diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 9bd1553676fc..8d2c9ac2b794 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,9 @@
+2003-12-08  David S. Miller  <davem@redhat.com>
+
+	PR libstdc++/12496
+	* config/cpu/sparc/atomicity.h (__exchange_and_add, __atomic_add):
+	Extend increment to _Atomic_word before giving to assembler.
+
 2003-12-06  Benjamin Kosnik  <bkoz@redhat.com>
 
 	* testsuite/ext/enc_filebuf/char/13189.cc: Guard for __enc_traits.
diff --git a/libstdc++-v3/config/cpu/sparc/atomicity.h b/libstdc++-v3/config/cpu/sparc/atomicity.h
index 4c9dbf6345dd..93e3dff51952 100644
--- a/libstdc++-v3/config/cpu/sparc/atomicity.h
+++ b/libstdc++-v3/config/cpu/sparc/atomicity.h
@@ -39,6 +39,7 @@ __attribute__ ((__unused__))
 __exchange_and_add (volatile _Atomic_word *__mem, int __val)
 {
   _Atomic_word __tmp1, __tmp2;
+  _Atomic_word __val_extended = __val;
 
   __asm__ __volatile__("1:	ldx	[%2], %0\n\t"
 		       "	add	%0, %3, %1\n\t"
@@ -47,7 +48,7 @@ __exchange_and_add (volatile _Atomic_word *__mem, int __val)
 		       "	brnz,pn	%0, 1b\n\t"
 		       "	 nop"
 		       : "=&r" (__tmp1), "=&r" (__tmp2)
-		       : "r" (__mem), "r" (__val)
+		       : "r" (__mem), "r" (__val_extended)
 		       : "memory");
   return __tmp2;
 }
@@ -57,6 +58,7 @@ __attribute__ ((__unused__))
 __atomic_add (volatile _Atomic_word* __mem, int __val)
 {
   _Atomic_word __tmp1, __tmp2;
+  _Atomic_word __val_extended = __val;
 
   __asm__ __volatile__("1:	ldx	[%2], %0\n\t"
 		       "	add	%0, %3, %1\n\t"
@@ -65,7 +67,7 @@ __atomic_add (volatile _Atomic_word* __mem, int __val)
 		       "	brnz,pn	%0, 1b\n\t"
 		       "	 nop"
 		       : "=&r" (__tmp1), "=&r" (__tmp2)
-		       : "r" (__mem), "r" (__val)
+		       : "r" (__mem), "r" (__val_extended)
 		       : "memory");
 }