lib/raid6: use vdupq_n_u8 to avoid endianness warnings

Clang warns: vector initializers are not compatible with NEON intrinsics
in big endian mode [-Wnonportable-vector-initialization]

While this is usually the case, it's not an issue for this case since
we're initializing the uint8x16_t (16x uint8_t's) with the same value.

Instead, use vdupq_n_u8 which both compilers lower into a single movi
instruction: https://godbolt.org/z/vBrgzt

This avoids the static storage for a constant value.

Link: https://github.com/ClangBuiltLinux/linux/issues/214
Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/lib/raid6/neon.uc b/lib/raid6/neon.uc
index d5242f5445511784bc821f3cd64a4487f2673c97..b7c68030da4fd94d5e6bf3efca157127288e9f9a 100644 (file)
--- a/lib/raid6/neon.uc
+++ b/lib/raid6/neon.uc
@@ -28,7 +28,6 @@
 
 typedef uint8x16_t unative_t;
 
-#define NBYTES(x) ((unative_t){x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x})
 #define NSIZE  sizeof(unative_t)
 
 /*
@@ -61,7 +60,7 @@ void raid6_neon$#_gen_syndrome_real(int disks, unsigned long bytes, void **ptrs)
        int d, z, z0;
 
        register unative_t wd$$, wq$$, wp$$, w1$$, w2$$;
-       const unative_t x1d = NBYTES(0x1d);
+       const unative_t x1d = vdupq_n_u8(0x1d);
 
        z0 = disks - 3;         /* Highest data disk */
        p = dptr[z0+1];         /* XOR parity */
@@ -92,7 +91,7 @@ void raid6_neon$#_xor_syndrome_real(int disks, int start, int stop,
        int d, z, z0;
 
        register unative_t wd$$, wq$$, wp$$, w1$$, w2$$;
-       const unative_t x1d = NBYTES(0x1d);
+       const unative_t x1d = vdupq_n_u8(0x1d);
 
        z0 = stop;              /* P/Q right side optimization */
        p = dptr[disks-2];      /* XOR parity */

diff --git a/lib/raid6/recov_neon_inner.c b/lib/raid6/recov_neon_inner.c
index 8cd20c9f834a1e8cc90e9a4f783f74a4244a5f7a..7d00c31a654706763eb29da6952bb7033e635eee 100644 (file)
--- a/lib/raid6/recov_neon_inner.c
+++ b/lib/raid6/recov_neon_inner.c
@@ -10,11 +10,6 @@
 
 #include <arm_neon.h>
 
-static const uint8x16_t x0f = {
-       0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f,
-       0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f,
-};
-
 #ifdef CONFIG_ARM
 /*
  * AArch32 does not provide this intrinsic natively because it does not
@@ -41,6 +36,7 @@ void __raid6_2data_recov_neon(int bytes, uint8_t *p, uint8_t *q, uint8_t *dp,
        uint8x16_t pm1 = vld1q_u8(pbmul + 16);
        uint8x16_t qm0 = vld1q_u8(qmul);
        uint8x16_t qm1 = vld1q_u8(qmul + 16);
+       uint8x16_t x0f = vdupq_n_u8(0x0f);
 
        /*
         * while ( bytes-- ) {
@@ -87,6 +83,7 @@ void __raid6_datap_recov_neon(int bytes, uint8_t *p, uint8_t *q, uint8_t *dq,
 {
        uint8x16_t qm0 = vld1q_u8(qmul);
        uint8x16_t qm1 = vld1q_u8(qmul + 16);
+       uint8x16_t x0f = vdupq_n_u8(0x0f);
 
        /*
         * while (bytes--) {