Re: [GIT PULL] x86/vdso changes for v3.16

[H. Peter Anvin]

This is a multi-part message in MIME format.On 06/06/2014 02:39 PM, Andy Lutomirski wrote:
>>
>> For accessing memory members doing it via a pointer is pretty much TRT,
>> but for things that might be in register it is undesirable to force it
>> out to memory.
> 
> Do you also believe in the folklore that GCC can optimize code
> sequences like the things in that header?  Because I'm pretty sure
> that no clang or gcc version I've ever seen can do it.
> 

I have seen gcc do some pretty sophisticated memory elision lately.
Don't know if that includes byte swaps.

> On the other hand, even a factor of ten in the time it takes to run
> vdso2c is completely irrelevant.

Yep, as I noted in the patch I sent (which is broken - updated one
included here.)

	-hpa