Use AVX2 to accelerate strto{upper,lower} (only on 'AVX2-native' builds for now)

On short strings, there is no difference in performance. However, for
strings around 10,000 bytes long, the AVX2-accelerated function is
about 55% faster than the SSE2-accelerated one.

Author: alexdowad

Zend/zend_operators.c

@@ -35,6 +35,9 @@
 # include <langinfo.h>
 #endif
 
+#ifdef ZEND_INTRIN_AVX2_NATIVE
+#include <immintrin.h>
+#endif
 #ifdef __SSE2__
 #include <emmintrin.h>
 #endif
@@ -54,7 +57,30 @@ static _locale_t current_locale = NULL;
 
 #define TYPE_PAIR(t1,t2) (((t1) << 4) | (t2))
 
-#if __SSE2__
+#ifdef ZEND_INTRIN_AVX2_NATIVE
+#define HAVE_BLOCKCONV
+
+#define BLOCKCONV_INIT_RANGE(start, end) \
+	const __m256i blconv_offset = _mm256_set1_epi8((signed char)(SCHAR_MIN - start)); \
+	const __m256i blconv_threshold = _mm256_set1_epi8(SCHAR_MIN + (end - start) + 1);
+
+#define BLOCKCONV_STRIDE sizeof(__m256i)
+
+#define BLOCKCONV_INIT_DELTA(delta) \
+	const __m256i blconv_delta = _mm256_set1_epi8(delta);
+
+#define BLOCKCONV_LOAD(input) \
+	__m256i blconv_operand = _mm256_loadu_si256((__m256i*)(input)); \
+	__m256i blconv_mask = _mm256_cmpgt_epi8(blconv_threshold, _mm256_add_epi8(blconv_operand, blconv_offset));
+
+#define BLOCKCONV_FOUND() _mm256_movemask_epi8(blconv_mask)
+
+#define BLOCKCONV_STORE(dest) \
+	__m256i blconv_add = _mm256_and_si256(blconv_mask, blconv_delta); \
+	__m256i blconv_result = _mm256_add_epi8(blconv_operand, blconv_add); \
+	_mm256_storeu_si256((__m256i*)(dest), blconv_result);
+
+#elif __SSE2__
 #define HAVE_BLOCKCONV
 
 /* Common code for SSE2 accelerated character case conversion */

ext/standard/tests/strings/strtoupper1.phpt

@@ -28,6 +28,11 @@ $strings = array (
   "zzzzzzzzzzzzzzzzzzzz",
   "````````````````````",
   "{{{{{{{{{{{{{{{{{{{{",
+  /* And the AVX2 implementation also */
+  "{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{",
+  "abcdefghijklmnopqrstuvwxyz01234",
+  "abcdefghijklmnopqrstuvwxyz012345",
+  "abcdefghijklmnopqrstuvwxyz0123456",
   "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 );
 
@@ -348,6 +353,18 @@ string(20) "````````````````````"
 string(20) "{{{{{{{{{{{{{{{{{{{{"
 
 -- Iteration 12 --
+string(40) "{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{"
+
+-- Iteration 13 --
+string(31) "ABCDEFGHIJKLMNOPQRSTUVWXYZ01234"
+
+-- Iteration 14 --
+string(32) "ABCDEFGHIJKLMNOPQRSTUVWXYZ012345"
+
+-- Iteration 15 --
+string(33) "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456"
+
+-- Iteration 16 --
 string(62) "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 
 *** Testing strtoupper() with two different case strings ***