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Re: gcc 3.4 > mainline performance regression
On 1/5/07, David Edelsohn <dje@watson.ibm.com> wrote:
>>>>> Steven Bosscher writes:
Steven> What does the code look like if you compile with -O2 -fgcse-sm?
Yep. Mark and I recently discussed whether gcse-sm should be
enabled by default at some optimization level. We're hiding performance
from GCC users.
The problem with it used to be that it was just very broken. When I
fixed PR24257, it was still not possible to bootstrap with gcse store
motion enabled.
Putting someone on fixing tree load&store motion is probably more
useful anyway, if you're going to do load&store motion for
performance. In RTL, we can't move loads and stores that are not
simple loads or stores (i.e. reg <- mem, or mem <- reg). There are two
very popular targets where this is the common case ;-)
Gr.
Steven