Merge pull request #4232 from facebook/convertSequences_SSE

Improve speed of ZSTD_compressSequencesAndLiterals() using AVX2

lib/common/compiler.h

@@ -224,13 +224,19 @@
 
 /* compile time determination of SIMD support */
 #if !defined(ZSTD_NO_INTRINSICS)
+#  if defined(__AVX2__)
+#    define ZSTD_ARCH_X86_AVX2
+#  endif
 #  if defined(__SSE2__) || defined(_M_AMD64) || (defined (_M_IX86) && defined(_M_IX86_FP) && (_M_IX86_FP >= 2))
 #    define ZSTD_ARCH_X86_SSE2
 #  endif
 #  if defined(__ARM_NEON) || defined(_M_ARM64)
 #    define ZSTD_ARCH_ARM_NEON
 #  endif
 #
+#  if defined(ZSTD_ARCH_X86_AVX2)
+#    include <immintrin.h>
+#  endif
 #  if defined(ZSTD_ARCH_X86_SSE2)
 #    include <emmintrin.h>
 #  elif defined(ZSTD_ARCH_ARM_NEON)
@@ -275,7 +281,7 @@
 #endif
 
 /*-**************************************************************
-*  Alignment check
+*  Alignment
 *****************************************************************/
 
 /* @return 1 if @u is a 2^n value, 0 otherwise
@@ -309,6 +315,19 @@ MEM_STATIC int ZSTD_isPower2(size_t u) {
 # endif
 #endif /* ZSTD_ALIGNOF */
 
+#ifndef ZSTD_ALIGNED
+/* C90-compatible alignment macro (GCC/Clang). Adjust for other compilers if needed. */
+# if defined(__GNUC__)
+#  define ZSTD_ALIGNED(a) __attribute__((aligned(a)))
+# elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) /* C11 */
+#  define ZSTD_ALIGNED(a) alignas(a)
+# else
+   /* this compiler will require its own alignment instruction */
+#  define ZSTD_ALIGNED(...)
+# endif
+#endif /* ZSTD_ALIGNED */
+
+
 /*-**************************************************************
 *  Sanitizer
 *****************************************************************/