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authorArd Biesheuvel <ardb@kernel.org>2022-02-05 16:23:45 +0100
committerHerbert Xu <herbert@gondor.apana.org.au>2022-02-11 20:39:39 +1100
commit297565aa22cfa80ab0f88c3569693aea0b6afb6d (patch)
tree86c452349612ec00b52d83c78900bcf45b6bbd8d /arch/alpha
parente8bf24bd439da1ee7f37c2b03f44c6ad37c0c8c0 (diff)
lib/xor: make xor prototypes more friendly to compiler vectorization
Modern compilers are perfectly capable of extracting parallelism from the XOR routines, provided that the prototypes reflect the nature of the input accurately, in particular, the fact that the input vectors are expected not to overlap. This is not documented explicitly, but is implied by the interchangeability of the various C routines, some of which use temporary variables while others don't: this means that these routines only behave identically for non-overlapping inputs. So let's decorate these input vectors with the __restrict modifier, which informs the compiler that there is no overlap. While at it, make the input-only vectors pointer-to-const as well. Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://github.com/ClangBuiltLinux/linux/issues/563 Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'arch/alpha')
-rw-r--r--arch/alpha/include/asm/xor.h53
1 files changed, 36 insertions, 17 deletions
diff --git a/arch/alpha/include/asm/xor.h b/arch/alpha/include/asm/xor.h
index 5aeb4fb3cb7c..e0de0c233ab9 100644
--- a/arch/alpha/include/asm/xor.h
+++ b/arch/alpha/include/asm/xor.h
@@ -5,24 +5,43 @@
* Optimized RAID-5 checksumming functions for alpha EV5 and EV6
*/
-extern void xor_alpha_2(unsigned long, unsigned long *, unsigned long *);
-extern void xor_alpha_3(unsigned long, unsigned long *, unsigned long *,
- unsigned long *);
-extern void xor_alpha_4(unsigned long, unsigned long *, unsigned long *,
- unsigned long *, unsigned long *);
-extern void xor_alpha_5(unsigned long, unsigned long *, unsigned long *,
- unsigned long *, unsigned long *, unsigned long *);
+extern void
+xor_alpha_2(unsigned long bytes, unsigned long * __restrict p1,
+ const unsigned long * __restrict p2);
+extern void
+xor_alpha_3(unsigned long bytes, unsigned long * __restrict p1,
+ const unsigned long * __restrict p2,
+ const unsigned long * __restrict p3);
+extern void
+xor_alpha_4(unsigned long bytes, unsigned long * __restrict p1,
+ const unsigned long * __restrict p2,
+ const unsigned long * __restrict p3,
+ const unsigned long * __restrict p4);
+extern void
+xor_alpha_5(unsigned long bytes, unsigned long * __restrict p1,
+ const unsigned long * __restrict p2,
+ const unsigned long * __restrict p3,
+ const unsigned long * __restrict p4,
+ const unsigned long * __restrict p5);
-extern void xor_alpha_prefetch_2(unsigned long, unsigned long *,
- unsigned long *);
-extern void xor_alpha_prefetch_3(unsigned long, unsigned long *,
- unsigned long *, unsigned long *);
-extern void xor_alpha_prefetch_4(unsigned long, unsigned long *,
- unsigned long *, unsigned long *,
- unsigned long *);
-extern void xor_alpha_prefetch_5(unsigned long, unsigned long *,
- unsigned long *, unsigned long *,
- unsigned long *, unsigned long *);
+extern void
+xor_alpha_prefetch_2(unsigned long bytes, unsigned long * __restrict p1,
+ const unsigned long * __restrict p2);
+extern void
+xor_alpha_prefetch_3(unsigned long bytes, unsigned long * __restrict p1,
+ const unsigned long * __restrict p2,
+ const unsigned long * __restrict p3);
+extern void
+xor_alpha_prefetch_4(unsigned long bytes, unsigned long * __restrict p1,
+ const unsigned long * __restrict p2,
+ const unsigned long * __restrict p3,
+ const unsigned long * __restrict p4);
+extern void
+xor_alpha_prefetch_5(unsigned long bytes, unsigned long * __restrict p1,
+ const unsigned long * __restrict p2,
+ const unsigned long * __restrict p3,
+ const unsigned long * __restrict p4,
+ const unsigned long * __restrict p5);
asm(" \n\
.text \n\