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Re: [patch i386]: Combine memory and indirect jump
- From: Segher Boessenkool <segher at kernel dot crashing dot org>
- To: Kai Tietz <ktietz70 at googlemail dot com>
- Cc: Steven Bosscher <stevenb dot gcc at gmail dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, Richard Henderson <rth at redhat dot com>
- Date: Thu, 12 Jun 2014 16:06:16 -0500
- Subject: Re: [patch i386]: Combine memory and indirect jump
- Authentication-results: sourceware.org; auth=none
- References: <CAEwic4brJeBvoe+J5ss=Qo+=qoo-=2nV0FnjdUxBhm-fV4aqeQ at mail dot gmail dot com> <CABu31nNwUoLaAo0QcD-3O1QYhBWpLsYuH0cMS-XOgz2W+8KMAA at mail dot gmail dot com> <CAEwic4Zwd4HECD+kxtkouyA3Urbyzh2NFar7kZ5XLdNnUK9w6A at mail dot gmail dot com> <CAEwic4anzQysfHqfQGgKF_Hu-c_hLY+mkWr2CzERVe=gQ5AWRw at mail dot gmail dot com> <20140612185258 dot GA9914 at gate dot crashing dot org> <CAEwic4aF2etKf1PXm4Bo-7O-Y7Eb3NN_2jG0-zTLcW46yDd_-w at mail dot gmail dot com>
> > Will that work on other targets?
> Well, this is the only point I am a bit concerned too. In general I
> wouldn't expect here any issues to run peephole after scheduling, as
> peephole doesn't do anything a new run of ira/lra would require.
My concern is that peepholes are rather fragile, so imho it is not
inconceivable that some target will generate wrong code when you add
an extra (later) peephole pass. Of course, we are in stage1.
My other concern is that running peepholes again after scheduling
could easily generate worse code.
So I think the effect of this change on other targets needs to be
> Anyway it would be good if a global maintainer could comment on that.