we have noticed that mesa-18.3.x segfault when it is compiled with LLVM/clang-7.0.x and run on older hardware.
After some deep digging we noticed this may be related to missing AVX instructions on these machines, even if we build for generic x86_64, i686 targets.
Fast workaround for eliminating segfaults was to build Mesa with gcc :(
Rebuilding Mesa with LLVM/clang-7.0.1 still segfaults.
Our users have reported this occurs on:
nvidia gfx card
AMD Athlon II X4 620
AMD Phenom II x4 N930
Intel Quad 9650
Intel i3 530
Links to bug reports:
Build logs for mesa compiled with LLVM/clang-7.0.1 can be found here
When building mesa with clang these flags are used
-pthread -mavx2 -mfma -mbmi2 -mf16c -DKNOB_ARCH=KNOB_ARCH_AVX2
[-pthread -mavx -DKNOB_ARCH=KNOB_ARCH_AVX
I'm confused, you're targeting generic x86_64, but compiling with -mavx and -mavx2?
Additionally, there's a bug with SWR (I can't find it right now), due to global constructors that mean that if you build SWR you have to have the special instructions it relies on.