[Interest] Qt and SSE2

[Thiago Macieira]

On Friday, 9 February 2018 08:36:59 PST Thiago Macieira wrote:
> > Qt is built with SSE2 by default since 5.3.0. Is there a reason for not
> > enabling by default SSE2 for application compilation ? If not I'll start
> > working on a change doing that.
> 
> Because we didn't want to force that on users. It's also easy to keep two
> libraries on Linux, one for SSE2 and one for earlier versions. That can't be
> done for binaries.
> 
> Enabling SSE2 alone won't gain you much. You must also either switch to SSE
> math (-mfp-math=sse)

One more thing: SSE2 is enabled by default on 64-bit, since it's part of the 
ABI, on all platforms. It's also enabled by default on 32-bit Mac (SSSE3 
actually is), since the first x86 Macs had that.

So that only leaves 32-bit builds for Windows and Linux, which are quickly 
disappearing. We haven't provided 32-bit binaries for Linux for a couple of 
releases already; the Windows ones are also disappearing.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center