Re: [PATCH] libstdc++-v3: Have aligned_alloc() on Newlib

On 13/08/18 12:55 +0100, Szabolcs Nagy wrote:
>On 09/08/18 10:08, Jonathan Wakely wrote:
>>On 09/08/18 06:56 +0200, Sebastian Huber wrote:
>>>On 08/08/18 16:33, Jonathan Wakely wrote:
>>>>On 08/08/18 16:22 +0200, Ulrich Weigand wrote:
>>>>>Jonathan Wakely wrote:
>>>>>
>>>>>>Aha, so newlib was using memalign previously:
>>>>>>
>>>>>>@@ -53,20 +54,24 @@ aligned_alloc (std::size_t al, std::size_t sz)
>>>>>> #else
>>>>>> extern "C" void *memalign(std::size_t boundary, std::size_t size);
>>>>>> #endif
>>>>>>-#define aligned_alloc memalign
>>>>>
>>>>>Yes, exactly ... this commit introduced the regression.
>>>>>
>>>>>>OK, I've regressed the branches then - I'll fix that.
>>>>
>>>>This should fix it. I'll finish testing and commit it.
>>>>
>>>>Sebastian, your patch to define HAVE_ALIGNED_ALLOC is OK for
>>>>gcc-7-branch and gcc-8-branch, because changing newlib from using
>>>>memalign to aligned_alloc is safe.
>>>
>>>Should I check in my patch in addition to your patch?
>>
>>Yes please, on trunk and 7 and 8. It's better to use the standard
>>aligned_alloc if available.
>>
>
>but the newlib aligned_alloc is broken on baremetal targets,
>it is implemented using posix_memalign which is not provided
>by the newlib malloc implementation (except on cygwin)

Ouch, OK, let's revert it. Using memalign is fine.

The original problem that I think Sebastian was trying to solve should
be fixed by r263409 anyway (and was backported to all branches).