https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77333
--- Comment #16 from Martin Jambor <jamborm at gcc dot gnu.org> ---
Please check whether the following patch (it is against trunk should
apply on top of GCC 6 too) fixes the issue for you.
It can potentially open a whole can of worms so I want to make sure it
helps before taking it further. Even if it does, I would also like to
ask you to run the whole gcc testsuite (as many languages as you can)
with and without the patch on i686-w64-mingw32 and compare the results
before I propose it on the mailing list.
diff --git a/gcc/cgraph.c b/gcc/cgraph.c
index ef2dc50282c..29ec61b3d0d 100644
--- a/gcc/cgraph.c
+++ b/gcc/cgraph.c
@@ -1425,7 +1425,7 @@ 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));
+ gimple_call_set_fntype (new_stmt, TREE_TYPE (e->callee->decl));
if (gimple_vdef (new_stmt)
&& TREE_CODE (gimple_vdef (new_stmt)) == SSA_NAME)
