https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93262
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Untested trunk fix on top of the PR93249 fix, so won't apply cleanly to older
stuff, will need reindentation:
--- tree-ssa-dse.c.jj2 2020-01-14 12:13:39.900589819 +0100
+++ tree-ssa-dse.c 2020-01-14 13:47:50.085009665 +0100
@@ -508,6 +508,22 @@ maybe_trim_memstar_call (ao_ref *ref, sb
/* Head trimming requires adjusting all the arguments. */
if (head_trim)
{
+ /* For __*_chk need to adjust also the last argument. */
+ if (gimple_call_num_args (stmt) == 4)
+ {
+ tree size = gimple_call_arg (stmt, 3);
+ if (!tree_fits_uhwi_p (size))
+ break;
+ if (!integer_all_onesp (size))
+ {
+ unsigned HOST_WIDE_INT sz = tree_to_uhwi (size);
+ if (sz < (unsigned) head_trim)
+ break;
+ tree arg = wide_int_to_tree (TREE_TYPE (size),
+ sz - head_trim);
+ gimple_call_set_arg (stmt, 3, arg);
+ }
+ }
tree *dst = gimple_call_arg_ptr (stmt, 0);
increment_start_addr (stmt, dst, head_trim);
tree *src = gimple_call_arg_ptr (stmt, 1);
@@ -527,6 +543,22 @@ maybe_trim_memstar_call (ao_ref *ref, sb
/* Head trimming requires adjusting all the arguments. */
if (head_trim)
{
+ /* For __*_chk need to adjust also the last argument. */
+ if (gimple_call_num_args (stmt) == 4)
+ {
+ tree size = gimple_call_arg (stmt, 3);
+ if (!tree_fits_uhwi_p (size))
+ break;
+ if (!integer_all_onesp (size))
+ {
+ unsigned HOST_WIDE_INT sz = tree_to_uhwi (size);
+ if (sz < (unsigned) head_trim)
+ break;
+ tree arg = wide_int_to_tree (TREE_TYPE (size),
+ sz - head_trim);
+ gimple_call_set_arg (stmt, 3, arg);
+ }
+ }
tree *dst = gimple_call_arg_ptr (stmt, 0);
increment_start_addr (stmt, dst, head_trim);
decrement_count (stmt, head_trim);
Now to figure out if we want a runtime testcase in
gcc.c-torture/execute/builtins/ or not...
