mirror of
https://gcc.gnu.org/git/gcc.git
synced 2026-02-22 12:00:03 -05:00
ecb3467328
One of the difficulties I ran into when familiarizing myself with
value-range.{h,cc} is that the comments and classes refer to
representations of "ranges", but the implementation has grown beyond
mere ranges of values (such as with bitmasks and NaN-tracking).
Arguably "range" could refer to the mathematical definition: the set
of possible outputs of a function, but I find it much clearer to think
of these classes as efficient representations of subsets of possible
values of a type.
This patch updates various leading comments in a way that clarifies
the intent of these classes (for me, at least).
gcc/ChangeLog:
* value-range.cc (irange_bitmask::irange_bitmask): Fix typo in
comment.
* value-range.h (class vrange): Update leading comment to refer
to "subsets" rather than "ranges". Allude to the available
subclasses. Warn that the classes can be over-approximations and
thus can introduce imprecision.
(class irange_bitmask): Updating leading comment to refer to
knowledge about a "value", rather than a "range". Reword
description of MASK and VALUE to clarify implementation, and
add an example.
(class irange): Update leading comment to refer to a
"subset of possible values" rather than a "range", and
that subclasses have responsibility for storage.
(class nan_state): Rewrite leading comment.
(class frange final): Update leading comment to refer to
subsets of possible values, rather than ranges, and to
consistently use "Nan" when capitalizing.
Signed-off-by: David Malcolm <dmalcolm@redhat.com>
This directory contains the GNU Compiler Collection (GCC). The GNU Compiler Collection is free software. See the files whose names start with COPYING for copying permission. The manuals, and some of the runtime libraries, are under different terms; see the individual source files for details. The directory INSTALL contains copies of the installation information as HTML and plain text. The source of this information is gcc/doc/install.texi. The installation information includes details of what is included in the GCC sources and what files GCC installs. See the file gcc/doc/gcc.texi (together with other files that it includes) for usage and porting information. An online readable version of the manual is in the files gcc/doc/gcc.info*. See http://gcc.gnu.org/bugs/ for how to report bugs usefully. Copyright years on GCC source files may be listed using range notation, e.g., 1987-2012, indicating that every year in the range, inclusive, is a copyrightable year that could otherwise be listed individually.