On Fri, Jun 5, 2009 at 12:53 PM, Alexandre Oliva <aol...@redhat.com> wrote: > On Jun 5, 2009, Richard Guenther <richard.guent...@gmail.com> wrote: > >> So if I understand the above right then VTA is a new source of >> code-generation differences with -g vs. -g0. > > It was, but that was before I spent several months stopping it from > being it ;-)
Obviously ;) > And once VTA is on and bootstrap-debug is the rule rather than the > exception (with RTH's suggestion, it will again be faster than normal > bootstrap, and catch even some regressions that current > BUILD_CONFIG=bootstrap-debug doesn't), it won't be just me catching and > fixing these ;-) IMHO we should make bootstrap-debug (that's the one building stage2 w/o debug info and stage3 with debug info, correct?) the default regardless of VTA going in or not. If it works on the primary and secondary targets of course ;) Can you submit a separate patch to do so? (maybe you did already) > FTR, in the last two or three merges, I've had more -fcompare-debug > regressions with VTA disabled than with it enabled. Perhaps we should > default to BUILD_CONFIG=bootstrap-debug? It would be a start, but it > wouldn't have caught all of the recent regressions. Some of them only > affected C++ and Ada testcases, and bootstrap-debug won't catch these. > It takes -fcompare-debug for the testsuite run or something equivalent > to do so. bootstrap-debug by default would be a start. Honestly I don't care too much about -g vs. -g0 differences as we build everything with -g and strip debug info later. But passing bootstrap-debug is a release goal that I will support. > Hopefully people who run automated testers can be talked into using the > -fcompare-debug option for the library builds and testsuite runs. > >> IMHO a much more convincing way to avoid code generation >> differences with -g vs. -g0 and VTA would be to _always_ have >> the debug statements/instructions around, regardless of -g/-g0 > > That's an option I haven't discarded, but I wouldn't be able to claim > VTA had zero cost when disabled if that was so. So what is the overhead of having the debug stmts/insns if you throw them away before var-tracking and do debug info the old way? Thanks, Richard.
