https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61265
--- Comment #2 from Chris Manghane <cmang at google dot com> ---
A slightly smaller program can reproduce this as well:
package main
var a = [1][0]int{B}[0]
var B = [0]int{}
func main() {}
This error occurs because in Gcc_backend::fill_in_array, the type of B, [0]int,
is represented using build_array_type(int, build_index_type(len - 1)), where
len is 0 in this case, giving it a range of [0:MAX_INT] where it should be
[0:0]. The following patch fixes this behavior:
Index: gcc/go/go-gcc.cc
======================================================================
--- a/gcc/go/go-gcc.cc
+++ b/gcc/go/go-gcc.cc
@@ -887,9 +887,13 @@ Gcc_backend::fill_in_array(Btype* fill, Btype*
element_type,
// build_index_type takes the maximum index, which is one less than
// the length.
- tree index_type_tree = build_index_type(fold_build2(MINUS_EXPR, sizetype,
- length_tree,
- size_one_node));
+ tree index_type_tree = NULL_TREE;
+ if (length_tree == size_zero_node)
+ index_type_tree = build_index_type(size_zero_node);
+ else
+ index_type_tree = build_index_type(fold_build2(MINUS_EXPR, sizetype,
+ length_tree,
+ size_one_node));
tree fill_tree = fill->get_tree();
TREE_TYPE(fill_tree) = element_type_tree;
