[U-Boot] [RFC PATCH v2] ARM: Avoid compiler optimization for usages of readb, writeb and friends.

Wolfgang Denk
2010-12-21T10:53:03Z

Dear Albert ARIBAUD,

In message <4D1083B4.2060704@free.fr> you wrote:
>
> > And I at your suggestion tried modifying the binary changing the extra
> > ldrb to a nop and it works.
>
> Seems like a compiler issue to me, as the preprocessed C source is the
> same for the register access and does not call for a re-read (that is
> what I wanted to see in the preprocessed version), yet the ASM sequence
> does the re-read.

I also tend to think this is a compiler problem. Searching the gcc
bugzilla entries for "ldrb" turns up quite a number of hits. I'm not
sure which of these we are running into here, but there are enough of
them so you can chose freely :-(

Best regards,

Wolfgang Denk

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