re PR ipa/70760 (wrong generated code for std::make_unique with -fipa-pta)

2016-04-27  Richard Biener  <rguenther@suse.de>

	PR ipa/70760
	* tree-ssa-structalias.c (find_func_aliases_for_call): Use
	aggregate_value_p to determine if a function result is
	returned by reference.
	(ipa_pta_execute): Functions having their address taken are
	not automatically nonlocal.

	* g++.dg/ipa/ipa-pta-2.C: New testcase.
	* gcc.dg/ipa/ipa-pta-1.c: Adjust.

From-SVN: r235511

gcc/ChangeLog

+2016-04-27  Richard Biener  <rguenther@suse.de>
+
+	PR ipa/70760
+	* tree-ssa-structalias.c (find_func_aliases_for_call): Use
+	aggregate_value_p to determine if a function result is
+	returned by reference.
+	(ipa_pta_execute): Functions having their address taken are
+	not automatically nonlocal.
+
 2016-04-27  Jakub Jelinek  <jakub@redhat.com>
 
 	PR sanitizer/70683

gcc/testsuite/ChangeLog

+2016-04-27  Richard Biener  <rguenther@suse.de>
+
+	PR ipa/70760
+	* g++.dg/ipa/ipa-pta-2.C: New testcase.
+	* gcc.dg/ipa/ipa-pta-1.c: Adjust.
+
 2016-04-27  Nathan Sidwell  <nathan@acm.org>
 
 	* g++.dg/cpp0x/constexpr-recursion3.C: New.

gcc/testsuite/g++.dg/ipa/ipa-pta-2.C

+// { dg-do run }
+// { dg-options "-O2 -fipa-pta" }
+
+extern "C" void abort (void);
+
+struct Y { ~Y(); int i; };
+
+Y::~Y () {}
+
+static Y __attribute__((noinline)) foo ()
+{
+  Y res;
+  res.i = 3;
+  return res;
+}
+
+static Y __attribute__((noinline)) bar ()
+{
+  Y res;
+  res.i = 42;
+  return res;
+}
+
+static Y (*fn) ();
+
+int a;
+int main()
+{
+  if (a)
+    fn = foo;
+  else
+    fn = bar;
+  Y res = fn ();
+  if (res.i != 42)
+    abort ();
+  return 0;
+}

gcc/testsuite/gcc.dg/ipa/ipa-pta-1.c

@@ -40,13 +40,10 @@ int main()
 }
 
 /* IPA PTA needs to handle indirect calls properly.  Verify that
-   both bar and foo get a (and only a) in their arguments points-to sets.
-   ???  As bar and foo have their address taken there might be callers
-   not seen by IPA PTA (if the address escapes the unit which we only compute
-   during IPA PTA...).  Thus the solution also includes NONLOCAL.  */
+   both bar and foo get a (and only a) in their arguments points-to sets.  */
 
 /* { dg-final { scan-ipa-dump "fn_1 = { bar foo }" "pta2" } } */
-/* { dg-final { scan-ipa-dump "bar.arg0 = { NONLOCAL a }" "pta2" } } */
-/* { dg-final { scan-ipa-dump "bar.arg1 = { NONLOCAL a }" "pta2" } } */
-/* { dg-final { scan-ipa-dump "foo.arg0 = { NONLOCAL a }" "pta2" } } */
-/* { dg-final { scan-ipa-dump "foo.arg1 = { NONLOCAL a }" "pta2" } } */
+/* { dg-final { scan-ipa-dump "bar.arg0 = { a }" "pta2" } } */
+/* { dg-final { scan-ipa-dump "bar.arg1 = { a }" "pta2" } } */
+/* { dg-final { scan-ipa-dump "foo.arg0 = { a }" "pta2" } } */
+/* { dg-final { scan-ipa-dump "foo.arg1 = { a }" "pta2" } } */

gcc/tree-ssa-structalias.c

@@ -4641,12 +4641,11 @@ find_func_aliases_for_call (struct function *fn, gcall *t)
 	  auto_vec<ce_s, 2> lhsc;
 	  struct constraint_expr rhs;
 	  struct constraint_expr *lhsp;
+	  bool aggr_p = aggregate_value_p (lhsop, gimple_call_fntype (t));
 
 	  get_constraint_for (lhsop, &lhsc);
 	  rhs = get_function_part_constraint (fi, fi_result);
-	  if (fndecl
-	      && DECL_RESULT (fndecl)
-	      && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
+	  if (aggr_p)
 	    {
 	      auto_vec<ce_s, 2> tem;
 	      tem.quick_push (rhs);
@@ -4656,22 +4655,19 @@ find_func_aliases_for_call (struct function *fn, gcall *t)
 	    }
 	  FOR_EACH_VEC_ELT (lhsc, j, lhsp)
 	    process_constraint (new_constraint (*lhsp, rhs));
-	}
 
-      /* If we pass the result decl by reference, honor that.  */
-      if (lhsop
-	  && fndecl
-	  && DECL_RESULT (fndecl)
-	  && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
-	{
-	  struct constraint_expr lhs;
-	  struct constraint_expr *rhsp;
+	  /* If we pass the result decl by reference, honor that.  */
+	  if (aggr_p)
+	    {
+	      struct constraint_expr lhs;
+	      struct constraint_expr *rhsp;
 
-	  get_constraint_for_address_of (lhsop, &rhsc);
-	  lhs = get_function_part_constraint (fi, fi_result);
-	  FOR_EACH_VEC_ELT (rhsc, j, rhsp)
-	    process_constraint (new_constraint (lhs, *rhsp));
-	  rhsc.truncate (0);
+	      get_constraint_for_address_of (lhsop, &rhsc);
+	      lhs = get_function_part_constraint (fi, fi_result);
+	      FOR_EACH_VEC_ELT (rhsc, j, rhsp)
+		  process_constraint (new_constraint (lhs, *rhsp));
+	      rhsc.truncate (0);
+	    }
 	}
 
       /* If we use a static chain, pass it along.  */
@@ -7686,30 +7682,13 @@ ipa_pta_execute (void)
 
       gcc_assert (!node->clone_of);
 
-      /* When parallelizing a code region, we split the region off into a
-	 separate function, to be run by several threads in parallel.  So for a
-	 function foo, we split off a region into a function
-	 foo._0 (void *foodata), and replace the region with some variant of a
-	 function call run_on_threads (&foo._0, data).  The '&foo._0' sets the
-	 address_taken bit for function foo._0, which would make it non-local.
-	 But for the purpose of ipa-pta, we can regard the run_on_threads call
-	 as a local call foo._0 (data),  so we ignore address_taken on nodes
-	 with parallelized_function set.
-	 Note: this is only safe, if foo and foo._0 are in the same lto
-	 partition.  */
-      bool node_address_taken = ((node->parallelized_function
-				  && !node->used_from_other_partition)
-				 ? false
-				 : node->address_taken);
-
       /* For externally visible or attribute used annotated functions use
 	 local constraints for their arguments.
 	 For local functions we see all callers and thus do not need initial
 	 constraints for parameters.  */
       bool nonlocal_p = (node->used_from_other_partition
 			 || node->externally_visible
-			 || node->force_output
-			 || node_address_taken);
+			 || node->force_output);
       node->call_for_symbol_thunks_and_aliases (refered_from_nonlocal_fn,
 						&nonlocal_p, true);