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Currently, the verifier inserts a zext instruction right after every 8-, 16- or 32-bit load-acquire, which is already zero-extending. Skip such redundant zext instructions. While we are here, update that already-obsolete comment about "skip the next instruction" in build_body(). Also change emit_atomic_rmw()'s parameters to keep it consistent with emit_atomic_ld_st(). Note that checking 'insn[1]' relies on 'insn' not being the last instruction, which should have been guaranteed by the verifier; we already use 'insn[1]' elsewhere in the file for similar purposes. Additionally, we don't check if 'insn[1]' is actually a zext for our load-acquire's dst_reg, or some other registers - in other words, here we are relying on the verifier to always insert a redundant zext right after a 8/16/32-bit load-acquire, for its dst_reg. Acked-by: Björn Töpel <bjorn@kernel.org> Reviewed-by: Pu Lehui <pulehui@huawei.com> Tested-by: Björn Töpel <bjorn@rivosinc.com> # QEMU/RVA23 Signed-off-by: Peilin Ye <yepeilin@google.com> Link: https://lore.kernel.org/r/10e90e0eab042f924d35ad0d1c1f7ca29f673152.1746588351.git.yepeilin@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.