Hi!
bootstrap-ubsan shows a couple of:
../../gcc/tree-chkp.c:694:37: runtime error: shift exponent 63 is too large for
32-bit type 'int'
errors.
1 << (TYPE_PRECISION (ptr_type_node) - 1)
should have been obviously
HOST_WIDE_INT_1U << (TYPE_PRECISION (ptr_type_node) - 1)
but even then, it is 1) unnecessarily complicated and expensive way
to create a pointer with just the MSB bit set and all other clear and
2) will not work if ptr_type_node has higher precision than HWI (just
theoretical possibility now)
For 1), e.g. fold_convert (ptr_type_node, integer_zero_node) is
better written as build_int_cst (ptr_type_node, 0), but still
we can actually avoid the fold_build_pointer_plus_hwi and folding
it altogether.
Bootstrapped/regtested on x86_64-linux and i686-linux (both normal
and bootstrap-ubsan), ok for trunk?
2017-07-19 Jakub Jelinek <ja...@redhat.com>
* tree-chkp.c (chkp_get_hard_register_var_fake_base_address):
Rewritten to avoid overflow for > 32-bit pointers.
--- gcc/tree-chkp.c.jj 2017-06-12 12:41:55.000000000 +0200
+++ gcc/tree-chkp.c 2017-06-19 12:57:24.670478544 +0200
@@ -690,9 +690,8 @@ chkp_erase_completed_bounds (void)
static tree
chkp_get_hard_register_var_fake_base_address ()
{
- tree base = fold_convert (ptr_type_node, integer_zero_node);
- unsigned HOST_WIDE_INT offset = 1 << (TYPE_PRECISION (ptr_type_node) - 1);
- return fold_build_pointer_plus_hwi (base, offset);
+ int prec = TYPE_PRECISION (ptr_type_node);
+ return wide_int_to_tree (ptr_type_node, wi::min_value (prec, SIGNED));
}
/* If we check bounds for a hard register variable, we cannot
Jakub
