https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87641
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- Author: redi Date: Thu Oct 18 15:38:50 2018 New Revision: 265270 URL: https://gcc.gnu.org/viewcvs?rev=265270&root=gcc&view=rev Log: PR libstdc++/87641 correctly initialize accumulator in valarray::sum() Use the value of the first element as the initial value of the __valarray_sum accumulator. Value-initialization might not create the additive identity for the value type. Make a similar change to __valarray_product even though it's only ever used internally with a value_type of size_t. PR libstdc++/87641 * include/bits/valarray_array.h (__valarray_sum): Use first element to initialize accumulator instead of value-initializing it. (__valarray_product<_Tp>): Move to ... * src/c++98/valarray.cc (__valarray_product<_Tp>): Here. Use first element to initialize accumulator. (__valarray_product(const valarray<size_t>&)): Remove const_cast made unnecessary by LWG 389. * testsuite/26_numerics/valarray/87641.cc: New test. Added: trunk/libstdc++-v3/testsuite/26_numerics/valarray/87641.cc Modified: trunk/libstdc++-v3/ChangeLog trunk/libstdc++-v3/include/bits/valarray_array.h trunk/libstdc++-v3/src/c++98/valarray.cc