diff mbox

Fix up various issues with missing lhs on calls with addressable return value (PR ipa/69241, PR c++/69649)

Message ID 20160203141357.GY3017@tucnak.redhat.com
State New
Headers show

Commit Message

Jakub Jelinek Feb. 3, 2016, 2:13 p.m. UTC 
Hi!

As mentioned in the PR, the expander now requires that calls with
TREE_ADDRESSABLE result type have lhs set (so that a temporary of the
type doesn't have to be created by the middle-end).

The first 3 hunks (gimplify.c and cgraphunit.c) are to fix noreturn
functions with such return types, by making sure they have the lhs.
The ipa-split.c changes force the *.part.N function to have void
return if we don't need the return value from the split function.
If the split part contains any MEM_REFs that refer to the DECL_BY_REFERENCE
RESULT_DECL SSA_NAME, then consider_split will already mark them
split_point->split_part_set_retval, and if we just the SSA_NAME otherwise,
we (missed optimization) give up on fn splitting in that case earlier (could
force split_point->split_part_set_retval instead and even that would be
handled well in this case).

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2016-02-03  Jakub Jelinek  <jakub@redhat.com>
	    Patrick Palka  <ppalka@gcc.gnu.org>

	PR ipa/69241
	PR c++/69649
	* gimplify.c (gimplify_modify_expr): Set lhs even for noreturn
	calls if the return type is TREE_ADDRESSABLE.
	* cgraphunit.c (cgraph_node::expand_thunk): Likewise.
	* ipa-split.c (split_function): Fix doubled "we" in comment.
	Use void return type for the split part even if
	!split_point->split_part_set_retval.

	* g++.dg/ipa/pr69241-1.C: New test.
	* g++.dg/ipa/pr69241-2.C: New test.
	* g++.dg/ipa/pr69241-3.C: New test.
	* g++.dg/ipa/pr69649.C: New test.


	Jakub
diff mbox

Patch

--- gcc/gimplify.c.jj	2016-02-02 20:42:00.000000000 +0100
+++ gcc/gimplify.c	2016-02-03 11:04:06.400757668 +0100
@@ -4828,7 +4828,8 @@  gimplify_modify_expr (tree *expr_p, gimp
 	    }
 	}
       notice_special_calls (call_stmt);
-      if (!gimple_call_noreturn_p (call_stmt))
+      if (!gimple_call_noreturn_p (call_stmt)
+	  || TREE_ADDRESSABLE (TREE_TYPE (*to_p)))
 	gimple_call_set_lhs (call_stmt, *to_p);
       assign = call_stmt;
     }
--- gcc/cgraphunit.c.jj	2016-01-20 10:55:15.000000000 +0100
+++ gcc/cgraphunit.c	2016-02-03 11:04:41.034279370 +0100
@@ -1703,7 +1703,8 @@  cgraph_node::expand_thunk (bool output_a
       bsi = gsi_start_bb (bb);
 
       /* Build call to the function being thunked.  */
-      if (!VOID_TYPE_P (restype) && !alias_is_noreturn)
+      if (!VOID_TYPE_P (restype)
+	  && (!alias_is_noreturn || TREE_ADDRESSABLE (restype)))
 	{
 	  if (DECL_BY_REFERENCE (resdecl))
 	    {
@@ -1770,7 +1771,7 @@  cgraph_node::expand_thunk (bool output_a
 	      || DECL_BY_REFERENCE (resdecl)))
         gimple_call_set_return_slot_opt (call, true);
 
-      if (restmp && !alias_is_noreturn)
+      if (restmp)
 	{
           gimple_call_set_lhs (call, restmp);
 	  gcc_assert (useless_type_conversion_p (TREE_TYPE (restmp),
--- gcc/ipa-split.c.jj	2016-01-04 14:55:52.000000000 +0100
+++ gcc/ipa-split.c	2016-02-03 13:01:45.905136051 +0100
@@ -1254,7 +1254,7 @@  split_function (basic_block return_bb, s
       else
 	main_part_return_p = true;
     }
-  /* The main part also returns if we we split on a fallthru edge
+  /* The main part also returns if we split on a fallthru edge
      and the split part returns.  */
   if (split_part_return_p)
     FOR_EACH_EDGE (e, ei, split_point->entry_bb->preds)
@@ -1364,8 +1364,9 @@  split_function (basic_block return_bb, s
   /* Now create the actual clone.  */
   cgraph_edge::rebuild_edges ();
   node = cur_node->create_version_clone_with_body
-    (vNULL, NULL, args_to_skip, !split_part_return_p, split_point->split_bbs,
-     split_point->entry_bb, "part");
+    (vNULL, NULL, args_to_skip,
+     !split_part_return_p || !split_point->split_part_set_retval,
+     split_point->split_bbs, split_point->entry_bb, "part");
 
   node->split_part = true;
 
--- gcc/testsuite/g++.dg/ipa/pr69241-1.C.jj	2016-02-03 10:56:10.624328263 +0100
+++ gcc/testsuite/g++.dg/ipa/pr69241-1.C	2016-02-03 11:01:18.600075039 +0100
@@ -0,0 +1,12 @@ 
+// PR ipa/69241
+// { dg-do compile }
+// { dg-options "-O2" }
+
+struct R { R (const R &) {} };
+__attribute__ ((noreturn)) R bar ();
+
+R
+foo ()
+{
+  bar ();
+}
--- gcc/testsuite/g++.dg/ipa/pr69241-2.C.jj	2016-02-03 10:56:07.996364556 +0100
+++ gcc/testsuite/g++.dg/ipa/pr69241-2.C	2016-02-03 11:01:42.958738639 +0100
@@ -0,0 +1,18 @@ 
+// PR ipa/69241
+// { dg-do compile }
+// { dg-options "-O2" }
+
+__attribute__((noreturn)) void foo (int);
+struct R { R (const R &) {} };
+
+R
+bar ()
+{
+  foo (0);
+}
+
+R
+baz ()
+{
+  foo (0);
+}
--- gcc/testsuite/g++.dg/ipa/pr69241-3.C.jj	2016-02-03 11:00:39.840610317 +0100
+++ gcc/testsuite/g++.dg/ipa/pr69241-3.C	2016-02-03 11:01:02.044303678 +0100
@@ -0,0 +1,12 @@ 
+// PR ipa/69241
+// { dg-do compile }
+// { dg-options "-O2" }
+
+struct R { int x[100]; };
+__attribute__ ((noreturn)) R bar ();
+
+void
+foo ()
+{
+  bar ();
+}
--- gcc/testsuite/g++.dg/ipa/pr69649.C.jj	2016-02-03 13:19:00.850845887 +0100
+++ gcc/testsuite/g++.dg/ipa/pr69649.C	2016-02-03 13:18:43.000000000 +0100
@@ -0,0 +1,36 @@ 
+// PR c++/69649
+// { dg-do compile }
+// { dg-options "-O2" }
+
+struct A { virtual void m1 (); };
+struct C : A { void m1 () { m1 (); } };
+template <class T> struct B
+{
+  T *t;
+  B (T *x) : t (x) { if (t) t->m1 (); }
+  B (const B &);
+};
+struct D : public C {};
+struct F : public D
+{
+  virtual B<D> m2 ();
+  virtual B<D> m3 ();
+  int m4 ();
+};
+struct G : F
+{
+  B<D> m2 ();
+  B<D> m3 ();
+};
+B<D> G::m2 ()
+{
+  if (m4 () == 0)
+    return this;
+  return 0;
+}
+B<D> G::m3 ()
+{
+  if (m4 () == 0)
+    return this;
+  return 0;
+}