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Re: init_reg_autoinc bug and how to describe regs that can't autoincdec
- From: kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)
- To: hans-peter dot nilsson at axis dot com
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Wed, 21 Nov 2007 15:36:51 EST
- Subject: Re: init_reg_autoinc bug and how to describe regs that can't autoincdec
- References: <200711212005.lALK5sUL013671@ignucius.se.axis.com>
> So, the main question is, how should this code change to also work for
> a register class that can't be used for autoincdeced but doesn't need
> secondary reloads at all?
I don't think it needs to. This is 13 years old, but my recollection is
that we wanted to avoid the need for secondary reloads on autoincs,
either because of efficiency or because, at that time at least, reload
didn't have the code to do it.
But if there *is* no secondary reload, then what's the problem with putting
a pseudo into an arbitrary register? Reload can generate the appropriate
moves to make it work.