aa27696b79
Beware, tm.texi doesn't tell the whole story: a defined HARD_FRAME_POINTER_REGNUM (different to FRAME_POINTER_REGNUM) is supposed to make work easier for reload, being able to easily tell actual frame-pointer-related addresses from those that happen to use the same register or something to that effect. On reasonable code the performance effect is barely measurable. Looking at libgcc changes for -march=v10, the effect (where noticeable) is mostly indeterminate churn. Instances where it's not just insns moved around at no obvious effect: one more insn for addvdi3, subvdi3; two insns more in floatdisf; three insns shorter fixunsdfdi. Some of those seem related to pairing r8 with r9. The only effect on coremark is an infinitesimal positive effect from a three(!) cycles total (from the 15 calls) faster execution paths in vfprintf_r. Local microbenchmarks give similar results. With that in mind and not forgetting that expectations in the register allocator and reload leaning towards HARD_FRAME_POINTER_REGNUM defined (and different to) FRAME_POINTER_REGNUM or to wit, "all the kids do it", why not. Note that the offset at elimination really is 0. gcc: * config/cris/cris.h (HARD_FRAME_POINTER_REGNUM): Define. Change FRAME_POINTER_REGNUM to correspond to a new faked register faked_fp, part of GENNONACR_REGS like faked_ap. (CRIS_FAKED_REGS_CONTENTS): New helper macro. (FIRST_PSEUDO_REGISTER, FIXED_REGISTERS, CALL_USED_REGISTERS): (REG_ALLOC_ORDER, REG_CLASS_CONTENTS, REGNO_OK_FOR_BASE_P) (ELIMINABLE_REGS, REGISTER_NAMES): Adjust accordingly. * config/cris/cris.md (CRIS_FP_REGNUM): Renumber to new faked register. (CRIS_REAL_FP_REGNUM): New constant. * config/cris/cris.c (cris_reg_saved_in_regsave_area): Check for HARD_FRAME_POINTER_REGNUM instead of FRAME_POINTER_REGNUM. (cris_initial_elimination_offset): Handle elimination changes to HARD_FRAME_POINTER_REGNUM instead of FRAME_POINTER_REGNUM and add one from FRAME_POINTER_REGNUM to HARD_FRAME_POINTER_REGNUM. (cris_expand_prologue, cris_expand_epilogue): Emit code for hard_frame_pointer_rtx instead of frame_pointer_rtx. |
||
|---|---|---|
| c++tools | ||
| config | ||
| contrib | ||
| fixincludes | ||
| gcc | ||
| gnattools | ||
| gotools | ||
| include | ||
| INSTALL | ||
| intl | ||
| libada | ||
| libatomic | ||
| libbacktrace | ||
| libcc1 | ||
| libcody | ||
| libcpp | ||
| libdecnumber | ||
| libffi | ||
| libgcc | ||
| libgfortran | ||
| libgo | ||
| libgomp | ||
| libhsail-rt | ||
| libiberty | ||
| libitm | ||
| libobjc | ||
| liboffloadmic | ||
| 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 | ||
| 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 | ||
| 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.