Commit 6fd15753 authored by Tom Stellard's avatar Tom Stellard
Browse files

Merging r313776: 

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r313776 | marshall | 2017-09-20 10:34:11 -0700 (Wed, 20 Sep 2017) | 1 line

Fix a bit of UB in __independent_bits_engine. Fixes PR#34663
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llvm-svn: 318236
parent e3d4cdb1

libcxx/include/algorithm

+3 −2
Original line number Diff line number Diff line
@@ -3013,6 +3013,7 @@ template<class _Engine, class _UIntType> 
_UIntType

__independent_bits_engine<_Engine, _UIntType>::__eval(true_type)

{

    const size_t _WRt = numeric_limits<result_type>::digits;

    result_type _Sp = 0;

    for (size_t __k = 0; __k < __n0_; ++__k)

    {
@@ -3021,7 +3022,7 @@ __independent_bits_engine<_Engine, _UIntType>::__eval(true_type) 
        {

            __u = __e_() - _Engine::min();

        } while (__u >= __y0_);

        if (__w0_ < _WDt)

        if (__w0_ < _WRt)

            _Sp <<= __w0_;

        else

            _Sp = 0;
@@ -3034,7 +3035,7 @@ __independent_bits_engine<_Engine, _UIntType>::__eval(true_type) 
        {

            __u = __e_() - _Engine::min();

        } while (__u >= __y1_);

        if (__w0_ < _WDt - 1)

        if (__w0_ < _WRt - 1)

            _Sp <<= __w0_ + 1;

        else

            _Sp = 0;