1 files changed, 91 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.c-torture/execute/cbrt.c b/gcc/testsuite/gcc.c-torture/execute/cbrt.c
new file mode 100644
index 00000000000..8f1fe68df1d
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/cbrt.c
@@ -0,0 +1,91 @@
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+*/
+
+#ifndef __vax__
+static const unsigned long
+	B1 = 715094163, /* B1 = (682-0.03306235651)*2**20 */
+	B2 = 696219795; /* B2 = (664-0.03306235651)*2**20 */
+
+static const double
+	C =  5.42857142857142815906e-01, /* 19/35     = 0x3FE15F15, 0xF15F15F1 */
+	D = -7.05306122448979611050e-01, /* -864/1225 = 0xBFE691DE, 0x2532C834 */
+	E =  1.41428571428571436819e+00, /* 99/70     = 0x3FF6A0EA, 0x0EA0EA0F */
+	F =  1.60714285714285720630e+00, /* 45/28     = 0x3FF9B6DB, 0x6DB6DB6E */
+	G =  3.57142857142857150787e-01; /* 5/14      = 0x3FD6DB6D, 0xB6DB6DB7 */
+
+double
+cbrtl (double x)
+{
+  long hx;
+  double r,s,w;
+  double lt;
+  unsigned sign;
+  union {
+    double t;
+    unsigned long pt[2];
+  } ut, ux;
+  int n0;
+
+  ut.t = 1.0;
+  n0 = (ut.pt[0] == 0);
+
+  ut.t = 0.0;
+  ux.t = x;
+
+  hx = ux.pt[n0];			/* high word of x */
+  sign=hx&0x80000000;			/* sign= sign(x) */
+  hx  ^=sign;
+  if(hx>=0x7ff00000) return(x+x);	/* cbrt(NaN,INF) is itself */
+  if((hx| ux.pt[1-n0])==0)
+    return(ux.t);			/* cbrt(0) is itself */
+
+  ux.pt[n0] = hx;
+  /* rough cbrt to 5 bits */
+  if(hx<0x00100000)			/* subnormal number */
+    {ut.pt[n0]=0x43500000;		/* set t= 2**54 */
+     ut.t*=x; ut.pt[n0]=ut.pt[n0]/3+B2;
+   }
+  else
+    ut.pt[n0]=hx/3+B1;
+
+  /* new cbrt to 23 bits, may be implemented in single precision */
+  r=ut.t*ut.t/ux.t;
+  s=C+r*ut.t;
+  ut.t*=G+F/(s+E+D/s);
+
+  /* chopped to 20 bits and make it larger than cbrt(x) */
+  ut.pt[1-n0]=0; ut.pt[n0]+=0x00000001;
+
+  /* one step newton iteration to 53 bits with error less than 0.667 ulps */
+  s=ut.t*ut.t;				/* t*t is exact */
+  r=ux.t/s;
+  w=ut.t+ut.t;
+  r=(r-ut.t)/(w+r);			/* r-s is exact */
+  ut.t=ut.t+ut.t*r;
+
+  /* restore the sign bit */
+  ut.pt[n0] |= sign;
+
+  lt = ut.t;
+  lt -= (lt - (x/(lt*lt))) * 0.333333333333333333333;
+  return lt;
+}
+
+main ()
+{
+  if ((int) (cbrtl (27.0) + 0.5) != 3)
+    abort ();
+
+  exit (0);
+}
+#else
+main () { exit (0); }
+#endif