[mlir] More Python bindings for AffineMap

[ftynse]

Summary

Now that the bindings for AffineExpr have been added, add more bindings for
constructing and inspecting AffineMap that consists of AffineExprs.

Depends On D94225

[ftynse]

mlir/lib/Bindings/Python/IRModules.cpp

3887–3904

These are instance methods that derive a new map from the given map in C++ so I kept them as such. An alternative approach is to make them static similarly to other get methods and take the map map as an explicit first argument.

[mehdi_amini]

mlir/lib/Bindings/Python/IRModules.cpp

3811

Can you spell the type here?

3875

Can't you take a vector of unsigned here? Pybind wouldn't be happy with it? It'll avoid the manual conversion.

3890

Seems like this would crash without more sanity checking here that none of the indices in resultPos overflow the AffineMap size.

I suspect other places have the same issue in sibling methods.

[ftynse]

Address review

mlir/include/mlir-c/AffineExpr.h

 //===-- mlir-c/AffineExpr.h - C API for MLIR Affine Expressions ---*- C -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM
 // Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef MLIR_C_AFFINEEXPR_H
 #define MLIR_C_AFFINEEXPR_H
 
-#include "mlir-c/AffineMap.h"
 #include "mlir-c/IR.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 //===----------------------------------------------------------------------===//
 /** Opaque type declarations.

mlir/include/mlir-c/AffineMap.h

 //===-- mlir-c/AffineMap.h - C API for MLIR Affine maps -----------*- C -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM
 // Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef MLIR_C_AFFINEMAP_H
 #define MLIR_C_AFFINEMAP_H
 
+#include "mlir-c/AffineExpr.h"
 #include "mlir-c/IR.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 //===----------------------------------------------------------------------===//
 /** Opaque type declarations.

 MLIR_CAPI_EXPORTED void mlirAffineMapDump(MlirAffineMap affineMap);
 
 /** Creates a zero result affine map with no dimensions or symbols in the
  * context. The affine map is owned by the context. */
 MLIR_CAPI_EXPORTED MlirAffineMap mlirAffineMapEmptyGet(MlirContext ctx);
 
 /** Creates a zero result affine map of the given dimensions and symbols in the
  * context. The affine map is owned by the context. */
+MLIR_CAPI_EXPORTED MlirAffineMap mlirAffineMapZeroResultGet(
+    MlirContext ctx, intptr_t dimCount, intptr_t symbolCount);
+
+/** Creates an affine map with results defined by the given list of affine
+ * expressions. The map resulting map also has the requested number of input
+ * dimensions and symbols, regardless of them being used in the results.
+ */
 MLIR_CAPI_EXPORTED MlirAffineMap mlirAffineMapGet(MlirContext ctx,
                                                   intptr_t dimCount,
-                                                  intptr_t symbolCount);
+                                                  intptr_t symbolCount,
+                                                  intptr_t nAffineExprs,
+                                                  MlirAffineExpr *affineExprs);
 
 /** Creates a single constant result affine map in the context. The affine map
  * is owned by the context. */
 MLIR_CAPI_EXPORTED MlirAffineMap mlirAffineMapConstantGet(MlirContext ctx,
                                                           int64_t val);
 
 /** Creates an affine map with 'numDims' identity in the context. The affine map
  * is owned by the context. */

 MLIR_CAPI_EXPORTED intptr_t mlirAffineMapGetNumDims(MlirAffineMap affineMap);
 
 /// Returns the number of symbols of the given affine map.
 MLIR_CAPI_EXPORTED intptr_t mlirAffineMapGetNumSymbols(MlirAffineMap affineMap);
 
 /// Returns the number of results of the given affine map.
 MLIR_CAPI_EXPORTED intptr_t mlirAffineMapGetNumResults(MlirAffineMap affineMap);
 
+/// Returns the result at the given position.
+MLIR_CAPI_EXPORTED MlirAffineExpr
+mlirAffineMapGetResult(MlirAffineMap affineMap, intptr_t pos);
+
 /** Returns the number of inputs (dimensions + symbols) of the given affine
  * map. */
 MLIR_CAPI_EXPORTED intptr_t mlirAffineMapGetNumInputs(MlirAffineMap affineMap);
 
 /** Checks whether the given affine map represents a subset of a symbol-less
  * permutation map. */
 MLIR_CAPI_EXPORTED bool
 mlirAffineMapIsProjectedPermutation(MlirAffineMap affineMap);

mlir/lib/Bindings/Python/IRModules.cpp

 //===- IRModules.cpp - IR Submodules of pybind module ---------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "IRModules.h"
 
 #include "Globals.h"
 #include "PybindUtils.h"
 
+#include "mlir-c/AffineMap.h"
 #include "mlir-c/Bindings/Python/Interop.h"
 #include "mlir-c/BuiltinAttributes.h"
 #include "mlir-c/BuiltinTypes.h"
 #include "mlir-c/Registration.h"
 #include "llvm/ADT/SmallVector.h"
 #include <pybind11/stl.h>
 
 namespace py = pybind11;
PyAffineExpr PyAffineExpr::createFromCapsule(py::object capsule) {
   if (mlirAffineExprIsNull(rawAffineExpr))
     throw py::error_already_set();
   return PyAffineExpr(
       PyMlirContext::forContext(mlirAffineExprGetContext(rawAffineExpr)),
       rawAffineExpr);
 }
 
 //------------------------------------------------------------------------------
-// PyAffineMap.
+// PyAffineMap and utilities.
 //------------------------------------------------------------------------------
 
+namespace {
+/// A list of expressions contained in an affine map. Internally these are
+/// stored as a consecutive array leading to inexpensive random access. Both
+/// the map and the expression are owned by the context so we need not bother
+/// with lifetime extension.
+class PyAffineMapExprList
+    : public Sliceable<PyAffineMapExprList, PyAffineExpr> {
+public:
+  static constexpr const char *pyClassName = "AffineExprList";
+
+  PyAffineMapExprList(PyAffineMap map, intptr_t startIndex = 0,
+                      intptr_t length = -1, intptr_t step = 1)
+      : Sliceable(startIndex,
+                  length == -1 ? mlirAffineMapGetNumResults(map) : length,
+                  step),
+        affineMap(map) {}
+
+  intptr_t getNumElements() { return mlirAffineMapGetNumResults(affineMap); }
+
+  PyAffineExpr getElement(intptr_t pos) {
+    return PyAffineExpr(affineMap.getContext(),
+                        mlirAffineMapGetResult(affineMap, pos));
+  }
+
+  PyAffineMapExprList slice(intptr_t startIndex, intptr_t length,
+                            intptr_t step) {
+    return PyAffineMapExprList(affineMap, startIndex, length, step);
+  }
+
+private:
+  PyAffineMap affineMap;
+};
+} // end namespace
+
 bool PyAffineMap::operator==(const PyAffineMap &other) {
   return mlirAffineMapEqual(affineMap, other.affineMap);
 }
 
 py::object PyAffineMap::getCapsule() {
   return py::reinterpret_steal<py::object>(mlirPythonAffineMapToCapsule(*this));
 }
 
void mlir::python::populateIRSubmodule(py::module &m) {
 
   //----------------------------------------------------------------------------
   // Mapping of PyAffineMap.
   //----------------------------------------------------------------------------
   py::class_<PyAffineMap>(m, "AffineMap")
       .def_property_readonly(MLIR_PYTHON_CAPI_PTR_ATTR,
                              &PyAffineMap::getCapsule)
       .def(MLIR_PYTHON_CAPI_FACTORY_ATTR, &PyAffineMap::createFromCapsule)
+      .def("__eq__",
+           [](PyAffineMap &self, PyAffineMap &other) { return self == other; })
+      .def("__eq__", [](PyAffineMap &self, py::object &other) { return false; })
+      .def("__str__",
+           [](PyAffineMap &self) {
+             PyPrintAccumulator printAccum;
+             mlirAffineMapPrint(self, printAccum.getCallback(),
+                                printAccum.getUserData());
+             return printAccum.join();
+           })
+      .def("__repr__",
+           [](PyAffineMap &self) {
+             PyPrintAccumulator printAccum;
+             printAccum.parts.append("AffineMap(");
+             mlirAffineMapPrint(self, printAccum.getCallback(),
+                                printAccum.getUserData());
+             printAccum.parts.append(")");
+             return printAccum.join();
+           })
+      .def_property_readonly(
+          "context",
+          [](PyAffineMap &self) { return self.getContext().getObject(); },
+          "Context that owns the Affine Map")
+      .def(
+          "dump", [](PyAffineMap &self) { mlirAffineMapDump(self); },
+          kDumpDocstring)
+      .def_static(
+          "get",
+          [](intptr_t dimCount, intptr_t symbolCount, py::list exprs,
+             DefaultingPyMlirContext context) {
+            SmallVector<MlirAffineExpr> affineExprs;
+            affineExprs.reserve(py::len(exprs));
+            for (py::handle expr : exprs) {
+              try {
+                affineExprs.push_back(expr.cast<PyAffineExpr>());
+              } catch (py::cast_error &err) {
+                std::string msg =
+                    std::string("Invalid expression when attempting to create "
+                                "an AffineMap (") +
+                    err.what() + ")";
+                throw py::cast_error(msg);
+              } catch (py::reference_cast_error &err) {
+                std::string msg =
+                    std::string("Invalid expression (None?) when attempting to "
+                                "create an AffineMap (") +
+                    err.what() + ")";
+                throw py::cast_error(msg);
+              }
+            }
+            MlirAffineMap map =
+                mlirAffineMapGet(context->get(), dimCount, symbolCount,
+                                 affineExprs.size(), affineExprs.data());
+            return PyAffineMap(context->getRef(), map);
+          },
+          py::arg("dim_count"), py::arg("symbol_count"), py::arg("exprs"),
+          py::arg("context") = py::none(),
+          "Gets a map with the given expressions as results.")
+      .def_static(
+          "get_constant",
+          [](intptr_t value, DefaultingPyMlirContext context) {
+            MlirAffineMap affineMap =
+                mlirAffineMapConstantGet(context->get(), value);
+            return PyAffineMap(context->getRef(), affineMap);
+          },
+          py::arg("value"), py::arg("context") = py::none(),
+          "Gets an affine map with a single constant result")
       .def_static(
           "get_empty",
           [](DefaultingPyMlirContext context) {
             MlirAffineMap affineMap = mlirAffineMapEmptyGet(context->get());
             return PyAffineMap(context->getRef(), affineMap);
           },
           py::arg("context") = py::none(), "Gets an empty affine map.")
-      .def_property_readonly(
-          "context",
-          [](PyAffineMap &self) { return self.getContext().getObject(); },
-          "Context that owns the Affine Map")
-      .def("__eq__",
-           [](PyAffineMap &self, PyAffineMap &other) { return self == other; })
-      .def("__eq__", [](PyAffineMap &self, py::object &other) { return false; })
-      .def(
-          "dump", [](PyAffineMap &self) { mlirAffineMapDump(self); },
-          kDumpDocstring);
+      .def_static(
+          "get_identity",
+          [](intptr_t nDims, DefaultingPyMlirContext context) {
+            MlirAffineMap affineMap =
+                mlirAffineMapMultiDimIdentityGet(context->get(), nDims);
+            return PyAffineMap(context->getRef(), affineMap);
+          },
+          py::arg("n_dims"), py::arg("context") = py::none(),
+          "Gets an identity map with the given number of dimensions.")
+      .def_static(
+          "get_minor_identity",
+          [](intptr_t nDims, intptr_t nResults,
+             DefaultingPyMlirContext context) {
+            MlirAffineMap affineMap =
+                mlirAffineMapMinorIdentityGet(context->get(), nDims, nResults);
+            return PyAffineMap(context->getRef(), affineMap);
+          },
+          py::arg("n_dims"), py::arg("n_results"),
+          py::arg("context") = py::none(),
+          "Gets a minor identity map with the given number of dimensions and "
+          "results.")
+      .def_static(
+          "get_permutation",
+          [](std::vector<unsigned> permutation,
+             DefaultingPyMlirContext context) {
+            MlirAffineMap affineMap = mlirAffineMapPermutationGet(
+                context->get(), permutation.size(), permutation.data());
+            return PyAffineMap(context->getRef(), affineMap);
+          },
+          py::arg("permutation"), py::arg("context") = py::none(),
+          "Gets an affine map that permutes its inputs.")
+      .def("get_submap",
+           [](PyAffineMap &self, std::vector<intptr_t> &resultPos) {
+             intptr_t numResults = mlirAffineMapGetNumResults(self);
+             for (intptr_t pos : resultPos) {
+               if (pos < 0 || pos >= numResults)
+                 throw py::value_error("result position out of bounds");
+             }
+             MlirAffineMap affineMap = mlirAffineMapGetSubMap(
+                 self, resultPos.size(), resultPos.data());
+             return PyAffineMap(self.getContext(), affineMap);
+           })
+      .def("get_major_submap",
+           [](PyAffineMap &self, intptr_t nResults) {
+             if (nResults >= mlirAffineMapGetNumResults(self))
+               throw py::value_error("number of results out of bounds");
+             MlirAffineMap affineMap =
+                 mlirAffineMapGetMajorSubMap(self, nResults);
+             return PyAffineMap(self.getContext(), affineMap);
+           })
+      .def("get_minor_submap",
+           [](PyAffineMap &self, intptr_t nResults) {
+             if (nResults >= mlirAffineMapGetNumResults(self))
+               throw py::value_error("number of results out of bounds");
+             MlirAffineMap affineMap =
+                 mlirAffineMapGetMinorSubMap(self, nResults);
+             return PyAffineMap(self.getContext(), affineMap);
+           })
+      .def_property_readonly(
+          "is_permutation",
+          [](PyAffineMap &self) { return mlirAffineMapIsPermutation(self); })
+      .def_property_readonly("is_projected_permutation",
+                             [](PyAffineMap &self) {
+                               return mlirAffineMapIsProjectedPermutation(self);
+                             })
+      .def_property_readonly(
+          "n_dims",
+          [](PyAffineMap &self) { return mlirAffineMapGetNumDims(self); })
+      .def_property_readonly(
+          "n_inputs",
+          [](PyAffineMap &self) { return mlirAffineMapGetNumInputs(self); })
+      .def_property_readonly(
+          "n_symbols",
+          [](PyAffineMap &self) { return mlirAffineMapGetNumSymbols(self); })
+      .def_property_readonly("results", [](PyAffineMap &self) {
+        return PyAffineMapExprList(self);
+      });
+  PyAffineMapExprList::bind(m);
 }

mlir/lib/CAPI/IR/AffineMap.cpp

 //===- AffineMap.cpp - C API for MLIR Affine Maps -------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "mlir-c/AffineMap.h"
 #include "mlir-c/IR.h"
+#include "mlir/CAPI/AffineExpr.h"
 #include "mlir/CAPI/AffineMap.h"
 #include "mlir/CAPI/IR.h"
 #include "mlir/CAPI/Utils.h"
 #include "mlir/IR/AffineMap.h"
 
 // TODO: expose the C API related to `AffineExpr` and mutable affine map.
 
 using namespace mlir;

 }
 
 void mlirAffineMapDump(MlirAffineMap affineMap) { unwrap(affineMap).dump(); }
 
 MlirAffineMap mlirAffineMapEmptyGet(MlirContext ctx) {
   return wrap(AffineMap::get(unwrap(ctx)));
 }
 
-MlirAffineMap mlirAffineMapGet(MlirContext ctx, intptr_t dimCount,
+MlirAffineMap mlirAffineMapZeroResultGet(MlirContext ctx, intptr_t dimCount,
                                          intptr_t symbolCount) {
   return wrap(AffineMap::get(dimCount, symbolCount, unwrap(ctx)));
 }
 
+MlirAffineMap mlirAffineMapGet(MlirContext ctx, intptr_t dimCount,
+                               intptr_t symbolCount, intptr_t nAffineExprs,
+                               MlirAffineExpr *affineExprs) {
+  SmallVector<AffineExpr, 4> exprs;
+  ArrayRef<AffineExpr> exprList = unwrapList(nAffineExprs, affineExprs, exprs);
+  return wrap(AffineMap::get(dimCount, symbolCount, exprList, unwrap(ctx)));
+}
+
 MlirAffineMap mlirAffineMapConstantGet(MlirContext ctx, int64_t val) {
   return wrap(AffineMap::getConstantMap(val, unwrap(ctx)));
 }
 
 MlirAffineMap mlirAffineMapMultiDimIdentityGet(MlirContext ctx,
                                                intptr_t numDims) {
   return wrap(AffineMap::getMultiDimIdentityMap(numDims, unwrap(ctx)));
 }

 intptr_t mlirAffineMapGetNumSymbols(MlirAffineMap affineMap) {
   return unwrap(affineMap).getNumSymbols();
 }
 
 intptr_t mlirAffineMapGetNumResults(MlirAffineMap affineMap) {
   return unwrap(affineMap).getNumResults();
 }
 
+MlirAffineExpr mlirAffineMapGetResult(MlirAffineMap affineMap, intptr_t pos) {
+  return wrap(unwrap(affineMap).getResult(static_cast<unsigned>(pos)));
+}
+
 intptr_t mlirAffineMapGetNumInputs(MlirAffineMap affineMap) {
   return unwrap(affineMap).getNumInputs();
 }
 
 bool mlirAffineMapIsProjectedPermutation(MlirAffineMap affineMap) {
   return unwrap(affineMap).isProjectedPermutation();
 }
 

mlir/test/Bindings/Python/ir_affine_map.py

def testAffineMapCapsule():
   # CHECK: mlir.ir.AffineMap._CAPIPtr
   affine_map_capsule = am1._CAPIPtr
   print(affine_map_capsule)
   am2 = AffineMap._CAPICreate(affine_map_capsule)
   assert am2 == am1
   assert am2.context is ctx
 
 run(testAffineMapCapsule)
+
+
+# CHECK-LABEL: TEST: testAffineMapGet
+def testAffineMapGet():
+  with Context() as ctx:
+    d0 = AffineDimExpr.get(0)
+    d1 = AffineDimExpr.get(1)
+    c2 = AffineConstantExpr.get(2)
+
+    # CHECK: (d0, d1)[s0, s1, s2] -> ()
+    map0 = AffineMap.get(2, 3, [])
+    print(map0)
+
+    # CHECK: (d0, d1)[s0, s1, s2] -> (d1, 2)
+    map1 = AffineMap.get(2, 3, [d1, c2])
+    print(map1)
+
+    # CHECK: () -> (2)
+    map2 = AffineMap.get(0, 0, [c2])
+    print(map2)
+
+    # CHECK: (d0, d1) -> (d0, d1)
+    map3 = AffineMap.get(2, 0, [d0, d1])
+    print(map3)
+
+    # CHECK: (d0, d1) -> (d1)
+    map4 = AffineMap.get(2, 0, [d1])
+    print(map4)
+
+    # CHECK: (d0, d1, d2) -> (d2, d0, d1)
+    map5 = AffineMap.get_permutation([2, 0, 1])
+    print(map5)
+
+    assert map1 == AffineMap.get(2, 3, [d1, c2])
+    assert AffineMap.get(0, 0, []) == AffineMap.get_empty()
+    assert map2 == AffineMap.get_constant(2)
+    assert map3 == AffineMap.get_identity(2)
+    assert map4 == AffineMap.get_minor_identity(2, 1)
+
+    try:
+      AffineMap.get(1, 1, [1])
+    except RuntimeError as e:
+      # CHECK: Invalid expression when attempting to create an AffineMap
+      print(e)
+
+    try:
+      AffineMap.get(1, 1, [None])
+    except RuntimeError as e:
+      # CHECK: Invalid expression (None?) when attempting to create an AffineMap
+      print(e)
+
+    try:
+      map3.get_submap([42])
+    except ValueError as e:
+      # CHECK: result position out of bounds
+      print(e)
+
+    try:
+      map3.get_minor_submap(42)
+    except ValueError as e:
+      # CHECK: number of results out of bounds
+      print(e)
+
+    try:
+      map3.get_major_submap(42)
+    except ValueError as e:
+      # CHECK: number of results out of bounds
+      print(e)
+
+run(testAffineMapGet)
+
+
+# CHECK-LABEL: TEST: testAffineMapDerive
+def testAffineMapDerive():
+  with Context() as ctx:
+    map5 = AffineMap.get_identity(5)
+
+    # CHECK: (d0, d1, d2, d3, d4) -> (d1, d2, d3)
+    map123 = map5.get_submap([1,2,3])
+    print(map123)
+
+    # CHECK: (d0, d1, d2, d3, d4) -> (d0, d1)
+    map01 = map5.get_major_submap(2)
+    print(map01)
+
+    # CHECK: (d0, d1, d2, d3, d4) -> (d3, d4)
+    map34 = map5.get_minor_submap(2)
+    print(map34)
+
+run(testAffineMapDerive)
+
+
+# CHECK-LABEL: TEST: testAffineMapProperties
+def testAffineMapProperties():
+  with Context():
+    d0 = AffineDimExpr.get(0)
+    d1 = AffineDimExpr.get(1)
+    d2 = AffineDimExpr.get(2)
+    map1 = AffineMap.get(3, 0, [d2, d0])
+    map2 = AffineMap.get(3, 0, [d2, d0, d1])
+    map3 = AffineMap.get(3, 1, [d2, d0, d1])
+    # CHECK: False
+    print(map1.is_permutation)
+    # CHECK: True
+    print(map1.is_projected_permutation)
+    # CHECK: True
+    print(map2.is_permutation)
+    # CHECK: True
+    print(map2.is_projected_permutation)
+    # CHECK: False
+    print(map3.is_permutation)
+    # CHECK: False
+    print(map3.is_projected_permutation)
+
+run(testAffineMapProperties)
+
+
+# CHECK-LABEL: TEST: testAffineMapExprs
+def testAffineMapExprs():
+  with Context():
+    d0 = AffineDimExpr.get(0)
+    d1 = AffineDimExpr.get(1)
+    d2 = AffineDimExpr.get(2)
+    map3 = AffineMap.get(3, 1, [d2, d0, d1])
+
+    # CHECK: 3
+    print(map3.n_dims)
+    # CHECK: 4
+    print(map3.n_inputs)
+    # CHECK: 1
+    print(map3.n_symbols)
+    assert map3.n_inputs == map3.n_dims + map3.n_symbols
+
+    # CHECK: 3
+    print(len(map3.results))
+    for expr in map3.results:
+      # CHECK: d2
+      # CHECK: d0
+      # CHECK: d1
+      print(expr)
+    for expr in map3.results[-1:-4:-1]:
+      # CHECK: d1
+      # CHECK: d0
+      # CHECK: d2
+      print(expr)
+    assert list(map3.results) == [d2, d0, d1]
+
+run(testAffineMapExprs)

mlir/test/CAPI/ir.c

int printBuiltinAttributes(MlirContext ctx) {
   mlirAttributeDump(sparseAttr);
   // CHECK: sparse<[4, 7], [0.000000e+00, 1.000000e+00]> : tensor<1x2xf32>
 
   return 0;
 }
 
 int printAffineMap(MlirContext ctx) {
   MlirAffineMap emptyAffineMap = mlirAffineMapEmptyGet(ctx);
-  MlirAffineMap affineMap = mlirAffineMapGet(ctx, 3, 2);
+  MlirAffineMap affineMap = mlirAffineMapZeroResultGet(ctx, 3, 2);
   MlirAffineMap constAffineMap = mlirAffineMapConstantGet(ctx, 2);
   MlirAffineMap multiDimIdentityAffineMap =
       mlirAffineMapMultiDimIdentityGet(ctx, 3);
   MlirAffineMap minorIdentityAffineMap =
       mlirAffineMapMinorIdentityGet(ctx, 3, 2);
   unsigned permutation[] = {1, 2, 0};
   MlirAffineMap permutationAffineMap = mlirAffineMapPermutationGet(
       ctx, sizeof(permutation) / sizeof(unsigned), permutation);
if (!mlirAffineExprEqual(affineDimExpr, otherDimExpr))
     return 18;
 
   if (mlirAffineExprIsNull(affineDimExpr))
     return 19;
 
   return 0;
 }
 
+int affineMapFromExprs(MlirContext ctx) {
+  MlirAffineExpr affineDimExpr = mlirAffineDimExprGet(ctx, 0);
+  MlirAffineExpr affineSymbolExpr = mlirAffineSymbolExprGet(ctx, 1);
+  MlirAffineExpr exprs[] = {affineDimExpr, affineSymbolExpr};
+  MlirAffineMap map = mlirAffineMapGet(ctx, 3, 3, 2, exprs);
+
+  // CHECK-LABEL: @affineMapFromExprs
+  fprintf(stderr, "@affineMapFromExprs");
+  // CHECK: (d0, d1, d2)[s0, s1, s2] -> (d0, s1)
+  mlirAffineMapDump(map);
+
+  if (mlirAffineMapGetNumResults(map) != 2)
+    return 1;
+
+  if (!mlirAffineExprEqual(mlirAffineMapGetResult(map, 0), affineDimExpr))
+    return 2;
+
+  if (!mlirAffineExprEqual(mlirAffineMapGetResult(map, 1), affineSymbolExpr))
+    return 3;
+
+  return 0;
+}
+
 int registerOnlyStd() {
   MlirContext ctx = mlirContextCreate();
   // The built-in dialect is always loaded.
   if (mlirContextGetNumLoadedDialects(ctx) != 1)
     return 1;
 
   MlirDialect std =
       mlirContextGetOrLoadDialect(ctx, mlirStandardDialectGetNamespace());
int main() {
   if (printBuiltinTypes(ctx))
     return 2;
   if (printBuiltinAttributes(ctx))
     return 3;
   if (printAffineMap(ctx))
     return 4;
   if (printAffineExpr(ctx))
     return 5;
-  if (registerOnlyStd())
+  if (affineMapFromExprs(ctx))
     return 6;
+  if (registerOnlyStd())
+    return 7;
 
   mlirContextDestroy(ctx);
 
   testDiagnostics();
   return 0;
 }