On Mon, Mar 16, 2020 at 07:46:57PM +0000, Richard Sandiford wrote: > > The write to "x" *before the asm* is deleted. I cannot think of any > > interpretation where that is correct (this does not involve inline asm > > at all: it is deleting an observable side effect before the exception). > > It's correct under the contract above :-)
That cannot be, because the generated code does the wrong thing before the asm is executed already (and without UB there is no time travel). > > Yes, obviously. The other option is to accept that almost all existing > > inline asm will have UB, with -fnon-call-exceptions. I think that is > > an even less desirable option. (I'm assuming we do not want that option). > Normally, for SSA names in something like: > > _1 = foo () > > the definition of _1 does not take place when foo throws. But that is not how RTL works, afaik. Segher
