Emit runtime type checks in legalizer.rs (#112)

* Emit runtime type checks in legalizer.rs

lib/cretonne/src/ir/instructions.rs

@@ -506,10 +506,14 @@ type BitSet16 = BitSet<u16>;
 /// A value type set describes the permitted set of types for a type variable.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct ValueTypeSet {
-    lanes: BitSet16,
-    ints: BitSet8,
-    floats: BitSet8,
-    bools: BitSet8,
+    /// Allowed lane sizes
+    pub lanes: BitSet16,
+    /// Allowed int widths
+    pub ints: BitSet8,
+    /// Allowed float widths
+    pub floats: BitSet8,
+    /// Allowed bool widths
+    pub bools: BitSet8,
 }
 
 impl ValueTypeSet {

lib/cretonne/src/legalizer/mod.rs

@@ -18,6 +18,8 @@ use flowgraph::ControlFlowGraph;
 use ir::{Function, Cursor, DataFlowGraph, InstructionData, Opcode, InstBuilder};
 use ir::condcodes::IntCC;
 use isa::{TargetIsa, Legalize};
+use bitset::BitSet;
+use ir::instructions::ValueTypeSet;
 
 mod boundary;
 mod split;