[Bug target/117952] host_detect_local_cpu returns NULL when built with Clang

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117952

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
+/* If we are compiling with GCC where %EBX register is fixed, then the
+   driver will just ignore -march and -mtune "native" target and will leave
+   to the newly built compiler to generate code for its default target.  */


It comes from that cpuid instruction will clobber the ebx register but ebx is
also used for the PIC register.