Merge branch 'ifunc.CxxUtils-20180611' into 'master'

CxxUtils: A few cleanups for multiversioned functions.

See merge request atlas/athena!12047

Control/CxxUtils/CxxUtils/bitscan.h

@@ -124,35 +124,6 @@ namespace CxxUtils {
   }
 
 
-  // We want to use the popcnt instruction for this if it's available.
-  // However, we're still compiling for a Model-T x86_64 by default.
-  // Use the target attribute and function multiversioning to use
-  // this instruction if it is in fact available.
-#if defined(__x86_64__) && HAVE_BITCOUNT_INTRINSICS && HAVE_FUNCTION_MULTIVERSIONING
-  /**
-   * Count number of set bits.
-   *
-   * @param x Number to check
-   * @return Number of bits set in x.
-   */
-  __attribute__ ((target ("popcnt")))
-  inline unsigned count_ones(unsigned x) {
-    return __builtin_popcount(x);
-  }
-
-  __attribute__ ((target ("popcnt")))
-  inline unsigned count_ones(unsigned long x) {
-    return __builtin_popcountl(x);
-  }
-
-
-  __attribute__ ((target ("popcnt")))
-  inline unsigned count_ones(unsigned long long x) {
-    return __builtin_popcountll(x);
-  }
-#endif // defined(__x86_64__) && HAVE_BITCOUNT_INTRINSICS && HAVE_FUNCTION_MULTIVERSIONING
-
-
   /**
    * Count number of set bits.
    *
@@ -160,7 +131,11 @@ namespace CxxUtils {
    * @return Number of bits set in x.
    */
 #if defined(__x86_64__) && HAVE_BITCOUNT_INTRINSICS && HAVE_FUNCTION_MULTIVERSIONING
-  __attribute__ ((target ("default")))
+  // We want to use the popcnt instruction for this if it's available.
+  // However, we're still compiling for a Model-T x86_64 by default.
+  // Use the target attribute and function multiversioning to use
+  // this instruction if it is in fact available.
+  __attribute__ ((target_clones ("popcnt,default")))
 #endif
   inline unsigned count_ones(unsigned x) {
 #if HAVE_BITCOUNT_INTRINSICS
@@ -171,7 +146,7 @@ namespace CxxUtils {
   }
 
 #if defined(__x86_64__) && HAVE_BITCOUNT_INTRINSICS && HAVE_FUNCTION_MULTIVERSIONING
-  __attribute__ ((target ("default")))
+  __attribute__ ((target_clones ("popcnt,default")))
 #endif
   inline unsigned count_ones(unsigned long x) {
 #if HAVE_BITCOUNT_INTRINSICS
@@ -183,7 +158,7 @@ namespace CxxUtils {
 
 
 #if defined(__x86_64__) && HAVE_BITCOUNT_INTRINSICS && HAVE_FUNCTION_MULTIVERSIONING
-  __attribute__ ((target ("default")))
+  __attribute__ ((target_clones ("popcnt,default")))
 #endif
   inline unsigned count_ones(unsigned long long x) {
 #if HAVE_BITCOUNT_INTRINSICS

Control/CxxUtils/CxxUtils/crc64.h

@@ -110,29 +110,6 @@ __attribute__ ((target ("pclmul")))
 uint64_t crc64 (const CRCTable& table,
                 const char* data,
                 size_t data_len);
-
-
-/**
- * @brief Find the CRC-64 of a string, with the default CRC.
- * @param table Precomputed CRC tables and constants.
- * @param data Pointer to the string to hash.
- * @param data_len Length of the string to hash, in bytes.
- *
- * This is the vectorized implementation, used on platforms with pclmul.
- */
-__attribute__ ((target ("pclmul")))
-uint64_t crc64 (const char* data,
-                size_t data_len);
-
-
-/**
- * @brief Find the CRC-64 of a string, using the default polynomial.
- * @param str The string to hash.
- *
- * This is the vectorized implementation, used on platforms with pclmul.
- */
-__attribute__ ((target ("pclmul")))
-uint64_t crc64 (const std::string& s);
 #endif // ATH_CRC64_VEC
 
 
@@ -156,12 +133,7 @@ uint64_t crc64 (const CRCTable& table,
  * @brief Find the CRC-64 of a string, with the default CRC.
  * @param data Pointer to the string to hash.
  * @param data_len Length of the string to hash, in bytes.
- *
- * This is the default implementation, used on platforms without pclmul.
  */
-#if ATH_CRC64_VEC
-__attribute__ ((target ("default")))
-#endif
 uint64_t crc64 (const char* data,
                 size_t data_len);
 
@@ -169,12 +141,7 @@ uint64_t crc64 (const char* data,
 /**
  * @brief Find the CRC-64 of a string, using the default polynomial.
  * @param str The string to hash.
- *
- * This is the default implementation, used on platforms without pclmul.
  */
-#if ATH_CRC64_VEC
-__attribute__ ((target ("default")))
-#endif
 uint64_t crc64 (const std::string& s);
 
 

Control/CxxUtils/CxxUtils/features.h

@@ -15,7 +15,7 @@
 
 
 /// Do we have function multiversioning?
-#if defined(__GNUC__) && !defined(__clang__) && !defined(__ICC)
+#if defined(__GNUC__) && !defined(__clang__) && !defined(__ICC) && !defined(__COVERITY__)
 # define HAVE_FUNCTION_MULTIVERSIONING 1
 #else
 # define HAVE_FUNCTION_MULTIVERSIONING 0

Control/CxxUtils/Root/crc64.cxx

@@ -674,34 +674,6 @@ uint64_t crc64 (const CRCTable& table,
 }
 
 
-/**
- * @brief Find the CRC-64 of a string, using a vectorized algorithm,
- *        with the default CRC.
- * @param table Precomputed CRC tables and constants.
- * @param data Pointer to the string to hash.
- * @param data_len Length of the string to hash, in bytes.
- */
-__attribute__ ((target ("pclmul")))
-uint64_t crc64 (const char* data,
-                size_t data_len)
-{
-  return crc64 (defaultCRCTable, data, data_len);
-}
-
-
-/**
- * @brief Find the CRC-64 of a string, using the default polynomial.
- * @param str The string to hash.
- *
- * This is the vectorized implementation, used on platforms with pclmul.
- */
-__attribute__ ((target ("pclmul")))
-uint64_t crc64 (const std::string& s)
-{
-  return crc64 (defaultCRCTable, s.data(), s.size());
-}
-
-
 #endif // ATH_CRC64_VEC
 
 
@@ -728,12 +700,7 @@ uint64_t crc64 (const CRCTable& table,
  * @brief Find the CRC-64 of a string, with the default CRC.
  * @param data Pointer to the string to hash.
  * @param data_len Length of the string to hash, in bytes.
- *
- * This is the default implementation, used on platforms without pclmul.
  */
-#if ATH_CRC64_VEC
-__attribute__ ((target ("default")))
-#endif
 uint64_t crc64 (const char* data,
                 size_t data_len)
 {
@@ -744,12 +711,7 @@ uint64_t crc64 (const char* data,
 /**
  * @brief Find the CRC-64 of a string, using the default polynomial.
  * @param str The string to hash.
- *
- * This is the default implementation, used on platforms without pclmul.
  */
-#if ATH_CRC64_VEC
-__attribute__ ((target ("default")))
-#endif
 uint64_t crc64 (const std::string& s)
 {
   return crc64 (defaultCRCTable, s.data(), s.size());