On 5/7/24 07:18, William F Pokorny wrote:
> So, the dynamic optimization situation on my i3 is today confusing / 
> worrying? The clang++ compile has the dynamic optimization:
> 
>   Dynamic optimizations:
>    CPU detected: Intel,SSE2,AVX,AVX2,FMA3
>    Noise generator: avx2fma3-intel (hand-optimized by Intel)
> 
> While the g++ compile has the dynamic optimization:
> 
>   Dynamic optimizations:
>    CPU detected: Intel,FMA3,FMA4
>    Noise generator: generic (portable)
> 
> The latter is safe, but likely not optimal. The clang++ compile is 
> finding the correct features for my i3.

For the record.

Yesterday, I found LLVM Project code with comments and code for handling 
gcc not accounting for 'cpuid' clobbering of one of the registers. 
Though they don't protect the register in the same way, it explains 
'some 'of the assembly code in our code base protecting the same 
register. Still unsure if this issue really why my g++ compiles don't 
use the same optimization as clang++'s.

Looking at what we have, I see all this code is now a bit dated and the 
set up is limited in comparison. I'm unsure I want to invest my time in 
it - thinking now about removing it all from yuqk as another general 
simplification.

Bill P.

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