I've looked at PR64277 and noticed we haven't been applying TLC to the
array-bound warning code for a long time. I noticed we don't
warn for out-of-bound return &a[11]; - fixed with the simplifications.
I also noticed that anti-range handling has off-by-one errors
(well, always applied ignore_off_by_one and to both ends of the array).
Bootstrap and regtest pending on x86_64-unknown-linux-gnu.
It doesn't help the testcase in PR64277 ([2/2] will somewhat).
Ok for trunk? (seems we never warned for returning &a[11] and
anti-range handling was broken all the time)
I can as well queue this for GCC 6.
Thanks,
Richard.
2015-01-26 Richard Biener <rguent...@suse.de>
PR tree-optimization/64277
* tree-vrp.c (check_array_ref): Fix anti-range handling,
simplify upper bound handling.
(search_for_addr_array): Simplify.
(check_array_bounds): Handle ADDR_EXPRs here.
(check_all_array_refs): Simplify.
* gcc.dg/Warray-bounds-12.c: New testcase.
* gcc.dg/Warray-bounds-13.c: Likewise.
Index: gcc/tree-vrp.c
===================================================================
*** gcc/tree-vrp.c (revision 220107)
--- gcc/tree-vrp.c (working copy)
*************** check_array_ref (location_t location, tr
*** 6546,6554 ****
if (vr && vr->type == VR_ANTI_RANGE)
{
if (TREE_CODE (up_sub) == INTEGER_CST
! && tree_int_cst_lt (up_bound, up_sub)
&& TREE_CODE (low_sub) == INTEGER_CST
! && tree_int_cst_lt (low_sub, low_bound))
{
warning_at (location, OPT_Warray_bounds,
"array subscript is outside array bounds");
--- 6546,6556 ----
if (vr && vr->type == VR_ANTI_RANGE)
{
if (TREE_CODE (up_sub) == INTEGER_CST
! && (ignore_off_by_one
! ? tree_int_cst_lt (up_bound, up_sub)
! : tree_int_cst_le (up_bound, up_sub))
&& TREE_CODE (low_sub) == INTEGER_CST
! && tree_int_cst_le (low_sub, low_bound))
{
warning_at (location, OPT_Warray_bounds,
"array subscript is outside array bounds");
*************** check_array_ref (location_t location, tr
*** 6557,6566 ****
}
else if (TREE_CODE (up_sub) == INTEGER_CST
&& (ignore_off_by_one
! ? (tree_int_cst_lt (up_bound, up_sub)
! && !tree_int_cst_equal (up_bound_p1, up_sub))
! : (tree_int_cst_lt (up_bound, up_sub)
! || tree_int_cst_equal (up_bound_p1, up_sub))))
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
--- 6559,6566 ----
}
else if (TREE_CODE (up_sub) == INTEGER_CST
&& (ignore_off_by_one
! ? !tree_int_cst_le (up_sub, up_bound_p1)
! : !tree_int_cst_le (up_sub, up_bound)))
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
*************** check_array_ref (location_t location, tr
*** 6593,6617 ****
static void
search_for_addr_array (tree t, location_t location)
{
- while (TREE_CODE (t) == SSA_NAME)
- {
- gimple g = SSA_NAME_DEF_STMT (t);
-
- if (gimple_code (g) != GIMPLE_ASSIGN)
- return;
-
- if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
- != GIMPLE_SINGLE_RHS)
- return;
-
- t = gimple_assign_rhs1 (g);
- }
-
-
- /* We are only interested in addresses of ARRAY_REF's. */
- if (TREE_CODE (t) != ADDR_EXPR)
- return;
-
/* Check each ARRAY_REFs in the reference chain. */
do
{
--- 6593,6598 ----
*************** check_array_bounds (tree *tp, int *walk_
*** 6701,6712 ****
if (TREE_CODE (t) == ARRAY_REF)
check_array_ref (location, t, false /*ignore_off_by_one*/);
! if (TREE_CODE (t) == MEM_REF
! || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
! search_for_addr_array (TREE_OPERAND (t, 0), location);
!
! if (TREE_CODE (t) == ADDR_EXPR)
! *walk_subtree = FALSE;
return NULL_TREE;
}
--- 6682,6692 ----
if (TREE_CODE (t) == ARRAY_REF)
check_array_ref (location, t, false /*ignore_off_by_one*/);
! else if (TREE_CODE (t) == ADDR_EXPR)
! {
! search_for_addr_array (t, location);
! *walk_subtree = FALSE;
! }
return NULL_TREE;
}
*************** check_all_array_refs (void)
*** 6736,6764 ****
{
gimple stmt = gsi_stmt (si);
struct walk_stmt_info wi;
! if (!gimple_has_location (stmt))
continue;
! if (is_gimple_call (stmt))
! {
! size_t i;
! size_t n = gimple_call_num_args (stmt);
! for (i = 0; i < n; i++)
! {
! tree arg = gimple_call_arg (stmt, i);
! search_for_addr_array (arg, gimple_location (stmt));
! }
! }
! else
! {
! memset (&wi, 0, sizeof (wi));
! wi.info = CONST_CAST (void *, (const void *)
! gimple_location_ptr (stmt));
!
! walk_gimple_op (gsi_stmt (si),
! check_array_bounds,
! &wi);
! }
}
}
}
--- 6716,6732 ----
{
gimple stmt = gsi_stmt (si);
struct walk_stmt_info wi;
! if (!gimple_has_location (stmt)
! || is_gimple_debug (stmt))
continue;
! memset (&wi, 0, sizeof (wi));
! wi.info = CONST_CAST (void *, (const void *)
! gimple_location_ptr (stmt));
!
! walk_gimple_op (gsi_stmt (si),
! check_array_bounds,
! &wi);
}
}
}
Index: gcc/testsuite/gcc.dg/Warray-bounds-12.c
===================================================================
*** gcc/testsuite/gcc.dg/Warray-bounds-12.c (revision 0)
--- gcc/testsuite/gcc.dg/Warray-bounds-12.c (working copy)
***************
*** 0 ****
--- 1,28 ----
+ /* { dg-do compile } */
+ /* { dg-options "-O2 -Warray-bounds" } */
+
+ int a[10];
+ int foo1 (int i)
+ {
+ if (i < 0 || i > 9)
+ return a[i]; /* { dg-warning "outside array bounds" } */
+ return 0;
+ }
+ int foo2 (int i)
+ {
+ if (i < 0 || i > 8)
+ return a[i]; /* { dg-bogus "outside array bounds" } */
+ return 0;
+ }
+ int *foo3 (int i)
+ {
+ if (i < 0 || i > 10)
+ return &a[i]; /* { dg-warning "outside array bounds" } */
+ return (void *)0;
+ }
+ int *foo4 (int i)
+ {
+ if (i < 0 || i > 9)
+ return &a[i]; /* { dg-bogus "outside array bounds" } */
+ return (void *)0;
+ }
Index: gcc/testsuite/gcc.dg/Warray-bounds-13.c
===================================================================
*** gcc/testsuite/gcc.dg/Warray-bounds-13.c (revision 0)
--- gcc/testsuite/gcc.dg/Warray-bounds-13.c (working copy)
***************
*** 0 ****
--- 1,20 ----
+ /* { dg-do compile } */
+ /* { dg-options "-O2 -Warray-bounds" } */
+
+ int a[10];
+ int *foo1 (int i)
+ {
+ return &a[10]; /* { dg-bogus "above array bounds" } */
+ }
+ int *foo2 (int i)
+ {
+ return &a[11]; /* { dg-warning "above array bounds" } */
+ }
+ int foo3 (int i)
+ {
+ return a[9]; /* { dg-bogus "above array bounds" } */
+ }
+ int foo4 (int i)
+ {
+ return a[10]; /* { dg-warning "above array bounds" } */
+ }
