[PATCH, PR 67133] Always change gimple fntype in cgraph_edge::redirect_call_stmt_to_callee

[Martin Jambor <mjambor@suse.cz>]

Hi,

even though PR 67133 has been avoided by a different patch, I believe
the patch below is the correct fix.  It modifies the function that
changes call statements according to call graph edges so that it
changes the fntype of the call statements also when
combined_args_to_skip is NULL.  This code path is taken for example
when a call is redirected to __builtin_unreachable and then the type
of the callee function is likely to mismatch with fntype of the
statement, which can confuse the compiler later on.

If we agree it is a good idea, I'd like to also propose a patch
making the gimple verifier check whether fntypes of direct call
statements match the types of the callee (or at least that they have
the same number of same-typed arguments).

The patch has been bootstrapped and tested on x86_64-linux, the
testcase is already checked in.  OK for trunk?

Thanks,

Martin


2015-08-17  Martin Jambor  <mjambor@suse.cz>

	PR middle-end/67133
	* cgraph.c (redirect_call_stmt_to_callee): Set gimple call fntype also
	when redirecting without removing any parameters.

diff --git a/gcc/cgraph.c b/gcc/cgraph.c
index 22a9852..5e5b308 100644
--- a/gcc/cgraph.c
+++ b/gcc/cgraph.c
@@ -1461,6 +1461,7 @@ cgraph_edge::redirect_call_stmt_to_callee (void)
     {
       new_stmt = e->call_stmt;
       gimple_call_set_fndecl (new_stmt, e->callee->decl);
+      gimple_call_set_fntype (new_stmt, TREE_TYPE (e->callee->decl));
       update_stmt_fn (DECL_STRUCT_FUNCTION (e->caller->decl), new_stmt);
     }