diff --git a/libguile/__scm.h b/libguile/__scm.h
index 170410577..0f6d24d6c 100644
--- a/libguile/__scm.h
+++ b/libguile/__scm.h
@@ -285,11 +285,12 @@ extern unsigned int scm_async_clock;
 
    However, GCC's volatile asm feature forms a barrier over which code is
    never moved. So if you add...
-	   asm volatile ("");
-   ...to each of the DEFER_INTS and ALLOW_INTS macros, the critical code
-   will always remain in place.  */
+	   asm ("");
+   ...to each of the DEFER_INTS and ALLOW_INTS macros, the critical
+   code will always remain in place.  asm's without inputs or outputs
+   are implicitly volatile. */
 #ifdef __GNUC__
-#define SCM_FENCE asm volatile ("")
+#define SCM_FENCE asm /* volatile */ ("")
 #else
 #define SCM_FENCE
 #endif
diff --git a/libguile/gc.c b/libguile/gc.c
index 6e77235f7..b6b1fb56a 100644
--- a/libguile/gc.c
+++ b/libguile/gc.c
@@ -1113,7 +1113,7 @@ scm_gc_sweep ()
 		if ((SCM_CDR (vcell) == 0) || (SCM_CDR (vcell) == 1))
 		  {
 		    SCM *p = (SCM *) SCM_GCCDR (scmptr);
- 		    m += (p[scm_struct_i_n_words] + 7) * sizeof (SCM);
+ 		    m += p[scm_struct_i_n_words] * sizeof (SCM) + 7;
 		    /* I feel like I'm programming in BCPL here... */
 		    free ((char *) p[scm_struct_i_ptr]);
 		  }