diff --git a/include/sirit/sirit.h b/include/sirit/sirit.h
index 698e6e0..94211c1 100644
--- a/include/sirit/sirit.h
+++ b/include/sirit/sirit.h
@@ -292,6 +292,9 @@ class Module {
     /// Unsigned-integer division of Operand 1 divided by Operand 2.
     Id OpUDiv(Id result_type, Id operand_1, Id operand_2);
 
+    /// Unsigned modulo operation of Operand 1 modulo Operand 2.
+    Id OpUMod(Id result_type, Id operand_1, Id operand_2);
+
     /// Floating-point division of Operand 1 divided by Operand 2.
     Id OpFDiv(Id result_type, Id operand_1, Id operand_2);
 
@@ -314,7 +317,7 @@ class Module {
 
     Id AddDeclaration(std::unique_ptr<Op> op);
 
-    Id AddAnnotation(std::unique_ptr<Op> op);
+    void AddAnnotation(std::unique_ptr<Op> op);
 
     Id GetGLSLstd450();
 
diff --git a/src/insts/annotation.cpp b/src/insts/annotation.cpp
index 400af8d..8f8305a 100644
--- a/src/insts/annotation.cpp
+++ b/src/insts/annotation.cpp
@@ -18,7 +18,8 @@ Id Module::Decorate(Id target, spv::Decoration decoration,
     op->Add(target);
     op->Add(static_cast<u32>(decoration));
     op->Add(literals);
-    return AddAnnotation(std::move(op));
+    AddAnnotation(std::move(op));
+    return target;
 }
 
 Id Module::MemberDecorate(Id structure_type, Literal member,
@@ -29,7 +30,8 @@ Id Module::MemberDecorate(Id structure_type, Literal member,
     op->Add(member);
     op->Add(static_cast<u32>(decoration));
     op->Add(literals);
-    return AddAnnotation(std::move(op));
+    AddAnnotation(std::move(op));
+    return structure_type;
 }
 
 } // namespace Sirit
diff --git a/src/insts/arithmetic.cpp b/src/insts/arithmetic.cpp
index 5cedb2c..64a6a8a 100644
--- a/src/insts/arithmetic.cpp
+++ b/src/insts/arithmetic.cpp
@@ -29,6 +29,7 @@ namespace Sirit {
 DEFINE_UNARY(OpFNegate, spv::Op::OpFNegate);
 
 DEFINE_BINARY(OpUDiv, spv::Op::OpUDiv)
+DEFINE_BINARY(OpUMod, spv::Op::OpUMod)
 DEFINE_BINARY(OpFDiv, spv::Op::OpFDiv)
 DEFINE_BINARY(OpIAdd, spv::Op::OpIAdd)
 
diff --git a/src/sirit.cpp b/src/sirit.cpp
index 6726985..be0b7fb 100644
--- a/src/sirit.cpp
+++ b/src/sirit.cpp
@@ -119,10 +119,9 @@ Id Module::AddDeclaration(std::unique_ptr<Op> op) {
     return id;
 }
 
-Id Module::AddAnnotation(std::unique_ptr<Op> op) {
+void Module::AddAnnotation(std::unique_ptr<Op> op) {
     const auto id = op.get();
     annotations.push_back(std::move(op));
-    return id;
 }
 
 Id Module::GetGLSLstd450() {