diff --git a/src/ir.cpp b/src/ir.cpp
index 2de2b2669..e00dc42ee 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -1713,6 +1713,7 @@ irValue *ir_add_local(irProcedure *proc, Entity *e, Ast *expr, bool zero_initial
 	if (zero_initialized) {
 		ir_emit_zero_init(proc, instr, expr);
 	}
+	set_procedure_abi_types(heap_allocator(), e->type);
 
 	// if (proc->module->generate_debug_info && expr != nullptr && proc->entity != nullptr) {
 	// if (proc->module->generate_debug_info && proc->entity != nullptr) {
diff --git a/src/ir_print.cpp b/src/ir_print.cpp
index f3840fce8..2baf1c2a0 100644
--- a/src/ir_print.cpp
+++ b/src/ir_print.cpp
@@ -354,7 +354,22 @@ void ir_print_proc_type_without_pointer(irFileBuffer *f, irModule *m, Type *t) {
 		if (i+1 == param_count && t->Proc.c_vararg) {
 			ir_write_string(f, str_lit("..."));
 		} else {
-			ir_print_type(f, m, t->Proc.abi_compat_params[i]);
+			Type *et = t->Proc.abi_compat_params[i];
+			if (is_type_tuple(et)) {
+				for_array(j, et->Tuple.variables) {
+					if (j > 0) ir_write_str_lit(f, ", ");
+
+					ir_print_type(f, m, et->Tuple.variables[j]->type);
+					if (e->flags&EntityFlag_NoAlias) {
+						ir_write_str_lit(f, " noalias");
+					}
+					ir_write_byte(f, ' ');
+					param_index++;
+				}
+				continue;
+			} else {
+				ir_print_type(f, m, et);
+			}
 		}
 
 		param_index++;
@@ -2111,30 +2126,50 @@ void ir_print_instr(irFileBuffer *f, irModule *m, irValue *value) {
 			TypeTuple *params = &proc_type->Proc.params->Tuple;
 			if (proc_type->Proc.c_vararg) {
 				isize i = 0;
+				isize arg_index = 0;
 				for (; i < params->variables.count-1; i++) {
 					Entity *e = params->variables[i];
 					GB_ASSERT(e != nullptr);
-					if (e->kind != Entity_Variable) continue;
+					if (e->kind != Entity_Variable) {
+						arg_index++;
+						continue;
+					}
 
 					if (param_index > 0) ir_write_str_lit(f, ", ");
 
 					Type *t = proc_type->Proc.abi_compat_params[i];
-					ir_print_type(f, m, t);
-					if (e->flags&EntityFlag_NoAlias) {
-						ir_write_str_lit(f, " noalias");
+					if (is_type_tuple(t)) {
+						for_array(j, t->Tuple.variables) {
+							if (j > 0) ir_write_str_lit(f, ", ");
+
+							irValue *arg = call->args[arg_index++];
+
+							ir_print_type(f, m, t->Tuple.variables[j]->type);
+							if (e->flags&EntityFlag_NoAlias) {
+								ir_write_str_lit(f, " noalias");
+							}
+							ir_write_byte(f, ' ');
+							ir_print_value(f, m, arg, t);
+							param_index++;
+						}
+					} else {
+						ir_print_type(f, m, t);
+						if (e->flags&EntityFlag_NoAlias) {
+							ir_write_str_lit(f, " noalias");
+						}
+						if (e->flags&EntityFlag_ImplicitReference) {
+							ir_write_str_lit(f, " nonnull dereferenceable");
+						}
+						ir_write_byte(f, ' ');
+						irValue *arg = call->args[arg_index++];
+						ir_print_value(f, m, arg, t);
+						param_index++;
 					}
-					if (e->flags&EntityFlag_ImplicitReference) {
-						ir_write_str_lit(f, " nonnull dereferenceable");
-					}
-					ir_write_byte(f, ' ');
-					irValue *arg = call->args[i];
-					ir_print_value(f, m, arg, t);
-					param_index++;
 				}
-				for (; i < call->args.count; i++) {
+				while (arg_index < call->args.count) {
 					if (param_index > 0) ir_write_str_lit(f, ", ");
 
-					irValue *arg = call->args[i];
+					irValue *arg = call->args[arg_index];
 					Type *t = ir_type(arg);
 					ir_print_type(f, m, t);
 					ir_write_byte(f, ' ');
diff --git a/src/types.cpp b/src/types.cpp
index b4d42d67a..cf8e603ba 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -3394,7 +3394,7 @@ gbString write_type_to_string(gbString str, Type *type) {
 
 	case Type_SimdVector:
 		if (type->SimdVector.is_x86_mmx) {
-			return "intrinsics.x86_mmx";
+			return gb_string_appendc(str, "intrinsics.x86_mmx");
 		} else {
 			str = gb_string_append_fmt(str, "#simd[%d]", cast(int)type->SimdVector.count);
 			str = write_type_to_string(str, type->SimdVector.elem);