Allow SymbolUserOpInterface operators to be used in RemoveDeadValues Pass (#117405)

This change removes the restriction on `SymbolUserOpInterface` operators
so they can be used with operators that implement `SymbolOpInterface`,
example:

`memref.global` implements `SymbolOpInterface` so it can be used with
`memref.get_global` which implements `SymbolUserOpInterface`

```
// Define a global constant array
memref.global "private" constant @global_array : memref<10xi32> = dense<[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]> : tensor<10xi32>

// Access this global constant within a function
func @use_global() {
  %0 = memref.get_global @global_array : memref<10xi32>
}
```

Reference: #116519 and
https://discourse.llvm.org/t/question-on-criteria-for-acceptable-ir-in-removedeadvaluespass/83131

---------

Co-authored-by: Zeeshan Siddiqui <[email protected]>

Author: codemzs

mlir/lib/Transforms/RemoveDeadValues.cpp

@@ -577,10 +577,8 @@ void RemoveDeadValues::runOnOperation() {
   WalkResult acceptableIR = module->walk([&](Operation *op) {
     if (op == module)
       return WalkResult::advance();
-    if (isa<BranchOpInterface>(op) ||
-        (isa<SymbolUserOpInterface>(op) && !isa<CallOpInterface>(op))) {
-      op->emitError() << "cannot optimize an IR with "
-                         "non-call symbol user ops or branch ops\n";
+    if (isa<BranchOpInterface>(op)) {
+      op->emitError() << "cannot optimize an IR with branch ops\n";
       return WalkResult::interrupt();
     }
     return WalkResult::advance();

mlir/test/Transforms/remove-dead-values.mlir

@@ -3,9 +3,12 @@
 // The IR is updated regardless of memref.global private constant
 //
 module {
-  memref.global "private" constant @__something_global : memref<i32> = dense<0>
+  // CHECK: memref.global "private" constant @__constant_4xi32 : memref<4xi32> = dense<[1, 2, 3, 4]> {alignment = 16 : i64}
+  memref.global "private" constant @__constant_4xi32 : memref<4xi32> = dense<[1, 2, 3, 4]> {alignment = 16 : i64}
   func.func @main(%arg0: i32) -> i32 {
     %0 = tensor.empty() : tensor<10xbf16>
+    // CHECK-NOT: memref.get_global
+    %1 = memref.get_global @__constant_4xi32 : memref<4xi32>
     // CHECK-NOT: tensor.empty
     return %arg0 : i32
   }
@@ -29,7 +32,7 @@ module @named_module_acceptable {
 //
 func.func @dont_touch_unacceptable_ir_has_cleanable_simple_op_with_branch_op(%arg0: i1) {
   %non_live = arith.constant 0 : i32
-  // expected-error @+1 {{cannot optimize an IR with non-call symbol user ops or branch ops}}
+  // expected-error @+1 {{cannot optimize an IR with branch ops}}
   cf.cond_br %arg0, ^bb1(%non_live : i32), ^bb2(%non_live : i32)
 ^bb1(%non_live_0 : i32):
   cf.br ^bb3