diff options
| author |   Eric Biggers <ebiggers@google.com> | 2025-02-10 13:07:41 -0800 |
|---|---|---|
| committer | Eric Biggers <ebiggers@google.com> | 2025-02-12 12:08:56 -0800 |
| commit | cf1ea3a7c1f63cba7d1dd313ee3accde0c0c8988 (patch) | |
| tree | b2e673e8e0f67ece26cf5d2078dfaff3869f32ed | |
| parent | x86/crc64: implement crc64_be and crc64_nvme using new template (diff) | |
| download | wireguard-linux-cf1ea3a7c1f63cba7d1dd313ee3accde0c0c8988.tar.xz wireguard-linux-cf1ea3a7c1f63cba7d1dd313ee3accde0c0c8988.zip | |
x86/crc32: improve crc32c_arch() code generation with clang
crc32c_arch() is affected by
https://github.com/llvm/llvm-project/issues/20571 where clang
unnecessarily spills the inputs to "rm"-constrained operands to the
stack. Replace "rm" with ASM_INPUT_RM which partially works around this
by expanding to "r" when the compiler is clang. This results in better
code generation with clang, though still not optimal.
Link: https://lore.kernel.org/r/20250210210741.471725-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
| -rw-r--r-- | arch/x86/lib/crc32-glue.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/lib/crc32-glue.c b/arch/x86/lib/crc32-glue.c index 9c3f9c1b7bb9..4b4721176799 100644 --- a/arch/x86/lib/crc32-glue.c +++ b/arch/x86/lib/crc32-glue.c @@ -55,10 +55,10 @@ u32 crc32c_arch(u32 crc, const u8 *p, size_t len) for (num_longs = len / sizeof(unsigned long); num_longs != 0; num_longs--, p += sizeof(unsigned long)) - asm(CRC32_INST : "+r" (crc) : "rm" (*(unsigned long *)p)); + asm(CRC32_INST : "+r" (crc) : ASM_INPUT_RM (*(unsigned long *)p)); for (len %= sizeof(unsigned long); len; len--, p++) - asm("crc32b %1, %0" : "+r" (crc) : "rm" (*p)); + asm("crc32b %1, %0" : "+r" (crc) : ASM_INPUT_RM (*p)); return crc; } |