re PR c/70093 (Instancing function with VM return type cases internal compiler…

re PR c/70093 (Instancing function with VM return type cases internal compiler error in 'assign_stack_temp_for_type'.)

	PR c/70093
	* c-typeck.c (build_function_call_vec): Create a TARGET_EXPR for
	nested functions returning VM types.

	* cgraphunit.c (cgraph_node::expand_thunk): Also build call to the
	function being thunked if the result type doesn't have fixed size.
	* gimplify.c (gimplify_modify_expr): Also set LHS if the result type
	doesn't have fixed size.

	* gcc.dg/nested-func-10.c: New test.
	* gcc.dg/nested-func-9.c: New test.

From-SVN: r234259

gcc/ChangeLog

+2016-03-16  Marek Polacek  <polacek@redhat.com>
+
+	PR c/70093
+	* cgraphunit.c (cgraph_node::expand_thunk): Also build call to the
+	function being thunked if the result type doesn't have fixed size.
+	* gimplify.c (gimplify_modify_expr): Also set LHS if the result type
+	doesn't have fixed size.
+
 2016-03-16  Bin Cheng  <bin.cheng@arm.com>
 
 	* tree-vect-loop.c (vect_analyze_loop_2): Fix wrong dump info by

gcc/c/ChangeLog

+2016-03-16  Marek Polacek  <polacek@redhat.com>
+
+	PR c/70093
+	* c-typeck.c (build_function_call_vec): Create a TARGET_EXPR for
+	nested functions returning VM types.
+
 2016-03-09  Cesar Philippidis  <cesar@codesourcery.com>
 
 	* c-parser.c (c_parser_oacc_loop): Update cclauses and clauses

gcc/c/c-typeck.c

@@ -3068,6 +3068,16 @@ build_function_call_vec (location_t loc, vec<location_t> arg_loc,
     result = build_call_array_loc (loc, TREE_TYPE (fntype),
 				   function, nargs, argarray);
 
+  /* In this improbable scenario, a nested function returns a VM type.
+     Create a TARGET_EXPR so that the call always has a LHS, much as
+     what the C++ FE does for functions returning non-PODs.  */
+  if (variably_modified_type_p (TREE_TYPE (fntype), NULL_TREE))
+    {
+      tree tmp = create_tmp_var_raw (TREE_TYPE (fntype));
+      result = build4 (TARGET_EXPR, TREE_TYPE (fntype), tmp, result,
+		       NULL_TREE, NULL_TREE);
+    }
+
   if (VOID_TYPE_P (TREE_TYPE (result)))
     {
       if (TYPE_QUALS (TREE_TYPE (result)) != TYPE_UNQUALIFIED)

gcc/cgraphunit.c

@@ -1708,7 +1708,9 @@ cgraph_node::expand_thunk (bool output_asm_thunks, bool force_gimple_thunk)
 
       /* Build call to the function being thunked.  */
       if (!VOID_TYPE_P (restype)
-	  && (!alias_is_noreturn || TREE_ADDRESSABLE (restype)))
+	  && (!alias_is_noreturn
+	      || TREE_ADDRESSABLE (restype)
+	      || TREE_CODE (TYPE_SIZE_UNIT (restype)) != INTEGER_CST))
 	{
 	  if (DECL_BY_REFERENCE (resdecl))
 	    {

gcc/gimplify.c

@@ -4838,7 +4838,8 @@ gimplify_modify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
 	}
       notice_special_calls (call_stmt);
       if (!gimple_call_noreturn_p (call_stmt)
-	  || TREE_ADDRESSABLE (TREE_TYPE (*to_p)))
+	  || TREE_ADDRESSABLE (TREE_TYPE (*to_p))
+	  || TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (*to_p))) != INTEGER_CST)
 	gimple_call_set_lhs (call_stmt, *to_p);
       assign = call_stmt;
     }

gcc/testsuite/ChangeLog

+2016-03-16  Marek Polacek  <polacek@redhat.com>
+
+	PR c/70093
+	* gcc.dg/nested-func-10.c: New test.
+	* gcc.dg/nested-func-9.c: New test.
+
 2016-03-16  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/68714

gcc/testsuite/gcc.dg/nested-func-10.c

+/* PR c/70093 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+void __attribute__((noinline, noclone))
+foo (int n)
+{
+  struct S { int a[n]; };
+
+  struct S __attribute__((noreturn))
+  fn (void)
+  {
+    __builtin_abort ();
+  }
+
+  auto struct S __attribute__((noreturn))
+  fn2 (void)
+  {
+    __builtin_abort ();
+  }
+
+  struct S x;
+  __typeof__ (fn ()) *p = &x;
+  switch (n)
+    {
+    case 1:
+      fn ();
+      break;
+    case 2:
+      fn2 ();
+      break;
+    case 3:
+      x = fn ();
+      if (x.a[0] != 42)
+	__builtin_abort ();
+      break;
+    case 4:
+      if (fn ().a[0] != 42)
+	__builtin_abort ();
+      break;
+    case 5:
+      if (p->a[0] != 42)
+	__builtin_abort ();
+      break;
+    case 6:
+      if (fn2 ().a[0] != 42)
+	__builtin_abort ();
+      break;
+    }
+}
+
+int
+main (void)
+{
+  foo (1);
+}

gcc/testsuite/gcc.dg/nested-func-9.c

+/* PR c/70093 */
+/* { dg-do run } */
+/* { dg-options "" } */
+
+void
+foo (int n)
+{
+  struct S { int a[n]; };
+
+  struct S
+  fn (void)
+  {
+    struct S s;
+    s.a[0] = 42;
+    return s;
+  }
+
+  auto struct S
+  fn2 (void)
+  {
+    return fn ();
+  }
+
+  struct S x;
+  fn ();
+  fn2 ();
+  x = fn ();
+
+  if (x.a[0] != 42)
+    __builtin_abort ();
+
+  if (fn ().a[0] != 42)
+    __builtin_abort ();
+
+  __typeof__ (fn ()) *p = &x;
+  if (p->a[0] != 42)
+    __builtin_abort ();
+
+  if (fn2 ().a[0] != 42)
+    __builtin_abort ();
+}
+
+int
+main (void)
+{
+  foo (1);
+}