c00e1e3aa5
This patch fixes both ICE regressions PR middle-end/105853 and
PR target/105856 caused by my recent patch to expand small const structs
as immediate constants. That patch updated code generation in three
places: two in expr.cc that call store_constructor directly, and the
third in calls.cc's load_register_parameters that expands its CONSTRUCTOR
via expand_expr, as store_constructor is local/static to expr.cc, and
the "public" API, should usually simply forward the constructor to the
appropriate store_constructor function.
Alas, despite the clean regression testing on multiple targets, the above
ICEs show that expand_expr isn't a suitable proxy for store_constructor,
and things that (I'd assumed) shouldn't affect how/whether a struct is
placed in a register [such as whether the struct is considered packed/
aligned or not] actually interfere with the optimization that is being
attempted.
The (proposed) solution is to export store_constructor (and it's helper
function int_expr_size) from expr.cc, by removing their static qualifier
and prototyping both functions in expr.h, so they can be called directly
from load_register_parameters in calls.cc. This cures both ICEs, but
almost as importantly improves code generation over GCC 12.
For PR 105853, GCC 12 generates:
compose_nd_na_ipv6_src:
movzx eax, WORD PTR eth_addr_zero[rip+2]
movzx edx, WORD PTR eth_addr_zero[rip]
movzx edi, WORD PTR eth_addr_zero[rip+4]
sal rax, 16
or rax, rdx
sal rdi, 32
or rdi, rax
xor eax, eax
jmp packet_set_nd
eth_addr_zero: .zero 6
where now (with this fix) GCC 13 generates:
compose_nd_na_ipv6_src:
xorl %edi, %edi
xorl %eax, %eax
jmp packet_set_nd
Likewise, for PR 105856 on ARM, we'd previously generate:
g_329_3:
movw r3, #:lower16:.LANCHOR0
movt r3, #:upper16:.LANCHOR0
ldr r0, [r3]
b func_19
but with this optimization we now generate:
g_329_3:
mov r0, #6
b func_19
2022-06-07 Roger Sayle <roger@nextmovesoftware.com>
gcc/ChangeLog
PR middle-end/105853
PR target/105856
* calls.cc (load_register_parameters): Call store_constructor
and int_expr_size directly instead of expanding via expand_expr.
* expr.cc (static void store_constructor): Don't prototype here.
(static HOST_WIDE_INT int_expr_size): Likewise.
(store_constructor): No longer static.
(int_expr_size): Likewise, no longer static.
* expr.h (store_constructor): Prototype here.
(int_expr_size): Prototype here.
gcc/testsuite/ChangeLog
PR middle-end/105853
PR target/105856
* gcc.dg/pr105853.c: New test case.
* gcc.dg/pr105856.c: New test case.
|
||
|---|---|---|
| INSTALL | ||
| c++tools | ||
| config | ||
| contrib | ||
| fixincludes | ||
| gcc | ||
| gnattools | ||
| gotools | ||
| include | ||
| intl | ||
| libada | ||
| libatomic | ||
| libbacktrace | ||
| libcc1 | ||
| libcody | ||
| libcpp | ||
| libdecnumber | ||
| libffi | ||
| libgcc | ||
| libgfortran | ||
| libgo | ||
| libgomp | ||
| libiberty | ||
| libitm | ||
| libobjc | ||
| liboffloadmic | ||
| libphobos | ||
| libquadmath | ||
| libsanitizer | ||
| libssp | ||
| libstdc++-v3 | ||
| libvtv | ||
| lto-plugin | ||
| maintainer-scripts | ||
| zlib | ||
| .dir-locals.el | ||
| .gitattributes | ||
| .gitignore | ||
| ABOUT-NLS | ||
| COPYING | ||
| COPYING.LIB | ||
| COPYING.RUNTIME | ||
| COPYING3 | ||
| COPYING3.LIB | ||
| ChangeLog | ||
| ChangeLog.jit | ||
| ChangeLog.tree-ssa | ||
| MAINTAINERS | ||
| Makefile.def | ||
| Makefile.in | ||
| Makefile.tpl | ||
| README | ||
| ar-lib | ||
| compile | ||
| config-ml.in | ||
| config.guess | ||
| config.rpath | ||
| config.sub | ||
| configure | ||
| configure.ac | ||
| depcomp | ||
| install-sh | ||
| libtool-ldflags | ||
| libtool.m4 | ||
| ltgcc.m4 | ||
| ltmain.sh | ||
| ltoptions.m4 | ||
| ltsugar.m4 | ||
| ltversion.m4 | ||
| lt~obsolete.m4 | ||
| missing | ||
| mkdep | ||
| mkinstalldirs | ||
| move-if-change | ||
| multilib.am | ||
| symlink-tree | ||
| test-driver | ||
| ylwrap | ||
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.