Hi, 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 :( https://github.com/OpenMandrivaAssociation/mesa/commit/4d330587a4d80012c5888e1a33a01a7a979b84e8 Rebuilding Mesa with LLVM/clang-7.0.1 still segfaults. Our users have reported this occurs on: r600 driver nvidia gfx card AMD Athlon II X4 620 AMD Phenom II x4 N930 Intel Quad 9650 Intel i3 530 Links to bug reports: https://issues.openmandriva.org/show_bug.cgi?id=2381 https://issues.openmandriva.org/show_bug.cgi?id=2393
Build logs for mesa compiled with LLVM/clang-7.0.1 can be found here https://abf.openmandriva.org/build_lists/351189
When building mesa with clang these flags are used -pthread -mavx2 -mfma -mbmi2 -mf16c -DKNOB_ARCH=KNOB_ARCH_AVX2 with gcc [-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.
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