Generate type check predicates for secondary type variables.

The encoding tables are keyed by the controlling type variable only. We
need to distinguish different encodings for instructions with multiple
type variables.

Add a TypePredicate instruction predicate which can check the type of an
instruction value operand. Combine type checks into the instruction
predicate for instructions with more than one type variable.

Add Intel encodings for fcvt_from_sint.f32.i64 which can now be
distinguished from fcvt_from_sint.f32.i32.

lib/cretonne/meta/cdsl/isa.py

@@ -1,7 +1,7 @@
 """Defining instruction set architectures."""
 from __future__ import absolute_import
 from collections import OrderedDict
-from .predicates import And
+from .predicates import And, TypePredicate
 from .registers import RegClass, Register, Stack
 from .ast import Apply
 from .types import ValueType
@@ -405,6 +405,13 @@ class Encoding(object):
 
         self.recipe = recipe
         self.encbits = encbits
+
+        # Add secondary type variables to the instruction predicate.
+        if len(self.typevars) > 1:
+            for tv, vt in zip(self.inst.other_typevars, self.typevars[1:]):
+                typred = TypePredicate.typevar_check(self.inst, tv, vt)
+                instp = And.combine(instp, typred)
+
         # Record specific predicates. Note that the recipe also has predicates.
         self.instp = instp
         self.isap = isap