On Mon, Oct 01, 2012 at 08:47:13AM +0200, Steven Bosscher wrote:
> The test case compiles just fine at -O2, only VRP has trouble with it.
> Let's try to stick with facts, not speculation.
I was talking about the other PR, PR26854, which from what I remember when
trying it myself and even the latest -O3 time reports from the reduced
testcase show that IRA/reload aren't there very significant (for -O3 IRA
takes ~ 6% and reload ~ 1%).
> I've put a lot of hard work into it to fix almost all scalability problems
> on this PR for gcc 4.8. LRA undoes all of that work. I understand it is
> painful for some people to hear, but I remain of opinion that LRA cannot be
> considered "ready" if it scales so much worse than everything else in the
> compiler.
Judging the whole implementation from just these corner cases and not how it
performs on other testcases (SPEC, rebuild a distro, ...) is IMHO not the
right thing, if Vlad thinks the corner cases are fixable during stage3; IMHO
we should allow LRA in, worst case it can be disabled by default even for
i?86/x86_64.
Jakub
