Do you mean if TARGET_ADDRES_COST (non-x86) is defined properly, this should be fixed? Or it requires extra patch?
Bingfeng > -----Original Message----- > From: Paolo Bonzini [mailto:paolo.bonz...@gmail.com] On > Behalf Of Paolo Bonzini > Sent: 23 December 2009 13:28 > To: Steven Bosscher > Cc: Bingfeng Mei; gcc@gcc.gnu.org; dber...@dberlin.org > Subject: Re: Unnecessary PRE optimization > > On 12/23/2009 01:01 PM, Steven Bosscher wrote: > > On Wed, Dec 23, 2009 at 12:49 PM, Bingfeng > Mei<b...@broadcom.com> wrote: > >> Hello, > >> I encounter an issue with PRE optimization, which created worse > > > > Is this at -O2 or -O3? > > I think this could be fixed if fwprop propagated addresses > into loops; > it doesn't because it made performance worse on x86. The > real reason is > "address_cost on x86 sucks and nobody knows how to fix it > exactly", but > the performance hit was bad enough that we (Steven Bosscher and I) > decided to put that hack into fwprop. > > Paolo > >
