[Development] Updating x86 SIMD support in Qt

[Thiago Macieira]

On Tuesday, 18 January 2022 19:01:06 PST Thiago Macieira wrote:
> 4) up the defaults from where they are today
> 
> Today, your default Qt build will always target the x86-64 baseline[*],
> including for i386, despite as I said no CPU failing to meet the next level
> for 9 years. I'd like to request we up that minimum.
> 
> By default, I'd like us to produce x86-64 v2 code, which is SSE4.

I've just realised the above cannot be done for Visual Studio because it can't 
generate code for SSE4. The /arch option[1] only has selections for AVX, AVX2 
and AVX512. This means Visual Studio binaries must remain where they are 
today.

So what shall we do for MinGW? Both compilers (Clang and GCC) *can* generate 
SSE4 code. But is it worth having a different minimum for MinGW compared ti 
MSVC?

[1] https://docs.microsoft.com/en-us/cpp/build/reference/arch-x64

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel DPG Cloud Engineering