Addressed the review comments

contrib/crc32-vpmsum-cmake/CMakeLists.txt

@@ -1,3 +1,5 @@
+# module crc32-vpmsum gets build along with the files vec_crc32.h and crc32_constants.h in crc32-vpmsum-cmake
+# Please see README.md for information about how to generate crc32_constants.h
 if (NOT ARCH_PPC64LE)
 	message (STATUS "crc32-vpmsum library is only supported on ppc64le")
     return()

contrib/crc32-vpmsum-cmake/README.md

@@ -1,8 +1,9 @@
 # To Generate crc32_constants.h 
 
-- Run make file in `../crc32-vpmsum` diretory using folling options and CRC polynomial. These options should use the same polynomial and order used by intel intrinisic functions
+- Run make file in `../crc32-vpmsum` directory using following options and CRC polynomial. These options should use the same polynomial and order used by intel intrinisic functions
 ```bash
 make crc32_constants.h CRC="0x11EDC6F41" OPTIONS="-x -r -c"
 ```
 - move the generated `crc32_constants.h` into this directory
 - To understand more about this go here: https://masterchef2209.wordpress.com/2020/06/17/guide-to-intel-sse4-2-crc-intrinisics-implementation-for-simde/
+- Here is the link to information about intel intrinsic functions: https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm_crc32_u64&ig_expand=1492,1493,1559

contrib/crc32-vpmsum-cmake/vec_crc32.h

@@ -1,6 +1,9 @@
 #ifndef VEC_CRC32
 #define VEC_CRC32
 
+#if ! ((defined(__PPC64__) || defined(__powerpc64__)) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
+#    error PowerPC architecture is expected
+#endif
 
 #ifdef __cplusplus
 extern "C" {
@@ -10,15 +13,9 @@ unsigned int crc32_vpmsum(unsigned int crc, const unsigned char *p, unsigned lon
 
 static inline uint32_t crc32_ppc(uint64_t crc, unsigned char const *buffer, size_t len)
 {
-	unsigned char *emptybuffer;
+    assert(buffer);
-    if (!buffer) {
-        emptybuffer = (unsigned char *)malloc(len);
-        bzero(emptybuffer, len);
-        crc = crc32_vpmsum(crc, emptybuffer, len);
-        free(emptybuffer);
-    } else {
     crc = crc32_vpmsum(crc, buffer, (unsigned long)len);
-    }
+
     return crc;
 }
 

src/Common/HashTable/Hash.h

@@ -91,10 +91,10 @@ inline DB::UInt64 intHashCRC32(DB::UInt64 x)
     return _mm_crc32_u64(-1ULL, x);
 #elif defined(__aarch64__) && defined(__ARM_FEATURE_CRC32)
     return __crc32cd(-1U, x);
-#elif defined(__s390x__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-    return s390x_crc32(-1U, x)
 #elif (defined(__PPC64__) || defined(__powerpc64__)) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
     return crc32_ppc(-1U, reinterpret_cast<const unsigned char *>(&x), sizeof(x));
+#elif defined(__s390x__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+    return s390x_crc32(-1U, x)
 #else
     /// On other platforms we do not have CRC32. NOTE This can be confusing.
     /// NOTE: consider using intHash32()
@@ -107,10 +107,10 @@ inline DB::UInt64 intHashCRC32(DB::UInt64 x, DB::UInt64 updated_value)
     return _mm_crc32_u64(updated_value, x);
 #elif defined(__aarch64__) && defined(__ARM_FEATURE_CRC32)
     return __crc32cd(static_cast<UInt32>(updated_value), x);
-#elif defined(__s390x__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
-    return s390x_crc32(updated_value, x);
 #elif (defined(__PPC64__) || defined(__powerpc64__)) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
     return crc32_ppc(updated_value, reinterpret_cast<const unsigned char *>(&x), sizeof(x));
+#elif defined(__s390x__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
+    return s390x_crc32(updated_value, x);
 #else
     /// On other platforms we do not have CRC32. NOTE This can be confusing.
     return intHash64(x) ^ updated_value;

src/Functions/FunctionsStringHash.cpp

@@ -40,10 +40,10 @@ struct Hash
         return _mm_crc32_u64(crc, val);
 #elif defined(__aarch64__) && defined(__ARM_FEATURE_CRC32)
         return __crc32cd(static_cast<UInt32>(crc), val);
-#elif defined(__s390x__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
-        return s390x_crc32(crc, val);
 #elif (defined(__PPC64__) || defined(__powerpc64__)) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
         return crc32_ppc(crc, reinterpret_cast<const unsigned char *>(&val), sizeof(val));
+#elif defined(__s390x__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
+        return s390x_crc32(crc, val);
 #else
         throw Exception("String hash is not implemented without sse4.2 support", ErrorCodes::NOT_IMPLEMENTED);
 #endif
@@ -55,10 +55,10 @@ struct Hash
         return _mm_crc32_u32(crc, val);
 #elif defined(__aarch64__) && defined(__ARM_FEATURE_CRC32)
         return __crc32cw(crc, val);
-#elif defined(__s390x__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
-        return s390x_crc32_u32(crc, val);
 #elif (defined(__PPC64__) || defined(__powerpc64__)) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
         return crc32_ppc(crc, reinterpret_cast<const unsigned char *>(&val), sizeof(val));
+#elif defined(__s390x__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
+        return s390x_crc32_u32(crc, val);
 #else
         throw Exception("String hash is not implemented without sse4.2 support", ErrorCodes::NOT_IMPLEMENTED);
 #endif
@@ -70,10 +70,10 @@ struct Hash
         return _mm_crc32_u16(crc, val);
 #elif defined(__aarch64__) && defined(__ARM_FEATURE_CRC32)
         return __crc32ch(crc, val);
-#elif defined(__s390x__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
-        return s390x_crc32_u16(crc, val);
 #elif (defined(__PPC64__) || defined(__powerpc64__)) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
         return crc32_ppc(crc, reinterpret_cast<const unsigned char *>(&val), sizeof(val));
+#elif defined(__s390x__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
+        return s390x_crc32_u16(crc, val);
 #else
         throw Exception("String hash is not implemented without sse4.2 support", ErrorCodes::NOT_IMPLEMENTED);
 #endif
@@ -85,10 +85,10 @@ struct Hash
         return _mm_crc32_u8(crc, val);
 #elif defined(__aarch64__) && defined(__ARM_FEATURE_CRC32)
         return __crc32cb(crc, val);
-#elif defined(__s390x__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
-        return s390x_crc32_u8(crc, val);
 #elif (defined(__PPC64__) || defined(__powerpc64__)) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
         return crc32_ppc(crc, reinterpret_cast<const unsigned char *>(&val), sizeof(val));
+#elif defined(__s390x__) && __BYTE_ORDER__==__ORDER_BIG_ENDIAN__
+        return s390x_crc32_u8(crc, val);
 #else
         throw Exception("String hash is not implemented without sse4.2 support", ErrorCodes::NOT_IMPLEMENTED);
 #endif

src/Functions/FunctionsStringSimilarity.cpp

@@ -74,10 +74,10 @@ struct NgramDistanceImpl
         return _mm_crc32_u64(code_points[2], combined) & 0xFFFFu;
 #elif defined(__aarch64__) && defined(__ARM_FEATURE_CRC32)
         return __crc32cd(code_points[2], combined) & 0xFFFFu;
-#elif defined(__s390x__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-        return s390x_crc32(code_points[2], combined) & 0xFFFFu;
 #elif (defined(__PPC64__) || defined(__powerpc64__)) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
         return crc32_ppc(code_points[2], reinterpret_cast<const unsigned char *>(&combined), sizeof(combined)) & 0xFFFFu;
+#elif defined(__s390x__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+        return s390x_crc32(code_points[2], combined) & 0xFFFFu;
 #else
         return (intHashCRC32(combined) ^ intHashCRC32(code_points[2])) & 0xFFFFu;
 #endif