[m-rev.] diff: update float_consistency test

[Zoltan Somogyi]

On 12-Jun-2003, Fergus Henderson <fjh at cs.mu.OZ.AU> wrote:
> Also, even with GCC, using `-ffloat-store' is not necessarily enough
> in general.  According to the GCC documentation, you also need to
> "store all pertinent intermediate computations into variables".
> The MLDS back-end does not guarantee that (for example, the
> --eliminate-local-vars optimization will violate it) and AFAIK the LLDS
> back-end doesn't guarantee it either

The LLDS backend doesn't have such a guarantee either.

> 	   If the new option is enabled, also disable --eliminate-local-vars,
> 	   and add documentation to the MLDS and LLDS back-ends indicating
> 	   that they must preserve stores to floating point variables
> 	   if this option is enabled.

Unfortunately, adding the documentation doesn't change the code to ensure
that it obeys the documentation :-(

Given this fact, I see option 1 as the only viable one, at least until
the backends are changed to make the appropriate guarantees.

Java of course makes the right guarantees (and I hope IL does too), but
pointing people who want max FP performance towards the Java or IL backend
is unfortunately somewhat premature :-(

Zoltan.
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