[Mlir-commits] [mlir] [MLIR] RemoveDeadValues: Allowing IRs with global constants to get dead values removed (PR #116519)

[Renat Idrisov]

https://github.com/parsifal-47 updated https://github.com/llvm/llvm-project/pull/116519

>From 0247d1b5d19b892c95649da0a485b7ad17bbd8ac Mon Sep 17 00:00:00 2001
From: Renat Idrisov <parsifal-47 at users.noreply.github.com>
Date: Sat, 16 Nov 2024 21:16:25 +0000
Subject: [PATCH 1/2] Allowing IRs with global constants to get dead values
 removed

---
 mlir/lib/Transforms/RemoveDeadValues.cpp     | 1 -
 mlir/test/Transforms/remove-dead-values.mlir | 6 +++---
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/mlir/lib/Transforms/RemoveDeadValues.cpp b/mlir/lib/Transforms/RemoveDeadValues.cpp
index 7e45f18b660ba7..edfb1969ab75c7 100644
--- a/mlir/lib/Transforms/RemoveDeadValues.cpp
+++ b/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";
diff --git a/mlir/test/Transforms/remove-dead-values.mlir b/mlir/test/Transforms/remove-dead-values.mlir
index 9f2be3331b6b4b..b06b3320706cc8 100644
--- a/mlir/test/Transforms/remove-dead-values.mlir
+++ b/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
   }
 }

>From c145899e5439bf2acd3a66013316c1915c63f98b Mon Sep 17 00:00:00 2001
From: Renat Idrisov <parsifal-47 at users.noreply.github.com>
Date: Mon, 18 Nov 2024 14:55:59 -0800
Subject: [PATCH 2/2] Address feedback from Code Review

---
 mlir/lib/Transforms/RemoveDeadValues.cpp     | 5 ++---
 mlir/test/Transforms/remove-dead-values.mlir | 4 ++--
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/mlir/lib/Transforms/RemoveDeadValues.cpp b/mlir/lib/Transforms/RemoveDeadValues.cpp
index edfb1969ab75c7..b82280dda8ba73 100644
--- a/mlir/lib/Transforms/RemoveDeadValues.cpp
+++ b/mlir/lib/Transforms/RemoveDeadValues.cpp
@@ -573,14 +573,13 @@ void RemoveDeadValues::runOnOperation() {
   Operation *module = getOperation();
 
   // The removal of non-live values is performed iff there are no branch ops,
-  // all symbol ops present in the IR are function-like, and all symbol user ops
-  // present in the IR are call-like.
+  // and all symbol user ops present in the IR are call-like.
   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-function symbol ops, "
+      op->emitError() << "cannot optimize an IR with "
                          "non-call symbol user ops or branch ops\n";
       return WalkResult::interrupt();
     }
diff --git a/mlir/test/Transforms/remove-dead-values.mlir b/mlir/test/Transforms/remove-dead-values.mlir
index b06b3320706cc8..47137fc6430fea 100644
--- a/mlir/test/Transforms/remove-dead-values.mlir
+++ b/mlir/test/Transforms/remove-dead-values.mlir
@@ -3,7 +3,7 @@
 // The IR is updated regardless of memref.global private constant
 //
 module {
-  memref.global "private" constant @__dont_touch_unacceptable_ir : memref<i32> = dense<0>
+  memref.global "private" constant @__something_global : memref<i32> = dense<0>
   func.func @main(%arg0: i32) -> i32 {
     %0 = tensor.empty() : tensor<10xbf16>
     // CHECK-NOT: tensor.empty
@@ -29,7 +29,7 @@ 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-function symbol ops, non-call symbol user ops or branch ops}}
+  // expected-error @+1 {{cannot optimize an IR with non-call symbol user ops or branch ops}}
   cf.cond_br %arg0, ^bb1(%non_live : i32), ^bb2(%non_live : i32)
 ^bb1(%non_live_0 : i32):
   cf.br ^bb3