On Tue, 2015-12-22 at 17:36 +0000, Alan Lawrence wrote: > On 22/12/15 16:05, Bill Schmidt wrote: > > On Tue, 2015-12-22 at 15:54 +0000, Alan Lawrence wrote: > >> On 21/12/15 13:13, Alan Lawrence wrote: > >>> This is a respin of previous patch series: > >>> https://gcc.gnu.org/ml/gcc-patches/2015-10/msg03271.html > >>> Minus three of the smaller patches having already been committed; with the > >>> updated version of the main patch to SRA; and the patches to DOM reworked > >>> to avoid constructing gimple stmt's. > >>> > >>> IMHO this feels quite invasive for stage 3, however, I note the PR/63679 > >>> (ssa-dom-cse-2.c being XFAILed on a bunch of platforms, and currently > >>> still > >>> FAILing on ARM) is a regression from gcc 4.9.1. So I'd ask maintainer's > >>> thoughts > >>> as to whether we should take this patch set for gcc 6. > >>> > >>> > >> > >> I've now tested the series on powerpc64-none-linux-gnu (gcc110) and > >> powerpc64le-none-linux-gnu (gcc112). > >> > >> On powerpc64le, this causes the same guality failures as on AArch64: > >> gcc.dg/guality/pr54970.c -O1 line 15 a[0] == 1 > >> gcc.dg/guality/pr54970.c -O1 line 20 a[0] == 1 > >> gcc.dg/guality/pr54970.c -O1 line 25 a[0] == 1 > >> and the same with other optimization flags. (I note that there are quite a > >> lot > >> of guality failures on both powerpc and also aarch64, which are generally > >> not > >> included in the posts on the gcc-testresults mailing list). > > > > That's interesting. I never see these for powerpc64le on my internal > > build system. I wonder what the difference is? > > I've ssh'd into gcc112.fsffrance.org, a power8 powerpc64le system; > and configure --with-cpu=power8 --disable-libsanitizer --with-long-double-128 > --enable-languages=c,c++,lto. > > Hmmm...ISTR one variable that can make a big difference is the version (or > absence!) of gdb...gcc112 has gdb "Fedora 7.8.2-38.fc21", copyright 2014, and > GDB 7.8 looks to have been released at the end of 2014.
I no longer use --disable-libsanitizer, but that doesn't seem relevant. I also use --disable-multilib, though I think thats the default for powerpc64le now; not sure. The GDB on my internal system is actually even older (7.7.1, from earlier in 2014), so I don't think that's necessarily to blame. Still seems mysterious. That said, for better or worse we've had a history of ignoring the guality failures for big-endian because we've seen so many of them, and they don't seem to reflect a real problem with the debugger. Understanding why they break hasn't managed to become a priority yet. I personally won't be upset if we have a few more than we did before, as it probably doesn't indicate anything relevant about your patch. Bill > > >> The same pr54970 tests still seem to pass on powerpc64 big-endian even > >> with the > >> patches. > > Ach, not quite. In fact those three are failing on powerpc64 bigendian even > *without* the patches (at all optimization levels besides -O0 where they > pass). > This is on gcc110, configure --enable-languages=c,c++,lto > --disable-libsanitizer > --with-cpu=power7 --with-long-double-128. GDB is Fedora 7.7.1-21.fc20, a bit > older, and I tested both unix/-m32 and unix/-m64 (following Bill Seurer's > posts > on gcc-testresults). > > I'll email a list of the failures I'm seeing offlist (summary: 186 on gcc112, > 148 on gcc110 with -m32, 395 on gcc112 with -m64); however, I suspect gdb > version is the difference we are looking for. > > Which *may* mean that with a more up-to-date GDB, it's possible those > failures > may not be introduced on ppc64le. (Or similarly AArch64.) Hmmm.... > > --Alan >
