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Re: GCSE store motion
- From: David Edelsohn <dje at watson dot ibm dot com>
- To: Roger Sayle <roger at eyesopen dot com>
- Cc: Daniel Berlin <dberlin at dberlin dot org>, gcc at gcc dot gnu dot org, Mark Mitchell <mark at codesourcery dot com>, "David S. Miller" <davem at redhat dot com>, Andreas Jaeger <aj at suse dot de>, Richard Henderson <rth at redhat dot com>
- Date: Wed, 15 May 2002 13:06:07 -0400
- Subject: Re: GCSE store motion
There is no argument that GCSE store motion and store merging can
be useful. The only question is whether the current implementation is
We all concede that the current GCSE store-motion implementation
does have an effect on a store in your example from glibc. We are asking
that GCSE store motion show demonstrable improvement in macroscopic
performance of code produced by GCC.
Maybe we should rearrange the disabling so that toplev.c defaults
flag_gcse_sm to 0 instead of disabling the optimization in gcse.c itself.
Then this file in glibc could be compiled with -fgcse-sm in the one
instance it has been shown to be useful.
When store motion shows performance improvement across a wider
range of applications, then we can enable that optimization by default.