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Re: latency in define_insn_reservation

From: Jim Wilson <wilson at specifixinc dot com>
To: ml at bitbash dot net
Cc: gcc at gcc dot gnu dot org
Date: Tue, 09 Dec 2003 22:05:30 -0800
Subject: Re: latency in define_insn_reservation
References: <20031209060818.26150.qmail@webmail-2-2.mesa1.secureserver.net>

ml@bitbash.net wrote:

If instr I is issued cycle = t and the results are usable in cylce t+1, should the latency in define_insn_reservation be 1 or 0?

The latency should be 1. Try looking at existing dfa scheduler descriptions. I doubt that you will find any that use a latency of zero, but there are lots that use a latency of 1 for simple instructions that you would expect to have single cycle latency. -- Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com

References:
- latency in define_insn_reservation
  - From: ml

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