Cleanup ValueType.get_names to with_bits form previous PR; Add computation of inverse image of typeset across a derived function - TypeSet.map_inverse; Change TypeVar.constrain_type to perform a more-general computation using inverse images of TypeSets; Tests for map_inverse;

lib/cretonne/meta/cdsl/test_typevar.py

@@ -4,6 +4,8 @@ from doctest import DocTestSuite
 from . import typevar
 from .typevar import TypeSet, TypeVar
 from base.types import i32, i16, b1, f64
+from itertools import product
+from functools import reduce
 
 
 def load_tests(loader, tests, ignore):
@@ -123,6 +125,58 @@ class TestTypeSet(TestCase):
         self.assertEqual(TypeSet(lanes=(4, 4), ints=(32, 32)).get_singleton(),
                          i32.by(4))
 
+    def test_map_inverse(self):
+        t = TypeSet(lanes=(1, 1), ints=(8, 8), floats=(32, 32))
+        self.assertEqual(t, t.map_inverse(TypeVar.SAMEAS))
+
+        # LANEOF
+        self.assertEqual(TypeSet(lanes=True, ints=(8, 8), floats=(32, 32)),
+                         t.map_inverse(TypeVar.LANEOF))
+        # Inverse of empty set is still empty across LANEOF
+        self.assertEqual(TypeSet(),
+                         TypeSet().map_inverse(TypeVar.LANEOF))
+
+        # ASBOOL
+        t = TypeSet(lanes=(1, 4), bools=(1, 64))
+        self.assertEqual(t.map_inverse(TypeVar.ASBOOL),
+                         TypeSet(lanes=(1, 4), ints=True, bools=True,
+                                 floats=True))
+
+        # Inverse image across ASBOOL of TS not involving b1 cannot have
+        # lanes=1
+        t = TypeSet(lanes=(1, 4), bools=(16, 32))
+        self.assertEqual(t.map_inverse(TypeVar.ASBOOL),
+                         TypeSet(lanes=(2, 4), ints=(16, 32), bools=(16, 32),
+                                 floats=(32, 32)))
+
+        # Half/Double Vector
+        t = TypeSet(lanes=(1, 1), ints=(8, 8))
+        t1 = TypeSet(lanes=(256, 256), ints=(8, 8))
+        self.assertEqual(t.map_inverse(TypeVar.DOUBLEVECTOR).size(), 0)
+        self.assertEqual(t1.map_inverse(TypeVar.HALFVECTOR).size(), 0)
+
+        t = TypeSet(lanes=(1, 16), ints=(8, 16), floats=(32, 32))
+        t1 = TypeSet(lanes=(64, 256), bools=(1, 32))
+
+        self.assertEqual(t.map_inverse(TypeVar.DOUBLEVECTOR),
+                         TypeSet(lanes=(1, 8), ints=(8, 16), floats=(32, 32)))
+        self.assertEqual(t1.map_inverse(TypeVar.HALFVECTOR),
+                         TypeSet(lanes=(128, 256), bools=(1, 32)))
+
+        # Half/Double Width
+        t = TypeSet(ints=(8, 8), floats=(32, 32), bools=(1, 8))
+        t1 = TypeSet(ints=(64, 64), floats=(64, 64), bools=(64, 64))
+        self.assertEqual(t.map_inverse(TypeVar.DOUBLEWIDTH).size(), 0)
+        self.assertEqual(t1.map_inverse(TypeVar.HALFWIDTH).size(), 0)
+
+        t = TypeSet(lanes=(1, 16), ints=(8, 16), floats=(32, 64))
+        t1 = TypeSet(lanes=(64, 256), bools=(1, 64))
+
+        self.assertEqual(t.map_inverse(TypeVar.DOUBLEWIDTH),
+                         TypeSet(lanes=(1, 16), ints=(8, 8), floats=(32, 32)))
+        self.assertEqual(t1.map_inverse(TypeVar.HALFWIDTH),
+                         TypeSet(lanes=(64, 256), bools=(16, 64)))
+
 
 class TestTypeVar(TestCase):
     def test_functions(self):
@@ -164,3 +218,57 @@ class TestTypeVar(TestCase):
         self.assertEqual(max(x.type_set.lanes), 4)
         self.assertEqual(len(x.type_set.floats), 0)
         self.assertEqual(len(x.type_set.bools), 0)
+
+    def test_stress_constrain_types(self):
+        # Get all 49 possible derived vars of lentgh 2. Since we have SAMEAS
+        # this includes singly derived and non-derived vars
+        funcs = [TypeVar.SAMEAS, TypeVar.LANEOF,
+                 TypeVar.ASBOOL, TypeVar.HALFVECTOR, TypeVar.DOUBLEVECTOR,
+                 TypeVar.HALFWIDTH, TypeVar.DOUBLEWIDTH]
+        v = list(product(*[funcs, funcs]))
+
+        # For each pair of derived variables
+        for (i1, i2) in product(v, v):
+            # Compute the derived sets for each  starting with a full typeset
+            full_ts = TypeSet(lanes=True, floats=True, ints=True, bools=True)
+            ts1 = reduce(lambda ts, func:   ts.map(func), i1, full_ts)
+            ts2 = reduce(lambda ts, func:   ts.map(func), i2, full_ts)
+
+            # Compute intersection
+            intersect = ts1.copy()
+            intersect &= ts2
+
+            # Propagate instersections backward
+            ts1_src = reduce(lambda ts, func:   ts.map_inverse(func),
+                             reversed(i1),
+                             intersect)
+            ts2_src = reduce(lambda ts, func:   ts.map_inverse(func),
+                             reversed(i2),
+                             intersect)
+
+            # If the intersection or its propagated forms are empty, then these
+            # two variables can never overlap. For example x.double_vector and
+            # x.lane_of.
+            if (intersect.size() == 0 or ts1_src.size() == 0 or
+                    ts2_src.size() == 0):
+                continue
+
+            # Should be safe to create derived tvs from ts1_src and ts2_src
+            tv1 = reduce(lambda tv, func:   TypeVar.derived(tv, func),
+                         i1,
+                         TypeVar.from_typeset(ts1_src))
+
+            tv2 = reduce(lambda tv, func:   TypeVar.derived(tv, func),
+                         i2,
+                         TypeVar.from_typeset(ts2_src))
+
+            # The typesets of the two derived variables should be subsets of
+            # the intersection we computed originally
+            assert tv1.get_typeset().issubset(intersect)
+            assert tv2.get_typeset().issubset(intersect)
+
+            # In the absence of AS_BOOL map(map_inverse(f)) == f so the
+            # typesets of tv1 and tv2 should be exactly intersection
+            assert (tv1.get_typeset() == tv2.get_typeset() and
+                    tv1.get_typeset() == intersect) or\
+                TypeVar.ASBOOL in set(i1 + i2)

lib/cretonne/meta/cdsl/types.py

@@ -3,8 +3,9 @@ from __future__ import absolute_import
 import math
 
 try:
-    from typing import Dict, List  # noqa
+    from typing import Dict, List, cast, TYPE_CHECKING # noqa
 except ImportError:
+    TYPE_CHECKING = False
     pass
 
 
@@ -97,7 +98,7 @@ class VectorType(ValueType):
         # type: (ScalarType, int) -> None
         assert isinstance(base, ScalarType), 'SIMD lanes must be scalar types'
         super(VectorType, self).__init__(
-                name=VectorType.get_name(base, lanes),
+                name='{}x{}'.format(base.name, lanes),
                 membytes=lanes*base.membytes,
                 doc="""
                 A SIMD vector with {} lanes containing a `{}` each.
@@ -111,11 +112,6 @@ class VectorType(ValueType):
         return ('VectorType(base={}, lanes={})'
                 .format(self.base.name, self.lanes))
 
-    @staticmethod
-    def get_name(base, lanes):
-        # type: (ValueType, int) -> str
-        return '{}x{}'.format(base.name, lanes)
-
 
 class IntType(ScalarType):
     """A concrete scalar integer type."""
@@ -124,7 +120,7 @@ class IntType(ScalarType):
         # type: (int) -> None
         assert bits > 0, 'IntType must have positive number of bits'
         super(IntType, self).__init__(
-                name=IntType.get_name(bits),
+                name='i{:d}'.format(bits),
                 membytes=bits // 8,
                 doc="An integer type with {} bits.".format(bits))
         self.bits = bits
@@ -134,9 +130,13 @@ class IntType(ScalarType):
         return 'IntType(bits={})'.format(self.bits)
 
     @staticmethod
-    def get_name(bits):
+    def with_bits(bits):
-        # type: (int) -> str
+        # type: (int) -> IntType
-        return 'i{:d}'.format(bits)
+        typ = ValueType.by_name('i{:d}'.format(bits))
+        if TYPE_CHECKING:
+            return cast(IntType, typ)
+        else:
+            return typ
 
 
 class FloatType(ScalarType):
@@ -146,7 +146,7 @@ class FloatType(ScalarType):
         # type: (int, str) -> None
         assert bits > 0, 'FloatType must have positive number of bits'
         super(FloatType, self).__init__(
-                name=FloatType.get_name(bits),
+                name='f{:d}'.format(bits),
                 membytes=bits // 8,
                 doc=doc)
         self.bits = bits
@@ -156,9 +156,13 @@ class FloatType(ScalarType):
         return 'FloatType(bits={})'.format(self.bits)
 
     @staticmethod
-    def get_name(bits):
+    def with_bits(bits):
-        # type: (int) -> str
+        # type: (int) -> FloatType
-        return 'f{:d}'.format(bits)
+        typ = ValueType.by_name('f{:d}'.format(bits))
+        if TYPE_CHECKING:
+            return cast(FloatType, typ)
+        else:
+            return typ
 
 
 class BoolType(ScalarType):
@@ -168,7 +172,7 @@ class BoolType(ScalarType):
         # type: (int) -> None
         assert bits > 0, 'BoolType must have positive number of bits'
         super(BoolType, self).__init__(
-                name=BoolType.get_name(bits),
+                name='b{:d}'.format(bits),
                 membytes=bits // 8,
                 doc="A boolean type with {} bits.".format(bits))
         self.bits = bits
@@ -178,6 +182,10 @@ class BoolType(ScalarType):
         return 'BoolType(bits={})'.format(self.bits)
 
     @staticmethod
-    def get_name(bits):
+    def with_bits(bits):
-        # type: (int) -> str
+        # type: (int) -> BoolType
-        return 'b{:d}'.format(bits)
+        typ = ValueType.by_name('b{:d}'.format(bits))
+        if TYPE_CHECKING:
+            return cast(BoolType, typ)
+        else:
+            return typ

lib/cretonne/meta/cdsl/typevar.py

@@ -8,18 +8,17 @@ from __future__ import absolute_import
 import math
 from . import types, is_power_of_two
 from copy import deepcopy
-from .types import ValueType, IntType, FloatType, BoolType
+from .types import IntType, FloatType, BoolType
 
 try:
     from typing import Tuple, Union, Iterable, Any, Set, TYPE_CHECKING # noqa
-    from typing import cast
     if TYPE_CHECKING:
         from srcgen import Formatter  # noqa
+        from .types import ValueType  # noqa
         Interval = Tuple[int, int]
         # An Interval where `True` means 'everything'
         BoolInterval = Union[bool, Interval]
 except ImportError:
-    TYPE_CHECKING = False
     pass
 
 MAX_LANES = 256
@@ -263,6 +262,16 @@ class TypeSet(object):
 
         return self
 
+    def issubset(self, other):
+        # type: (TypeSet) -> bool
+        """
+        Return true iff self is a subset of other
+        """
+        return self.lanes.issubset(other.lanes) and \
+            self.ints.issubset(other.ints) and \
+            self.floats.issubset(other.floats) and \
+            self.bools.issubset(other.bools)
+
     def lane_of(self):
         # type: () -> TypeSet
         """
@@ -292,9 +301,9 @@ class TypeSet(object):
         Return a TypeSet describing the image of self across halfwidth
         """
         new = self.copy()
-        new.ints = set([x/2 for x in self.ints if x > 8])
+        new.ints = set([x//2 for x in self.ints if x > 8])
-        new.floats = set([x/2 for x in self.floats if x > 32])
+        new.floats = set([x//2 for x in self.floats if x > 32])
-        new.bools = set([x/2 for x in self.bools if x > 8])
+        new.bools = set([x//2 for x in self.bools if x > 8])
 
         return new
 
@@ -317,7 +326,7 @@ class TypeSet(object):
         Return a TypeSet describing the image of self across halfvector
         """
         new = self.copy()
-        new.lanes = set([x/2 for x in self.lanes if x > 1])
+        new.lanes = set([x//2 for x in self.lanes if x > 1])
 
         return new
 
@@ -331,6 +340,67 @@ class TypeSet(object):
 
         return new
 
+    def map(self, func):
+        # type: (str) -> TypeSet
+        """
+        Return the image of self across the derived function func
+        """
+        if (func == TypeVar.SAMEAS):
+            return self
+        elif (func == TypeVar.LANEOF):
+            return self.lane_of()
+        elif (func == TypeVar.ASBOOL):
+            return self.as_bool()
+        elif (func == TypeVar.HALFWIDTH):
+            return self.half_width()
+        elif (func == TypeVar.DOUBLEWIDTH):
+            return self.double_width()
+        elif (func == TypeVar.HALFVECTOR):
+            return self.half_vector()
+        elif (func == TypeVar.DOUBLEVECTOR):
+            return self.double_vector()
+        else:
+            assert False, "Unknown derived function: " + func
+
+    def map_inverse(self, func):
+        # type: (str) -> TypeSet
+        """
+        Return the inverse image of self across the derived function func
+        """
+        # The inverse of the empty set is always empty
+        if (self.size() == 0):
+            return self
+
+        if (func == TypeVar.SAMEAS):
+            return self
+        elif (func == TypeVar.LANEOF):
+            new = self.copy()
+            new.lanes = set([2**i for i in range(0, int_log2(MAX_LANES)+1)])
+            return new
+        elif (func == TypeVar.ASBOOL):
+            new = self.copy()
+            new.ints = self.bools.difference(set([1]))
+            new.floats = self.bools.intersection(set([32, 64]))
+
+            if 1 not in self.bools:
+                try:
+                    # If the range doesn't have b1, then the domain can't
+                    # include scalars, as as_bool(scalar)=b1
+                    new.lanes.remove(1)
+                except KeyError:
+                    pass
+            return new
+        elif (func == TypeVar.HALFWIDTH):
+            return self.double_width()
+        elif (func == TypeVar.DOUBLEWIDTH):
+            return self.half_width()
+        elif (func == TypeVar.HALFVECTOR):
+            return self.double_vector()
+        elif (func == TypeVar.DOUBLEVECTOR):
+            return self.half_vector()
+        else:
+            assert False, "Unknown derived function: " + func
+
     def size(self):
         # type: () -> int
         """
@@ -346,25 +416,20 @@ class TypeSet(object):
         typesets containing 1 type.
         """
         assert self.size() == 1
+        scalar_type = None  # type: types.ScalarType
         if len(self.ints) > 0:
-            bits = tuple(self.ints)[0]
+            scalar_type = IntType.with_bits(tuple(self.ints)[0])
-            scalar_type = ValueType.by_name(IntType.get_name(bits))
         elif len(self.floats) > 0:
-            bits = tuple(self.floats)[0]
+            scalar_type = FloatType.with_bits(tuple(self.floats)[0])
-            scalar_type = ValueType.by_name(FloatType.get_name(bits))
         else:
-            bits = tuple(self.bools)[0]
+            scalar_type = BoolType.with_bits(tuple(self.bools)[0])
-            scalar_type = ValueType.by_name(BoolType.get_name(bits))
 
         nlanes = tuple(self.lanes)[0]
 
         if nlanes == 1:
             return scalar_type
         else:
-            if TYPE_CHECKING:
+            return scalar_type.by(nlanes)
-                return cast(types.ScalarType, scalar_type).by(nlanes)
-            else:
-                return scalar_type.by(nlanes)
 
 
 class TypeVar(object):
@@ -483,6 +548,14 @@ class TypeVar(object):
         """Create a type variable that is a function of another."""
         return TypeVar(None, None, base=base, derived_func=derived_func)
 
+    @staticmethod
+    def from_typeset(ts):
+        # type: (TypeSet) -> TypeVar
+        """ Create a type variable from a type set."""
+        tv = TypeVar(None, None)
+        tv.type_set = ts
+        return tv
+
     def change_to_derived(self, base, derived_func):
         # type: (TypeVar, str) -> None
         """Change this type variable into a derived one."""
@@ -615,6 +688,17 @@ class TypeVar(object):
         else:
             return self.name
 
+    def constrain_types_by_ts(self, ts):
+        # type: (TypeSet) -> None
+        """
+        Constrain the range of types this variable can assume to a subset of
+        those in the typeset ts.
+        """
+        if not self.is_derived:
+            self.type_set &= ts
+        else:
+            self.base.constrain_types_by_ts(ts.map_inverse(self.derived_func))
+
     def constrain_types(self, other):
         # type: (TypeVar) -> None
         """
@@ -628,18 +712,7 @@ class TypeVar(object):
         if a is b:
             return
 
-        if not a.is_derived and not b.is_derived:
+        a.constrain_types_by_ts(b.get_typeset())
-            a.type_set &= b.type_set
-            return
-
-        # TODO: Implement constraints for derived type variables.
-        #
-        # If a and b are both derived with the same derived_func, we could say
-        # `a.base.constrain_types(b.base)`, but unless the derived_func is
-        # injective, that may constrain `a.base` more than necessary.
-        #
-        # For the fully general case, we would need to compute an image typeset
-        # for `b` and propagate a `a.derived_func` pre-image to `a.base`.
 
     def get_typeset(self):
         # type: () -> TypeSet