Opotimize "scno >= 0 && scno < nsyscalls" check

gcc can't figure out on its own that this check can be done with
single compare, and does two compares. We can help it by casting
scno to unsigned long: ((unsigned long)(scno) < nsyscalls)

* defs.h: New macro SCNO_IN_RANGE(long_var).
* count.c (count_syscall): Use SCNO_IN_RANGE() instead of open-coded check.
* syscall.c (getrval2): Use SCNO_IN_RANGE() instead of open-coded check.
This fixes a bug: missing check for scno < 0 and scno > nsyscalls
instead of scno >= nsyscalls.
(get_scno): Use SCNO_IN_RANGE() instead of open-coded check.
This fixes a bug: scno > nsyscalls instead of scno >= nsyscalls.
(known_scno): Use SCNO_IN_RANGE() instead of open-coded check.
(internal_syscall): Likewise.
(syscall_enter): Likewise.
(trace_syscall_entering): Likewise.
(get_error): Likewise.
(trace_syscall_exiting): Likewise.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/count.c b/count.c
index 86b1953..77fc919 100644
--- a/count.c
+++ b/count.c
@@ -50,7 +50,7 @@ static struct timeval shortest = { 1000000, 0 };
 void
 count_syscall(struct tcb *tcp, struct timeval *tv)
 {
-	if (tcp->scno < 0 || tcp->scno >= nsyscalls)
+	if (!SCNO_IN_RANGE(tcp->scno))
 		return;
 
 	if (!counts) {