transformations: Fix bug in memref-stream-unnest-out-parameters

tests/filecheck/transforms/memref_stream_unnest_out_parameters.mlir

@@ -26,4 +26,30 @@ memref_stream.generic {
 // CHECK-NEXT:      %{{.*}} = arith.addf %{{.*}}, %{{.*}} : f64
 // CHECK-NEXT:      memref_stream.yield %{{.*}} : f64
 // CHECK-NEXT:    }
+
+%X, %Y, %Z  = "test.op"() : () -> (memref<1x1x8x8xf64>, memref<1x1x3x3xf64>, memref<1x1x6x6xf64>)
+
+memref_stream.generic {
+    bounds = [#builtin.int<1>, #builtin.int<1>, #builtin.int<6>, #builtin.int<6>, #builtin.int<1>, #builtin.int<3>, #builtin.int<3>],
+    indexing_maps = [
+    affine_map<(d0, d1, d2, d3, d4, d5, d6) -> (d0, d4, d2 + d5, d3 + d6)>,
+    affine_map<(d0, d1, d2, d3, d4, d5, d6) -> (d1, d4, d5, d6)>,
+    affine_map<(d0, d1, d2, d3, d4, d5, d6) -> (d0, d1, d2, d3)>
+    ],
+    iterator_types = ["parallel", "parallel", "parallel", "parallel", "reduction", "reduction", "reduction"]
+} ins(%X, %Y : memref<1x1x8x8xf64>, memref<1x1x3x3xf64>) outs(%Z : memref<1x1x6x6xf64>) {
+^0(%x : f64, %y : f64, %acc : f64):
+    %prod = arith.mulf %x, %y fastmath<fast> : f64
+    %res = arith.addf %prod, %acc fastmath<fast> : f64
+    memref_stream.yield %res : f64
+}
+
+// CHECK-NEXT:    %X, %Y, %Z = "test.op"() : () -> (memref<1x1x8x8xf64>, memref<1x1x3x3xf64>, memref<1x1x6x6xf64>)
+// CHECK-NEXT:    memref_stream.generic {bounds = [#builtin.int<1>, #builtin.int<1>, #builtin.int<6>, #builtin.int<6>, #builtin.int<1>, #builtin.int<3>, #builtin.int<3>], indexing_maps = [affine_map<(d0, d1, d2, d3, d4, d5, d6) -> (d0, d4, (d2 + d5), (d3 + d6))>, affine_map<(d0, d1, d2, d3, d4, d5, d6) -> (d1, d4, d5, d6)>, affine_map<(d0, d1, d2, d3) -> (d0, d1, d2, d3)>], iterator_types = ["parallel", "parallel", "parallel", "parallel", "reduction", "reduction", "reduction"]} ins(%X, %Y : memref<1x1x8x8xf64>, memref<1x1x3x3xf64>) outs(%Z : memref<1x1x6x6xf64>) {
+// CHECK-NEXT:    ^1(%x : f64, %y : f64, %acc : f64):
+// CHECK-NEXT:      %prod_1 = arith.mulf %x, %y fastmath<fast> : f64
+// CHECK-NEXT:      %res = arith.addf %prod_1, %acc fastmath<fast> : f64
+// CHECK-NEXT:      memref_stream.yield %res : f64
+// CHECK-NEXT:    }
+
 // CHECK-NEXT:  }

xdsl/dialects/memref_stream.py

@@ -386,6 +386,10 @@ def get_static_loop_ranges(
             tuple(bound.data for bound in self.bounds.data[min_dims:]),
         )
 
+    @property
+    def is_imperfectly_nested(self) -> bool:
+        return bool(self.get_static_loop_ranges()[1])
+
     def _print_init(self, printer: Printer, init: SSAValue | None):
         if init is None:
             printer.print_string("None")

xdsl/transforms/memref_stream_unnest_out_parameters.py

@@ -22,10 +22,16 @@ class UnnestOutParametersPattern(RewritePattern):
     def match_and_rewrite(
         self, op: memref_stream.GenericOp, rewriter: PatternRewriter
     ) -> None:
+        if op.is_imperfectly_nested:
+            # Already unnested
+            return
+
         num_outputs = len(op.outputs)
         if not num_outputs:
             return
 
+        num_inputs = len(op.inputs)
+
         num_parallel = sum(
             i == memref_stream.IteratorTypeAttr.parallel() for i in op.iterator_types
         )
@@ -37,10 +43,10 @@ def match_and_rewrite(
 
         parallel_dims = (True,) * num_parallel + (False,) * num_reduction
 
-        maps = op.indexing_maps.data[num_parallel:]
+        maps = op.indexing_maps.data[num_inputs:]
         new_maps = ArrayAttr(
             (
-                *op.indexing_maps.data[:num_parallel],
+                *op.indexing_maps.data[:num_inputs],
                 *(AffineMapAttr(m.data.compress_dims(parallel_dims)) for m in maps),
             )
         )