meson: drop --enable-avx* options

Just detect compiler support and always enable the optimizations if
it is avilable; warn if the user did request AVX2/AVX512 use via
-Dx86_version= but the intrinsics are not available.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

meson.build

@@ -3097,22 +3097,16 @@ config_host_data.set('CONFIG_ASM_HWPROBE_H',
                      cc.has_header_symbol('asm/hwprobe.h',
                                           'RISCV_HWPROBE_EXT_ZBA'))
 
-config_host_data.set('CONFIG_AVX2_OPT', get_option('avx2') \
-  .require(have_cpuid_h, error_message: 'cpuid.h not available, cannot enable AVX2') \
-  .require(cc.links('''
-    #include <cpuid.h>
+if have_cpuid_h
+  have_avx2 = cc.links('''
     #include <immintrin.h>
     static int __attribute__((target("avx2"))) bar(void *a) {
       __m256i x = *(__m256i *)a;
       return _mm256_testz_si256(x, x);
     }
     int main(int argc, char *argv[]) { return bar(argv[argc - 1]); }
-  '''), error_message: 'AVX2 not available').allowed())
-
-config_host_data.set('CONFIG_AVX512BW_OPT', get_option('avx512bw') \
-  .require(have_cpuid_h, error_message: 'cpuid.h not available, cannot enable AVX512BW') \
-  .require(cc.links('''
-    #include <cpuid.h>
+  ''')
+  have_avx512bw = cc.links('''
     #include <immintrin.h>
     static int __attribute__((target("avx512bw"))) bar(void *a) {
       __m512i *x = a;
@@ -3120,7 +3114,21 @@ config_host_data.set('CONFIG_AVX512BW_OPT', get_option('avx512bw') \
       return res[1];
     }
     int main(int argc, char *argv[]) { return bar(argv[0]); }
-  '''), error_message: 'AVX512BW not available').allowed())
+  ''')
+  if get_option('x86_version') >= '3' and not have_avx2
+    error('Cannot enable AVX optimizations due to missing intrinsics')
+  elif get_option('x86_version') >= '4' and not have_avx512bw
+    error('Cannot enable AVX512 optimizations due to missing intrinsics')
+  endif
+else
+  have_avx2 = false
+  have_avx512bw = false
+  if get_option('x86_version') >= '3'
+    error('Cannot enable AVX optimizations due to missing cpuid.h')
+  endif
+endif
+config_host_data.set('CONFIG_AVX2_OPT', have_avx2)
+config_host_data.set('CONFIG_AVX512BW_OPT', have_avx512bw)
 
 # For both AArch64 and AArch32, detect if builtins are available.
 config_host_data.set('CONFIG_ARM_AES_BUILTIN', cc.compiles('''

meson_options.txt

@@ -123,10 +123,6 @@ option('valgrind', type : 'feature', value: 'auto',
 option('membarrier', type: 'feature', value: 'disabled',
        description: 'membarrier system call (for Linux 4.14+ or Windows')
 
-option('avx2', type: 'feature', value: 'auto',
-       description: 'AVX2 optimizations')
-option('avx512bw', type: 'feature', value: 'auto',
-       description: 'AVX512BW optimizations')
 option('keyring', type: 'feature', value: 'auto',
        description: 'Linux keyring support')
 option('libkeyutils', type: 'feature', value: 'auto',

scripts/meson-buildoptions.sh

@@ -97,8 +97,6 @@ meson_options_help() {
   printf "%s\n" '  alsa            ALSA sound support'
   printf "%s\n" '  attr            attr/xattr support'
   printf "%s\n" '  auth-pam        PAM access control'
-  printf "%s\n" '  avx2            AVX2 optimizations'
-  printf "%s\n" '  avx512bw        AVX512BW optimizations'
   printf "%s\n" '  blkio           libblkio block device driver'
   printf "%s\n" '  bochs           bochs image format support'
   printf "%s\n" '  bpf             eBPF support'
@@ -244,10 +242,6 @@ _meson_option_parse() {
     --audio-drv-list=*) quote_sh "-Daudio_drv_list=$2" ;;
     --enable-auth-pam) printf "%s" -Dauth_pam=enabled ;;
     --disable-auth-pam) printf "%s" -Dauth_pam=disabled ;;
-    --enable-avx2) printf "%s" -Davx2=enabled ;;
-    --disable-avx2) printf "%s" -Davx2=disabled ;;
-    --enable-avx512bw) printf "%s" -Davx512bw=enabled ;;
-    --disable-avx512bw) printf "%s" -Davx512bw=disabled ;;
     --enable-gcov) printf "%s" -Db_coverage=true ;;
     --disable-gcov) printf "%s" -Db_coverage=false ;;
     --enable-lto) printf "%s" -Db_lto=true ;;