On later x86 processors with AVX SIMD support, with gcc or a compiler that has a compatible syntax for inline assembly instructions, run a small program that executes the xgetbv instruction with input OP. This can be used to detect if the OS supports AVX instruction usage.
On output, the values of the eax and edx registers are stored as hexadecimal strings as "eax:edx" in the cache variable ax_cv_gcc_x86_avx_xgetbv.
If the xgetbv instruction fails (because you are running a cross-compiler, or because you are not using gcc, or because you are on a processor that doesn’t have this instruction), ax_cv_gcc_x86_avx_xgetbv_OP is set to the string "unknown".
This macro mainly exists to be used in AX_EXT.
Download the latest version of ax_gcc_x86_avx_xgetbv.m4 or browse the macro’s revision history.
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