On 2016-05-10 9:43 PM, Lawrence Mandel wrote:
> On Tue, May 10, 2016 at 7:05 PM, Ehsan Akhgari <ehsan.akhg...@gmail.com
> <mailto:ehsan.akhg...@gmail.com>> wrote:
> 
>     On 2016-05-10 4:45 PM, Gregory Szorc wrote:
>     > On Thu, May 5, 2016 at 9:26 PM, Gregory Szorc <g...@mozilla.com 
> <mailto:g...@mozilla.com>> wrote:
>     >
>     >> There is a compiler bug in VS2015 that results in SSE instructions 
> being
>     >> emitted when they shouldn't be. Since Firefox still needs to remain
>     >> compatible with ancient hardware that doesn't support SSE, this is 
> causing
>     >> crashes on Firefox built with VS2015 (see bug 1265615).
>     >>
>     >> The good news is glandium found a pretty minimal reproduce case and
>     >> reported the bug to Microsoft.
>     >>
>     >> The bad news is the issue still reproduces in the latest pre-release
>     >> version of the Visual C++ toolchain.
>     >>
>     >> The worse news is we'll have to revert to building Firefox 48 (current
>     >> Aurora) and 49 (current central) with VS2013. Bugs 1270664 and 1270714
>     >> track. Aurora will likely land soon. Central might take a few days, as 
> I
>     >> believe VS2013 is a bit broken on central at the moment.
>     >>
>     >
>     > We have a change in plans.
>     >
>     > bsmedberg says we can require SSE. So that means the VS2015 bug emitting
>     > SSE instructions isn't an issue.
> 
>     Firstly, great to hear this!
> 
>     But since the topic of when to drop support for legacy platforms seems
>     to be coming up a few times per week these days, it would be helpful to
>     document somewhere how the decision to drop support for processors not
>     supporting SSE was reached.  Do we have data covering what number of
>     users will be affected by this change?  Do we have guidelines on what's
>     the threshold for supporting other similar legacy configs?
> 
>     It would be helpful to see some information about this shared here.
> 
> I don't know how this specific decision was reached but I did speak with
> Chris Cooper and Peter Dolanjski about developing criteria/guidelines
> for support today. I don't expect us to have something this month but we
> will flesh this out as part of the ongoing conversation about platform
> support.

Thank you, that would be super helpful!
_______________________________________________
dev-platform mailing list
dev-platform@lists.mozilla.org
https://lists.mozilla.org/listinfo/dev-platform

Reply via email to