--- src/cairo-fixed-private.h
+++ src/cairo-fixed-private.h
@@ -61,7 +61,7 @@
 static inline cairo_fixed_t
 _cairo_fixed_from_int (int i)
 {
-    return i << CAIRO_FIXED_FRAC_BITS;
+    return (unsigned)i << CAIRO_FIXED_FRAC_BITS;
 }
 
 /* This is the "magic number" approach to converting a double into fixed
@@ -249,7 +249,7 @@
     } else if ((f >> CAIRO_FIXED_FRAC_BITS) > INT16_MAX) {
 	x = INT32_MAX;
     } else {
-	x = f << (16 - CAIRO_FIXED_FRAC_BITS);
+	x = (uint32_t)f << (16 - CAIRO_FIXED_FRAC_BITS);
     }
 
     return x;
--- src/cairo-gstate.c
+++ src/cairo-gstate.c
@@ -2297,7 +2297,7 @@
 		if (!drop || KEEP_GLYPH (transformed_glyphs[j]))
 		    j++;
 	    }
-	    memcpy (transformed_clusters, clusters,
+	    if (num_clusters != 0) memcpy (transformed_clusters, clusters,
 		    num_clusters * sizeof (cairo_text_cluster_t));
 	} else {
 	    const cairo_glyph_t *cur_glyph;
@@ -2352,7 +2352,7 @@
 		if (! drop || KEEP_GLYPH (transformed_glyphs[j]))
 		    j++;
 	    }
-	    memcpy (transformed_clusters, clusters,
+	    if (num_clusters != 0) memcpy (transformed_clusters, clusters,
 		    num_clusters * sizeof (cairo_text_cluster_t));
 	} else {
 	    const cairo_glyph_t *cur_glyph;
--- src/cairo-image-source.c
+++ src/cairo-image-source.c
@@ -509,7 +509,7 @@
 	return pixman_image_create_solid_fill (&color);
 
     case CAIRO_FORMAT_RGB24_888:
-	pixel = *(uint32_t *) (image->data + y * image->stride + 3 * x);
+	pixel = (uint32_t)(image->data + y * image->stride + 3 * x)[0] | ((uint32_t)(image->data + y * image->stride + 3 * x)[1] << 8) | ((uint32_t)(image->data + y * image->stride + 3 * x)[2] << 16);
 	pixel &= 0x00ffffff; /* ignore next pixel bits */
 	if (pixel == 0)
 	    return _pixman_black_image ();
--- src/cairo-surface.c
+++ src/cairo-surface.c
@@ -2849,7 +2849,7 @@
 
     if (_cairo_scaled_font_has_color_glyphs (scaled_font)) {
         utf8_copy = malloc (sizeof (char) * utf8_len);
-        memcpy (utf8_copy, utf8, sizeof (char) * utf8_len);
+        if (utf8_len != 0) memcpy (utf8_copy, utf8, sizeof (char) * utf8_len);
         utf8 = utf8_copy;
 
         status = composite_color_glyphs (surface, op,
--- src/cairo-tor-scan-converter.c
+++ src/cairo-tor-scan-converter.c
@@ -253,7 +253,7 @@
 #elif GRID_XY == 15
 #  define  GRID_AREA_TO_ALPHA(c)  (((c) << 4) + (c))
 #elif GRID_XY == 2*256*15
-#  define  GRID_AREA_TO_ALPHA(c)  (((c) + ((c)<<4) + 256) >> 9)
+#  define  GRID_AREA_TO_ALPHA(c)  (((c) + ((uint32_t)(c)<<4) + 256) >> 9)
 #else
 #  define  GRID_AREA_TO_ALPHA(c)  (((c)*255 + GRID_XY/2) / GRID_XY)
 #endif
--- src/cairo-xlib-render-compositor.c
+++ src/cairo-xlib-render-compositor.c
@@ -1849,8 +1849,8 @@
 	    return _cairo_error (CAIRO_STATUS_NO_MEMORY);
     }
 
-    dx = -dst_x << 16;
-    dy = -dst_y << 16;
+    dx = (unsigned)-dst_x << 16;
+    dy = (unsigned)-dst_y << 16;
     for (i = 0; i < traps->num_traps; i++) {
 	cairo_trapezoid_t *t = &traps->traps[i];
 
--- src/cairo-xlib-surface-shm.c
+++ src/cairo-xlib-surface-shm.c
@@ -1152,9 +1152,11 @@
     cairo_surface_t *surface;
 
     surface = NULL;
-    if (has_shm (other))
-	surface = &_cairo_xlib_shm_surface_create (other, format, width, height,
-						   FALSE, has_shm_pixmaps (other))->image.base;
+    if (has_shm (other)) {
+	cairo_xlib_shm_surface_t * shm_surface = _cairo_xlib_shm_surface_create (other, format, width, height,
+						   FALSE, has_shm_pixmaps (other));
+	if (shm_surface) surface = &shm_surface->image.base;
+    }
 
     return surface;
 }