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@

diff --git a/regress/sys/kern/signal/fpsig/fpsig.c b/regress/sys/kern/signal/fpsig/fpsig.c
index ae4e368..5830ab1 100644 (file)
--- 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);