Upgrade to C++20 and use portable definition of unlikely attribute

Signed-off-by: Fabio Cannizzo <fabio.cannizzo@gmail.com>

Author: fabiocannizzo

meson.build

@@ -1,7 +1,7 @@
 project('x86-simd-sort', 'cpp',
         version : '7.0.x',
         license : 'BSD 3-clause',
-        default_options : ['cpp_std=c++17'])
+        default_options : ['cpp_std=c++20'])
 fs = import('fs')
 cpp = meson.get_compiler('cpp')
 src = include_directories('src')

src/avx512-16bit-qsort.hpp

@@ -590,7 +590,7 @@ avx512_qsort_fp16(uint16_t *arr,
 
     if (arrsize > 1) {
         arrsize_t nan_count = 0;
-        if (UNLIKELY(hasnan)) {
+        if (hasnan) [[unlikely]] {
             nan_count = replace_nan_with_inf<vtype, uint16_t>(arr, arrsize);
         }
         if (descending) {
@@ -623,7 +623,7 @@ avx512_qselect_fp16(uint16_t *arr,
     arrsize_t index_first_elem = 0;
     arrsize_t index_last_elem = arrsize - 1;
 
-    if (UNLIKELY(hasnan)) {
+    if (hasnan) [[unlikely]] {
         if (descending) {
             index_first_elem = move_nans_to_start_of_array(arr, arrsize);
         }

src/xss-common-includes.h

@@ -42,20 +42,14 @@
 #define X86_SIMD_SORT_INLINE_ONLY inline
 #define X86_SIMD_SORT_INLINE static inline
 #define X86_SIMD_SORT_FINLINE static __forceinline
-#define LIKELY(x) (x)
-#define UNLIKELY(x) (x)
 #elif defined(__GNUC__)
 #define X86_SIMD_SORT_INLINE_ONLY inline
 #define X86_SIMD_SORT_INLINE static inline
 #define X86_SIMD_SORT_FINLINE static inline __attribute__((always_inline))
-#define LIKELY(x) __builtin_expect((x), 1)
-#define UNLIKELY(x) __builtin_expect((x), 0)
 #else
 #define X86_SIMD_SORT_INLINE_ONLY
 #define X86_SIMD_SORT_INLINE static
 #define X86_SIMD_SORT_FINLINE static
-#define LIKELY(x) (x)
-#define UNLIKELY(x) (x)
 #endif
 
 #if defined(__INTEL_COMPILER) and !defined(__SANITIZE_ADDRESS__)

src/xss-common-keyvaluesort.hpp

@@ -595,7 +595,7 @@ X86_SIMD_SORT_INLINE void xss_qsort_kv(
     if (minarrsize) {
         arrsize_t index_last_elem = arrsize - 1;
         if constexpr (xss::fp::is_floating_point_v<T1>) {
-            if (UNLIKELY(hasnan)) {
+            if (hasnan) [[unlikely]] {
                 index_last_elem
                         = move_nans_to_end_of_array<T1, T2, full_vector<T1>>(
                                 keys, indexes, arrsize);
@@ -692,7 +692,7 @@ X86_SIMD_SORT_INLINE void xss_select_kv(T1 *keys,
 
         arrsize_t index_last_elem = arrsize - 1;
         if constexpr (xss::fp::is_floating_point_v<T1>) {
-            if (UNLIKELY(hasnan)) {
+            if (hasnan) [[unlikely]] {
                 index_last_elem
                         = move_nans_to_end_of_array<T1, T2, full_vector<T1>>(
                                 keys, indexes, arrsize);

src/xss-common-qsort.h

@@ -660,7 +660,7 @@ X86_SIMD_SORT_INLINE void xss_qsort(T *arr, arrsize_t arrsize, bool hasnan)
     if (arrsize > 1) {
         arrsize_t nan_count = 0;
         if constexpr (xss::fp::is_floating_point_v<T>) {
-            if (UNLIKELY(hasnan)) {
+            if (hasnan) [[unlikely]] {
                 nan_count = replace_nan_with_inf<vtype>(arr, arrsize);
             }
         }
@@ -726,7 +726,7 @@ xss_qselect(T *arr, arrsize_t k, arrsize_t arrsize, bool hasnan)
     arrsize_t index_last_elem = arrsize - 1;
 
     if constexpr (xss::fp::is_floating_point_v<T>) {
-        if (UNLIKELY(hasnan)) {
+        if (hasnan) [[unlikely]] {
             if constexpr (descending) {
                 index_first_elem = move_nans_to_start_of_array(arr, arrsize);
             }