mirror of
git://gcc.gnu.org/git/gcc.git
synced 2025-04-06 02:50:27 +08:00
6dc82826ba
Suppose we have:
(insn (set (reg:FPRX2 70) (subreg:FPRX2 (reg/v:TF 63) 0)))
where operand_loc[0] points to r70 and operand_loc[1] points to r63.
If r63 is spilled, remove_pseudos() will change this insn to:
(insn (set (reg:FPRX2 70)
(subreg:FPRX2 (mem/c:TF (plus:DI (reg:DI %fp)
(const_int 144))))))
This is fine so far: rtx pointed to by operand_loc[1] has been changed
from (reg) to (mem), but its slot is still under (subreg). However,
alter_subreg() will simplify this insn to:
(insn (set (reg:FPRX2 70)
(mem/c:FPRX2 (plus:DI (reg:DI %fp) (const_int 144)))))
The (subreg) is gone, and therefore operand_loc[1] is no longer valid.
This will prevent process_insn_for_elimination() from updating the spill
slot offset, causing miscompilation: different instructions will refer
to the same spill slot using different offsets.
Fix by clearing all the cached data, and not just used_insn_alternative.
gcc/ChangeLog:
2021-01-13 Ilya Leoshkevich <iii@linux.ibm.com>
* lra-spills.c (remove_pseudos): Call lra_update_insn_recog_data()
after calling alter_subreg() on a (mem).
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.