On 07/09/2015 11:43 PM, Martin Liška wrote: > This final version which I agreed with Richard Sandiford. > Hope this can be finally installed to trunk? > > Patch can bootstrap and survive regression tests on x86_64-linux-gnu.
Unfortunately, this still crashes on my SPU toolchain build machine, for pretty much the same reason outlined here: https://gcc.gnu.org/ml/gcc-patches/2015-06/msg00868.html However, the host compiler no longer miscompiles these lines: empty_shared_hash = new shared_hash_def; empty_shared_hash->refcount = 1; But that is simply because that "new" now goes to the default heap-based allocator from the standard library. There is a "shared_hash_def_pool", but that's apparently not being used for anything -- this probably was not intended? But now the following lines are miscompiled: elt_list *el = elt_list_pool.allocate (); el->next = next; el->elt = elt; from new_elt_list in cselib.c. Again, the "allocate" call ends simply with a cast: header = m_returned_free_list; m_returned_free_list = header->next; return (void *)(header); and type-based aliasing now states the access to "header->next" in allocate must not alias the access to "el->next" in new_elt_list, but clearly it does. (Since there is no C++ operator new involved at all anymore, this clearly violates even the C aliasing rules ...) I really think the allocate routine needs to be more careful to avoid violating aliasing, e.g. by using memcpy or union-based type-punning to access its free list info. Bye, Ulrich -- Dr. Ulrich Weigand GNU/Linux compilers and toolchain ulrich.weig...@de.ibm.com
