Messages in this thread | | | Date | Tue, 26 Feb 2019 07:39:57 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [RFC PATCH] tools/memory-model: Remove (dep ; rfi) from ppo |
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On Tue, Feb 26, 2019 at 03:47:30PM +0100, Peter Zijlstra wrote: > On Tue, Feb 26, 2019 at 06:28:45AM -0800, Paul E. McKenney wrote: > > I must confess to not being all that sympathetic to code that takes > > advantage of happenstance stack-frame layout. Is there some reason > > we need that? > > Not that I'm aware; but if it gets this 'obvious' case wrong, I worry > what else it gets wrong. > > At the very least we should get this fixed and compile a kernel with the > fixed compiler to see what (if anything) changes in the generated code > and analyse the changes (if any) to make sure we were ok (or not). > > I mean; yes that example is UB, but the result is also clearly batshit > insane.
My understanding is that their goal is better analysis of pointer aliasing, and that this case is a side effect.
Thanx, Paul
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