Add support for setting presets.

Fixes #11.

Presets are groups of settings and values applied at once. This is used
as a shorthand in test files, so for example "isa intel nehalem" enables
all of the CPUID bits that the Nehalem micro-architecture provides.

lib/cretonne/src/isa/intel/settings.rs

@@ -7,3 +7,27 @@ use std::fmt;
 // `Flags` struct with an impl for all of the settings defined in
 // `lib/cretonne/meta/cretonne/settings.py`.
 include!(concat!(env!("OUT_DIR"), "/settings-intel.rs"));
+
+#[cfg(test)]
+mod tests {
+    use super::{builder, Flags};
+    use settings::{self, Configurable};
+
+    #[test]
+    fn presets() {
+        let shared = settings::Flags::new(&settings::builder());
+
+        // Nehalem has SSE4.1 but not BMI1.
+        let mut b1 = builder();
+        b1.enable("nehalem").unwrap();
+        let f1 = Flags::new(&shared, &b1);
+        assert_eq!(f1.has_sse41(), true);
+        assert_eq!(f1.has_bmi1(), false);
+
+        let mut b2 = builder();
+        b2.enable("haswell").unwrap();
+        let f2 = Flags::new(&shared, &b2);
+        assert_eq!(f2.has_sse41(), true);
+        assert_eq!(f2.has_bmi1(), true);
+    }
+}