On 03/03/20 17:13 -0500, Patrick Palka wrote:
On Tue, 3 Mar 2020, Patrick Palka wrote:
When deciding whether to perform the memset optimization in ranges::fill_n, we
were crucially neglecting to check whether the output pointer's value type is a
byte type. This patch adds such a check to the problematic condition in
ranges::fill_n.
I think the __is_byte<_Tp>::__value check, which checks that the fill type is a
byte type, is too restrictive. It means that we won't enable the memset
optimization in the following example:
char c[100];
ranges::fill(c, 37);
since the fill type is deduced to be int here. It seems we could get away
with instead just checking that _Tp is an integral type; I've added a TODO
about this in the code.
Here's v2 of the patch which actually replaces the aforementioned
conservative condition with integral<_Tp>, following discussion on IRC.
OK for master, thanks.
