GCC modified for the FreeChainXenon project
d54151df3b
The optimize_range_tests_to_bit_test optimization normally emits a range
test first:
if (entry_test_needed)
{
tem = build_range_check (loc, optype, unshare_expr (exp),
false, lowi, high);
if (tem == NULL_TREE || is_gimple_val (tem))
continue;
}
so during the bit test we already know that exp is in the [lowi, high]
range, but skips it if we have range info which tells us this isn't
necessary.
Also, normally it emits shifts by exp - lowi counter, but has an
optimization to use just exp counter if the mask isn't a more expensive
constant in that case and lowi is > 0 and high is smaller than prec.
The following testcase is miscompiled because the two abnormal cases
are triggered. The range of exp is [43, 43][48, 48][95, 95], so we on
64-bit arch decide we don't need the entry test, because 95 - 43 < 64.
And we also decide to use just exp as counter, because the range test
tests just for exp == 43 || exp == 48, so high is smaller than 64 too.
Because 95 is in the exp range, we can't do that, we'd either need to
do a range test first, i.e.
if (exp - 43U <= 48U - 43U) if ((1UL << exp) & mask1))
or need to subtract lowi from the shift counter, i.e.
if ((1UL << (exp - 43)) & mask2)
but can't do both unless r.upper_bound () is < prec.
The following patch ensures that.
2024-05-08 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/114965
* tree-ssa-reassoc.cc (optimize_range_tests_to_bit_test): Don't try to
optimize away exp - lowi subtraction from shift count unless entry
test is emitted or unless r.upper_bound () is smaller than prec.
* gcc.c-torture/execute/pr114965.c: New test.
(cherry picked from commit 9adec2d91e62a479474ae79df5b455fd4b8463ba)
|
||
|---|---|---|
| .github | ||
| c++tools | ||
| config | ||
| contrib | ||
| fixincludes | ||
| gcc | ||
| gnattools | ||
| gotools | ||
| include | ||
| INSTALL | ||
| libada | ||
| libatomic | ||
| libbacktrace | ||
| libcc1 | ||
| libcody | ||
| libcpp | ||
| libdecnumber | ||
| libffi | ||
| libgcc | ||
| libgfortran | ||
| libgm2 | ||
| libgo | ||
| libgomp | ||
| libgrust | ||
| libiberty | ||
| libitm | ||
| libobjc | ||
| libphobos | ||
| libquadmath | ||
| libsanitizer | ||
| libssp | ||
| libstdc++-v3 | ||
| libvtv | ||
| lto-plugin | ||
| maintainer-scripts | ||
| zlib | ||
| .dir-locals.el | ||
| .gitattributes | ||
| .gitignore | ||
| ABOUT-NLS | ||
| ar-lib | ||
| ChangeLog | ||
| ChangeLog.jit | ||
| ChangeLog.tree-ssa | ||
| compile | ||
| config-ml.in | ||
| config.guess | ||
| config.rpath | ||
| config.sub | ||
| configure | ||
| configure.ac | ||
| COPYING | ||
| COPYING.LIB | ||
| COPYING.RUNTIME | ||
| COPYING3 | ||
| COPYING3.LIB | ||
| depcomp | ||
| install-sh | ||
| libtool-ldflags | ||
| libtool.m4 | ||
| ltgcc.m4 | ||
| ltmain.sh | ||
| ltoptions.m4 | ||
| ltsugar.m4 | ||
| ltversion.m4 | ||
| lt~obsolete.m4 | ||
| MAINTAINERS | ||
| Makefile.def | ||
| Makefile.in | ||
| Makefile.tpl | ||
| missing | ||
| mkdep | ||
| mkinstalldirs | ||
| move-if-change | ||
| multilib.am | ||
| README | ||
| SECURITY.txt | ||
| symlink-tree | ||
| test-driver | ||
| ylwrap | ||
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.