diff --git a/libgloss/arm/_exit.c b/libgloss/arm/_exit.c
index ca2d21c43..4a071df58 100644
--- a/libgloss/arm/_exit.c
+++ b/libgloss/arm/_exit.c
@@ -1,6 +1,6 @@
 #include <_ansi.h>
 
-int _kill (int, int);
+int _kill (int, int) __attribute__((__noreturn__));
 void _exit (int);
 
 void
diff --git a/libgloss/arm/_kill.c b/libgloss/arm/_kill.c
index 278ded73a..34a6ffddf 100644
--- a/libgloss/arm/_kill.c
+++ b/libgloss/arm/_kill.c
@@ -2,7 +2,7 @@
 #include <signal.h>
 #include "swi.h"
 
-int _kill (int, int);
+int _kill (int, int) __attribute__((__noreturn__));
 
 int
 _kill (int pid, int sig)
@@ -41,12 +41,14 @@ _kill (int pid, int sig)
 
 #if SEMIHOST_V2
 if (_has_ext_exit_extended ())
-  return do_AngelSWI (insn, block);
+  do_AngelSWI (insn, block);
 else
 #endif
-  return do_AngelSWI (insn, (void*)block[0]);
+  do_AngelSWI (insn, (void*)block[0]);
 
 #else
   asm ("swi %a0" :: "i" (SWI_Exit));
 #endif
+
+  __builtin_unreachable();
 }
diff --git a/newlib/libc/sys/arm/syscalls.c b/newlib/libc/sys/arm/syscalls.c
index d2a65cbb4..87ddca706 100644
--- a/newlib/libc/sys/arm/syscalls.c
+++ b/newlib/libc/sys/arm/syscalls.c
@@ -30,7 +30,7 @@ int	_stat		(const char *, struct stat *);
 int	_fstat		(int, struct stat *);
 void *	_sbrk		(ptrdiff_t);
 pid_t	_getpid		(void);
-int	_kill		(int, int);
+int	_kill		(int, int) __attribute__((__noreturn__));
 void	_exit		(int);
 int	_close		(int);
 int	_swiclose	(int);
@@ -432,15 +432,18 @@ _kill (int pid, int sig)
   /* Note: The pid argument is thrown away.  */
   switch (sig) {
 	  case SIGABRT:
-		  return do_AngelSWI (AngelSWI_Reason_ReportException,
-				  (void *) ADP_Stopped_RunTimeError);
+		  do_AngelSWI (AngelSWI_Reason_ReportException,
+			       (void *) ADP_Stopped_RunTimeError);
+		  __builtin_unreachable();
 	  default:
-		  return do_AngelSWI (AngelSWI_Reason_ReportException,
-				  (void *) ADP_Stopped_ApplicationExit);
+		  do_AngelSWI (AngelSWI_Reason_ReportException,
+			       (void *) ADP_Stopped_ApplicationExit);
   }
 #else
   asm ("swi %a0" :: "i" (SWI_Exit));
 #endif
+
+  __builtin_unreachable();
 }
 
 void