Assign a type variable to all VALUE operands.

A few operands have a fixed type assigned. Create a singleton type
variable for these exceptions. Most instructions are polymorphic, so
this is a little overhead.

Eliminate the Operand.typ field and replace it with an Operand.typevar
field which is always a TypeVar, but which only exists in VALUE
operands.

lib/cretonne/meta/cdsl/instructions.py

@@ -130,10 +130,10 @@ class Instruction(object):
         """
         poly_ins = [
                 i for i in self.format.value_operands
-                if self.ins[i].typ.free_typevar()]
+                if self.ins[i].typevar.free_typevar()]
         poly_outs = [
                 i for i, o in enumerate(self.outs)
-                if o.typ.free_typevar()]
+                if o.is_value() and o.typevar.free_typevar()]
         self.is_polymorphic = len(poly_ins) > 0 or len(poly_outs) > 0
         if not self.is_polymorphic:
             return
@@ -143,7 +143,7 @@ class Instruction(object):
         typevar_error = None
         if self.format.typevar_operand is not None:
             try:
-                tv = self.ins[self.format.typevar_operand].typ
+                tv = self.ins[self.format.typevar_operand].typevar
                 if tv is tv.free_typevar():
                     self.other_typevars = self._verify_ctrl_typevar(tv)
                     self.ctrl_typevar = tv
@@ -160,7 +160,7 @@ class Instruction(object):
                 else:
                     raise RuntimeError(
                             "typevar_operand must be a free type variable")
-            tv = self.outs[0].typ
+            tv = self.outs[0].typevar
             if tv is not tv.free_typevar():
                 raise RuntimeError("first result must be a free type variable")
             self.other_typevars = self._verify_ctrl_typevar(tv)
@@ -181,7 +181,7 @@ class Instruction(object):
         other_tvs = []
         # Check value inputs.
         for opidx in self.format.value_operands:
-            typ = self.ins[opidx].typ
+            typ = self.ins[opidx].typevar
             tv = typ.free_typevar()
             # Non-polymorphic or derived form ctrl_typevar is OK.
             if tv is None or tv is ctrl_typevar:
@@ -200,7 +200,9 @@ class Instruction(object):
 
         # Check outputs.
         for result in self.outs:
-            typ = result.typ
+            if not result.is_value():
+                continue
+            typ = result.typevar
             tv = typ.free_typevar()
             # Non-polymorphic or derived from ctrl_typevar is OK.
             if tv is None or tv is ctrl_typevar:

lib/cretonne/meta/cdsl/operands.py

@@ -40,10 +40,6 @@ class OperandKind(object):
         # type: () -> str
         return 'OperandKind({})'.format(self.name)
 
-    def free_typevar(self):
-        # Return the free typevariable controlling the type of this operand.
-        return None
-
 #: An SSA value operand. This is a value defined by another instruction.
 VALUE = OperandKind(
         'value', """
@@ -129,11 +125,15 @@ class Operand(object):
         # type: (str, OperandSpec, str) -> None
         self.name = name
         self.__doc__ = doc
-        self.typ = typ
+
+        # Decode the operand spec and set self.kind.
+        # Only VALUE operands have a typevar member.
         if isinstance(typ, ValueType):
             self.kind = VALUE
+            self.typevar = TypeVar.singleton(typ)
         elif isinstance(typ, TypeVar):
             self.kind = VALUE
+            self.typevar = typ
         else:
             assert isinstance(typ, OperandKind)
             self.kind = typ
@@ -142,8 +142,9 @@ class Operand(object):
         # type: () -> str
         if self.__doc__:
             return self.__doc__
-        else:
-            return self.typ.__doc__
+        if self.kind is VALUE:
+            return self.typevar.__doc__
+        return self.kind.__doc__
 
     def __str__(self):
         # type: () -> str

lib/cretonne/meta/cdsl/test_typevar.py

@@ -3,6 +3,7 @@ from unittest import TestCase
 from doctest import DocTestSuite
 from . import typevar
 from .typevar import TypeSet, TypeVar
+from base.types import i32
 
 
 def load_tests(loader, tests, ignore):
@@ -62,3 +63,18 @@ class TestTypeVar(TestCase):
         self.assertEqual(str(x3.double_width()), '`DoubleWidth(x3)`')
         with self.assertRaises(AssertionError):
             x3.half_width()
+
+    def test_singleton(self):
+        x = TypeVar.singleton(i32)
+        self.assertEqual(str(x), '`i32`')
+        self.assertEqual(x.type_set.min_int, 32)
+        self.assertEqual(x.type_set.max_int, 32)
+        self.assertEqual(x.type_set.min_lanes, 1)
+        self.assertEqual(x.type_set.max_lanes, 1)
+
+        x = TypeVar.singleton(i32.by(4))
+        self.assertEqual(str(x), '`i32x4`')
+        self.assertEqual(x.type_set.min_int, 32)
+        self.assertEqual(x.type_set.max_int, 32)
+        self.assertEqual(x.type_set.min_lanes, 4)
+        self.assertEqual(x.type_set.max_lanes, 4)

lib/cretonne/meta/cdsl/types.py

@@ -30,8 +30,9 @@ class ValueType(object):
         # type: () -> str
         return self.name
 
-    def free_typevar(self):
-        return None
+    def rust_name(self):
+        # type: () -> str
+        return 'types::' + self.name.upper()
 
     @staticmethod
     def by_name(name):
@@ -63,10 +64,6 @@ class ScalarType(ValueType):
         # type: () -> str
         return 'ScalarType({})'.format(self.name)
 
-    def rust_name(self):
-        # type: () -> str
-        return 'types::' + self.name.upper()
-
     def by(self, lanes):
         # type: (int) -> VectorType
         """

lib/cretonne/meta/cdsl/typevar.py

@@ -6,6 +6,7 @@ polymorphic by using type variables.
 """
 from __future__ import absolute_import
 import math
+from . import types
 
 try:
     from typing import Tuple, Union # noqa
@@ -242,6 +243,7 @@ class TypeVar(object):
         # type: (str, str, BoolInterval, BoolInterval, BoolInterval, bool, BoolInterval, TypeVar, str) -> None # noqa
         self.name = name
         self.__doc__ = doc
+        self.singleton_type = None  # type: types.ValueType
         self.is_derived = isinstance(base, TypeVar)
         if base:
             assert self.is_derived
@@ -258,6 +260,34 @@ class TypeVar(object):
                     floats=floats,
                     bools=bools)
 
+    @staticmethod
+    def singleton(typ):
+        # type: (types.ValueType) -> TypeVar
+        """Create a type variable that can only assume a single type."""
+        if isinstance(typ, types.VectorType):
+            scalar = typ.base
+            lanes = (typ.lanes, typ.lanes)
+        elif isinstance(typ, types.ScalarType):
+            scalar = typ
+            lanes = (1, 1)
+
+        ints = None
+        floats = None
+        bools = None
+
+        if isinstance(scalar, types.IntType):
+            ints = (scalar.bits, scalar.bits)
+        elif isinstance(scalar, types.FloatType):
+            floats = (scalar.bits, scalar.bits)
+        elif isinstance(scalar, types.BoolType):
+            bools = (scalar.bits, scalar.bits)
+
+        tv = TypeVar(
+                typ.name, 'typeof({})'.format(typ),
+                ints, floats, bools, simd=lanes)
+        tv.singleton_type = typ
+        return tv
+
     def __str__(self):
         # type: () -> str
         return "`{}`".format(self.name)
@@ -317,5 +347,8 @@ class TypeVar(object):
         # type: () -> TypeVar
         if self.is_derived:
             return self.base
+        elif self.singleton_type:
+            # A singleton type variable is not a proper free variable.
+            return None
         else:
             return self

lib/cretonne/meta/gen_instr.py

@@ -5,10 +5,14 @@ from __future__ import absolute_import
 import srcgen
 import constant_hash
 from unique_table import UniqueTable, UniqueSeqTable
+from cdsl.operands import ImmediateKind
 import cdsl.types
-import cdsl.operands
 from cdsl.formats import InstructionFormat
 
+from cdsl.instructions import Instruction  # noqa
+from cdsl.operands import Operand  # noqa
+from cdsl.typevar import TypeVar  # noqa
+
 
 def gen_formats(fmt):
     # type: (srcgen.Formatter) -> None
@@ -302,6 +306,7 @@ def gen_opcodes(groups, fmt):
 
 
 def get_constraint(op, ctrl_typevar, type_sets):
+    # type: (Operand, TypeVar, UniqueTable) -> str
     """
     Get the value type constraint for an SSA value operand, where
     `ctrl_typevar` is the controlling type variable.
@@ -312,22 +317,22 @@ def get_constraint(op, ctrl_typevar, type_sets):
     - `Free(idx)` where `idx` is an index into `type_sets`.
     - `Same`, `Lane`, `AsBool` for controlling typevar-derived constraints.
     """
-    assert op.kind is cdsl.operands.VALUE
-    t = op.typ
+    assert op.is_value()
+    tv = op.typevar
 
     # A concrete value type.
-    if isinstance(t, cdsl.types.ValueType):
-        return 'Concrete({})'.format(t.rust_name())
+    if tv.singleton_type:
+        return 'Concrete({})'.format(tv.singleton_type.rust_name())
 
-    if t.free_typevar() is not ctrl_typevar:
-        assert not t.is_derived
-        return 'Free({})'.format(type_sets.add(t.type_set))
+    if tv.free_typevar() is not ctrl_typevar:
+        assert not tv.is_derived
+        return 'Free({})'.format(type_sets.add(tv.type_set))
 
-    if t.is_derived:
-        assert t.base is ctrl_typevar, "Not derived directly from ctrl_typevar"
-        return t.derived_func
+    if tv.is_derived:
+        assert tv.base is ctrl_typevar, "Not derived from ctrl_typevar"
+        return tv.derived_func
 
-    assert t is ctrl_typevar
+    assert tv is ctrl_typevar
     return 'Same'
 
 
@@ -486,6 +491,7 @@ def gen_member_inits(iform, fmt):
 
 
 def gen_inst_builder(inst, fmt):
+    # type: (Instruction, srcgen.Formatter) -> None
     """
     Emit a method for generating the instruction `inst`.
 
@@ -502,10 +508,10 @@ def gen_inst_builder(inst, fmt):
     if inst.is_polymorphic and not inst.use_typevar_operand:
         args.append('{}: Type'.format(inst.ctrl_typevar.name))
 
-    tmpl_types = list()
-    into_args = list()
+    tmpl_types = list()  # type: List[str]
+    into_args = list()  # type: List[str]
     for op in inst.ins:
-        if isinstance(op.kind, cdsl.operands.ImmediateKind):
+        if isinstance(op.kind, ImmediateKind):
             t = 'T{}{}'.format(1 + len(tmpl_types), op.kind.name)
             tmpl_types.append('{}: Into<{}>'.format(t, op.kind.rust_type))
             into_args.append(op.name)
@@ -553,7 +559,7 @@ def gen_inst_builder(inst, fmt):
                 # The format constructor will resolve the result types from the
                 # type var.
                 args.append('ctrl_typevar')
-            elif inst.outs[inst.value_results[0]].typ == inst.ctrl_typevar:
+            elif inst.outs[inst.value_results[0]].typevar == inst.ctrl_typevar:
                 # The format constructor expects a simple result type.
                 # No type transformation needed from the controlling type
                 # variable.
@@ -567,13 +573,12 @@ def gen_inst_builder(inst, fmt):
         else:
             # This non-polymorphic instruction has a fixed result type.
             args.append(
-                    'types::' +
-                    inst.outs[inst.value_results[0]].typ.name.upper())
+                    inst.outs[inst.value_results[0]]
+                    .typevar.singleton_type.rust_name())
 
         args.extend(op.name for op in inst.ins)
-        args = ', '.join(args)
         # Call to the format constructor,
-        fcall = 'self.{}({})'.format(inst.format.name, args)
+        fcall = 'self.{}({})'.format(inst.format.name, ', '.join(args))
 
         if len(inst.value_results) == 0:
             fmt.line(fcall + '.0')