Hi!
The FRE devirtualization unlike gimple-fold or other places would transform
some method call with TREE_ADDRESSABLE lhs into __builtin_unreachable call
with the same lhs, which is invalid (__builtin_unreachable returns void).
Also, gimple_call_fntype has not been adjusted in these cases.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk? What about 6.x? Do you prefer it in 6.2, or 6.3?
2016-08-16 Jakub Jelinek <ja...@redhat.com>
PR middle-end/77259
* tree-ssa-pre.c (eliminate_dom_walker::before_dom_children): If
turning a call into __builtin_unreachable-like noreturn call, adjust
gimple_call_set_fntype and remove lhs if needed.
* g++.dg/ipa/devirt-52.C: New test.
--- gcc/tree-ssa-pre.c.jj 2016-08-12 17:33:46.000000000 +0200
+++ gcc/tree-ssa-pre.c 2016-08-16 11:24:53.605976981 +0200
@@ -4543,6 +4543,32 @@ eliminate_dom_walker::before_dom_childre
lang_hooks.decl_printable_name (fn, 2));
}
gimple_call_set_fndecl (call_stmt, fn);
+ /* If changing the call to __builtin_unreachable
+ or similar noreturn function, adjust gimple_call_fntype
+ too. */
+ if ((gimple_call_flags (call_stmt) & ECF_NORETURN)
+ && VOID_TYPE_P (TREE_TYPE (TREE_TYPE (fn)))
+ && TYPE_ARG_TYPES (TREE_TYPE (fn))
+ && (TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (fn)))
+ == void_type_node))
+ gimple_call_set_fntype (call_stmt, TREE_TYPE (fn));
+ tree lhs = gimple_call_lhs (call_stmt);
+ /* If the call becomes noreturn, remove the lhs. */
+ if (lhs
+ && gimple_call_noreturn_p (call_stmt)
+ && (VOID_TYPE_P (TREE_TYPE (gimple_call_fntype
+ (call_stmt)))
+ || should_remove_lhs_p (lhs)))
+ {
+ if (TREE_CODE (lhs) == SSA_NAME)
+ {
+ tree var = create_tmp_var (TREE_TYPE (lhs));
+ tree def = get_or_create_ssa_default_def (cfun, var);
+ gimple *new_stmt = gimple_build_assign (lhs, def);
+ gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT);
+ }
+ gimple_call_set_lhs (call_stmt, NULL_TREE);
+ }
maybe_remove_unused_call_args (cfun, call_stmt);
gimple_set_modified (stmt, true);
}
--- gcc/testsuite/g++.dg/ipa/devirt-52.C.jj 2016-08-16 11:08:49.943108247
+0200
+++ gcc/testsuite/g++.dg/ipa/devirt-52.C 2016-08-16 11:32:25.295300721
+0200
@@ -0,0 +1,56 @@
+// PR middle-end/77259
+// { dg-do compile { target c++11 } }
+// { dg-options "-O2" }
+
+template <typename, typename = int> class A;
+template <typename, typename> struct A
+{
+ A (A &&);
+};
+template <typename S, typename T, typename U>
+A<S> operator+(S *, const A<T, U> &);
+template <typename S, typename T, typename U>
+void operator+(const A<T, U> &, S *);
+struct B
+{
+ template <typename V> B (V);
+};
+template <typename V> V foo (B) {}
+class C;
+template <typename> struct D
+{
+ C *operator->() { return d; }
+ C *d;
+};
+struct C
+{
+ virtual A<int> bar ();
+};
+struct E
+{
+ ~E ();
+ virtual A<char> bar (const B &) const;
+};
+template <typename> struct F : E
+{
+};
+template <typename W> struct F<D<W>> : E
+{
+ A<char> bar (const B &) const try
+ {
+ D<W> a = baz ();
+ }
+ catch (int)
+ {
+ }
+ D<W> baz () const
+ {
+ D<C> b = foo<D<C>>(0);
+ "" + b->bar () + "";
+ }
+};
+struct G : F<D<int>>
+{
+ G (int);
+};
+void test () { G (0); }
Jakub
