Allowing IRs with global constants to get dead values removed

Author: parsifal-47

mlir/lib/Transforms/RemoveDeadValues.cpp

@@ -579,7 +579,6 @@ void RemoveDeadValues::runOnOperation() {
     if (op == module)
       return WalkResult::advance();
     if (isa<BranchOpInterface>(op) ||
-        (isa<SymbolOpInterface>(op) && !isa<FunctionOpInterface>(op)) ||
         (isa<SymbolUserOpInterface>(op) && !isa<CallOpInterface>(op))) {
       op->emitError() << "cannot optimize an IR with non-function symbol ops, "
                          "non-call symbol user ops or branch ops\n";

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

@@ -1,12 +1,12 @@
 // RUN: mlir-opt %s -remove-dead-values -split-input-file -verify-diagnostics | FileCheck %s
 
-// The IR remains untouched because of the presence of a non-function-like
-// symbol op inside the module (const @__dont_touch_unacceptable_ir).
+// The IR is updated regardless of memref.global private constant
 //
 module {
-// expected-error @+1 {{cannot optimize an IR with non-function symbol ops, non-call symbol user ops or branch ops}}
   memref.global "private" constant @__dont_touch_unacceptable_ir : memref<i32> = dense<0>
   func.func @main(%arg0: i32) -> i32 {
+    %0 = tensor.empty() : tensor<10xbf16>
+    // CHECK-NOT: tensor.empty
     return %arg0 : i32
   }
 }