Make the floating-point computations a sligthly teeny bit more complex (but

real), to prevent llvm panzers from optimizing too aggressively and generating
code which does not touch the slightest floating point register on some
platforms.

ok otto@

1 files changed, 24 insertions, 9 deletions

diff --git a/regress/sys/kern/signal/fpsig/fpsig.c b/regress/sys/kern/signal/fpsig/fpsig.c
index ae4e368e0d8..5830ab10b91 100644
--- a/regress/sys/kern/signal/fpsig/fpsig.c
+++ b/regress/sys/kern/signal/fpsig/fpsig.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fpsig.c,v 1.2 2005/07/15 07:28:33 otto Exp $	*/
+/*	$OpenBSD: fpsig.c,v 1.3 2022/10/25 19:55:31 miod Exp $	*/
 
 /*
  * Public domain.  2005, Otto Moerbeek
@@ -11,8 +11,9 @@
 #include <err.h>
 #include <signal.h>
 #include <unistd.h>
+#include <sys/time.h>
 
-#define LIMIT	10.0
+#define LIMIT	11.1
 
 volatile sig_atomic_t count;
 
@@ -24,10 +25,8 @@ handler(int signo)
 {
 	double a, b, c = 0.0;
 
-	if (signo)
-		alarm(1);
-	for (a = 0.0; a < LIMIT; a++)
-		for (b = 0.0; b < LIMIT; b++)
+	for (a = 0.0; a < LIMIT; a += 1.1)
+		for (b = 0.0; b < LIMIT; b += 1.1)
 			c += a * a + b * b;
 
 	if (signo) {
@@ -40,14 +39,30 @@ handler(int signo)
 int
 main()
 {
-	signal(SIGALRM, handler);
+	struct itimerval it = {
+		.it_interval =  { .tv_sec = 0, .tv_usec = 10000 },
+		.it_value =  { .tv_sec = 0, .tv_usec = 10000 }
+	};
+
 	/* initialize global vars */
 	handler(0);
 	handler(1);
+
+	signal(SIGALRM, handler);
+	setitimer(ITIMER_REAL, &it, NULL);
 	
-	while (count < 10) {
+	while (count < 10000) {
 		handler(0);
-		if (g1 != g2)
+	double a, b, h1 = g1, h2 = g2;
+
+	for (a = 0.0; a < LIMIT; a += 1.1)
+		for (b = 0.0; b < LIMIT; b += 1.1)
+			h1 += a * a + b * b;
+	for (a = 0.0; a < LIMIT; a += 1.1)
+		for (b = 0.0; b < LIMIT; b += 1.1)
+			h2 += a * a + b * b;
+
+		if (h1 != h2)
 			errx(1, "%f %f", g1, g2);
 	}
 	return (0);