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Re: Relax restriction slightly on integral mode structs
- From: Jim Wilson <wilson at tuliptree dot org>
- To: Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Thu, 08 May 2003 18:36:12 -0400
- Subject: Re: Relax restriction slightly on integral mode structs
- References: <10305042212.AA15165@vlsi1.ultra.nyu.edu>
Richard Kenner wrote:
We can allow non-BLKmode RECORD_TYPEs even if a field crosses a word
boundary if that field is larger than a word since we have code to handle
This looks like a potential silent ABI change.
The default function argument/return macros check for BLKmode objects
and handle them specially. The result is that if you change the rule
that decides whether a structure is BLKmode or not, then you are most
likely changing the ABI for at least one target.
Of course, the function argument/return macros are broken, since they
should be checking types instead of modes, but we are stuck with them
for now. Thus we need to be careful about making gratuitous changes to
the code that decides whether a structure is BLKmode or not.