d6bedcfcef
Integer division by zero is undefined behavior anyway, and there are
already many platforms where neither the GCC port and the hardware do
anything to trap on division by zero. So any portable program shall not
rely on SIGFPE on division by zero, in both theory and practice. As the
result, there is no real reason to cost two additional instructions just
for the trap on division by zero with a new ISA.
One remaining reason to trap on division by zero may be debugging,
especially while -fsanitize=integer-divide-by-zero is not implemented
for LoongArch yet. To make debugging easier, keep -mcheck-zero-division
as the default for -O0 and -Og, but use -mno-check-zero-division as the
default for all other optimization levels.
Backport this behavior change for 12.2, so 12.1 will be the only release
with a different default.
Co-authored-by: Lulu Cheng <chenglulu@loongson.cn>
gcc/ChangeLog:
* config/loongarch/loongarch.cc (loongarch_check_zero_div_p):
New static function.
(loongarch_idiv_insns): Use loongarch_check_zero_div_p instead
of TARGET_CHECK_ZERO_DIV.
(loongarch_output_division): Likewise.
* common/config/loongarch/loongarch-common.cc
(TARGET_DEFAULT_TARGET_FLAGS): Remove unneeded hook.
* doc/invoke.texi: Update to match the new behavior.
gcc/testsuite/ChangeLog:
* gcc.c-torture/execute/20101011-1.c (dg-additional-options):
add -mcheck-zero-division for LoongArch targets.
(cherry picked from commit
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README
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.