[Bug target/77333] Incorrect stack adjust in epilogue when targeting i686-w64-mingw32

[jamborm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77333

--- Comment #17 from Martin Jambor <jamborm at gcc dot gnu.org> ---
OK, so it turns out I botched my testing and the patch from the
previous commit cause PR57330 and we would need something like the
patch below (with a big fat comment why the condition is necessary, if
we go this way at all, that is).  Still, I need someone to test this
really helps to fix the problem and to do a testsuite run.

[PR 77333] Set clone call fntype to callee type

2017-02-03  Martin Jambor  <mjambor@suse.cz>

        PR target/77333
        * cgraph.c (redirect_call_stmt_to_callee): Set call stmt fntype to
        type of the decl if lhs has compatible type.

diff --git a/gcc/cgraph.c b/gcc/cgraph.c
index ef2dc50282c..b91de6788c7 100644
--- a/gcc/cgraph.c
+++ b/gcc/cgraph.c
@@ -1425,7 +1425,15 @@ cgraph_edge::redirect_call_stmt_to_callee (void)
        new_stmt = chkp_copy_call_skip_bounds (new_stmt);

       gimple_call_set_fndecl (new_stmt, e->callee->decl);
-      gimple_call_set_fntype (new_stmt, gimple_call_fntype (e->call_stmt));
+
+      tree lhs = gimple_call_lhs (new_stmt);
+      tree decl_restype = TREE_TYPE (TREE_TYPE (e->callee->decl));
+      if (lhs
+         && (VOID_TYPE_P (decl_restype)
+             || !useless_type_conversion_p (TREE_TYPE (lhs), decl_restype)))
+       gimple_call_set_fntype (new_stmt, gimple_call_fntype (e->call_stmt));
+      else
+       gimple_call_set_fntype (new_stmt, TREE_TYPE (e->callee->decl));

       if (gimple_vdef (new_stmt)
          && TREE_CODE (gimple_vdef (new_stmt)) == SSA_NAME)