core: Add support for typed SSA values in isa

`isa(arg, SSAValue[T])` will check that `arg` is an SSA value, and that
its type is `T`.

stack-info: PR: #3988, branch: math-fehr/stack/3

tests/test_is_satisfying_hint.py

@@ -9,11 +9,13 @@
     IntegerAttr,
     IntegerType,
     StringAttr,
+    i32,
 )
-from xdsl.ir import Attribute, ParametrizedAttribute
+from xdsl.ir import Attribute, ParametrizedAttribute, SSAValue
 from xdsl.irdl import BaseAttr, EqAttrConstraint, ParameterDef, irdl_attr_definition
 from xdsl.utils.hints import isa
 from xdsl.utils.isattr import isattr
+from xdsl.utils.test_value import TestSSAValue
 
 
 class Class1:
@@ -398,3 +400,16 @@ def test_isattr():
     assert not isattr(IntAttr(1), BaseAttr(StringAttr))
     assert isattr(IntAttr(1), EqAttrConstraint(IntAttr(1)))
     assert not isattr(IntAttr(1), EqAttrConstraint(IntAttr(2)))
+
+
+################################################################################
+# SSAValue
+################################################################################
+
+
+def test_ssavalue():
+    a = TestSSAValue(i32)
+
+    assert isa(a, SSAValue)
+    assert isa(a, SSAValue[IntegerType])
+    assert not isa(a, SSAValue[StringAttr])

xdsl/utils/hints.py

@@ -15,7 +15,7 @@
     get_origin,
 )
 
-from xdsl.ir import ParametrizedAttribute
+from xdsl.ir import ParametrizedAttribute, SSAValue
 from xdsl.utils.exceptions import VerifyException
 
 if TYPE_CHECKING:
@@ -102,6 +102,17 @@ def isa(arg: Any, hint: "TypeForm[_T]") -> TypeGuard[_T]:
         except VerifyException:
             return False
 
+    if origin is SSAValue:
+        if not isinstance(arg, SSAValue):
+            return False
+        arg = cast(SSAValue, arg)
+        constraint = irdl_to_attr_constraint(get_args(hint)[0])
+        try:
+            constraint.verify(arg.type, ConstraintContext())
+            return True
+        except VerifyException:
+            return False
+
     raise ValueError(f"isa: unsupported type hint '{hint}' {get_origin(hint)}")