diff --git a/libguile/gc.h b/libguile/gc.h
index bebfeb995..01b252021 100644
--- a/libguile/gc.h
+++ b/libguile/gc.h
@@ -85,37 +85,40 @@ typedef scm_cell * SCM_CELLPTR;
 /* Low level cell data accessing macros:
  */
 
-#define SCM_VALIDATE_CELL(x) \
-        ((void) \
-	 (SCM_DEBUG_CELL_ACCESSES ? (!scm_cellp (x) ? (abort (), 0) : 1) : 1))
+#if SCM_DEBUG_CELL_ACCESSES == 1
+#define SCM_VALIDATE_CELL(cell, expr) \
+  (!scm_cellp (cell) ? abort (), 0 : (expr))
+#else
+#define SCM_VALIDATE_CELL(cell, expr) expr
+#endif
 
-#define SCM_CELL_WORD(x, n) \
-    ((SCM_VALIDATE_CELL (x)), \
-     (((scm_bits_t *) SCM2PTR (x)) [n]))
+#define SCM_CELL_WORD(x, n)					\
+    SCM_VALIDATE_CELL ((x),					\
+		       ((scm_bits_t *) SCM2PTR (x)) [n])
 #define SCM_CELL_WORD_0(x) SCM_CELL_WORD (x, 0)
 #define SCM_CELL_WORD_1(x) SCM_CELL_WORD (x, 1)
 #define SCM_CELL_WORD_2(x) SCM_CELL_WORD (x, 2)
 #define SCM_CELL_WORD_3(x) SCM_CELL_WORD (x, 3)
 
-#define SCM_CELL_OBJECT(x, n) \
-    ((SCM_VALIDATE_CELL (x)), \
-     (SCM_PACK (((scm_bits_t *) SCM2PTR (x)) [n])))
+#define SCM_CELL_OBJECT(x, n)						\
+    SCM_VALIDATE_CELL ((x),						\
+		       SCM_PACK (((scm_bits_t *) SCM2PTR (x)) [n]))
 #define SCM_CELL_OBJECT_0(x) SCM_CELL_OBJECT (x, 0)
 #define SCM_CELL_OBJECT_1(x) SCM_CELL_OBJECT (x, 1)
 #define SCM_CELL_OBJECT_2(x) SCM_CELL_OBJECT (x, 2)
 #define SCM_CELL_OBJECT_3(x) SCM_CELL_OBJECT (x, 3)
 
-#define SCM_SET_CELL_WORD(x, n, v) \
-    ((SCM_VALIDATE_CELL (x)), \
-     ((((scm_bits_t *) SCM2PTR (x)) [n]) = (scm_bits_t) (v)))
+#define SCM_SET_CELL_WORD(x, n, v)					    \
+    SCM_VALIDATE_CELL ((x),						    \
+		       ((scm_bits_t *) SCM2PTR (x)) [n] = (scm_bits_t) (v))
 #define SCM_SET_CELL_WORD_0(x, v) SCM_SET_CELL_WORD (x, 0, v)
 #define SCM_SET_CELL_WORD_1(x, v) SCM_SET_CELL_WORD (x, 1, v)
 #define SCM_SET_CELL_WORD_2(x, v) SCM_SET_CELL_WORD (x, 2, v)
 #define SCM_SET_CELL_WORD_3(x, v) SCM_SET_CELL_WORD (x, 3, v)
 
-#define SCM_SET_CELL_OBJECT(x, n, v) \
-    ((SCM_VALIDATE_CELL (x)), \
-     ((((scm_bits_t *) SCM2PTR (x)) [n]) = SCM_UNPACK (v)))
+#define SCM_SET_CELL_OBJECT(x, n, v)					  \
+    SCM_VALIDATE_CELL ((x),						  \
+		       ((scm_bits_t *) SCM2PTR (x)) [n] = SCM_UNPACK (v))
 #define SCM_SET_CELL_OBJECT_0(x, v) SCM_SET_CELL_OBJECT (x, 0, v)
 #define SCM_SET_CELL_OBJECT_1(x, v) SCM_SET_CELL_OBJECT (x, 1, v)
 #define SCM_SET_CELL_OBJECT_2(x, v) SCM_SET_CELL_OBJECT (x, 2, v)