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Re: i386 CONST_COSTS take 2
- To: jh at suse dot cz (Jan Hubicka)
- Subject: Re: i386 CONST_COSTS take 2
- From: Joern Rennecke <amylaar at redhat dot com>
- Date: Thu, 21 Jun 2001 17:58:12 +0100 (BST)
- Cc: amylaar at redhat dot com (Joern Rennecke), jh at suse dot cz (Jan Hubicka),gcc-patches at gcc dot gnu dot org, rth at cygnus dot com, patches at x86-64 dot org
> Shouldn't we be be able to teach reload and register allocator to eliminate
> the cost completely? We are able to re-incarnate such values w/o spilling,
> so proper tunning of preferences should do the trick.
> What I worry about are the extra instructions in sequences of two instructions
> with same constant, where extra load is just a lose. These are common.
That is somewhat complex, as you would have to combine some of the
functionality of life range splitting, reload and cse...