[PATCH] Fix llroundl

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

ldbl-96 llroundl(4294967295.5) returns 0, although it should return
4294967296LL.
The problem is that on this input i0 == 0xffffffff, i1 == 0x80000000, j0 == 31,
so llroundl rounds up (by doing ++i0, which overflows and is suddenly 0).
Fixed with a patch below, where the rounding is already done on long long
variable.

2001-06-04  Jakub Jelinek  <jakub@redhat.com>

	* math/libm-test.inc (llround_test): Add two new llround tests.
	* sysdeps/ieee754/ldbl-96/s_llroundl.c (__llroundl): Don't allow
	overflow when rounding away from zero.

--- libc/math/libm-test.inc.jj	Wed May 23 09:21:45 2001
+++ libc/math/libm-test.inc	Mon Jun  4 10:01:59 2001
@@ -3302,6 +3302,13 @@ llround_test (void)
   /* 0x100000000000000 */
   TEST_f_L (llround, 72057594037927936.0, 72057594037927936LL);
 
+#ifndef TEST_FLOAT
+  /* 0x100000000 */
+  TEST_f_L (llround, 4294967295.5, 4294967296LL);
+  /* 0x200000000 */
+  TEST_f_L (llround, 8589934591.5, 8589934592LL);
+#endif
+
   END (llround);
 }
 
--- libc/sysdeps/ieee754/ldbl-96/s_llroundl.c.jj	Wed Jul 14 02:14:08 1999
+++ libc/sysdeps/ieee754/ldbl-96/s_llroundl.c	Mon Jun  4 09:50:49 2001
@@ -1,5 +1,5 @@
 /* Round long double value to long long int.
-   Copyright (C) 1997 Free Software Foundation, Inc.
+   Copyright (C) 1997, 2001 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
 
@@ -59,13 +59,13 @@ __llroundl (long double x)
       else
 	{
 	  u_int32_t j = i1 + (0x80000000 >> (j0 - 31));
+
+	  result = (long long int) i0;
 	  if (j < i1)
-	    ++i0;
+	    ++result;
 
-	  if (j0 == 31)
-	    result = (long long int) i0;
-	  else
-	    result = ((long long int) i0 << (j0 - 31)) | (j >> (63 - j0));
+	  if (j0 > 31)
+	    result = (result << (j0 - 31)) | (j >> (63 - j0));
 	}
     }
   else

	Jakub