dblaikie added a comment. In D141625#4094742 <https://reviews.llvm.org/D141625#4094742>, @steven_wu wrote:
> In D141625#4067225 <https://reviews.llvm.org/D141625#4067225>, @dblaikie > wrote: > >> In D141625#4066961 <https://reviews.llvm.org/D141625#4066961>, @steven_wu >> wrote: >> >>> No, reverse iteration will not break diff test for a small number of decls. >>> Everything will be in reverse order so it is the same. >> >> Hmm, I'm not sure I'm following why that is - could you explain this in more >> detail? The usual problem is that, say, we're outputting based on an >> unstable order - even two items would be enough to cause a test of that to >> fail in either forward or reverse iteration mode until the order is >> stabilized. >> >> Is that not the case here? Is there some interaction between iteration order >> that's part of the nondeterminism here? > > In order to make a test that will break before the change with reverse > iteration, the test needs to check that the decls/records are serialized into > the module in a pre deterministic order. It can't be just diff the output of > two runs with a small input because small input will not overflow the > smallptrset, thus the reverse iteration outputs from two runs will very > likely to be identical, just in a different order from forward iteration. Sure, I think I'm with you there - but the current test checks that the decls/records are serialized into the module in a pre-deterministic order, right? So it doesn't seem like a reverse iteration-failing test would be more involved/brittle/less robust than the test being added here? Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D141625/new/ https://reviews.llvm.org/D141625 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
