37a231cc75
For testcase
void __cond_swap(double* __x, double* __y) {
bool __r = (*__x < *__y);
auto __tmp = __r ? *__x : *__y;
*__y = __r ? *__y : *__x;
*__x = __tmp;
}
GCC-14 with -O2 and -march=x86-64 options generates the following code:
__cond_swap(double*, double*):
movsd xmm1, QWORD PTR [rdi]
movsd xmm0, QWORD PTR [rsi]
comisd xmm0, xmm1
jbe .L2
movq rax, xmm1
movapd xmm1, xmm0
movq xmm0, rax
.L2:
movsd QWORD PTR [rsi], xmm1
movsd QWORD PTR [rdi], xmm0
ret
rax is used to save and restore DFmode value. In RA both GENERAL_REGS
and SSE_REGS cost zero since we didn't disparage the
alternative in movdf_internal pattern, according to register
allocation order, GENERAL_REGS is allocated. The patch add ? for
alternative (r,v) and (v,r) just like we did for movsf/hf/bf_internal
pattern, after that we get optimal RA.
__cond_swap:
.LFB0:
.cfi_startproc
movsd (%rdi), %xmm1
movsd (%rsi), %xmm0
comisd %xmm1, %xmm0
jbe .L2
movapd %xmm1, %xmm2
movapd %xmm0, %xmm1
movapd %xmm2, %xmm0
.L2:
movsd %xmm1, (%rsi)
movsd %xmm0, (%rdi)
ret
gcc/ChangeLog:
PR target/110170
* config/i386/i386.md (movdf_internal): Disparage slightly for
2 alternatives (r,v) and (v,r) by adding constraint modifier
'?'.
gcc/testsuite/ChangeLog:
* gcc.target/i386/pr110170-3.c: New test.
|
||
|---|---|---|
| c++tools | ||
| config | ||
| contrib | ||
| fixincludes | ||
| gcc | ||
| gnattools | ||
| gotools | ||
| include | ||
| INSTALL | ||
| intl | ||
| libada | ||
| libatomic | ||
| libbacktrace | ||
| libcc1 | ||
| libcody | ||
| libcpp | ||
| libdecnumber | ||
| libffi | ||
| libgcc | ||
| libgfortran | ||
| libgm2 | ||
| libgo | ||
| libgomp | ||
| 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 | ||
| 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.