diff --git a/src/hb-ot-shape-complex-misc.cc b/src/hb-ot-shape-complex-misc.cc
index 5880e32af..99e54f6e0 100644
--- a/src/hb-ot-shape-complex-misc.cc
+++ b/src/hb-ot-shape-complex-misc.cc
@@ -132,14 +132,15 @@ _hb_ot_shape_complex_setup_masks_thai (hb_ot_map_t *map, hb_buffer_t *buffer, hb
   unsigned int count = buffer->len;
   for (buffer->idx = 0; buffer->idx < count;)
   {
-    if (likely (!IS_SARA_AM (buffer->info[buffer->idx].codepoint))) {
+    hb_codepoint_t u = buffer->info[buffer->idx].codepoint;
+    if (likely (!IS_SARA_AM (u))) {
       buffer->next_glyph ();
       continue;
     }
 
     /* Is SARA AM. Decompose and reorder. */
-    uint16_t decomposed[2] = {NIKHAHIT_FROM_SARA_AM (buffer->info[buffer->idx].codepoint),
-			      SARA_AA_FROM_SARA_AM (buffer->info[buffer->idx].codepoint)};
+    uint16_t decomposed[2] = {uint16_t (NIKHAHIT_FROM_SARA_AM (u)),
+			      uint16_t (SARA_AA_FROM_SARA_AM (u))};
     buffer->replace_glyphs (1, 2, decomposed);
     if (unlikely (buffer->in_error))
       return;