1 files changed, 52 insertions, 4 deletions

diff --git a/src/llvm_backend_proc.cpp b/src/llvm_backend_proc.cpp
index 610c34de2..5270d6c30 100644
--- a/src/llvm_backend_proc.cpp
+++ b/src/llvm_backend_proc.cpp
@@ -253,6 +253,11 @@ gb_internal lbProcedure *lb_create_procedure(lbModule *m, Entity *entity, bool i
 			if (e->flags&EntityFlag_NoAlias) {
 				lb_add_proc_attribute_at_index(p, offset+parameter_index, "noalias");
 			}
+			if (e->flags&EntityFlag_NoCapture) {
+				if (is_type_internally_pointer_like(e->type)) {
+					lb_add_proc_attribute_at_index(p, offset+parameter_index, "nocapture");
+				}
+			}
 			parameter_index += 1;
 		}
 	}
@@ -517,6 +522,7 @@ gb_internal void lb_begin_procedure_body(lbProcedure *p) {
 	lb_start_block(p, p->entry_block);
 
 	map_init(&p->direct_parameters);
+	p->variadic_reuses.allocator = heap_allocator();
 
 	GB_ASSERT(p->type != nullptr);
 
@@ -3450,17 +3456,59 @@ gb_internal lbValue lb_build_call_expr_internal(lbProcedure *p, Ast *expr) {
 					}
 					isize slice_len = var_args.count;
 					if (slice_len > 0) {
-						lbAddr slice = lb_add_local_generated(p, slice_type, true);
-						lbAddr base_array = lb_add_local_generated(p, alloc_type_array(elem_type, slice_len), true);
+						lbAddr slice = {};
+
+						for (auto const &vr : p->variadic_reuses) {
+							if (are_types_identical(vr.slice_type, slice_type)) {
+								slice = vr.slice_addr;
+								break;
+							}
+						}
+
+						DeclInfo *d = decl_info_of_entity(p->entity);
+						if (d != nullptr && slice.addr.value == nullptr) {
+							for (auto const &vr : d->variadic_reuses) {
+								if (are_types_identical(vr.slice_type, slice_type)) {
+								#if LLVM_VERSION_MAJOR >= 13
+									// NOTE(bill): No point wasting even more memory, just reuse this stack variable too
+									if (p->variadic_reuses.count > 0) {
+										slice = p->variadic_reuses[0].slice_addr;
+									} else {
+										slice = lb_add_local_generated(p, slice_type, true);
+									}
+									// NOTE(bill): Change the underlying type to match the specific type
+									slice.addr.type = alloc_type_pointer(slice_type);
+								#else
+									slice = lb_add_local_generated(p, slice_type, true);
+								#endif
+									array_add(&p->variadic_reuses, lbVariadicReuseSlices{slice_type, slice});
+									break;
+								}
+							}
+						}
+
+						lbValue base_array_ptr = p->variadic_reuse_base_array_ptr.addr;
+						if (d != nullptr && base_array_ptr.value == nullptr) {
+							i64 max_bytes = d->variadic_reuse_max_bytes;
+							i64 max_align = gb_max(d->variadic_reuse_max_align, 16);
+							p->variadic_reuse_base_array_ptr = lb_add_local_generated(p, alloc_type_array(t_u8, max_bytes), true);
+							lb_try_update_alignment(p->variadic_reuse_base_array_ptr.addr, cast(unsigned)max_align);
+							base_array_ptr = p->variadic_reuse_base_array_ptr.addr;
+						}
+
+						GB_ASSERT(base_array_ptr.value != nullptr);
+						GB_ASSERT(slice.addr.value != nullptr);
+
+						base_array_ptr = lb_emit_conv(p, base_array_ptr, alloc_type_pointer(alloc_type_array(elem_type, slice_len)));
 
 						for (isize i = 0; i < var_args.count; i++) {
-							lbValue addr = lb_emit_array_epi(p, base_array.addr, cast(i32)i);
+							lbValue addr = lb_emit_array_epi(p, base_array_ptr, cast(i32)i);
 							lbValue var_arg = var_args[i];
 							var_arg = lb_emit_conv(p, var_arg, elem_type);
 							lb_emit_store(p, addr, var_arg);
 						}
 
-						lbValue base_elem = lb_emit_array_epi(p, base_array.addr, 0);
+						lbValue base_elem = lb_emit_array_epi(p, base_array_ptr, 0);
 						lbValue len = lb_const_int(p->module, t_int, slice_len);
 						lb_fill_slice(p, slice, base_elem, len);