This fixes an issue that shows up in PR56210.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2013-03-18 Richard Biener <rguent...@suse.de>
PR tree-optimization/56210
* tree-ssa-structalias.c (find_func_aliases_for_builtin_call):
Handle string / character search functions.
* tree-ssa-alias.c (ref_maybe_used_by_call_p_1): Likewise.
Index: gcc/tree-ssa-structalias.c
===================================================================
*** gcc/tree-ssa-structalias.c (revision 195751)
--- gcc/tree-ssa-structalias.c (working copy)
*************** find_func_aliases_for_builtin_call (gimp
*** 4196,4201 ****
--- 4257,4285 ----
return true;
}
break;
+ /* String / character search functions return a pointer into the
+ source string or NULL. */
+ case BUILT_IN_INDEX:
+ case BUILT_IN_STRCHR:
+ case BUILT_IN_STRRCHR:
+ case BUILT_IN_MEMCHR:
+ case BUILT_IN_STRSTR:
+ case BUILT_IN_STRPBRK:
+ if (gimple_call_lhs (t))
+ {
+ tree src = gimple_call_arg (t, 0);
+ get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
+ constraint_expr nul;
+ nul.var = nothing_id;
+ nul.offset = 0;
+ nul.type = ADDRESSOF;
+ rhsc.safe_push (nul);
+ get_constraint_for (gimple_call_lhs (t), &lhsc);
+ process_all_all_constraints (lhsc, rhsc);
+ lhsc.release();
+ rhsc.release();
+ }
+ return true;
/* Trampolines are special - they set up passing the static
frame. */
case BUILT_IN_INIT_TRAMPOLINE:
Index: gcc/tree-ssa-alias.c
===================================================================
*** gcc/tree-ssa-alias.c (revision 195751)
--- gcc/tree-ssa-alias.c (working copy)
*************** ref_maybe_used_by_call_p_1 (gimple call,
*** 1314,1319 ****
--- 1314,1356 ----
size);
return refs_may_alias_p_1 (&dref, ref, false);
}
+ /* These read memory pointed to by the first argument. */
+ case BUILT_IN_INDEX:
+ case BUILT_IN_STRCHR:
+ case BUILT_IN_STRRCHR:
+ {
+ ao_ref dref;
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 0),
+ NULL_TREE);
+ return refs_may_alias_p_1 (&dref, ref, false);
+ }
+ /* These read memory pointed to by the first argument with size
+ in the third argument. */
+ case BUILT_IN_MEMCHR:
+ {
+ ao_ref dref;
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 0),
+ gimple_call_arg (call, 2));
+ return refs_may_alias_p_1 (&dref, ref, false);
+ }
+ /* These read memory pointed to by the first and second arguments. */
+ case BUILT_IN_STRSTR:
+ case BUILT_IN_STRPBRK:
+ {
+ ao_ref dref;
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 0),
+ NULL_TREE);
+ if (refs_may_alias_p_1 (&dref, ref, false))
+ return true;
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 1),
+ NULL_TREE);
+ return refs_may_alias_p_1 (&dref, ref, false);
+ }
+
/* The following builtins do not read from memory. */
case BUILT_IN_FREE:
case BUILT_IN_MALLOC:
