5cce817119
This patch looks for pseudo registers that are live across a call and for which no call-preserved hard registers exist. It then recomputes the pseudos as necessary to ensure that they are no longer live across a call. The comment at the head of the file describes the approach. A new target hook selects which modes should be treated in this way. By default none are, in which case the pass is skipped very early. It might also be worth looking for cases like: C1: R1 := f (...) ... C2: R2 := f (...) C3: R1 := C2 and giving the same value number to C1 and C3, effectively treating it like: C1: R1 := f (...) ... C2: R2 := f (...) C3: R1 := f (...) Another (much more expensive) enhancement would be to apply value numbering to all pseudo registers (not just rematerialisation candidates), so that we can handle things like: C1: R1 := f (...R2...) ... C2: R1 := f (...R3...) where R2 and R3 hold the same value. But the current pass seems to catch the vast majority of cases. 2018-01-13 Richard Sandiford <richard.sandiford@linaro.org> gcc/ * Makefile.in (OBJS): Add early-remat.o. * target.def (select_early_remat_modes): New hook. * doc/tm.texi.in (TARGET_SELECT_EARLY_REMAT_MODES): New hook. * doc/tm.texi: Regenerate. * targhooks.h (default_select_early_remat_modes): Declare. * targhooks.c (default_select_early_remat_modes): New function. * timevar.def (TV_EARLY_REMAT): New timevar. * passes.def (pass_early_remat): New pass. * tree-pass.h (make_pass_early_remat): Declare. * early-remat.c: New file. * config/aarch64/aarch64.c (aarch64_select_early_remat_modes): New function. (TARGET_SELECT_EARLY_REMAT_MODES): Define. gcc/testsuite/ * gcc.target/aarch64/sve/spill_1.c: Also test that no predicates are spilled. * gcc.target/aarch64/sve/spill_2.c: New test. * gcc.target/aarch64/sve/spill_3.c: Likewise. * gcc.target/aarch64/sve/spill_4.c: Likewise. * gcc.target/aarch64/sve/spill_5.c: Likewise. * gcc.target/aarch64/sve/spill_6.c: Likewise. * gcc.target/aarch64/sve/spill_7.c: Likewise. From-SVN: r256636 |
||
|---|---|---|
| config | ||
| contrib | ||
| fixincludes | ||
| gcc | ||
| gnattools | ||
| gotools | ||
| include | ||
| INSTALL | ||
| intl | ||
| libada | ||
| libatomic | ||
| libbacktrace | ||
| libcc1 | ||
| libcpp | ||
| libdecnumber | ||
| libffi | ||
| libgcc | ||
| libgfortran | ||
| libgo | ||
| libgomp | ||
| libhsail-rt | ||
| libiberty | ||
| libitm | ||
| libmpx | ||
| libobjc | ||
| liboffloadmic | ||
| libquadmath | ||
| libsanitizer | ||
| libssp | ||
| libstdc++-v3 | ||
| libvtv | ||
| lto-plugin | ||
| maintainer-scripts | ||
| zlib | ||
| .dir-locals.el | ||
| .gitattributes | ||
| .gitignore | ||
| ABOUT-NLS | ||
| ChangeLog | ||
| ChangeLog.jit | ||
| ChangeLog.tree-ssa | ||
| compile | ||
| config-ml.in | ||
| config.guess | ||
| config.rpath | ||
| config.sub | ||
| configure | ||
| configure.ac | ||
| COPYING | ||
| COPYING3 | ||
| COPYING3.LIB | ||
| COPYING.LIB | ||
| COPYING.RUNTIME | ||
| depcomp | ||
| install-sh | ||
| libtool-ldflags | ||
| libtool.m4 | ||
| lt~obsolete.m4 | ||
| ltgcc.m4 | ||
| ltmain.sh | ||
| ltoptions.m4 | ||
| ltsugar.m4 | ||
| ltversion.m4 | ||
| MAINTAINERS | ||
| Makefile.def | ||
| Makefile.in | ||
| Makefile.tpl | ||
| missing | ||
| mkdep | ||
| mkinstalldirs | ||
| move-if-change | ||
| README | ||
| symlink-tree | ||
| 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.