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Re: [RFC] failures found while pounding on GCC trunk
On 23 Sep 2007 09:54:29 -0700, Ian Lance Taylor <iant@google.com> wrote:
> "Richard Guenther" <richard.guenther@gmail.com> writes:
>
> > > We've got a test case with gcc 4.2 for which compilation time goes
> > > from nine minutes to 30 seconds when we use that option. I know the
> > > code is much better in mainline. Still, I would prefer to keep the
> > > option unless we are certain that similar compilation time blowouts
> > > can not occur. Lots of code can profit from optimization even with
> > > struct aliasing turned off.
> >
> > Well, ATM the flag doesn't work. And honestly we have enough "kinds"
> > of alias bugs - adding another knob to get different wrong-code bugs
> > doesn't look too appealing to me ;)
>
> Well, if the -fno-tree-salias flag now causes wrong-code bugs then I
> certainly agree that it should be eliminated.
I didn't say that ;) But I certainly expect salias to expose/hide bugs
there because MPT grouping will be changed. At the moment
-fno-tree-salias simply ICEs.
Richard.