libm: Add a couple of tests for scalbn

These check for a bug handling overflow in scalbn caused by compiler
optimization of integer overflow.

Signed-off-by: Keith Packard <keithp@keithp.com>

Author: keith-packard

newlib/libm/test/math.c

@@ -588,6 +588,20 @@ run_vector_1 (int vector,
        fresult = (float) ((pdblfunc)(func))(arg1, &result2);
        ffinish2(f, vector, fresult, result2, p, args, name);
      }
+     else if (strcmp(args,"ddi") == 0)
+     {
+       typedef double (*pdblfunc)(double, int);
+
+       result = ((pdblfunc)func) (arg1, (int) arg2);
+       finish(f, vector, result, p, args, name);
+     }
+     else if (strcmp(args,"ffi") == 0)
+     {
+       typedef float (*pdblfunc)(float, int);
+
+       fresult = ((pdblfunc)func) (arg1, (int) arg2);
+       ffinish(f, vector, fresult, p, args, name);
+     }
     p++;
   }
   if (vector)
@@ -656,6 +670,8 @@ test_math (int vector)
   test_modff(vector);
   test_pow_vec(vector);
   test_powf_vec(vector);
+  test_scalbn(vector);
+  test_scalbnf(vector);
   test_sin(vector);
   test_sinf(vector);
   test_sinh(vector);

newlib/libm/test/meson.build

@@ -96,6 +96,7 @@ math_test_src = [
   'modff_vec.c',
   'pow_vec.c',
   'powf_vec.c',
+  'scalbn_vec.c',
   'sinf_vec.c',
   'sinhf_vec.c',
   'sinh_vec.c',

newlib/libm/test/scalbn_vec.c

@@ -0,0 +1,45 @@
+/*
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright © 2021 Keith Packard
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above
+ *    copyright notice, this list of conditions and the following
+ *    disclaimer in the documentation and/or other materials provided
+ *    with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "test.h"
+
+one_line_type scalbn_vec[] = {
+    { 64, 0, 123, __LINE__, 0x3ff00000, 0x00000000, 0x3ff00000, 0x00000000, 0x00000000, 0x00000000 }, /* 1 = f(1, 0); */
+    { 64, 0, 123, __LINE__, 0x7ff00000, 0x00000000, 0x3ff00000, 0x00000000, 0x40c38800, 0x00000000 }, /* +inf = f(1, 10000); */
+    { 64, 0, 123, __LINE__, 0x7ff00000, 0x00000000, 0x3ff00000, 0x00000000, 0x41dfffff, 0xffc00000 }, /* +inf = f(1, 0x7fffffff); */
+    { 0 },
+};
+
+void test_scalbn(int m) { run_vector_1(m, scalbn_vec, (void*)scalbn,"scalbn","ddi"); }
+void test_scalbnf(int m) { run_vector_1(m, scalbn_vec, (void*)scalbnf,"scalbnf","ffi"); }

newlib/libm/test/test.h

@@ -480,6 +480,12 @@ test_pow_vec(int vector);
 void
 test_powf_vec(int vector);
 
+void
+test_scalbn(int vector);
+
+void
+test_scalbnf(int vector);
+
 void
 test_sin(int vector);