- On x86, LLVM has robust detection for the CPU name. If a CPU like skylake has AVX disabled, it will fall back to something without AVX (nehalem)
- On ARM, detection is not as robust. For instance, on my snapdragon 8 gen 2, it assumes that we have SVE support, as the cortex-x3 supports SVE.
- If an ARM cpu is paired with other cpus from another generation which doesn't support the same instructions as the cortex-x3, or if the cortex-x3 just has SVE disabled for no apparant reason (in the case of the snapdragon 8 gen 2)
- We need to actually detect that ourselves.
- Beyond SVE also detect support for some instructions that might be useful SPU LLVM when optimized with intrinsics.
Malcolm
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