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Re: i386 and asm jumping
- From: Erik Schnetter <schnetter at uni-tuebingen dot de>
- To: gcc at gcc dot gnu dot org
- Date: Wed, 8 May 2002 01:20:08 +0200
- Subject: Re: i386 and asm jumping
- Organization: Theoretische Astrophysik Tuebingen
Peter Barada wrote:
> Jumps in asm statements will create problems since the optimizers have
> no knowledge that there is a possible change in flow caused by the asm
> statement, and hence will not have an accurate flow diagram of the
> function. From there its all downhill.
That is true. However, the same could be said from asm code changing
registers. The solution is to tell the compiler about all possible branch
destinations of a piece of asm code. Possibly with branch probabilities...
The question remains whether someone will think this is worthwhile
implementing, or whether this someone rather fixes the machine description in
question.
Another approach is to postprocess the generated assembler code, before the
assembler sees it.
-erik
--
Erik Schnetter <schnetter@uni-tuebingen.de>
Web: http://www.tat.physik.uni-tuebingen.de/~schnette/