[Libre-soc-bugs] [Bug 251] Initial 3D MESA non-accelerated software-only driver is needed

[bugzilla-daemon at libre-soc.org]

https://bugs.libre-soc.org/show_bug.cgi?id=251

--- Comment #24 from Luke Kenneth Casson Leighton <lkcl at lkcl.net> ---
https://github.com/mesa3d/mesa/blob/master/src/amd/llvm/ac_llvm_build.c#L4083

that's a big file.  went through it briefly. i "get" the conversion of e.g. nir
add to llvm add (etc).

more here:

https://github.com/mesa3d/mesa/blob/master/src/amd/llvm/ac_nir_to_llvm.c#L859

again more conversion.  interesting that for recip sqrt a special
llvm.amdgcn.rsqr is needed.

we will add rsqrt as an actual opcode to the instruction set however obviously
not for x86/POWER9 scalar. this tends to suggest that llvm is the best place
for "llvm.rsqrt" and for x86 (etc) it would be llvm that had a pass converting
that to 1/sqrt(x)

-- 
You are receiving this mail because:
You are on the CC list for the bug.