Re: Fixed-point branch?

[Bernd Schmidt <bernds_cb1 at t-online dot de>]

Fu, Chao-Ying wrote:
>   I attached a diff file for 14 files of the new structures
> and documents.  You and other maintainers are welcome to
> check it.  Thanks a lot!
> 
> Note: 14 files are =>
> genmodes.c mode-classes.def machmode.def machmode.h tree.def tree.h
> tree.c rtl.def rtl.h rtl.c fixed-value.h fixed-value.c
> doc/extend.texi doc/rtl.texi doc/c-tree.texi doc/md.texi

Random comments..

> +  unsigned saturating_flag : 1; /* FIXME.  This new flag increases the size of
> +                                  tree_common by a full word.  */

Sounds undesirable.  We need to look hard for a way to avoid this.

> +ACCUM_MODE (HA, 2, 8, 7); /* s8.7 */
> +ACCUM_MODE (SA, 4, 16, 15); /* s16.15 */
> +ACCUM_MODE (DA, 8, 32, 31); /* s32.31 */
> +ACCUM_MODE (TA, 16, 64, 63); /* s64.63 */

Lots of predefined types and modes in this patch.  What about targets
with other requirements (the Blackfin has 40 bit (8 + 32) accumulators)?

For vectors, we let the targets define the supported modes.  Why do we
want something else for fractional support?

> +int
> +fixed_zerop (tree expr)
> +{
> +  return TREE_CODE (expr) == FIXED_CST
> +        && double_int_zero_p (TREE_FIXED_CST (expr).data);
> +}

Formatting - this needs parentheses.  Elsewhere too.

> +static tree
> +make_or_reuse_fract_type (unsigned size, int unsignedp, int satp)

Comments before functions.


Bernd
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