[PATCH] Fix tree_function_versioning with void type DECL_RESULT (PR tree-optimization/51865)

[Jakub Jelinek]

Hi!

The recent changes in tree_function_versioning broke the following
testcase.  If DECL_RESULT exists, but has void type, then we used to
remap_decl it before, but now we don't, so in this case the same RESULT_DECL
is used in two different functions, which upsets ipa-pta, but could upset
other code too.

Fixed by calling remap_decl again for void type.  Bootstrapped/regtested
on x86_64-linux and i686-linux (on x86_64 including ada).  Ok for trunk?

2012-01-15  Jakub Jelinek  <ja...@redhat.com>

        PR tree-optimization/51865
        * tree-inline.c (tree_function_versioning): Call remap_decl
        on DECL_RESULT whenever it has VOID_TYPE_P type.

        * gcc.dg/pr51865.c: New test.

--- gcc/tree-inline.c.jj        2012-01-13 21:47:35.000000000 +0100
+++ gcc/tree-inline.c   2012-01-15 20:00:00.350918475 +0100
@@ -5201,9 +5201,9 @@ tree_function_versioning (tree old_decl,
     /* Add local vars.  */
     add_local_variables (DECL_STRUCT_FUNCTION (old_decl), cfun, &id, false);
 
-  if (VOID_TYPE_P (TREE_TYPE (DECL_RESULT (old_decl))))
+  if (DECL_RESULT (old_decl) == NULL_TREE)
     ;
-  else if (skip_return)
+  else if (skip_return && !VOID_TYPE_P (TREE_TYPE (DECL_RESULT (old_decl))))
     {
       DECL_RESULT (new_decl)
        = build_decl (DECL_SOURCE_LOCATION (DECL_RESULT (old_decl)),
--- gcc/testsuite/gcc.dg/pr51865.c.jj   2012-01-15 20:09:00.035734459 +0100
+++ gcc/testsuite/gcc.dg/pr51865.c      2012-01-15 20:08:42.000000000 +0100
@@ -0,0 +1,25 @@
+/* PR tree-optimization/51865 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fipa-pta" } */
+
+void fn (const char *, const char *) __attribute__ ((__noreturn__));
+int var;
+
+inline void
+foo (void)
+{
+  if (__builtin_expect (var != 0, 0))
+    fn ("a", "b");
+};
+
+void
+bar (void)
+{
+  foo ();
+};
+
+void
+baz (void)
+{
+  foo ();
+};

        Jakub