check_c_source_compiles("
  #include <stdio.h>
  int main(void) {
    double a = 0.0;
    if (__builtin_expect(a < 0, 0)) {
      a = 0.0;
    }
    a = a + 1.0;
    printf(\"a=%g\", a);
    return 0;
  }
" SUNDIALS_C_COMPILER_HAS_BUILTIN_EXPECT)