libm: fix rint/scalb testcase failures

These failures no longer happen:

Failure: Test: scalb (2.0, 0.5) == NaN plus invalid exception
Failure: Test: scalb (3.0, -2.5) == NaN plus invalid exception
Failure: Test: rint (0.5) == 0.0
Failure: Test: rint (1.5) == 2.0
Failure: Test: rint (2.5) == 2.0
Failure: Test: rint (3.5) == 4.0
Failure: Test: rint (4.5) == 4.0
Failure: Test: rint (-0.5) == -0.0
Failure: Test: rint (-1.5) == -2.0
Failure: Test: rint (-2.5) == -2.0
Failure: Test: rint (-3.5) == -4.0
Failure: Test: rint (-4.5) == -4.0

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 27 insertions, 6 deletions

diff --git a/test/math/rint.c b/test/math/rint.c
index 04c195385..c7bfab920 100644
--- a/test/math/rint.c
+++ b/test/math/rint.c
@@ -1,11 +1,32 @@
 #include <math.h>
 #include <stdlib.h>
+#include <stdint.h>
 #include <stdio.h>
 
-int main(void) {
-    double d1, d2;
-    d1 = 0.6;  d2 = rint(d1);
-    printf("d1 = %f, d2 = %f\n", d1, d2);
-    return 0;
-}
+#define check_d1(func, param, expected) \
+do { \
+	int err; hex_union ur; hex_union up; \
+	up.f = param; ur.f = result = func(param); \
+	errors += (err = (result != expected)); \
+	err \
+	? printf("FAIL: %s(%g/"HEXFMT")=%g/"HEXFMT" (expected %g)\n", \
+		#func, (param), (long long)up.hex, result, (long long)ur.hex, expected) \
+	: printf("PASS: %s(%g)=%g\n", #func, (param), result); \
+} while (0)
+
+#define HEXFMT "%08llx"
+typedef union {
+	double f;
+	uint64_t hex;
+} hex_union;
+double result;
+
+int errors = 0;
 
+int main(void)
+{
+	check_d1(rint, 0.6, 1.0);
+
+        printf("Errors: %d\n", errors);
+        return errors;
+}