On Fri, 2017-10-20 at 18:46 +0300, Alexander Monakov wrote: > On Fri, 20 Oct 2017, Torvald Riegel wrote: > > On Thu, 2017-10-19 at 15:31 +0300, Alexander Monakov wrote: > > > On Thu, 19 Oct 2017, Andrew Haley wrote: > > > > No, you did not. This looks like a bug. Please report it. > > > > > > This bug is fixed on trunk, so should work from gcc-8 onwards (PR 80640). > > > > The test case is invalid (I added some more detail as a comment on this > > bug). > > Sorry, I was imprecise. To be clear, the issue I referred to above as the > "bug [that was] fixed on trunk" is the issue Andrew Haley pointed out: when > GCC transitioned from GIMPLE to RTL IR, empty RTL was emitted for the fence > statement, losing its compile-time effect as a compiler memory barrier > entirely.
What I tried to convey was that I think this can be a (part of a) valid implementation on certain hardware, and when considering C11/C++11 or more recent, which require programs to not have any data races (as defined by these standards).
