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Re: Scheduling of asm()
- From: Paul Koning <pkoning at equallogic dot com>
- To: falk dot hueffner at student dot uni-tuebingen dot de
- Cc: gcc at gcc dot gnu dot org
- Date: Fri, 4 Jan 2002 17:55:52 -0500 (EST)
- Subject: Re: Scheduling of asm()
- References: <87y9jdzqpx.fsf@student.uni-tuebingen.de>
>>>>> "Falk" == Falk Hueffner <falk.hueffner@student.uni-tuebingen.de> writes:
Falk> Hi, When I experimented with some Alpha instructions, I found
Falk> out there seems to be no way to communicate the scheduling
Falk> class of an asm() instruction to gcc, leading to somewhat
Falk> suboptimal code. Would it be reasonably easy to add such a
Falk> facility? Either the user could mangle it into the asm
Falk> statement, or gcc could try to parse the string for a known
Falk> instruction. I would give it a try if somebody tells me whether
Falk> this is feasible...
I would LOVE to have that for other targets too.
Supplying the schedule class seems like the right answer; it may well
be that you will want to supply an instruction that the compiler would
never issue on its own and therefore has no reason to know about. An
example valid for MIPS (and for Alpha as well, if I remember
correctly) is the Prefetch instruction.
paul