From: Sebastian Pop <spop@amazon.com>
Date: Wed, 17 Apr 2019 15:03:37 +0000 (+0000)
Subject: [AArch64] Use NEON to initialize zend_hash
X-Git-Tag: php-7.4.0alpha1~338
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=6fad150cfdec697cb1b789447d10056f009a208d;p=php

[AArch64] Use NEON to initialize zend_hash

On A72, google-benchmark measure before and after the patch:
--------------------------------------------------------------
Benchmark                    Time             CPU   Iterations
--------------------------------------------------------------
BM_hash_init_before       43.6 ns         43.6 ns     16052937
BM_hash_init_after        27.0 ns         27.0 ns     25877296

Patch written by Ali Saidi <alisaidi@amazon.com>
and Sebastian Pop <spop@amazon.com>
---

diff --git a/Zend/zend_hash.c b/Zend/zend_hash.c
index e4024d9688..56695c4229 100644
--- a/Zend/zend_hash.c
+++ b/Zend/zend_hash.c
@@ -22,6 +22,10 @@
 #include "zend_globals.h"
 #include "zend_variables.h"
 
+#if defined(__aarch64__)
+# include <arm_neon.h>
+#endif
+
 #ifdef __SSE2__
 # include <mmintrin.h>
 # include <emmintrin.h>
@@ -156,6 +160,14 @@ static zend_always_inline void zend_hash_real_init_mixed_ex(HashTable *ht)
 			_mm_storeu_si128((__m128i*)&HT_HASH_EX(data,  8), xmm0);
 			_mm_storeu_si128((__m128i*)&HT_HASH_EX(data, 12), xmm0);
 		} while (0);
+#elif defined(__aarch64__)
+		do {
+			int32x4_t t = vdupq_n_s32(-1);
+			vst1q_s32((int32_t*)&HT_HASH_EX(data,  0), t);
+			vst1q_s32((int32_t*)&HT_HASH_EX(data,  4), t);
+			vst1q_s32((int32_t*)&HT_HASH_EX(data,  8), t);
+			vst1q_s32((int32_t*)&HT_HASH_EX(data, 12), t);
+		} while (0);
 #else
 		HT_HASH_EX(data,  0) = -1;
 		HT_HASH_EX(data,  1) = -1;