Author: marshall
Date: Fri Feb 10 14:49:08 2017
New Revision: 294779
URL: http://llvm.org/viewvc/llvm-project?rev=294779&view=rev
Log:
Make lcm/gcd work better in edge cases. Fixes a UBSAN failure.
Modified:
libcxx/trunk/include/experimental/numeric
libcxx/trunk/include/numeric
libcxx/trunk/test/std/experimental/numeric/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
libcxx/trunk/test/std/experimental/numeric/numeric.ops/numeric.ops.lcm/lcm.pass.cpp
libcxx/trunk/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
libcxx/trunk/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.pass.cpp
Modified: libcxx/trunk/include/experimental/numeric
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/experimental/numeric?rev=294779&r1=294778&r2=294779&view=diff
==============================================================================
--- libcxx/trunk/include/experimental/numeric (original)
+++ libcxx/trunk/include/experimental/numeric Fri Feb 10 14:49:08 2017
@@ -45,18 +45,23 @@ inline namespace fundamentals_v2 {
_LIBCPP_BEGIN_NAMESPACE_LFTS_V2
-template <typename _Tp, bool _IsSigned = is_signed<_Tp>::value> struct __abs;
+template <typename _Result, typename _Source, bool _IsSigned =
is_signed<_Source>::value> struct __abs;
-template <typename _Tp>
-struct __abs<_Tp, true> {
+template <typename _Result, typename _Source>
+struct __abs<_Result, _Source, true> {
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
- _Tp operator()(_Tp __t) const noexcept { return __t >= 0 ? __t : -__t; }
+ _Result operator()(_Source __t) const noexcept
+ {
+ if (__t >= 0) return __t;
+ if (__t == numeric_limits<_Source>::min()) return
-static_cast<_Result>(__t);
+ return -__t;
+ }
};
-template <typename _Tp>
-struct __abs<_Tp, false> {
+template <typename _Result, typename _Source>
+struct __abs<_Result, _Source, false> {
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
- _Tp operator()(_Tp __t) const noexcept { return __t; }
+ _Result operator()(_Source __t) const noexcept { return __t; }
};
@@ -79,8 +84,8 @@ gcd(_Tp __m, _Up __n)
static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value),
"Second argument to gcd cannot be bool" );
using _Rp = common_type_t<_Tp,_Up>;
using _Wp = make_unsigned_t<_Rp>;
- return static_cast<_Rp>(__gcd(static_cast<_Wp>(__abs<_Tp>()(__m)),
- static_cast<_Wp>(__abs<_Up>()(__n))));
+ return static_cast<_Rp>(__gcd(static_cast<_Wp>(__abs<_Rp, _Tp>()(__m)),
+ static_cast<_Wp>(__abs<_Rp, _Up>()(__n))));
}
template<class _Tp, class _Up>
@@ -95,8 +100,8 @@ lcm(_Tp __m, _Up __n)
return 0;
using _Rp = common_type_t<_Tp,_Up>;
- _Rp __val1 = __abs<_Tp>()(__m) / gcd(__m,__n);
- _Up __val2 = __abs<_Up>()(__n);
+ _Rp __val1 = __abs<_Rp, _Tp>()(__m) / gcd(__m, __n);
+ _Rp __val2 = __abs<_Rp, _Up>()(__n);
_LIBCPP_ASSERT((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow
in lcm");
return __val1 * __val2;
}
Modified: libcxx/trunk/include/numeric
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/numeric?rev=294779&r1=294778&r2=294779&view=diff
==============================================================================
--- libcxx/trunk/include/numeric (original)
+++ libcxx/trunk/include/numeric Fri Feb 10 14:49:08 2017
@@ -201,18 +201,23 @@ iota(_ForwardIterator __first, _ForwardI
#if _LIBCPP_STD_VER > 14
-template <typename _Tp, bool _IsSigned = is_signed<_Tp>::value> struct __abs;
+template <typename _Result, typename _Source, bool _IsSigned =
is_signed<_Source>::value> struct __abs;
-template <typename _Tp>
-struct __abs<_Tp, true> {
+template <typename _Result, typename _Source>
+struct __abs<_Result, _Source, true> {
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
- _Tp operator()(_Tp __t) const noexcept { return __t >= 0 ? __t : -__t; }
+ _Result operator()(_Source __t) const noexcept
+ {
+ if (__t >= 0) return __t;
+ if (__t == numeric_limits<_Source>::min()) return
-static_cast<_Result>(__t);
+ return -__t;
+ }
};
-template <typename _Tp>
-struct __abs<_Tp, false> {
+template <typename _Result, typename _Source>
+struct __abs<_Result, _Source, false> {
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
- _Tp operator()(_Tp __t) const noexcept { return __t; }
+ _Result operator()(_Source __t) const noexcept { return __t; }
};
@@ -220,7 +225,7 @@ template<class _Tp>
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
_Tp __gcd(_Tp __m, _Tp __n)
{
- static_assert((!is_signed<_Tp>::value), "" );
+ static_assert((!is_signed<_Tp>::value), "");
return __n == 0 ? __m : __gcd<_Tp>(__n, __m % __n);
}
@@ -235,8 +240,8 @@ gcd(_Tp __m, _Up __n)
static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value),
"Second argument to gcd cannot be bool" );
using _Rp = common_type_t<_Tp,_Up>;
using _Wp = make_unsigned_t<_Rp>;
- return static_cast<_Rp>(__gcd(static_cast<_Wp>(__abs<_Tp>()(__m)),
- static_cast<_Wp>(__abs<_Up>()(__n))));
+ return static_cast<_Rp>(__gcd(static_cast<_Wp>(__abs<_Rp, _Tp>()(__m)),
+ static_cast<_Wp>(__abs<_Rp, _Up>()(__n))));
}
template<class _Tp, class _Up>
@@ -251,8 +256,8 @@ lcm(_Tp __m, _Up __n)
return 0;
using _Rp = common_type_t<_Tp,_Up>;
- _Rp __val1 = __abs<_Tp>()(__m) / gcd(__m,__n);
- _Up __val2 = __abs<_Up>()(__n);
+ _Rp __val1 = __abs<_Rp, _Tp>()(__m) / gcd(__m, __n);
+ _Rp __val2 = __abs<_Rp, _Up>()(__n);
_LIBCPP_ASSERT((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow
in lcm");
return __val1 * __val2;
}
Modified:
libcxx/trunk/test/std/experimental/numeric/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/numeric/numeric.ops/numeric.ops.gcd/gcd.pass.cpp?rev=294779&r1=294778&r2=294779&view=diff
==============================================================================
---
libcxx/trunk/test/std/experimental/numeric/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
(original)
+++
libcxx/trunk/test/std/experimental/numeric/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
Fri Feb 10 14:49:08 2017
@@ -129,4 +129,11 @@ int main()
assert((do_test<long, int>(non_cce)));
assert((do_test<int, long long>(non_cce)));
assert((do_test<long long, int>(non_cce)));
+
+// LWG#2792
+ {
+ auto res = std::gcd((int64_t)1234, (int32_t)-2147483648);
+ static_assert( std::is_same<decltype(res), std::common_type<int64_t,
int32_t>::type>::value, "");
+ assert(res == 2);
+ }
}
Modified:
libcxx/trunk/test/std/experimental/numeric/numeric.ops/numeric.ops.lcm/lcm.pass.cpp
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/numeric/numeric.ops/numeric.ops.lcm/lcm.pass.cpp?rev=294779&r1=294778&r2=294779&view=diff
==============================================================================
---
libcxx/trunk/test/std/experimental/numeric/numeric.ops/numeric.ops.lcm/lcm.pass.cpp
(original)
+++
libcxx/trunk/test/std/experimental/numeric/numeric.ops/numeric.ops.lcm/lcm.pass.cpp
Fri Feb 10 14:49:08 2017
@@ -128,4 +128,12 @@ int main()
assert((do_test<long, int>(non_cce)));
assert((do_test<int, long long>(non_cce)));
assert((do_test<long long, int>(non_cce)));
+
+// LWG#2792
+ {
+ auto res1 = std::lcm((int64_t)1234, (int32_t)-2147483648);
+ (void) std::lcm<int, unsigned long>(INT_MIN, 2); // this used to trigger
UBSAN
+ static_assert( std::is_same<decltype(res1), std::common_type<int64_t,
int32_t>::type>::value, "");
+ assert(res1 == 1324997410816LL);
+ }
}
Modified:
libcxx/trunk/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp?rev=294779&r1=294778&r2=294779&view=diff
==============================================================================
--- libcxx/trunk/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp
(original)
+++ libcxx/trunk/test/std/numerics/numeric.ops/numeric.ops.gcd/gcd.pass.cpp Fri
Feb 10 14:49:08 2017
@@ -8,7 +8,6 @@
//===----------------------------------------------------------------------===//
//
// UNSUPPORTED: c++98, c++03, c++11, c++14
-// XFAIL: ubsan
// <numeric>
Modified:
libcxx/trunk/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.pass.cpp
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.pass.cpp?rev=294779&r1=294778&r2=294779&view=diff
==============================================================================
--- libcxx/trunk/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.pass.cpp
(original)
+++ libcxx/trunk/test/std/numerics/numeric.ops/numeric.ops.lcm/lcm.pass.cpp Fri
Feb 10 14:49:08 2017
@@ -8,7 +8,6 @@
//===----------------------------------------------------------------------===//
//
// UNSUPPORTED: c++98, c++03, c++11, c++14
-// XFAIL: ubsan
// <numeric>
// template<class _M, class _N>
@@ -132,8 +131,9 @@ int main()
// LWG#2837
{
- auto res = std::lcm((int64_t)1234, (int32_t)-2147483648);
- static_assert( std::is_same<decltype(res), std::common_type<int64_t,
int32_t>::type>::value, "");
- assert(res == -1324997410816LL);
+ auto res1 = std::lcm((int64_t)1234, (int32_t)-2147483648);
+ (void) std::lcm<int, unsigned long>(INT_MIN, 2); // this used to trigger
UBSAN
+ static_assert( std::is_same<decltype(res1), std::common_type<int64_t,
int32_t>::type>::value, "");
+ assert(res1 == 1324997410816LL);
}
}
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