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Re: Wrong code: missing input reload
- From: Bernd Schmidt <bernds at codesourcery dot com>
- To: Georg-Johann Lay <avr at gjlay dot de>
- Cc: Eric Botcazou <ebotcazou at adacore dot com>, Richard Henderson <rth at redhat dot com>, gcc at gcc dot gnu dot org
- Date: Wed, 01 Jun 2011 17:54:07 +0200
- Subject: Re: Wrong code: missing input reload
- References: <4DDE5B4A.30803@gjlay.de> <201105261956.43067.ebotcazou@adacore.com> <4DDEB1B2.5090705@gjlay.de> <201105262351.47369.ebotcazou@adacore.com> <4DE6460A.2050306@gjlay.de> <4DE64944.7070202@codesourcery.com> <4DE65C29.3090105@gjlay.de>
On 06/01/2011 05:35 PM, Georg-Johann Lay wrote:
> The reason for why a subreg of hardreg is there during reload is that
> on avr, r29:r28 is the frame pointer (word_mode is QI and Pmode is
> HI). Because in many places of the compiler, there are tests like "if
> (regno == FRAME_POINTER_REGNUM)", the high byte of the frame pointer
> gets garbaged.
Maybe it would help for your port to define a separate
FRAME_POINTER_REGNUM, able to hold an HImode value, which then gets
eliminated to HARD_FRAME_POINTER_REGNUM? This mechanism is used on many
other ports if you need examples.
Bernd