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Re: Store scheduling with DFA scheduler
- From: David Edelsohn <dje at watson dot ibm dot com>
- To: Nathan Sidwell <nathan at codesourcery dot com>
- Cc: Jon Beniston <jon at beniston dot com>, gcc at gcc dot gnu dot org
- Date: Tue, 26 Apr 2005 09:49:18 -0400
- Subject: Re: Store scheduling with DFA scheduler
- References: <200504251936.j3PJaBke003918@mx1.messagewash.net> <426E1E8D.3090607@codesourcery.com>
>>>>> Nathan Sidwell writes:
>> (define_insn_reservation "arith" 1 (eq_attr "type" "arith") "x")
>> (define_insn_reservation "loads" 2 (eq_attr "type" "load") "x,m")
>> (define_insn_reservation "stores" 3 (eq_attr "type" "store") "x,m*2")
Nathan> Stores don't really have a 'result', why have you set the cycle
Nathan> count to 3? Shouldn't it be '1'? (then you won't need store bypasses
Nathan> for autoincrements)
Stores do have results: memory. If one does not have a store
bypass in the processor, one needs to model the delay for the result to
appear in the cache and be available for a subsequent load.
David