[7728] gnulib update

[gavinsmith0123]

Revision: 7728
          http://svn.sv.gnu.org/viewvc/?view=rev&root=texinfo&revision=7728
Author:   gavin
Date:     2017-04-15 04:08:47 -0400 (Sat, 15 Apr 2017)
Log Message:
-----------
gnulib update

Modified Paths:
--------------
    trunk/gnulib/lib/intprops.h

Modified: trunk/gnulib/lib/intprops.h
===================================================================
--- trunk/gnulib/lib/intprops.h 2017-04-14 17:53:38 UTC (rev 7727)
+++ trunk/gnulib/lib/intprops.h 2017-04-15 08:08:47 UTC (rev 7728)
@@ -389,10 +389,10 @@
    (_Generic \
     (*(r), \
      signed char: \
-       _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned char, \
+       _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
                         signed char, SCHAR_MIN, SCHAR_MAX), \
      short int: \
-       _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned short int, \
+       _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
                         short int, SHRT_MIN, SHRT_MAX), \
      int: \
        _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
@@ -406,10 +406,10 @@
 #else
 # define _GL_INT_OP_WRAPV(a, b, r, op, builtin, overflow) \
    (sizeof *(r) == sizeof (signed char) \
-    ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned char, \
+    ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
                        signed char, SCHAR_MIN, SCHAR_MAX) \
     : sizeof *(r) == sizeof (short int) \
-    ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned short int, \
+    ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
                        short int, SHRT_MIN, SHRT_MAX) \
     : sizeof *(r) == sizeof (int) \
     ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
@@ -431,9 +431,8 @@
 
 /* Store the low-order bits of A <op> B into *R, where the operation
    is given by OP.  Use the unsigned type UT for calculation to avoid
-   overflow problems.  *R's type is T, with extremal values TMIN and
-   TMAX.  T must be a signed integer type.  Return 1 if the result
-   overflows.  */
+   overflow problems.  *R's type is T, with extrema TMIN and TMAX.
+   T must be a signed integer type.  Return 1 if the result overflows.  */
 #define _GL_INT_OP_CALC(a, b, r, op, overflow, ut, t, tmin, tmax) \
   (sizeof ((a) op (b)) < sizeof (t) \
    ? _GL_INT_OP_CALC1 ((t) (a), (t) (b), r, op, overflow, ut, t, tmin, tmax) \
@@ -442,17 +441,34 @@
   ((overflow (a, b) \
     || (EXPR_SIGNED ((a) op (b)) && ((a) op (b)) < (tmin)) \
     || (tmax) < ((a) op (b))) \
-   ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t, tmin, tmax), 1) \
-   : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t, tmin, tmax), 0))
+   ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t), 1) \
+   : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t), 0))
 
-/* Return A <op> B, where the operation is given by OP.  Use the
-   unsigned type UT for calculation to avoid overflow problems.
-   Convert the result to type T without overflow by subtracting TMIN
-   from large values before converting, and adding it afterwards.
-   Compilers can optimize all the operations except OP.  */
-#define _GL_INT_OP_WRAPV_VIA_UNSIGNED(a, b, op, ut, t, tmin, tmax) \
-  (((ut) (a) op (ut) (b)) <= (tmax) \
-   ? (t) ((ut) (a) op (ut) (b)) \
-   : ((t) (((ut) (a) op (ut) (b)) - (tmin)) + (tmin)))
+/* Return A <op> B, where the operation is given by OP.  Return the
+   low-order bits of the mathematically-correct answer.  Use the
+   unsigned type UT for calculation to avoid undefined behavior on
+   signed integer overflow.  Assume that conversion to the result type
+   T yields the low-order bits in the usual way.  UT is at least as
+   wide as T and is no narrower than unsigned int, T is two's
+   complement, and there is no padding or trap representations.
 
+   According to the C standard, converting UT to T yields an
+   implementation-defined result or signal for values outside T's range.
+   So, the standard way to convert UT to T is to subtract TMIN from
+   greater-than-TMAX values before converting them to T, and to add
+   TMIN afterwards, where TMIN and TMAX are T's extrema.
+   However, in practice there is no need to subtract and add TMIN.
+   E.g., GCC converts to signed integers in the usual way; see:
+   https://gcc.gnu.org/onlinedocs/gcc/Integers-implementation.html
+   All other known C compilers are similar to GCC in this respect.
+   Furthermore, Oracle Studio 12.3 x86 has a bug when implementing the
+   standard way; see:
+   http://lists.gnu.org/archive/html/bug-gnulib/2017-04/msg00049.html
+
+   So, implement this operation in the usual way rather than in
+   the standard way.  */
+
+#define _GL_INT_OP_WRAPV_VIA_UNSIGNED(a, b, op, ut, t) \
+  ((t) ((ut) (a) op (ut) (b)))
+
 #endif /* _GL_INTPROPS_H */