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From: DJ Delorie <dj@redhat.com>
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In-reply-to: <20040118223751.GB14927@redhat.com> (message from Richard
	Henderson on Sun, 18 Jan 2004 14:37:51 -0800)
Subject: Re: Can we speed up the gcc_target structure?
References: <20040118083738.10772.qmail@gossamer.airs.com> <200401181357.i0IDvpWF004706@caip.rutgers.edu> <Pine.LNX.4.58.0401182111570.9475@digraph.polyomino.org.uk> <20040118220522.GA14767@redhat.com> <20040118222201.GD11268@atrey.karlin.mff.cuni.cz> <20040118223751.GB14927@redhat.com>
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> > What is preventing us from declaring the structure as constant so we
> > should get propagation even with current design?
> 
> Targets that modify the structure at startup.

Maybe I'm misremembering, but wasn't one of the goals of using the
target structure to be able to switch them at runtime?  If so, a
command line argument could change the pointer to point to a different
structure, which completely invalidates all such optimizations.