Summary:
When a seed sequence would lead to having no non-zero significant bits
in the initial state of a `mersenne_twister_engine`, the fallback is to
flip the most significant bit of the first value that appears in the
textual representation of the initial state.
rand.eng.mers describes this as setting the value to be 2 to the power
of one less than w; the previous value encoded in the implementation,
namely one less than "2 to the power of w", is replaced by the correct
value in this patch.
Reviewers: mclow.lists, EricWF, jasonliu
Reviewed By: mclow.lists
Subscribers: mclow.lists, jasonliu, EricWF, christof, ldionne, cfe-commits
Differential Revision: https://reviews.llvm.org/D50736
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339969 91177308-0d34-0410-b5e6-96231b3b80d8
test/std/input.output/iostream.format/input.streams/istream.unformatted/get.pass.cpp
Add static_cast<char> because basic_istream::get() returns int_type (N4606 27.7.2.3 [istream.unformatted]/4).
test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.inserters.arithmetic/minus1.pass.cpp
Add static_cast<char> because toupper() returns int (C11 7.4.2.2/1).
test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/assign_t.pass.cpp
This test is intentionally writing doubles to ostream_iterator<int>.
It's silencing -Wliteral-conversion for Clang, so I'm adding C4244 silencing for MSVC.
test/std/language.support/support.limits/limits/numeric.limits.members/infinity.pass.cpp
Given `extern float zero;`, the expression `1./zero` has type double, which emits a truncation warning
when being passed to test<float>() taking float. The fix is to say `1.f/zero` which has type float.
test/std/numerics/complex.number/cmplx.over/arg.pass.cpp
test/std/numerics/complex.number/cmplx.over/norm.pass.cpp
These tests were constructing std::complex<double>(x, 0), emitting truncation warnings when x is long long.
Saying static_cast<double>(x) avoids this.
test/std/numerics/rand/rand.eng/rand.eng.lcong/seed_result_type.pass.cpp
This was using `int s` to construct and seed a linear_congruential_engine<T, stuff>, where T is
unsigned short/unsigned int/unsigned long/unsigned long long. That emits a truncation warning in the
unsigned short case. Because the range [0, 20) is tiny and we aren't doing anything else with the index,
we can just iterate with `T s`.
test/std/re/re.traits/value.pass.cpp
regex_traits<wchar_t>::value()'s first parameter is wchar_t (N4606 28.7 [re.traits]/13). This loop is
using int to iterate through ['g', 0xFFFF), emitting a truncation warning from int to wchar_t
(which is 16-bit for some of us). Because the bound is exclusive, we can just iterate with wchar_t.
test/std/strings/basic.string/string.cons/size_char_alloc.pass.cpp
This test is a little strange. It's trying to verify that basic_string's (InIt, InIt) range constructor
isn't confused by "N copies of C" when N and C have the same integral type. To do this, it was
testing (100, 65), but that eventually emits truncation warnings from int to char. There's a simple way
to avoid this - passing (static_cast<char>(100), static_cast<char>(65)) also exercises the disambiguation.
(And 100 is representable even when char has a signed range.)
test/std/strings/string.view/string.view.hash/string_view.pass.cpp
Add static_cast<char_type> because `'0' + i` has type int.
test/std/utilities/function.objects/bind/func.bind/func.bind.bind/nested.pass.cpp
What's more horrible than nested bind()? pow() overloads! This operator()(T a, T b) was assuming that
std::pow(a, b) can be returned as T. (In this case, T is int.) However, N4606 26.9.1 [cmath.syn]/2
says that pow(int, int) returns double, so this was truncating double to int.
Adding static_cast<T> silences this.
test/std/utilities/function.objects/unord.hash/integral.pass.cpp
This was iterating `for (int i = 0; i <= 5; ++i)` and constructing `T t(i);` but that's truncating
when T is short. (And super truncating when T is bool.) Adding static_cast<T> silences this.
test/std/utilities/utility/exchange/exchange.pass.cpp
First, this was exchanging 67.2 into an int, but that's inherently truncating.
Changing this to static_cast<short>(67) avoids the truncation while preserving the
"what if T and U are different" test coverage.
Second, this was exchanging {} with the explicit type float into an int, and that's also
inherently truncating. Specifying short is just as good.
test/std/utilities/utility/pairs/pairs.spec/make_pair.pass.cpp
Add static_cast<short>. Note that this affects template argument deduction for make_pair(),
better fulfilling the test's intent. For example, this was saying
`typedef std::pair<int, short> P1; P1 p1 = std::make_pair(3, 4);` but that was asking
make_pair() to return pair<int, int>, which was then being converted to pair<int, short>.
(pair's converting constructors are tested elsewhere.)
Now, std::make_pair(3, static_cast<short>(4)) actually returns pair<int, short>.
(There's still a conversion from pair<nullptr_t, short> to pair<unique_ptr<int>, short>.)
Fixes D27544.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@289111 91177308-0d34-0410-b5e6-96231b3b80d8
When initializing unsigned integers to their maximum values, change "const T M(~0);" to "const T M(static_cast<T>(-1));".
~0 and -1 are equivalent, but I consider the -1 form to be significantly clearer (and more consistent with other tests).
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@287827 91177308-0d34-0410-b5e6-96231b3b80d8
In C++11 mode and newer, use real static_asserts.
In C++03 mode, min() and max() aren't constexpr, so use plain asserts.
One test triggers MSVC's warning C4310 "cast truncates constant value".
The code is valid, and yet the warning is valid, so I'm silencing it
through push-disable-pop.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@287391 91177308-0d34-0410-b5e6-96231b3b80d8
