Status of SEE and Autovectorization patches?

[H. J. Lu]

On Thu, May 04, 2006 at 01:18:37PM -0700, Mark Mitchell wrote:
> H. J. Lu wrote:
> 
> > export BOOT_CFLAGS="-g -O2 -fsee" CXXFLAGS="-g -O2 -fsee" FCFLAGS="-g -O2 -fsee" GCJFLAGS="-g -O2 -fsee" SYSROOT_CFLAGS_FOR_TARGET="-g -O2 -fsee"
> > # ..../configure
> > # make BOOT_CFLAGS="-g -O2 -fsee" CXXFLAGS="-g -O2 -fsee" FCFLAGS="-g -O2 -fsee" GCJFLAGS="-g -O2 -fsee" SYSROOT_CFLAGS_FOR_TARGET="-g -O2 -fsee"
> > 
> > to configure and build gcc on Linux/x86 and Linux/x86-64.
> 
> That certainly does suggest a bug in the SEE patches.  They needn't do
> anything useful on IA32/AMD64, but they should presumably either (a) not
> cause a bootstrap failure on these architectures, or (b) be disabled on
> these architectures.
> 

FWIW, I am for SEE. But I think it can only be turned on with -O3 in
a backend. If we want to turn it on with -O3 for all targets, we should

1. Use -fsee on gcc itself first:

# export BOOT_CFLAGS="-g -O2 -fsee" CXXFLAGS="-g -O2 -fsee" FCFLAGS="-g -O2 -fsee" GCJFLAGS="-g -O2 -fsee" SYSROOT_CFLAGS_FOR_TARGET="-g -O2 -fsee"
# ..../configure
# make BOOT_CFLAGS="-g -O2 -fsee" CXXFLAGS="-g -O2 -fsee" FCFLAGS="-g -O2 -fsee" GCJFLAGS="-g -O2 -fsee" SYSROOT_CFLAGS_FOR_TARGET="-g -O2 -fsee"

to make sure that there are no serious problems with SEE.

2. We have demonstrated that SEE helps on most major platforms.


H.J.