[Mlir-commits] [mlir] Fix RemoveDeadValues: Bail out early when there are no terminators (PR #133316)

[llvmlistbot at llvm.org]

https://github.com/hiraditya created https://github.com/llvm/llvm-project/pull/133316

Fixes: #131765

>From 3db58f8caa6d5abcc3c036f858201fc22c521a78 Mon Sep 17 00:00:00 2001
From: AdityaK <hiraditya at msn.com>
Date: Thu, 27 Mar 2025 21:05:38 +0000
Subject: [PATCH] Fix RemoveDeadValues: Bail out early when there are no
 terminators

Fixes: #131765
---
 mlir/lib/Transforms/RemoveDeadValues.cpp     |  2 ++
 mlir/test/Transforms/remove-dead-values.mlir | 15 +++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/mlir/lib/Transforms/RemoveDeadValues.cpp b/mlir/lib/Transforms/RemoveDeadValues.cpp
index c20c54551cdf8..92c05d87a002d 100644
--- a/mlir/lib/Transforms/RemoveDeadValues.cpp
+++ b/mlir/lib/Transforms/RemoveDeadValues.cpp
@@ -305,6 +305,8 @@ static void processFuncOp(FunctionOpInterface funcOp, Operation *module,
   // since it forwards only to non-live value(s) (%1#1).
   Operation *lastReturnOp = funcOp.back().getTerminator();
   size_t numReturns = lastReturnOp->getNumOperands();
+  if (numReturns == 0)
+    return;
   BitVector nonLiveRets(numReturns, true);
   for (SymbolTable::SymbolUse use : uses) {
     Operation *callOp = use.getUser();
diff --git a/mlir/test/Transforms/remove-dead-values.mlir b/mlir/test/Transforms/remove-dead-values.mlir
index e549926b90456..21d53b0742e07 100644
--- a/mlir/test/Transforms/remove-dead-values.mlir
+++ b/mlir/test/Transforms/remove-dead-values.mlir
@@ -446,6 +446,21 @@ func.func @kernel(%arg0: memref<18xf32>) {
 
 // -----
 
+
+// CHECK-LABEL: llvm_unreachable
+// CHECK-LABEL: @fn_with_llvm_unreachable
+// CHECK-LABEL: @main
+// CHECK: llvm.return
+module @llvm_unreachable {
+  func.func private @fn_with_llvm_unreachable(%arg0: tensor<4x4xf32>) -> tensor<4x4xi1> {
+    llvm.unreachable
+  }
+  func.func private @main(%arg0: tensor<4x4xf32>) {
+    %0 = call @fn_with_llvm_unreachable(%arg0) : (tensor<4x4xf32>) -> tensor<4x4xi1>
+    llvm.return
+  }
+}
+
 // CHECK: func.func private @no_block_func_declaration()
 func.func private @no_block_func_declaration() -> ()