diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/ir/bits.h | 6 | ||||
| -rw-r--r-- | src/support/bits.cpp | 14 |
2 files changed, 9 insertions, 11 deletions
diff --git a/src/ir/bits.h b/src/ir/bits.h index 6b0697280..8b28bb031 100644 --- a/src/ir/bits.h +++ b/src/ir/bits.h @@ -43,9 +43,9 @@ struct Bits { if (mask == 0) { return 0; // trivially not a mask } - // otherwise, see if adding one turns this into a 1-bit thing, 00011111 + 1 - // => 00100000 - if (PopCount(mask + 1) != 1) { + // otherwise, see if x & (x + 1) turns this into non-zero value + // 00011111 & (00011111 + 1) => 0 + if (mask & (mask + 1)) { return 0; } // this is indeed a mask diff --git a/src/support/bits.cpp b/src/support/bits.cpp index f57a6d0e8..8dc0f31df 100644 --- a/src/support/bits.cpp +++ b/src/support/bits.cpp @@ -21,8 +21,6 @@ #ifdef _MSC_VER #include <intrin.h> -#define __builtin_popcount __popcnt -#define __builtin_popcountll __popcnt64 #endif namespace wasm { @@ -36,16 +34,16 @@ template<> int PopCount<uint8_t>(uint8_t v) { } template<> int PopCount<uint16_t>(uint16_t v) { -#if __has_builtin(__builtin_popcount) || defined(__GNUC__) || defined(_MSC_VER) - return (int)__builtin_popcount(v); +#if __has_builtin(__builtin_popcount) || defined(__GNUC__) + return __builtin_popcount(v); #else return PopCount((uint8_t)(v & 0xFF)) + PopCount((uint8_t)(v >> 8)); #endif } template<> int PopCount<uint32_t>(uint32_t v) { -#if __has_builtin(__builtin_popcount) || defined(__GNUC__) || defined(_MSC_VER) - return (int)__builtin_popcount(v); +#if __has_builtin(__builtin_popcount) || defined(__GNUC__) + return __builtin_popcount(v); #else // See Stanford bithacks, counting bits set in parallel, "best method": // http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel @@ -56,8 +54,8 @@ template<> int PopCount<uint32_t>(uint32_t v) { } template<> int PopCount<uint64_t>(uint64_t v) { -#if __has_builtin(__builtin_popcount) || defined(__GNUC__) || defined(_MSC_VER) - return (int)__builtin_popcountll(v); +#if __has_builtin(__builtin_popcount) || defined(__GNUC__) + return __builtin_popcountll(v); #else return PopCount((uint32_t)v) + PopCount((uint32_t)(v >> 32)); #endif |