On Tue, Mar 29, 2016 at 7:16 PM, Jakub Jelinek <ja...@redhat.com> wrote: > On Tue, Mar 29, 2016 at 12:01:20PM -0500, Bill Schmidt wrote: >> Again, this is good information to know about. But the "stuff" we were >> talking about was the failures on powerpc*, and I took what you said to >> mean that nobody was working on those. It sounds like you're saying >> that the community has spent time on debug improvements for optimized >> code on x86_64/i?86, but only for that target. Is that a fair >> statement? If so, it seems unsurprising that you would get more bug > > Well, most of the analysis has been done on x86_64/i?86. The bug fixes, > DWARF enhancements etc. were then in various areas, if something has been > improved through some GIMPLE change, then likely all targets benefited, > if it was something at the RTL level (or var-tracking pass itself), then > it really depends on the various properties of the machine descriptions, > argument passing etc. > I'm not saying it is possible to have all the guality tests pass at all > optimization levels on all targets, sometimes the value of some variable > is really lost through optimizations and can't be reconstructed in any way, > sometimes it is too costly to track it, etc. > In other cases we have yet to create new DWARF extensions, known stuff is > e.g. debugging vectorized loops, what kind of user experience we want for > users if single set of instructions handles multiple iterations of the loop? > Do we want user to think he is seeing e.g. the first iteration, then the > fifth one, then ninth etc., or provide enough info for the debuggers so that > the user could find out he is in vectorized loop and explicitly request > he is e.g. interested in the 3rd iteration instead of 1st? > Then there will be certainly cases where even without adding any extensions > one can just add some smarts to var-tracking, or change other GCC internals > to handle some stuff better.
Yes, I think we _do_ need some dg-effective-target stuff for guality as some tests currently fail on arm (IIRC, I've only once did some non-x86 digging into guality fails) because of ABI issues that make a middle-end debuginfo fix incomplete (or impossible, don't remember). For powerpc somebody needs to look at a few regressions towards x86_64 and see if there's a similar pattern - adding arch specific xfails (or adding effective targets) is a good way to make progress as well. Hell, even slapping a xfail powerpc*-*-* on all current ppc FAILs would be better than simply disabling all of guality for ppc. Richard. > Jakub