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d45d243749
Otherwise it would pick various -march flags based on the CPU of the compiling system, using beautiful code like this: ```` 63 AC_CACHE_CHECK(for x86 cpuid $1 output, ax_cv_gcc_x86_cpuid_$1, 64 [AC_RUN_IFELSE([AC_LANG_PROGRAM([#include <stdio.h>], [ 65 int op = $1, eax, ebx, ecx, edx; 66 FILE *f; 67 __asm__("cpuid" 68 : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) 69 : "a" (op)); 70 f = fopen("conftest_cpuid", "w"); if (!f) return 1; 71 fprintf(f, "%x:%x:%x:%x\n", eax, ebx, ecx, edx); 72 fclose(f); 73 return 0; 74 ])], ... 121 AC_CACHE_CHECK([whether avx is supported], [ax_cv_have_avx_ext], 122 [ 123 ax_cv_have_avx_ext=no 124 if test "$((0x$ecx>>28&0x01))" = 1; then 125 ax_cv_have_avx_ext=yes 126 fi 127 ]) ```` |
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