Re: [PATCH] New option to support asymmetric integer ranges in gfortran

[Scott Robert Ladd <coyote at coyotegulch dot com>]

Paul Brook wrote:
> <pedant>No blank lines between changeLog entries</pedant>
> Either your mailer or mine seems to have mangled the whitespace in the patch 
> sufficiently that it won't apply. Other than that the contents of the patch 
> look ok.

Do you want me to make a new patch including the changes discussed 
below, or should I send you the existing patch as an attachment?

> However it does raise a couple of related latent bugs, which I think should be 
> fixed while we're working in this area.

Ah, yes, the butterfly affect...

> * The code for MIN and MAX (& poss. others) intrinsics in trans-intrinsics.c 
> assumes that largest representable values are +-huge(). They should use 
> min_int and max_int. I think the library functions in libgfortran are ok.

> * gfc_simplify_not is borken, and only works by chance most of the time. 
> Consider (not(huge(i) - 1) > 0)

> * max_int is set to the largest unsigned integer, not the largest 
> representable value. Fixing this also requires fixing gfc_simplift_not, as 
> mentioned above.

I'll take a look at these over the weekend.

> P.S. In case you hadn't found them, -fdump-parse-tree and -fdump-tree-original 
> are usedful when debugging this stuff.

Thanks for the pointer.

..Scott

--
Scott Robert Ladd
Coyote Gulch Productions (http://www.coyotegulch.com)
Software Invention for High-Performance Computing