commit 1f2ab1728ca07dafa1f504c7a62ab9d106ef6be4
Author: Doran Moppert <dmoppert@redhat.com>
Date:   Mon Jul 25 11:00:06 2016 +0930

    same as [5c82d91], other side of if (likely(h == 1))

diff --git a/src/cairo-image-compositor.c b/src/cairo-image-compositor.c
index 48072f8..7b279d9 100644
--- a/src/cairo-image-compositor.c
+++ b/src/cairo-image-compositor.c
@@ -2266,7 +2266,7 @@ _fill_xrgb32_lerp_opaque_spans (void *abstract_renderer, int y, int h,
 			do {
 			    int len = spans[1].x - spans[0].x;
 			    uint32_t *d = (uint32_t*)(r->u.fill.data + r->u.fill.stride*yy + spans[0].x*4);
-			    while (len--)
+			    while (len-- > 0)
 				*d++ = r->u.fill.pixel;
 			    yy++;
 			} while (--hh);
@@ -2276,7 +2276,7 @@ _fill_xrgb32_lerp_opaque_spans (void *abstract_renderer, int y, int h,
 		    do {
 			int len = spans[1].x - spans[0].x;
 			uint32_t *d = (uint32_t *)(r->u.fill.data + r->u.fill.stride*yy + spans[0].x*4);
-			while (len--) {
+			while (len-- > 0) {
 			    *d = lerp8x4 (r->u.fill.pixel, a, *d);
 			    d++;
 			}