On 05/05/15 15:29, Jakub Jelinek wrote: > On Tue, May 05, 2015 at 02:20:43PM +0100, Richard Earnshaw wrote: >> On 05/05/15 14:06, Jakub Jelinek wrote: >>> On Tue, May 05, 2015 at 02:02:19PM +0100, Richard Earnshaw wrote: >>>> In a literal sense, yes. However, even K&R & stdarg have standard >>>> promotion and conversion rules (size < int => int, floats promoted to >>>> double, etc). What are those rules for GCC's overaligned types (ie >>>> where in the docs does it say what happens and how a back-end should >>>> interpret them)? Shouldn't the mid-end be doing that work so as to >>> >>> For the middle-end, the TYPE_ALIGN info on expression types is considered >>> useless, you can get there anything. There is no conversion rule to what >>> you get for myalignedint + int, or (myalignedint) int, or (int) >>> myalignedint, etc. >>> >>>> create a consistent view of the values passed into the back-end? It >>>> seems to me that at present the back-end has to be psychic as to what is >>>> really happening. >>> >>> No, the backend just shouldn't consider TYPE_ALIGN on the scalars, and it >>> seems only arm ever looks at that. >>> >> >> Nothing in the specification for TARGET_FUNCTION_ARG (or any of the >> related functions) makes any mention of this... > > While this requirement isn't documented, it is clearly common sense or at > least something any kind of testing would reveal immediately.
Then clearly no such tests exist in the testsuite :-( R. > And it is nothing broken recently (except that with the SRA changes it hits > much more often), looking e.g. at GCC 3.2, I'm seeing that expand_call is on > that testcase also called with pretty random TYPE_ALIGN on the argument > types; we didn't have GIMPLE then, so it is nothing that GIMPLE brought in. > > Jakub >
