[Bug jit/66594] jitted code should use -mtune=native

["dmalcolm at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66594

--- Comment #3 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Some notes:

The following archs seem to implement a "host_detect_local_cpu" C++ callback,
implementing the spec-language function "local_cpu_detect":

grep -nH -e host_detect_local_cpu */*/*.h
config/aarch64/aarch64.h:944:extern const char *host_detect_local_cpu (int
argc, const char **argv);
config/aarch64/aarch64.h:946:  { "local_cpu_detect", host_detect_local_cpu },  
                \
config/alpha/linux.h:95:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/alpha/linux.h:97:  { "local_cpu_detect", host_detect_local_cpu },
config/arm/arm.h:2246:extern const char *host_detect_local_cpu (int argc, const
char **argv);
config/arm/arm.h:2248:  { "local_cpu_detect", host_detect_local_cpu },         
        \
config/i386/i386.h:604:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/i386/i386.h:606:  { "local_cpu_detect", host_detect_local_cpu },
config/mips/gnu-user.h:111:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/mips/gnu-user.h:113:  { "local_cpu_detect", host_detect_local_cpu },
config/rs6000/rs6000.h:204:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/rs6000/rs6000.h:206:  { "local_cpu_detect", host_detect_local_cpu },
config/s390/s390.h:129:extern const char *s390_host_detect_local_cpu (int argc,
const char **argv);
config/s390/s390.h:131:  { "local_cpu_detect", s390_host_detect_local_cpu },
config/sparc/linux64.h:133:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/sparc/linux64.h:135:  { "local_cpu_detect", host_detect_local_cpu },
config/sparc/linux.h:44:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/sparc/linux.h:46:  { "local_cpu_detect", host_detect_local_cpu },
config/sparc/sol2.h:203:extern const char *host_detect_local_cpu (int argc,
const char **argv);
config/sparc/sol2.h:205:  { "local_cpu_detect", host_detect_local_cpu },


aarch64.h has:
# define MCPU_MTUNE_NATIVE_SPECS                                        \
   " %{march=native:%<march=native %:local_cpu_detect(arch)}"           \
   " %{mcpu=native:%<mcpu=native %:local_cpu_detect(cpu)}"              \
   " %{mtune=native:%<mtune=native %:local_cpu_detect(tune)}"


alpha/linux.h has:
# define MCPU_MTUNE_NATIVE_SPECS                                        \
   " %{mcpu=native:%<mcpu=native %:local_cpu_detect(cpu)}"              \
   " %{mtune=native:%<mtune=native %:local_cpu_detect(tune)}"


arm.h has:
# define MCPU_MTUNE_NATIVE_SPECS                                        \
   " %{march=native:%<march=native %:local_cpu_detect(arch)}"           \
   " %{mcpu=native:%<mcpu=native %:local_cpu_detect(cpu)}"              \
   " %{mtune=native:%<mtune=native %:local_cpu_detect(tune)}"


i386.h has:
#ifndef HAVE_LOCAL_CPU_DETECT
#define CC1_CPU_SPEC CC1_CPU_SPEC_1
#else
#define CC1_CPU_SPEC CC1_CPU_SPEC_1 \
"%{march=native:%>march=native %:local_cpu_detect(arch) \
  %{!mtune=*:%>mtune=native %:local_cpu_detect(tune)}} \
%{mtune=native:%>mtune=native %:local_cpu_detect(tune)}"
#endif
#endif


mips/gnu-user.h has:
# define MARCH_MTUNE_NATIVE_SPECS                               \
  " %{march=native:%<march=native %:local_cpu_detect(arch)}"    \
  " %{mtune=native:%<mtune=native %:local_cpu_detect(tune)}"

#define HAVE_LOCAL_CPU_DETECT
#define ASM_CPU_NATIVE_SPEC "%:local_cpu_detect(asm)"

#else
#define ASM_CPU_NATIVE_SPEC "%(asm_default)"
#endif


rs6000.h has:
#ifndef CC1_CPU_SPEC
#ifdef HAVE_LOCAL_CPU_DETECT
#define CC1_CPU_SPEC \
"%{mcpu=native:%<mcpu=native %:local_cpu_detect(cpu)} \
 %{mtune=native:%<mtune=native %:local_cpu_detect(tune)}"
#else
#define CC1_CPU_SPEC ""
#endif
#endif


s390.h has:
# define MARCH_MTUNE_NATIVE_SPECS                               \
  " %{march=native:%<march=native %:local_cpu_detect(arch)}"    \
  " %{mtune=native:%<mtune=native %:local_cpu_detect(tune)}"


sparc/linux64.h, sparc/linux.h and sparc/sol2.h have:
# define MCPU_MTUNE_NATIVE_SPECS                                        \
   " %{mcpu=native:%<mcpu=native %:local_cpu_detect(cpu)}"              \
   " %{mtune=native:%<mtune=native %:local_cpu_detect(tune)}"