diff --git a/configure.ac b/configure.ac
index 174b61e9..948d1e1a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -259,6 +259,7 @@ AC_PROG_CC_STDC
 AC_PROG_CXX
 AC_C_CONST
 AC_C_RESTRICT
+AX_GCC_VAR_ATTRIBUTE(vector_size)
 AC_PROG_RANLIB
 AC_PROG_INSTALL
 AC_PROG_LN_S
diff --git a/doc/binding.xml b/doc/binding.xml
index 3c27a515..6ed37b94 100644
--- a/doc/binding.xml
+++ b/doc/binding.xml
@@ -172,7 +172,7 @@ from gi.repository import Vips
     You can now use all of the libvips introspection machinery, as noted above.
   </para>
   <para>
-    Unfortunately g-o-i has some strong disadvantages. It is not very portable, since you will need a g-o-i layer for whatever platform you are targetting, it does not cross-compile well since typelibs include a lot of very-low level data (such as exact structure layouts), and installation for your users is likely to be tricky.
+    Unfortunately g-o-i has some strong disadvantages. It is not very portable, since you will need a g-o-i layer for whatever platform you are targetting; it does not cross-compile well, since typelibs include a lot of very-low level data (such as exact structure layouts); and installation for your users is likely to be tricky.
   </para>
   <para>
     If you have a choice, I would recommend simply using FFI.
diff --git a/libvips/conversion/composite.cpp b/libvips/conversion/composite.cpp
index 31b279a1..58196298 100644
--- a/libvips/conversion/composite.cpp
+++ b/libvips/conversion/composite.cpp
@@ -487,6 +487,9 @@ vips_composite_blend_mul( VipsBlendMode mode,
 	B[bands] = aR;
 }
 
+/* We have a vector path with gcc's vector attr.
+ */
+#ifdef HAVE_VAR_ATTRIBUTE_VECTOR_SIZE
 /* A vector of four floats.
  */
 typedef float v4f __attribute__((vector_size(4 * sizeof(float))));
@@ -674,6 +677,7 @@ vips_composite_blend_mul_3float( VipsBlendMode mode, v4f &B, float *A_memory )
 
 	B[3] = aR;
 }
+#endif /*HAVE_VAR_ATTRIBUTE_VECTOR_SIZE*/
 
 /* A is the new pixel coming in, B is the double pixel we are accumulating.
  */
@@ -716,6 +720,7 @@ static void vips_combine_pixels( VipsComposite *composite,
 	tq[bands] = B[bands];
 }
 
+#ifdef HAVE_VAR_ATTRIBUTE_VECTOR_SIZE
 static void 
 vips_combine_pixels_3float( VipsComposite *composite,
 	VipsPel *q, VipsPel **p )
@@ -738,6 +743,7 @@ vips_combine_pixels_3float( VipsComposite *composite,
 	*((v4f *) tq) = R;
 	tq[3] = B[3];
 }
+#endif /*HAVE_VAR_ATTRIBUTE_VECTOR_SIZE*/
 
 static int
 vips_composite_gen( VipsRegion *output_region,
@@ -767,10 +773,12 @@ vips_composite_gen( VipsRegion *output_region,
 		for( x = 0; x < r->width; x++ ) {
 			switch( input_regions[0]->im->BandFmt ) {
 			case VIPS_FORMAT_FLOAT:
+#ifdef HAVE_VAR_ATTRIBUTE_VECTOR_SIZE
 				if( composite->bands == 3 ) 
 					vips_combine_pixels_3float( composite, 
 						q, p ); 
 				else
+#endif /*HAVE_VAR_ATTRIBUTE_VECTOR_SIZE*/
 					vips_combine_pixels<float>( composite, 
 						q, p );
 				break;