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.
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
