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Re: [PATCH] Teach VRP to derive ranges from SWITCH_EXPR (fix PR21258)
On Fri, 2007-04-13 at 07:55 -0400, Diego Novillo wrote:
> Richard Guenther wrote on 04/13/07 05:20:
>
> > No noticable slowdowns, I have applied the patch to mainline. A patch
> > for 14495 is in work.
>
> I forgot to ask, what was the net effect of the optimization in terms of
> code size or performance of generated code?
FWIW, I wouldn't have expected much of a code speed improvement, it's
rare that a SWITCH_EXPR is on the critical path *and* there's
opportunity for improvement via VRP derived ranges related to the
switch statement.
It might be interesting to see if we can zap the code in
tree-ssa-dom.c::record_edge_info -- in theory it should be
subsumed by VRP.
Jeff