RE: RFC/RFA: patch for PR 22156: improve SRA for bit-fields

["Dave Korn" <dave dot korn at artimi dot com>]

On 07 May 2007 00:55, Alexandre Oliva wrote:

>> In the testcase, the structure contains exactly 2 fields, which are both
>> words.  How does this relate to what you're saying?
> 
> Two SImode fields that are laid out in such a way that they can be
> accessed with a single DImode access.  The first patch used to
> consider it profitable to create a single variable for them.
> 
> With the latest two patchlets on top of the big patch I last posted,
> it won't, and will rather avoid creating blocks wider than a word.
> This should appease your concerns.  But it will still create a single
> variable for say a sequence of 4 chars (assuming a word is 4 bytes
> long).

  Alex, I'm not sure I completely grasp the intent of this patch, and I'm sure
you've considered this already, but I just wanted to verify: this isn't going
to cause over-reads when someone uses bitfields to describe and access
memory-mapped i/o registers, is it?


    cheers,
      DaveK
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