[Mlir-commits] [mlir] 8181c3d - [MLIR][Python] Expose the insertion point of pattern rewriter (#161001)
llvmlistbot at llvm.org
llvmlistbot at llvm.org
Sat Oct 4 20:12:14 PDT 2025
Author: Twice
Date: 2025-10-05T11:12:11+08:00
New Revision: 8181c3deae482769937bdcee68f381df4141eb24
URL: https://github.com/llvm/llvm-project/commit/8181c3deae482769937bdcee68f381df4141eb24
DIFF: https://github.com/llvm/llvm-project/commit/8181c3deae482769937bdcee68f381df4141eb24.diff
LOG: [MLIR][Python] Expose the insertion point of pattern rewriter (#161001)
In [#160520](https://github.com/llvm/llvm-project/pull/160520), we
discussed the current limitations of PDL rewriting in Python (see [this
comment](https://github.com/llvm/llvm-project/pull/160520#issuecomment-3332326184)).
At the moment, we cannot create new operations in PDL native (python)
rewrite functions because the `PatternRewriter` APIs are not exposed.
This PR introduces bindings to retrieve the insertion point of the
`PatternRewriter`, enabling users to create new operations within Python
rewrite functions. With this capability, more complex rewrites e.g. with
branching and loops that involve op creations become possible.
---------
Co-authored-by: Maksim Levental <maksim.levental at gmail.com>
Added:
Modified:
mlir/include/mlir-c/Rewrite.h
mlir/lib/Bindings/Python/IRCore.cpp
mlir/lib/Bindings/Python/IRModule.h
mlir/lib/Bindings/Python/Rewrite.cpp
mlir/lib/CAPI/Transforms/Rewrite.cpp
mlir/test/python/integration/dialects/pdl.py
Removed:
################################################################################
diff --git a/mlir/include/mlir-c/Rewrite.h b/mlir/include/mlir-c/Rewrite.h
index 77be1f480eacf..5dd285ee076c4 100644
--- a/mlir/include/mlir-c/Rewrite.h
+++ b/mlir/include/mlir-c/Rewrite.h
@@ -101,6 +101,12 @@ mlirRewriterBaseGetInsertionBlock(MlirRewriterBase rewriter);
MLIR_CAPI_EXPORTED MlirBlock
mlirRewriterBaseGetBlock(MlirRewriterBase rewriter);
+/// Returns the operation right after the current insertion point
+/// of the rewriter. A null MlirOperation will be returned
+// if the current insertion point is at the end of the block.
+MLIR_CAPI_EXPORTED MlirOperation
+mlirRewriterBaseGetOperationAfterInsertion(MlirRewriterBase rewriter);
+
//===----------------------------------------------------------------------===//
/// Block and operation creation/insertion/cloning
//===----------------------------------------------------------------------===//
@@ -310,6 +316,14 @@ MLIR_CAPI_EXPORTED MlirLogicalResult mlirApplyPatternsAndFoldGreedily(
MlirModule op, MlirFrozenRewritePatternSet patterns,
MlirGreedyRewriteDriverConfig);
+//===----------------------------------------------------------------------===//
+/// PatternRewriter API
+//===----------------------------------------------------------------------===//
+
+/// Cast the PatternRewriter to a RewriterBase
+MLIR_CAPI_EXPORTED MlirRewriterBase
+mlirPatternRewriterAsBase(MlirPatternRewriter rewriter);
+
//===----------------------------------------------------------------------===//
/// PDLPatternModule API
//===----------------------------------------------------------------------===//
diff --git a/mlir/lib/Bindings/Python/IRCore.cpp b/mlir/lib/Bindings/Python/IRCore.cpp
index 32b2b0c648cff..7b1710656243a 100644
--- a/mlir/lib/Bindings/Python/IRCore.cpp
+++ b/mlir/lib/Bindings/Python/IRCore.cpp
@@ -2046,6 +2046,9 @@ PyInsertionPoint::PyInsertionPoint(PyOperationBase &beforeOperationBase)
: refOperation(beforeOperationBase.getOperation().getRef()),
block((*refOperation)->getBlock()) {}
+PyInsertionPoint::PyInsertionPoint(PyOperationRef beforeOperationRef)
+ : refOperation(beforeOperationRef), block((*refOperation)->getBlock()) {}
+
void PyInsertionPoint::insert(PyOperationBase &operationBase) {
PyOperation &operation = operationBase.getOperation();
if (operation.isAttached())
diff --git a/mlir/lib/Bindings/Python/IRModule.h b/mlir/lib/Bindings/Python/IRModule.h
index edbd73eade906..e706be3b4d32a 100644
--- a/mlir/lib/Bindings/Python/IRModule.h
+++ b/mlir/lib/Bindings/Python/IRModule.h
@@ -841,6 +841,8 @@ class PyInsertionPoint {
PyInsertionPoint(const PyBlock &block);
/// Creates an insertion point positioned before a reference operation.
PyInsertionPoint(PyOperationBase &beforeOperationBase);
+ /// Creates an insertion point positioned before a reference operation.
+ PyInsertionPoint(PyOperationRef beforeOperationRef);
/// Shortcut to create an insertion point at the beginning of the block.
static PyInsertionPoint atBlockBegin(PyBlock &block);
diff --git a/mlir/lib/Bindings/Python/Rewrite.cpp b/mlir/lib/Bindings/Python/Rewrite.cpp
index 836f44fd7d4be..9e3d9703c82e8 100644
--- a/mlir/lib/Bindings/Python/Rewrite.cpp
+++ b/mlir/lib/Bindings/Python/Rewrite.cpp
@@ -26,6 +26,30 @@ using namespace mlir::python;
namespace {
+class PyPatternRewriter {
+public:
+ PyPatternRewriter(MlirPatternRewriter rewriter)
+ : base(mlirPatternRewriterAsBase(rewriter)),
+ ctx(PyMlirContext::forContext(mlirRewriterBaseGetContext(base))) {}
+
+ PyInsertionPoint getInsertionPoint() const {
+ MlirBlock block = mlirRewriterBaseGetInsertionBlock(base);
+ MlirOperation op = mlirRewriterBaseGetOperationAfterInsertion(base);
+
+ if (mlirOperationIsNull(op)) {
+ MlirOperation owner = mlirBlockGetParentOperation(block);
+ auto parent = PyOperation::forOperation(ctx, owner);
+ return PyInsertionPoint(PyBlock(parent, block));
+ }
+
+ return PyInsertionPoint(PyOperation::forOperation(ctx, op));
+ }
+
+private:
+ MlirRewriterBase base;
+ PyMlirContextRef ctx;
+};
+
#if MLIR_ENABLE_PDL_IN_PATTERNMATCH
static nb::object objectFromPDLValue(MlirPDLValue value) {
if (MlirValue v = mlirPDLValueAsValue(value); !mlirValueIsNull(v))
@@ -84,7 +108,8 @@ class PyPDLPatternModule {
void *userData) -> MlirLogicalResult {
nb::handle f = nb::handle(static_cast<PyObject *>(userData));
return logicalResultFromObject(
- f(rewriter, results, objectsFromPDLValues(nValues, values)));
+ f(PyPatternRewriter(rewriter), results,
+ objectsFromPDLValues(nValues, values)));
},
fn.ptr());
}
@@ -98,7 +123,8 @@ class PyPDLPatternModule {
void *userData) -> MlirLogicalResult {
nb::handle f = nb::handle(static_cast<PyObject *>(userData));
return logicalResultFromObject(
- f(rewriter, results, objectsFromPDLValues(nValues, values)));
+ f(PyPatternRewriter(rewriter), results,
+ objectsFromPDLValues(nValues, values)));
},
fn.ptr());
}
@@ -143,7 +169,9 @@ class PyFrozenRewritePatternSet {
/// Create the `mlir.rewrite` here.
void mlir::python::populateRewriteSubmodule(nb::module_ &m) {
- nb::class_<MlirPatternRewriter>(m, "PatternRewriter");
+ nb::class_<PyPatternRewriter>(m, "PatternRewriter")
+ .def_prop_ro("ip", &PyPatternRewriter::getInsertionPoint,
+ "The current insertion point of the PatternRewriter.");
//----------------------------------------------------------------------------
// Mapping of the PDLResultList and PDLModule
//----------------------------------------------------------------------------
diff --git a/mlir/lib/CAPI/Transforms/Rewrite.cpp b/mlir/lib/CAPI/Transforms/Rewrite.cpp
index 0d56259e469af..c15a73b991f5d 100644
--- a/mlir/lib/CAPI/Transforms/Rewrite.cpp
+++ b/mlir/lib/CAPI/Transforms/Rewrite.cpp
@@ -70,6 +70,17 @@ MlirBlock mlirRewriterBaseGetBlock(MlirRewriterBase rewriter) {
return wrap(unwrap(rewriter)->getBlock());
}
+MlirOperation
+mlirRewriterBaseGetOperationAfterInsertion(MlirRewriterBase rewriter) {
+ mlir::RewriterBase *base = unwrap(rewriter);
+ mlir::Block *block = base->getInsertionBlock();
+ mlir::Block::iterator it = base->getInsertionPoint();
+ if (it == block->end())
+ return {nullptr};
+
+ return wrap(std::addressof(*it));
+}
+
//===----------------------------------------------------------------------===//
/// Block and operation creation/insertion/cloning
//===----------------------------------------------------------------------===//
@@ -317,6 +328,10 @@ inline MlirPatternRewriter wrap(mlir::PatternRewriter *rewriter) {
return {rewriter};
}
+MlirRewriterBase mlirPatternRewriterAsBase(MlirPatternRewriter rewriter) {
+ return wrap(static_cast<mlir::RewriterBase *>(unwrap(rewriter)));
+}
+
//===----------------------------------------------------------------------===//
/// PDLPatternModule API
//===----------------------------------------------------------------------===//
diff --git a/mlir/test/python/integration/dialects/pdl.py b/mlir/test/python/integration/dialects/pdl.py
index c8e6197e03842..fe27dd4203a21 100644
--- a/mlir/test/python/integration/dialects/pdl.py
+++ b/mlir/test/python/integration/dialects/pdl.py
@@ -16,6 +16,7 @@ def construct_and_print_in_module(f):
print(module)
return f
+
def get_pdl_patterns():
# Create a rewrite from add to mul. This will match
# - operation name is arith.addi
@@ -121,8 +122,10 @@ def load_myint_dialect():
# This PDL pattern is to fold constant additions,
-# i.e. add(constant0, constant1) -> constant2
-# where constant2 = constant0 + constant1.
+# including two patterns:
+# 1. add(constant0, constant1) -> constant2
+# where constant2 = constant0 + constant1;
+# 2. add(x, 0) or add(0, x) -> x.
def get_pdl_pattern_fold():
m = Module.create()
i32 = IntegerType.get_signless(32)
@@ -237,3 +240,87 @@ def test_pdl_register_function_constraint(module_):
apply_patterns_and_fold_greedily(module_, frozen)
return module_
+
+
+# This pattern is to expand constant to additions
+# unless the constant is no more than 1,
+# e.g. 3 -> 1 + 2 -> 1 + (1 + 1).
+def get_pdl_pattern_expand():
+ m = Module.create()
+ i32 = IntegerType.get_signless(32)
+ with InsertionPoint(m.body):
+
+ @pdl.pattern(benefit=1, sym_name="myint_constant_expand")
+ def pat():
+ t = pdl.TypeOp(i32)
+ cst = pdl.AttributeOp()
+ pdl.apply_native_constraint([], "is_one", [cst])
+ op0 = pdl.OperationOp(
+ name="myint.constant", attributes={"value": cst}, types=[t]
+ )
+
+ @pdl.rewrite()
+ def rew():
+ expanded = pdl.apply_native_rewrite(
+ [pdl.OperationType.get()], "expand", [cst]
+ )
+ pdl.ReplaceOp(op0, with_op=expanded)
+
+ def is_one(rewriter, results, values):
+ cst = values[0].value
+ return cst <= 1
+
+ def expand(rewriter, results, values):
+ cst = values[0].value
+ c1 = cst // 2
+ c2 = cst - c1
+ with rewriter.ip:
+ op1 = Operation.create(
+ "myint.constant",
+ results=[i32],
+ attributes={"value": IntegerAttr.get(i32, c1)},
+ )
+ op2 = Operation.create(
+ "myint.constant",
+ results=[i32],
+ attributes={"value": IntegerAttr.get(i32, c2)},
+ )
+ res = Operation.create(
+ "myint.add", results=[i32], operands=[op1.result, op2.result]
+ )
+ results.append(res)
+
+ pdl_module = PDLModule(m)
+ pdl_module.register_constraint_function("is_one", is_one)
+ pdl_module.register_rewrite_function("expand", expand)
+ return pdl_module.freeze()
+
+
+# CHECK-LABEL: TEST: test_pdl_register_function_expand
+# CHECK: %0 = "myint.constant"() {value = 1 : i32} : () -> i32
+# CHECK: %1 = "myint.constant"() {value = 1 : i32} : () -> i32
+# CHECK: %2 = "myint.add"(%0, %1) : (i32, i32) -> i32
+# CHECK: %3 = "myint.constant"() {value = 1 : i32} : () -> i32
+# CHECK: %4 = "myint.constant"() {value = 1 : i32} : () -> i32
+# CHECK: %5 = "myint.constant"() {value = 1 : i32} : () -> i32
+# CHECK: %6 = "myint.add"(%4, %5) : (i32, i32) -> i32
+# CHECK: %7 = "myint.add"(%3, %6) : (i32, i32) -> i32
+# CHECK: %8 = "myint.add"(%2, %7) : (i32, i32) -> i32
+# CHECK: return %8 : i32
+ at construct_and_print_in_module
+def test_pdl_register_function_expand(module_):
+ load_myint_dialect()
+
+ module_ = Module.parse(
+ """
+ func.func @f() -> i32 {
+ %0 = "myint.constant"() { value = 5 }: () -> (i32)
+ return %0 : i32
+ }
+ """
+ )
+
+ frozen = get_pdl_pattern_expand()
+ apply_patterns_and_fold_greedily(module_, frozen)
+
+ return module_
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