[mlir] fix assertion failure in remove-dead-values

Author: Menooker

mlir/lib/Transforms/RemoveDeadValues.cpp

@@ -705,7 +705,8 @@ static void cleanUpDeadVals(RDVFinalCleanupList &list) {
 
   // 4. Operands
   for (auto &o : list.operands) {
-    o.op->eraseOperands(o.nonLive);
+    if (o.nonLive.size() > 0)
+      o.op->eraseOperands(o.nonLive);
   }
 
   // 5. Results

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

@@ -510,3 +510,25 @@ module {
 // CHECK: %[[yield:.*]] = arith.addf %{{.*}}, %{{.*}} : f32
 // CHECK: linalg.yield %[[yield]] : f32
 // CHECK-NOT: arith.subf
+
+
+// -----
+
+// check that ops with zero operands are correctly handled
+
+module {
+  func.func @test_zero_operands(%I: memref<10xindex>, %I2: memref<10xf32>) {
+    %v0 = arith.constant 0 : index
+    %result = memref.alloca_scope -> index {
+      %c = arith.addi %v0, %v0 : index
+      memref.store %c, %I[%v0] : memref<10xindex>
+      memref.alloca_scope.return %c: index
+    }
+    func.return
+  }
+}
+
+// CHECK-LABEL: func @test_zero_operands
+// CHECK: memref.alloca_scope
+// CHECK: memref.store
+// CHECK-NOT: memref.alloca_scope.return