Hi!
As the testcase shows, deciding on whether to convert an argument or not
based on TYPE_SIZE is wrong. While the old __sync_* builtins in the
_[1248]/_16 variants only had a VPTR as first argument and optionally
I[1248]/I16 argument or arguments that should be converted, the new
__atomic_* builtins also have PTR arguments (e.g. the expected pointer),
BOOL (e.g. weak argument) or INT (e.g. the *memmodel arguments).
Those have invariant types that shouldn't be adjusted based on what type the
first pointer points to. I[1248]/I16 arguments are unsigned integers,
the arguments that we don't want to adjust are BOOLEAN_TYPE/POINTER_TYPE
or signed integers, so I think we should convert only unsigned
INTEGER_TYPEs.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2012-02-13 Jakub Jelinek <ja...@redhat.com>
PR c++/52215
* c-common.c (sync_resolve_params): Don't decide whether to convert
or not based on TYPE_SIZE comparison, convert whenever arg_type
is unsigned INTEGER_TYPE.
* g++.dg/ext/atomic-1.C: New test.
--- gcc/c-family/c-common.c.jj 2012-01-26 09:22:17.000000000 +0100
+++ gcc/c-family/c-common.c 2012-02-13 14:49:15.204685590 +0100
@@ -9336,10 +9336,12 @@ sync_resolve_params (location_t loc, tre
return false;
}
- /* Only convert parameters if the size is appropriate with new format
- sync routines. */
- if (orig_format
- || tree_int_cst_equal (TYPE_SIZE (ptype), TYPE_SIZE (arg_type)))
+ /* Only convert parameters if arg_type is unsigned integer type with
+ new format sync routines, i.e. don't attempt to convert pointer
+ arguments (e.g. EXPECTED argument of __atomic_compare_exchange_n),
+ bool arguments (e.g. WEAK argument) or signed int arguments (memmodel
+ kinds). */
+ if (TREE_CODE (arg_type) == INTEGER_TYPE && TYPE_UNSIGNED (arg_type))
{
/* Ideally for the first conversion we'd use convert_for_assignment
so that we get warnings for anything that doesn't match the pointer
--- gcc/testsuite/g++.dg/ext/atomic-1.C.jj 2012-02-13 14:54:33.337864794
+0100
+++ gcc/testsuite/g++.dg/ext/atomic-1.C 2012-02-13 14:53:13.000000000 +0100
@@ -0,0 +1,12 @@
+// PR c++/52215
+// { dg-do compile }
+
+enum E { ZERO };
+
+int
+main ()
+{
+ E e = ZERO;
+ __atomic_compare_exchange_n (&e, &e, e, true, __ATOMIC_ACQ_REL,
+ __ATOMIC_RELAXED);
+}
Jakub
