[Mlir-commits] [mlir] [mlir][memref] Fix hoist-static-allocs option of buffer-results-to-out-params when function parameters are returned (PR #102093)

[donald chen]

================
@@ -34,4 +34,15 @@ func.func @basic_dynamic(%d: index) -> (memref<?xf32>) {
   %b = memref.alloc(%d) : memref<?xf32>
   "test.source"(%b)  : (memref<?xf32>) -> ()
   return %b : memref<?xf32>
-}
\ No newline at end of file
+}
+
+// CHECK-LABEL:   func @return_arg(
+// CHECK-SAME:        %[[ARG0:.*]]: memref<128x256xf32>, %[[ARG1:.*]]: memref<128x256xf32>, %[[ARG2:.*]]: memref<128x256xf32>) {
+// CHECK:           "test.source"(%[[ARG0]], %[[ARG1]])
+// CHECK-NOT:       memref.copy
+// CHECK:           return
+// CHECK:         }
+func.func @return_arg(%arg0: memref<128x256xf32>, %arg1: memref<128x256xf32>) -> memref<128x256xf32> {
+  "test.source"(%arg0, %arg1)  : (memref<128x256xf32>, memref<128x256xf32>) -> ()
+  return %arg0 : memref<128x256xf32>
+}
----------------
cxy-1993 wrote:

As we disscussed before: Even though mayHoistStaticAlloc is true, this can still confuse users. Originally, users expected the value in the returned memref to be identical to %arg0. After the copy, it's different.

https://github.com/llvm/llvm-project/pull/102093