interpreter: (pdl) add an initial version of EqSat PDLMatcher (#3574)

This is an initial attempt of adding a PDL matcher for EqSat e-class
ops.

---------

Co-authored-by: Jianyi Cheng <[email protected]>

tests/interpreters/test_eqsat_pdl_interpreter.py

@@ -0,0 +1,51 @@
+from xdsl.dialects import eqsat, pdl
+from xdsl.dialects.builtin import (
+    IntegerType,
+    StringAttr,
+)
+from xdsl.interpreters.eqsat_pdl import EqsatPDLMatcher
+
+
+def test_match_type():
+    matcher = EqsatPDLMatcher()
+
+    pdl_op = pdl.TypeOp()
+    ssa_value = pdl_op.result
+    ssa_value = eqsat.EClassOp(ssa_value).result
+    xdsl_value = StringAttr("a")
+
+    # New value
+    assert matcher.match_type(ssa_value, pdl_op, xdsl_value)
+    assert matcher.matching_context == {ssa_value: xdsl_value}
+
+    # Same value
+    assert matcher.match_type(ssa_value, pdl_op, xdsl_value)
+    assert matcher.matching_context == {ssa_value: xdsl_value}
+
+    # Other value
+    assert not matcher.match_type(ssa_value, pdl_op, StringAttr("b"))
+    assert matcher.matching_context == {ssa_value: xdsl_value}
+
+
+def test_match_fixed_type():
+    matcher = EqsatPDLMatcher()
+
+    pdl_op = pdl.TypeOp(IntegerType(32))
+    xdsl_value = IntegerType(32)
+    ssa_value = pdl_op.result
+    ssa_value = eqsat.EClassOp(ssa_value).result
+
+    assert matcher.match_type(ssa_value, pdl_op, xdsl_value)
+    assert matcher.matching_context == {ssa_value: xdsl_value}
+
+
+def test_not_match_fixed_type():
+    matcher = EqsatPDLMatcher()
+
+    pdl_op = pdl.TypeOp(IntegerType(64))
+    xdsl_value = IntegerType(32)
+    ssa_value = pdl_op.result
+    ssa_value = eqsat.EClassOp(ssa_value).result
+
+    assert not matcher.match_type(ssa_value, pdl_op, xdsl_value)
+    assert matcher.matching_context == {}

xdsl/interpreters/eqsat_pdl.py

@@ -0,0 +1,22 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+from xdsl.dialects import eqsat, pdl
+from xdsl.interpreters.pdl import PDLMatcher
+from xdsl.ir import SSAValue
+
+
+@dataclass
+class EqsatPDLMatcher(PDLMatcher):
+    def match_operand(
+        self, ssa_val: SSAValue, pdl_op: pdl.OperandOp, xdsl_val: SSAValue
+    ):
+        owner = xdsl_val.owner
+        assert isinstance(owner, eqsat.EClassOp)
+        assert (
+            len(owner.operands) == 1
+        ), "newly converted eqsat always has 1 element in eclass"
+        arg = owner.operands[0]
+        res = super().match_operand(ssa_val, pdl_op, arg)
+        return res