transformations: (memref-to-dsd) Support pre-existing GetMemDsd ops

tests/filecheck/transforms/memref-to-dsd.mlir

@@ -106,6 +106,14 @@ builtin.module {
 // CHECK-NEXT: %28 = "csl.load_var"(%27) : (!csl.var<!csl<dsd mem1d_dsd>>) -> !csl<dsd mem1d_dsd>
 // CHECK-NEXT: "csl.store_var"(%27, %28) : (!csl.var<!csl<dsd mem1d_dsd>>, !csl<dsd mem1d_dsd>) -> ()
 
+// ensure that pre-existing get_mem_dsd ops access the underlying buffer, not the get_mem_dsd created on top of it
+
+%36 = arith.constant 510 : i16
+%37 = "csl.get_mem_dsd"(%b, %36) : (memref<510xf32>, i16) -> !csl<dsd mem1d_dsd>
+
+// CHECK-NEXT: %29 = arith.constant 510 : i16
+// CHECK-NEXT: %30 = "csl.get_mem_dsd"(%b, %29) : (memref<510xf32>, i16) -> !csl<dsd mem1d_dsd>
+
 }) {sym_name = "program"} :  () -> ()
 }
 // CHECK-NEXT: }) {"sym_name" = "program"} :  () -> ()

xdsl/transforms/memref_to_dsd.py

@@ -17,7 +17,7 @@
     StridedLayoutAttr,
     UnrealizedConversionCastOp,
 )
-from xdsl.ir import Attribute, Operation, SSAValue
+from xdsl.ir import Attribute, Operation, OpResult, SSAValue
 from xdsl.passes import ModulePass
 from xdsl.pattern_rewriter import (
     GreedyRewritePatternApplier,
@@ -64,6 +64,31 @@ def match_and_rewrite(self, op: memref.Alloc, rewriter: PatternRewriter, /):
         rewriter.replace_matched_op([zeros_op, *shape, dsd_op])
 
 
+class FixGetDsdOnGetDsd(RewritePattern):
+    """
+    This rewrite pattern resolves GetMemDsdOp being called on GetMemDsdOp instead of the underlying buffer,
+    a side effect created by `LowerAllocOpPass` in case of pre-existing GetMemDsdOp ops being present in
+    the program that were created outside of this pass.
+    """
+
+    @op_type_rewrite_pattern
+    def match_and_rewrite(self, op: csl.GetMemDsdOp, rewriter: PatternRewriter, /):
+        if isinstance(op.base_addr.type, csl.DsdType):
+            if isinstance(op.base_addr, OpResult) and isinstance(
+                op.base_addr.op, csl.GetMemDsdOp
+            ):
+                rewriter.replace_matched_op(
+                    csl.GetMemDsdOp.build(
+                        operands=[op.base_addr.op.base_addr, op.sizes],
+                        properties=op.properties,
+                        attributes=op.attributes,
+                        result_types=op.result_types,
+                    )
+                )
+            else:
+                raise ValueError("Failed to resolve GetMemDsdOp called on dsd type")
+
+
 class LowerSubviewOpPass(RewritePattern):
     """Lowers memref.subview to dsd ops"""
 
@@ -335,3 +360,7 @@ def apply(self, ctx: MLContext, op: ModuleOp) -> None:
             apply_recursively=False,
         )
         forward_pass.rewrite_module(op)
+        cleanup_pass = PatternRewriteWalker(
+            FixGetDsdOnGetDsd(),
+        )
+        cleanup_pass.rewrite_module(op)