The following fixes a bug in PTA analysis manifesting in wrong
pointer equality folding.
Bootstrap and regtest running on x86_64-unknown-linux-gnu.
Richard.
2016-10-06 Richard Biener <rguent...@suse.de>
PR tree-optimization/77879
* tree-ssa-structalias.c (handle_const_call): Properly handle
NRV return slots.
(handle_pure_call): Likewise.
Index: gcc/tree-ssa-structalias.c
===================================================================
--- gcc/tree-ssa-structalias.c (revision 240828)
+++ gcc/tree-ssa-structalias.c (working copy)
@@ -4063,15 +4063,34 @@ handle_const_call (gcall *stmt, vec<ce_s
{
struct constraint_expr rhsc;
unsigned int k;
+ bool need_uses = false;
/* Treat nested const functions the same as pure functions as far
as the static chain is concerned. */
if (gimple_call_chain (stmt))
{
varinfo_t uses = get_call_use_vi (stmt);
+ make_constraint_to (uses->id, gimple_call_chain (stmt));
+ need_uses = true;
+ }
+
+ /* And if we applied NRV the address of the return slot escapes as well. */
+ if (gimple_call_return_slot_opt_p (stmt)
+ && gimple_call_lhs (stmt) != NULL_TREE
+ && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
+ {
+ varinfo_t uses = get_call_use_vi (stmt);
+ auto_vec<ce_s> tmpc;
+ get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
+ make_constraints_to (uses->id, tmpc);
+ need_uses = true;
+ }
+
+ if (need_uses)
+ {
+ varinfo_t uses = get_call_use_vi (stmt);
make_any_offset_constraints (uses);
make_transitive_closure_constraints (uses);
- make_constraint_to (uses->id, gimple_call_chain (stmt));
rhsc.var = uses->id;
rhsc.offset = 0;
rhsc.type = SCALAR;
@@ -4140,6 +4159,22 @@ handle_pure_call (gcall *stmt, vec<ce_s>
make_constraint_to (uses->id, gimple_call_chain (stmt));
}
+ /* And if we applied NRV the address of the return slot. */
+ if (gimple_call_return_slot_opt_p (stmt)
+ && gimple_call_lhs (stmt) != NULL_TREE
+ && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
+ {
+ if (!uses)
+ {
+ uses = get_call_use_vi (stmt);
+ make_any_offset_constraints (uses);
+ make_transitive_closure_constraints (uses);
+ }
+ auto_vec<ce_s> tmpc;
+ get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
+ make_constraints_to (uses->id, tmpc);
+ }
+
/* Pure functions may return call-used and nonlocal memory. */
if (uses)
{
