[patch] fix std::chrono::duration literals

[Jonathan Wakely]

This fixes errors when using 0s or 1'000s to create durations.

Tested x86_64-linux, committed to trunk.


commit c57e645222ac9bf476ef5b6414773b5f4e2b86fc
Author: Jonathan Wakely <jwak...@redhat.com>
Date:   Sun Jun 22 18:06:42 2014 +0100

    	* include/bits/parse_numbers.h (_Number_help): Fix divide-by-zero.
    	* include/std/chrono (_Checked_integral_constant): Allow zero.
    	* testsuite/20_util/duration/literals/values.cc: Test non-positive
    	values and digit separators.

diff --git a/libstdc++-v3/include/bits/parse_numbers.h b/libstdc++-v3/include/bits/parse_numbers.h
index a29d127..f46c59c 100644
--- a/libstdc++-v3/include/bits/parse_numbers.h
+++ b/libstdc++-v3/include/bits/parse_numbers.h
@@ -190,10 +190,11 @@ namespace __parse_int
       using __digit = _Digit<_Base, _Dig>;
       using __valid_digit = typename __digit::__valid;
       using __next = _Number_help<_Base,
-				  _Pow / (_Base * __valid_digit::value),
+				  __valid_digit::value ? _Pow / _Base : _Pow,
 				  _Digs...>;
       using type = __ull_constant<_Pow * __digit::value + __next::type::value>;
-      static_assert((type::value / _Pow) == __digit::value, "overflow");
+      static_assert((type::value / _Pow) == __digit::value,
+		    "integer literal does not fit in unsigned long long");
     };
 
   template<unsigned _Base, unsigned long long _Pow, char _Dig>
@@ -214,7 +215,6 @@ namespace __parse_int
     { };
 
 //------------------------------------------------------------------------------
-//  This _Parse_int is the same 'level' as the old _Base_dispatch.
 
   template<char... _Digs>
     struct _Parse_int;
diff --git a/libstdc++-v3/include/std/chrono b/libstdc++-v3/include/std/chrono
index 39ad5e3..88eaa16 100644
--- a/libstdc++-v3/include/std/chrono
+++ b/libstdc++-v3/include/std/chrono
@@ -791,7 +791,7 @@ _GLIBCXX_END_NAMESPACE_VERSION
       struct _Checked_integral_constant
       : integral_constant<_Rep, static_cast<_Rep>(_Val)>
       {
-	static_assert(_Checked_integral_constant::value > 0
+	static_assert(_Checked_integral_constant::value >= 0
 		      && _Checked_integral_constant::value == _Val,
 		      "literal value cannot be represented by duration type");
       };
diff --git a/libstdc++-v3/testsuite/20_util/duration/literals/values.cc b/libstdc++-v3/testsuite/20_util/duration/literals/values.cc
index f55c32f..ce86358 100644
--- a/libstdc++-v3/testsuite/20_util/duration/literals/values.cc
+++ b/libstdc++-v3/testsuite/20_util/duration/literals/values.cc
@@ -56,6 +56,12 @@ test03()
   VERIFY( workday == std::chrono::hours(8) );
   auto fworkday = 8.0h;
   VERIFY( (fworkday == std::chrono::duration<long double, std::ratio<3600,1>>(8.0L)) );
+  auto immediate = 0s;
+  VERIFY( immediate == std::chrono::seconds(0) );
+  auto minute_ago = -1min;
+  VERIFY( minute_ago == std::chrono::minutes(-1) );
+  auto separated = 1'000'000s;
+  VERIFY( separated == std::chrono::seconds(1'000'000) );
 }
 
 int