Problem with pseudo-reg syntax in RTL frontend

David Malcolm dmalcolm@redhat.com
Fri Dec 16 15:32:00 GMT 2016


On Fri, 2016-12-16 at 14:28 +0100, Bernd Schmidt wrote:
> On 12/14/2016 05:57 PM, David Malcolm wrote:
> > Any preferences? (or other syntax ideas?).  My preference is one of
> > the
> > currently-unused sigils e.g. "@3", or to wrap them in braces "{3}".
> 
> Either might work, I'd vaguely prefer <3> over {3} but they're 
> equivalent really. Maybe using "@" is simplest if it's unused.

I mostly implemented @, but ran into an issue: it leads to lexer errors
when parsing "__RTL"-tagged functions within cc1, where the lexer
complains about the stray CPP_ATSIGN token:

  gcc.dg/rtl/aarch64/asr_div1.c:12:25: error: stray '@' in program

We could add a flag to the preprocessor to support this token when
within c_parser_parse_rtl_body, but it seems simpler to just use a
different syntax: '<3>'.  I'm working on the '<3>' syntax.

Dave



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