Check highest bit of word using SIGNB instead of cast to signed_word

(refactoring)

* allchblk.c (GC_merge_unmapped): Replace overflow check
(signed_word)(sz1+sz2)>0 to !((sz1+sz2)&SIGNB).
* allchblk.c (GC_freehblk): Likewise.
* mark.c (GC_mark_from): Replace (signed_word)descr>=0 expression
to !(descr&SIGNB).
* ptr_chck.c (GC_is_visible): Likewise.

1 files changed, 1 insertions, 1 deletions

diff --git a/ptr_chck.c b/ptr_chck.c
index 0cc8a726..a363563a 100644
--- a/ptr_chck.c
+++ b/ptr_chck.c
@@ -240,7 +240,7 @@ GC_API void * GC_CALL GC_is_visible(void *p)
                     /* For now we just punt.                            */
                     break;
                 case GC_DS_PER_OBJECT:
-                    if ((signed_word)descr >= 0) {
+                    if (!(descr & SIGNB)) {
                       descr = *(word *)((ptr_t)base + (descr & ~GC_DS_TAGS));
                     } else {
                       ptr_t type_descr = *(ptr_t *)base;