diff --git a/src/codegen.cpp b/src/codegen.cpp
index d664a21ecc..2170da10ac 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -2216,7 +2216,7 @@ static bool iter_function_params_c_abi(CodeGen *g, ZigType *fn_type, FnWalk *fn_
             assert(handle_is_ptr(ty));
             switch (fn_walk->id) {
                 case FnWalkIdAttrs:
-                    addLLVMArgAttr(llvm_fn, fn_walk->data.attrs.gen_i, "byval");
+                    ZigLLVMAddByValAttr(llvm_fn, fn_walk->data.attrs.gen_i + 1, get_llvm_type(g, ty));
                     addLLVMArgAttrInt(llvm_fn, fn_walk->data.attrs.gen_i, "align", get_abi_alignment(g, ty));
                     // Byvalue parameters must not have address 0
                     addLLVMArgAttr(llvm_fn, fn_walk->data.attrs.gen_i, "nonnull");
diff --git a/src/zig_llvm.cpp b/src/zig_llvm.cpp
index c033d7af96..b82d0c51ba 100644
--- a/src/zig_llvm.cpp
+++ b/src/zig_llvm.cpp
@@ -723,6 +723,16 @@ void ZigLLVMSetFastMath(LLVMBuilderRef builder_wrapped, bool on_state) {
     }
 }
 
+void ZigLLVMAddByValAttr(LLVMValueRef fn_ref, unsigned ArgNo, LLVMTypeRef type_val) {
+    Function *func = unwrap<Function>(fn_ref);
+    const AttributeList attr_set = func->getAttributes();
+    AttrBuilder attr_builder;
+    Type *llvm_type = unwrap<Type>(type_val);
+    attr_builder.addByValAttr(llvm_type);
+    const AttributeList new_attr_set = attr_set.addAttributes(func->getContext(), ArgNo, attr_builder);
+    func->setAttributes(new_attr_set);
+}
+
 void ZigLLVMAddFunctionAttr(LLVMValueRef fn_ref, const char *attr_name, const char *attr_value) {
     Function *func = unwrap<Function>(fn_ref);
     const AttributeList attr_set = func->getAttributes();
diff --git a/src/zig_llvm.h b/src/zig_llvm.h
index 210f245efe..10b6d24364 100644
--- a/src/zig_llvm.h
+++ b/src/zig_llvm.h
@@ -213,6 +213,7 @@ ZIG_EXTERN_C struct ZigLLVMDILocation *ZigLLVMGetDebugLoc(unsigned line, unsigne
 ZIG_EXTERN_C void ZigLLVMSetFastMath(LLVMBuilderRef builder_wrapped, bool on_state);
 
 ZIG_EXTERN_C void ZigLLVMAddFunctionAttr(LLVMValueRef fn, const char *attr_name, const char *attr_value);
+ZIG_EXTERN_C void ZigLLVMAddByValAttr(LLVMValueRef fn_ref, unsigned ArgNo, LLVMTypeRef type_val);
 ZIG_EXTERN_C void ZigLLVMAddFunctionAttrCold(LLVMValueRef fn);
 
 ZIG_EXTERN_C void ZigLLVMParseCommandLineOptions(size_t argc, const char *const *argv);