fixed zend_hash_init() when the lzcnt instruction isn't supported

diff --git a/Zend/zend_hash.c b/Zend/zend_hash.c
index fd0d27fb07c557d43f95b306d89853cef211479d..e496e5898b8ce4aeae77c88d4526a3c693634aad 100644 (file)
--- a/Zend/zend_hash.c
+++ b/Zend/zend_hash.c
@@ -101,25 +101,24 @@ static const uint32_t uninitialized_bucket = {INVALID_IDX};
 
 ZEND_API void _zend_hash_init(HashTable *ht, uint32_t nSize, dtor_func_t pDestructor, zend_bool persistent ZEND_FILE_LINE_DC)
 {
+#if defined(ZEND_WIN32)
+       unsigned long index;
+#endif
        /* Use big enough power of 2 */
-#if defined(PHP_WIN32) && !defined(__clang__)
-       if (nSize <= 8) {
-               ht->nTableSize = 8;
-       } else if (nSize >= 0x80000000) {
-               /* prevent overflow */
-               ht->nTableSize = 0x80000000;
-       } else {
-               ht->nTableSize = 1U << __lzcnt(nSize);
-               if (ht->nTableSize < nSize) {
-                       ht->nTableSize <<= 1;
-               }
-       }
-#else
        /* size should be between 8 and 0x80000000 */
        nSize = (nSize <= 8 ? 8 : (nSize >= 0x80000000 ? 0x80000000 : nSize));
-# if defined(__GNUC__)
+
+#if defined(ZEND_WIN32)
+       if (BitScanReverse(&index, nSize - 1)) {
+               ht->nTableSize = 0x2 << ((31 - index) ^ 0x1f);
+       } else {
+               /* nSize is ensured to be in the valid range, fall back to it
+                  rather than using an undefined bis scan result. */
+               ht->nTableSize = nSize;
+       }
+#elif defined(__GNUC__)
        ht->nTableSize =  0x2 << (__builtin_clz(nSize - 1) ^ 0x1f);
-# else
+#else
        nSize -= 1;
        nSize |= (nSize >> 1);
        nSize |= (nSize >> 2);
@@ -127,7 +126,6 @@ ZEND_API void _zend_hash_init(HashTable *ht, uint32_t nSize, dtor_func_t pDestru
        nSize |= (nSize >> 8);
        nSize |= (nSize >> 16);
        ht->nTableSize = nSize + 1;
-# endif
 #endif
 
        ht->nTableMask = 0;