Re: [PING] Target hook for rewriting inline asm constraints

["Michael Meissner" <michael.meissner@amd.com>]

On Tue, Oct 30, 2007 at 12:54:24PM +0100, Andreas Krebbel wrote:
> Hello,
> 
> could a C front end and/or middle end maintainer please have a look at
> this one:
> 
> http://gcc.gnu.org/ml/gcc-patches/2007-10/msg01407.html

I'm catching up on my backlog.

Here are the nit-picky comments about the change:

First, fixed size string arrays (result and tmp in c_parser_asm_operands) is
not a good idea.

Second, using repeated strlen calls to grow the string is also not a good idea
(in c_parser_asm_operand).

Third the local variables for c_parser_asm_operand should be moved into the
outer scope.

Fourth, you added the include file tm_p.h to the includes of c-parser.c, but I
did not see a corresponding modification to Makefile.in for this dependency.

Now, getting on the broader scope issues about the patch, I can sympathize with
the desire, but I think this is really opening up a can of worms if we let the
back end rewrite asm constraints like this.  I'm also not sure I understand
what the exact problem is.  I would imagine if you have address modes that are
allowed in some cases, but not others, this is better expressed in
GO_IF_MODE_DEPENDENT_ADDRESS instead of GO_IF_LEGITIMATE_ADDRESS.

-- 
Michael Meissner, AMD
90 Central Street, MS 83-29, Boxborough, MA, 01719, USA
michael.meissner@amd.com