ) \
 G_STMT_START { \
 	TYPE t = (A); \
@@ -155,23 +180,6 @@ G_STMT_START { \
 
 #define VIPS_CLIP_NONE( V, SEQ ) {}
 
-/* The built-in isnan and isinf functions provided by gcc 4+ and clang are
- * up to 7x faster than their libc equivalent included from <math.h>.
- */
-#if defined(__clang__) || (__GNUC__ >= 4)
-#define VIPS_ISNAN( V ) __builtin_isnan( V )
-#define VIPS_ISINF( V ) __builtin_isinf( V )
-#define VIPS_FLOOR( V ) __builtin_floor( V )
-#define VIPS_CEIL( V ) __builtin_ceil( V )
-#define VIPS_RINT( V ) __builtin_rint( V )
-#else
-#define VIPS_ISNAN( V ) isnan( V )
-#define VIPS_ISINF( V ) isinf( V )
-#define VIPS_FLOOR( V ) floor( V )
-#define VIPS_CEIL( V ) ceil( V )
-#define VIPS_RINT( R ) ((int) ((R) > 0 ? ((R) + 0.5) : ((R) - 0.5)))
-#endif
-
 /* Not all platforms have PATH_MAX (eg. Hurd) and we don't need a platform one
  * anyway, just a static buffer big enough for almost any path.
  */