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.
Andrew Pinski
authored
I noticed while looking into some code generation of bitmap_single_bit_set_p,
that sometimes:
```
if (uns > 1)
return 0;
return uns == 1;
```
Would not optimize down to just:
```
return uns == 1;
```
In this case, VRP likes to change `a == 1` into `(bool)a` if
a has a range of [0,1] due to `a <= 1` side of the branch.
We might end up with this similar code even without VRP,
in the case of builtin-sprintf-warn-23.c (and Wrestrict.c), we had:
```
if (s < 0 || 1 < s)
s = 0;
```
Which is the same as `s = ((unsigned)s) <= 1 ? s : 0`;
So we should be able to catch that also.
This adds 2 patterns to catch `(uns <= 1) & uns` and
`(uns > 1) ? 0 : uns` and convert those into:
`(convert) uns == 1`.
OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
PR tree-optimization/109959
gcc/ChangeLog:
* match.pd (`(a > 1) ? 0 : (cast)a`, `(a <= 1) & (cast)a`):
New patterns.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/builtin-sprintf-warn-23.c: Remove xfail.
* c-c++-common/Wrestrict.c: Update test and remove some xfail.
* gcc.dg/tree-ssa/cmpeq-1.c: New test.
* gcc.dg/tree-ssa/cmpeq-2.c: New test.
* gcc.dg/tree-ssa/cmpeq-3.c: New test.