Re: SIMPLE: A language-independent tree IR

[Toon Moene <toon at moene dot indiv dot nluug dot nl>]

"Joseph S. Myers" wrote:

> On Wed, 2 Jan 2002, Diego Novillo wrote:
> 
> > Any tree expression that does not conform to this must be broken
> > down into a sequence of these 14 expressions.  For reference, I'm
> > attaching SIMPLE's BNF grammar.  For instance,
> 
> One thing I'd like in language-independent trees (at some level) is that
> ordering (sequence point) and aliasing constraints are explicitly
> represented (that is, language-dependent trees, in which these are
> implicit, are converted to language-independent trees, in which these are
> explicit).

Good point.  The concept of sequence point has no equivalent in Fortran,
for example.

> There may be other C assumptions in the current tree forms to consider and
> maybe change - for example, are the C rules that overflow of signed
> integer arithmetic is undefined appropriate for all languages, or is this
> another matter that should be explicitly represented in the various forms?

Fortran doesn't even define the concept of overflowing of INTEGERs
(which are always signed in arithmetic context).

-- 
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