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re PR middle-end/36902 (Array bound warning with dead code after optimization)

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2009-04-18  Manuel López-Ibáñez  <manu@gcc.gnu.org>

	PR middle-end/36902
	* tree-vrp.c (check_array_ref): Pass a location_t instead of a
	pointer. Use warning_at instead of warning.
	(search_for_addr_array): Likewise.
	(check_array_bounds): Likewise.
	(check_all_array_refs): Check that the incoming edge is not in the
	list of edges to be removed.
	(check_all_array_refs): Avoid the temporal pointer.
	(vrp_visit_cond_stmt): Fix typo.
	(simplify_switch_using_ranges): Handle the case where the switch
	index is an integer constant.
testsuite/
	* gcc.dg/pr36902.c: New.

From-SVN: r146305
This commit is contained in:
Manuel López-Ibáñez 2009-04-18 09:24:45 +00:00
parent 0e097268ba
commit 92ef7fb19a
4 changed files with 135 additions and 25 deletions
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14
gcc/ChangeLog
View file

@ -1,3 +1,17 @@
2009-04-18 Manuel López-Ibáñez <manu@gcc.gnu.org>
PR middle-end/36902
* tree-vrp.c (check_array_ref): Pass a location_t instead of a
pointer. Use warning_at instead of warning.
(search_for_addr_array): Likewise.
(check_array_bounds): Likewise.
(check_all_array_refs): Check that the incoming edge is not in the
list of edges to be removed.
(check_all_array_refs): Avoid the temporal pointer.
(vrp_visit_cond_stmt): Fix typo.
(simplify_switch_using_ranges): Handle the case where the switch
index is an integer constant.
2009-04-18 Adam Nemet <anemet@caviumnetworks.com>
* config/mips/mips.c (mips_final_postscan_insn): Make it static.

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2009-04-18 Manuel López-Ibáñez <manu@gcc.gnu.org>
PR middle-end/36902
* gcc.dg/pr36902.c: New.
2009-04-17 Diego Novillo <dnovillo@google.com>
* gcc.c-torture/execute/builtins/strlen-3.c: Fix ODR

61
gcc/testsuite/gcc.dg/pr36902.c Normal file
View file

@ -0,0 +1,61 @@
/* PR middle-end/36902 Array bound warning with dead code after optimization */
/* { dg-do compile } */
/* { dg-options "-O2 -Warray-bounds -Wall -Wextra" } */
typedef unsigned char __u8;
typedef unsigned short __u16;
static inline unsigned char *
foo(unsigned char * to, const unsigned char * from, int n)
{
switch ( n )
{
case 3:
*to = *from;
break;
case 5:
to[4] = from [4];
break;
}
return to;
}
struct {
int size_of_select;
unsigned char pcr_select[4];
} sel;
int bar(void)
{
static unsigned char buf[64];
sel.size_of_select = 3;
foo(buf, sel.pcr_select, sel.size_of_select);
return 1;
}
static inline unsigned char *
foo2(unsigned char * to, const unsigned char * from, int n)
{
switch ( n )
{
case 3:
*to = *from;
break;
case 5:
to[4] = from [4]; /* { dg-warning "array subscript is above array bounds" } */
break;
}
return to;
}
int baz(void)
{
static unsigned char buf[64];
sel.size_of_select = 5;
foo2(buf, sel.pcr_select, sel.size_of_select);
return 1;
}

80
gcc/tree-vrp.c
View file

@ -4996,7 +4996,7 @@ insert_range_assertions (void)
IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
static void
check_array_ref (tree ref, const location_t *location, bool ignore_off_by_one)
check_array_ref (tree ref, location_t location, bool ignore_off_by_one)
{
value_range_t* vr = NULL;
tree low_sub, up_sub;
@ -5035,8 +5035,8 @@ check_array_ref (tree ref, const location_t *location, bool ignore_off_by_one)
&& TREE_CODE (low_sub) == INTEGER_CST
&& tree_int_cst_lt (low_sub, low_bound))
{
warning (OPT_Warray_bounds,
"%Harray subscript is outside array bounds", location);
warning_at (location, OPT_Warray_bounds,
"array subscript is outside array bounds");
TREE_NO_WARNING (ref) = 1;
}
}
@ -5050,15 +5050,15 @@ check_array_ref (tree ref, const location_t *location, bool ignore_off_by_one)
0),
up_sub)))
{
warning (OPT_Warray_bounds, "%Harray subscript is above array bounds",
location);
warning_at (location, OPT_Warray_bounds,
"array subscript is above array bounds");
TREE_NO_WARNING (ref) = 1;
}
else if (TREE_CODE (low_sub) == INTEGER_CST
&& tree_int_cst_lt (low_sub, low_bound))
{
warning (OPT_Warray_bounds, "%Harray subscript is below array bounds",
location);
warning_at (location, OPT_Warray_bounds,
"array subscript is below array bounds");
TREE_NO_WARNING (ref) = 1;
}
}
@ -5067,7 +5067,7 @@ check_array_ref (tree ref, const location_t *location, bool ignore_off_by_one)
address of an ARRAY_REF, and call check_array_ref on it. */
static void
search_for_addr_array (tree t, const location_t *location)
search_for_addr_array (tree t, location_t location)
{
while (TREE_CODE (t) == SSA_NAME)
{
@ -5115,11 +5115,11 @@ check_array_bounds (tree *tp, int *walk_subtree, void *data)
*walk_subtree = TRUE;
if (TREE_CODE (t) == ARRAY_REF)
check_array_ref (t, location, false /*ignore_off_by_one*/);
check_array_ref (t, *location, false /*ignore_off_by_one*/);
if (TREE_CODE (t) == INDIRECT_REF
|| (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
search_for_addr_array (TREE_OPERAND (t, 0), location);
search_for_addr_array (TREE_OPERAND (t, 0), *location);
if (TREE_CODE (t) == ADDR_EXPR)
*walk_subtree = FALSE;
@ -5141,9 +5141,23 @@ check_all_array_refs (void)
/* Skip bb's that are clearly unreachable. */
if (single_pred_p (bb))
{
basic_block pred_bb = EDGE_PRED (bb, 0)->src;
int i;
bool reachable = true;
edge e2;
edge e = EDGE_PRED (bb, 0);
basic_block pred_bb = e->src;
gimple ls = NULL;
for (i = 0; VEC_iterate (edge, to_remove_edges, i, e2); ++i)
if (e == e2)
{
reachable = false;
break;
}
if (!reachable)
continue;
if (!gsi_end_p (gsi_last_bb (pred_bb)))
ls = gsi_stmt (gsi_last_bb (pred_bb));
@ -5157,7 +5171,6 @@ check_all_array_refs (void)
for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
{
gimple stmt = gsi_stmt (si);
const location_t *location = gimple_location_ptr (stmt);
struct walk_stmt_info wi;
if (!gimple_has_location (stmt))
continue;
@ -5169,13 +5182,14 @@ check_all_array_refs (void)
for (i = 0; i < n; i++)
{
tree arg = gimple_call_arg (stmt, i);
search_for_addr_array (arg, location);
search_for_addr_array (arg, gimple_location (stmt));
}
}
else
{
memset (&wi, 0, sizeof (wi));
wi.info = CONST_CAST (void *, (const void *) location);
wi.info = CONST_CAST (void *, (const void *)
gimple_location_ptr (stmt));
walk_gimple_op (gsi_stmt (si),
check_array_bounds,
@ -5875,7 +5889,7 @@ vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
returned.
If there is no CASE_LABEL for VAL and the is one that is larger than VAL,
If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
it is placed in IDX and false is returned.
If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
@ -6860,19 +6874,35 @@ simplify_switch_using_ranges (gimple stmt)
tree vec2;
switch_update su;
if (TREE_CODE (op) != SSA_NAME)
if (TREE_CODE (op) == SSA_NAME)
{
vr = get_value_range (op);
/* We can only handle integer ranges. */
if (vr->type != VR_RANGE
|| symbolic_range_p (vr))
return false;
/* Find case label for min/max of the value range. */
take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
}
else if (TREE_CODE (op) == INTEGER_CST)
{
take_default = !find_case_label_index (stmt, 1, op, &i);
if (take_default)
{
i = 1;
j = 0;
}
else
{
j = i;
}
}
else
return false;
vr = get_value_range (op);
/* We can only handle integer ranges. */
if (vr->type != VR_RANGE
|| symbolic_range_p (vr))
return false;
/* Find case label for min/max of the value range. */
n = gimple_switch_num_labels (stmt);
take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
/* Bail out if this is just all edges taken. */
if (i == 1