GNU C Library master sources branch master updated. glibc-2.22-373-gd7025ba

jsm28@sourceware.org jsm28@sourceware.org
Tue Oct 13 23:31:00 GMT 2015


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http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=d7025badd8bae7ff8bc37551d868a22832a7bc94

commit d7025badd8bae7ff8bc37551d868a22832a7bc94
Author: Joseph Myers <joseph@codesourcery.com>
Date:   Tue Oct 13 23:30:20 2015 +0000

    Fix powerpc32 llround, llroundf exceptions (bug 19125).
    
    The powerpc32 implementations of llroundf and llround produce spurious
    and missing exceptions (some arising from such exceptions from
    conversions to long long, some present even when fctidz is used).
    
    This patch fixes those problems in a similar way to the llrint /
    llrintf fixes.  The spurious exceptions in the fctidz case for large
    arguments arise from a converted value that saturated as LLONG_MAX
    being converted back to float or double (the conversion back being
    inexact, but "inexact" must not be raised together with "invalid"),
    and from the subtraction x - xrf also being inexact for sufficiently
    large arguments (whether the saturation was to LLONG_MAX or
    LLONG_MIN); those are fixed by returning early if the argument is
    large enough that no rounding is needed.
    
    This code is not used for --with-cpu=power4 builds (I suspect the code
    used in that case may also produce spurious "inexact" exceptions, but
    that's something to investigate later).
    
    Tested for powerpc.
    
    	[BZ #19125]
    	* sysdeps/powerpc/powerpc32/fpu/s_llround.c: Include <limits.h>,
    	<math_private.h> and <stdint.h>.
    	(__llround): Avoid conversions to and from long long int, and
    	subtractions, where those might raise spurious exceptions.
    	* sysdeps/powerpc/powerpc32/fpu/s_llroundf.c: Include
    	<math_private.h> and <stdint.h>.
    	(__llroundf): Avoid conversions to and from long long int, and
    	subtractions, where those might raise spurious exceptions.

diff --git a/ChangeLog b/ChangeLog
index 3334436..0a049d2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2015-10-13  Joseph Myers  <joseph@codesourcery.com>
+
+	[BZ #19125]
+	* sysdeps/powerpc/powerpc32/fpu/s_llround.c: Include <limits.h>,
+	<math_private.h> and <stdint.h>.
+	(__llround): Avoid conversions to and from long long int, and
+	subtractions, where those might raise spurious exceptions.
+	* sysdeps/powerpc/powerpc32/fpu/s_llroundf.c: Include
+	<math_private.h> and <stdint.h>.
+	(__llroundf): Avoid conversions to and from long long int, and
+	subtractions, where those might raise spurious exceptions.
+
 2015-10-13  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* sysdeps/unix/sysv/linux/adjtime.c (ADJTIME): Use
diff --git a/NEWS b/NEWS
index 7f39543..6d39148 100644
--- a/NEWS
+++ b/NEWS
@@ -19,7 +19,7 @@ Version 2.23
   18870, 18872, 18873, 18875, 18887, 18921, 18951, 18952, 18956, 18961,
   18966, 18967, 18969, 18970, 18977, 18980, 18981, 18985, 19003, 19012,
   19016, 19018, 19032, 19046, 19049, 19050, 19059, 19071, 19076, 19077,
-  19078, 19079, 19085, 19086, 19088, 19094, 19095, 19124
+  19078, 19079, 19085, 19086, 19088, 19094, 19095, 19124, 19125
 
 * The obsolete header <regexp.h> has been removed.  Programs that require
   this header must be updated to use <regex.h> instead.
diff --git a/sysdeps/powerpc/powerpc32/fpu/s_llround.c b/sysdeps/powerpc/powerpc32/fpu/s_llround.c
index 85514a1..bdee74b 100644
--- a/sysdeps/powerpc/powerpc32/fpu/s_llround.c
+++ b/sysdeps/powerpc/powerpc32/fpu/s_llround.c
@@ -16,8 +16,11 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#include <limits.h>
 #include <math.h>
 #include <math_ldbl_opt.h>
+#include <math_private.h>
+#include <stdint.h>
 
 /* Round to the nearest integer, with values exactly on a 0.5 boundary
    rounded away from zero, regardless of the current rounding mode.
@@ -27,7 +30,42 @@
 long long int
 __llround (double x)
 {
-  long long xr = (long long) x;
+  long long xr;
+  if (HAVE_PPC_FCTIDZ)
+    xr = (long long) x;
+  else
+    {
+      /* Avoid incorrect exceptions from libgcc conversions (as of GCC
+	 5): <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59412>.  */
+      if (fabs (x) < 0x1p31)
+	xr = (long long int) (long int) x;
+      else
+	{
+	  uint64_t i0;
+	  EXTRACT_WORDS64 (i0, x);
+	  int exponent = ((i0 >> 52) & 0x7ff) - 0x3ff;
+	  if (exponent < 63)
+	    {
+	      unsigned long long int mant
+		= (i0 & ((1ULL << 52) - 1)) | (1ULL << 52);
+	      if (exponent < 52)
+		/* llround is not required to raise "inexact".  */
+		mant >>= 52 - exponent;
+	      else
+		mant <<= exponent - 52;
+	      xr = (long long int) ((i0 & (1ULL << 63)) != 0 ? -mant : mant);
+	    }
+	  else if (x == (double) LLONG_MIN)
+	    xr = LLONG_MIN;
+	  else
+	    xr = (long long int) (long int) x << 32;
+	}
+    }
+  /* Avoid spurious "inexact" converting LLONG_MAX to double, and from
+     subtraction when the result is out of range, by returning early
+     for arguments large enough that no rounding is needed.  */
+  if (!(fabs (x) < 0x1p52))
+    return xr;
   double xrf = (double) xr;
 
   if (x >= 0.0)
diff --git a/sysdeps/powerpc/powerpc32/fpu/s_llroundf.c b/sysdeps/powerpc/powerpc32/fpu/s_llroundf.c
index 8ce4b26..6c67857 100644
--- a/sysdeps/powerpc/powerpc32/fpu/s_llroundf.c
+++ b/sysdeps/powerpc/powerpc32/fpu/s_llroundf.c
@@ -17,6 +17,8 @@
    <http://www.gnu.org/licenses/>.  */
 
 #include <math.h>
+#include <math_private.h>
+#include <stdint.h>
 
 /* Round to the nearest integer, with values exactly on a 0.5 boundary
    rounded away from zero, regardless of the current rounding mode.
@@ -26,7 +28,33 @@
 long long int
 __llroundf (float x)
 {
-  long long xr = (long long) x;
+  long long xr;
+  if (HAVE_PPC_FCTIDZ)
+    xr = (long long) x;
+  else
+    {
+      float ax = fabsf (x);
+      /* Avoid incorrect exceptions from libgcc conversions (as of GCC
+	 5): <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59412>.  */
+      if (ax < 0x1p31f)
+	xr = (long long int) (long int) x;
+      else if (!(ax < 0x1p55f))
+	xr = (long long int) (long int) (x * 0x1p-32f) << 32;
+      else
+	{
+	  uint32_t i0;
+	  GET_FLOAT_WORD (i0, x);
+	  int exponent = ((i0 >> 23) & 0xff) - 0x7f;
+	  unsigned long long int mant = (i0 & 0x7fffff) | 0x800000;
+	  mant <<= exponent - 23;
+	  xr = (long long int) ((i0 & 0x80000000) != 0 ? -mant : mant);
+	}
+    }
+  /* Avoid spurious "inexact" converting LLONG_MAX to float, and from
+     subtraction when the result is out of range, by returning early
+     for arguments large enough that no rounding is needed.  */
+  if (!(fabsf (x) < 0x1p23f))
+    return xr;
   float xrf = (float) xr;
 
   if (x >= 0.0)

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                                  |   12 ++++++++
 NEWS                                       |    2 +-
 sysdeps/powerpc/powerpc32/fpu/s_llround.c  |   40 +++++++++++++++++++++++++++-
 sysdeps/powerpc/powerpc32/fpu/s_llroundf.c |   30 ++++++++++++++++++++-
 4 files changed, 81 insertions(+), 3 deletions(-)


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