File pr36765.diff of Package gcc43
2008-07-11 Richard Guenther <rguenther@suse.de>
PR tree-optimization/36765
* tree-ssa-alias.c (compute_flow_insensitive_aliasing): Add
aliases from HEAP vars to SMTs.
* gcc.c-torture/execute/pr36765.c: New testcase.
Index: gcc/tree-ssa-alias.c
===================================================================
*** gcc/tree-ssa-alias.c (revision 137712)
--- gcc/tree-ssa-alias.c (working copy)
*************** have_common_aliases_p (bitmap tag1aliase
*** 2370,2375 ****
--- 2370,2377 ----
static void
compute_flow_insensitive_aliasing (struct alias_info *ai)
{
+ referenced_var_iterator rvi;
+ tree var;
size_t i;
timevar_push (TV_FLOW_INSENSITIVE);
*************** compute_flow_insensitive_aliasing (struc
*** 2460,2465 ****
--- 2462,2485 ----
add_may_alias (tag1, tag2);
}
}
+
+ /* We have to add all HEAP variables to all SMTs aliases bitmaps.
+ As we don't know which effective type the HEAP will have we cannot
+ do better here and we need the conflicts with obfuscated pointers
+ (a simple (*(int[n] *)ptr)[i] will do, with ptr from a VLA array
+ allocation). */
+ for (i = 0; i < ai->num_pointers; i++)
+ {
+ struct alias_map_d *p_map = ai->pointers[i];
+ tree tag = symbol_mem_tag (p_map->var);
+
+ FOR_EACH_REFERENCED_VAR (var, rvi)
+ {
+ if (var_ann (var)->is_heapvar)
+ add_may_alias (tag, var);
+ }
+ }
+
timevar_pop (TV_FLOW_INSENSITIVE);
}
Index: gcc/testsuite/gcc.c-torture/execute/pr36765.c
===================================================================
*** gcc/testsuite/gcc.c-torture/execute/pr36765.c (revision 0)
--- gcc/testsuite/gcc.c-torture/execute/pr36765.c (revision 0)
***************
*** 0 ****
--- 1,15 ----
+ int __attribute__((noinline))
+ foo(int i)
+ {
+ int *p = __builtin_malloc (4 * sizeof(int));
+ *p = 0;
+ p[i] = 1;
+ return *p;
+ }
+ extern void abort (void);
+ int main()
+ {
+ if (foo(0) != 1)
+ abort ();
+ return 0;
+ }