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* [PATCH v1 1/1] remove switch statement in vector8_shift_{left,right}
@ 2026-07-02 00:30 Nathan Bossart <nathan@postgresql.org>
0 siblings, 0 replies; 1+ messages in thread
From: Nathan Bossart @ 2026-07-02 00:30 UTC (permalink / raw)
---
src/include/port/simd.h | 29 +++--------------------------
1 file changed, 3 insertions(+), 26 deletions(-)
diff --git a/src/include/port/simd.h b/src/include/port/simd.h
index 50615aec7f4..25a26c81cce 100644
--- a/src/include/port/simd.h
+++ b/src/include/port/simd.h
@@ -548,10 +548,6 @@ vector8_pack_16(const Vector8 v1, const Vector8 v2)
/*
* Unsigned shift left of each 32-bit element in the vector by "i" bits.
- *
- * XXX AArch64 requires an integer literal, so we have to list all expected
- * values of "i" from all callers in a switch statement. If you add a new
- * caller, be sure your expected values of "i" are handled.
*/
#ifndef USE_NO_SIMD
static inline Vector8
@@ -560,24 +556,13 @@ vector8_shift_left(const Vector8 v1, int i)
#ifdef USE_SSE2
return _mm_slli_epi32(v1, i);
#elif defined(USE_NEON)
- switch (i)
- {
- case 4:
- return (Vector8) vshlq_n_u32((Vector32) v1, 4);
- default:
- Assert(false);
- return vector8_broadcast(0);
- }
+ return (Vector8) vshlq_u32((Vector32) v1, vdupq_n_s32(i));
#endif
}
#endif /* ! USE_NO_SIMD */
/*
* Unsigned shift right of each 32-bit element in the vector by "i" bits.
- *
- * XXX AArch64 requires an integer literal, so we have to list all expected
- * values of "i" from all callers in a switch statement. If you add a new
- * caller, be sure your expected values of "i" are handled.
*/
#ifndef USE_NO_SIMD
static inline Vector8
@@ -586,16 +571,8 @@ vector8_shift_right(const Vector8 v1, int i)
#ifdef USE_SSE2
return _mm_srli_epi32(v1, i);
#elif defined(USE_NEON)
- switch (i)
- {
- case 4:
- return (Vector8) vshrq_n_u32((Vector32) v1, 4);
- case 8:
- return (Vector8) vshrq_n_u32((Vector32) v1, 8);
- default:
- Assert(false);
- return vector8_broadcast(0);
- }
+ /* negative shift count means right shift */
+ return (Vector8) vshlq_u32((Vector32) v1, vdupq_n_s32(-i));
#endif
}
#endif /* ! USE_NO_SIMD */
--
2.50.1 (Apple Git-155)
--9YipY07vKHAnXga/--
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