r265270 - in /trunk/libstdc++-v3: ChangeLog inc...

[redi@gcc.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