On 23/02/19 01:26 +0000, Jonathan Wakely wrote:
>On 23/02/19 02:06 +0100, Jakub Jelinek wrote:
>>On Sat, Feb 23, 2019 at 01:02:20AM +0000, Jonathan Wakely wrote:
>>>	PR libstdc++/89446
>>>	* include/bits/char_traits.h (__constant_char_array): Check index is
>>>	in range before dereferencing.
>>>	* testsuite/21_strings/basic_string_view/operators/char/89446.cc:
>>>	New test.
>>>
>>>Tested x86_64-linux, committed to gcc-8-branch and gcc-7-branch.
>>
>>And not trunk?  The bug is still there, even when it should be usually
>>ifdefed out because __builtin_is_constexpr_evaluated() should be supported.
>
>Yes, that's a bigger patch (with some cleanup) which is coming
>shortly.

Here's the patch for trunk. When the size is zero we can just return,
we don't need to do the __builtin_constant_p checks.

Tested powerpc64le-linux, committed to trunk.