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Re: gcc 3.1 is still very slow, compared to 2.95.3


In message <20020519.051034.71945092.davem@redhat.com>, "David S. Miller" write
s:
 >    From: Jan Hubicka <jh@suse.cz>
 >    Date: Sun, 19 May 2002 14:17:50 +0200
 > 
 >    > The Sparc output is very perplexing because GCC eliminated one of
 >    > the byte stores that overlapped the store of "code" but not both
 >    > of them!
 > 
 >    :) I think this is present in the flow.c dead store ellimination - it che
 > cks
 >    address for equivalence.
 >    
 > Looks like we have discovered a bug in dead store elimination :-)
The generic DSE code only eliminates stores where the address expressions
are identical -- so it would not eliminate a byte store that is subsumed by
a word store.

I don't think adding that capability would be all that difficult.

jeff



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