meson: move int128 checks from configure

(note: the test isn't working as intended, the next patches fixes it)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

configure

@@ -2481,41 +2481,6 @@ if compile_prog "" "" ; then
     int128=yes
 fi
 
-#########################################
-# See if 128-bit atomic operations are supported.
-
-atomic128=no
-if test "$int128" = "yes"; then
-  cat > $TMPC << EOF
-int main(void)
-{
-  unsigned __int128 x = 0, y = 0;
-  y = __atomic_load(&x, 0);
-  __atomic_store(&x, y, 0);
-  __atomic_compare_exchange(&x, &y, x, 0, 0, 0);
-  return 0;
-}
-EOF
-  if compile_prog "" "" ; then
-    atomic128=yes
-  fi
-fi
-
-cmpxchg128=no
-if test "$int128" = yes && test "$atomic128" = no; then
-  cat > $TMPC << EOF
-int main(void)
-{
-  unsigned __int128 x = 0, y = 0;
-  __sync_val_compare_and_swap_16(&x, y, x);
-  return 0;
-}
-EOF
-  if compile_prog "" "" ; then
-    cmpxchg128=yes
-  fi
-fi
-
 ########################################
 # check if ccache is interfering with
 # semantic analysis of macros
@@ -2959,18 +2924,6 @@ if test "$have_tsan" = "yes" && test "$have_tsan_iface_fiber" = "yes" ; then
     echo "CONFIG_TSAN=y" >> $config_host_mak
 fi
 
-if test "$int128" = "yes" ; then
-  echo "CONFIG_INT128=y" >> $config_host_mak
-fi
-
-if test "$atomic128" = "yes" ; then
-  echo "CONFIG_ATOMIC128=y" >> $config_host_mak
-fi
-
-if test "$cmpxchg128" = "yes" ; then
-  echo "CONFIG_CMPXCHG128=y" >> $config_host_mak
-fi
-
 if test "$rdma" = "yes" ; then
   echo "CONFIG_RDMA=y" >> $config_host_mak
   echo "RDMA_LIBS=$rdma_libs" >> $config_host_mak

meson.build

@@ -1869,6 +1869,45 @@ config_host_data.set('CONFIG_ATOMIC64', cc.links('''
     return 0;
   }'''))
 
+has_int128 = cc.links('''
+  __int128_t a;
+  __uint128_t b;
+  int main (void) {
+    a = a + b;
+    b = a * b;
+    a = a * a;
+    return 0;
+  }''')
+
+config_host_data.set('CONFIG_INT128', has_int128)
+
+if has_int128
+  has_atomic128 = cc.links('''
+    int main(void)
+    {
+      unsigned __int128 x = 0, y = 0;
+      y = __atomic_load(&x, 0);
+      __atomic_store(&x, y, 0);
+      __atomic_compare_exchange(&x, &y, x, 0, 0, 0);
+      return 0;
+    }''')
+
+  config_host_data.set('CONFIG_ATOMIC128', has_atomic128)
+
+  if not has_atomic128
+    has_cmpxchg128 = cc.links('''
+      int main(void)
+      {
+        unsigned __int128 x = 0, y = 0;
+        __sync_val_compare_and_swap_16(&x, y, x);
+        return 0;
+      }
+    ''')
+
+    config_host_data.set('CONFIG_CMPXCHG128', has_cmpxchg128)
+  endif
+endif
+
 config_host_data.set('CONFIG_GETAUXVAL', cc.links(gnu_source_prefix + '''
   #include <sys/auxv.h>
   int main(void) {