The following fixes a bogus Warray-bound warning by consolidating some
(slightly bogus) duplicate code in tree-vrp.c
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
Richard.
2016-02-25 Richard Biener <rguent...@suse.de>
PR tree-optimization/48795
* tree-vrp.c (check_array_ref): Use array_at_struct_end_p.
* gcc.dg/Warray-bounds-18.c: New testcase.
Index: gcc/tree-vrp.c
===================================================================
*** gcc/tree-vrp.c (revision 233693)
--- gcc/tree-vrp.c (working copy)
*************** check_array_ref (location_t location, tr
*** 6450,6456 ****
value_range *vr = NULL;
tree low_sub, up_sub;
tree low_bound, up_bound, up_bound_p1;
- tree base;
if (TREE_NO_WARNING (ref))
return;
--- 6450,6455 ----
*************** check_array_ref (location_t location, tr
*** 6465,6491 ****
/* Accesses to trailing arrays via pointers may access storage
beyond the types array bounds. */
! base = get_base_address (ref);
! if ((warn_array_bounds < 2)
! && base && TREE_CODE (base) == MEM_REF)
! {
! tree cref, next = NULL_TREE;
!
! if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
! return;
!
! cref = TREE_OPERAND (ref, 0);
! if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
! for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
! next && TREE_CODE (next) != FIELD_DECL;
! next = DECL_CHAIN (next))
! ;
!
! /* If this is the last field in a struct type or a field in a
! union type do not warn. */
! if (!next)
! return;
! }
low_bound = array_ref_low_bound (ref);
up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound,
--- 6464,6472 ----
/* Accesses to trailing arrays via pointers may access storage
beyond the types array bounds. */
! if (warn_array_bounds < 2
! && array_at_struct_end_p (ref))
! return;
low_bound = array_ref_low_bound (ref);
up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound,
Index: gcc/testsuite/gcc.dg/Warray-bounds-18.c
===================================================================
*** gcc/testsuite/gcc.dg/Warray-bounds-18.c (revision 0)
--- gcc/testsuite/gcc.dg/Warray-bounds-18.c (working copy)
***************
*** 0 ****
--- 1,25 ----
+ /* { dg-do compile } */
+ /* { dg-options "-O2 -Warray-bounds" } */
+
+ typedef struct
+ {
+ int len;
+ char data[1];
+ } rec;
+
+ int
+ p(rec *r, int len);
+
+ int
+ f (char prm1, char prm2)
+ {
+ char buf[10];
+
+ rec *r1 = (rec *)&buf;
+
+ r1->len = 10;
+ r1->data[0] = prm1;
+ r1->data[1] = prm2; /* { dg-bogus "above array bounds" } */
+
+ return p(r1, r1->len);
+ }
