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Re: gcc-3.3 problem with reloading byte into address register onColdFire

From: Jim Wilson <wilson at tuliptree dot org>
To: Peter Barada <peter at baradas dot org>
Cc: gcc at gcc dot gnu dot org
Date: Thu, 03 Jul 2003 19:19:58 -0700
Subject: Re: gcc-3.3 problem with reloading byte into address register onColdFire
References: <20030702133736.DF05198B1D@baradas.org>

Peter Barada wrote:

I've stumbled across a problem with reload trying to load a byte into
an address register, something legal on m68k, but illegal on ColdFire:

There is nothing in LIMIT_RELOAD_CLASS or PREFERRED_RELOAD_CLASS to handle this. Note that both of them handle the case where CLASS != ADDR_REGS. I.e., if we don't have ADDR_REGS, then we force it into DATA_REGS because we know both DATA_REGS is OK. And if it is ADDR_REGS then we leave it alone because we know ADDR_REGS is OK. It looks like the 5200 specific movqi pattern is bogus.

I'd wonder if the problem is BASE_REG_CLASS which is ADDR_REGS. There is MODE_BASE_REG_CLASS which lets you define one which is mode specific.

Otherwise, maybe you need to define CANNOT_CHANGE_MODE_CLASS to prevent reload from changing an ADDR_REGS/SImode reference to a ADDR_REGS/QImode reference when TARGET_5200.

Jim

Follow-Ups:
- Re: gcc-3.3 problem with reloading byte into address register onColdFire
  - From: Peter Barada
- Re: gcc-3.3 problem with reloading byte into address register onColdFire
  - From: Peter Barada

References:
- gcc-3.3 problem with reloading byte into address register on ColdFire
  - From: Peter Barada

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