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authorYann Collet <Cyan4973@users.noreply.github.com>2021-08-09 19:58:58 (GMT)
committerGitHub <noreply@github.com>2021-08-09 19:58:58 (GMT)
commite78eeec86e696f318a0ad1e71d6ad50555d1c0a9 (patch)
treecb5e7e6c965cad6d89a154d729d8168833a35ba0 /lib/lz4.c
parent57ed27f46ef2870c2d692d82ec7d4fcb759bfba9 (diff)
parent1a2e8f4e3077cdafbaf15278bfe393c64263215c (diff)
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Merge pull request #1017 from fanzeyi/fix-clang-cl-msvc
fix clang-cl _tzcnt_u64 not defined issue
Diffstat (limited to 'lib/lz4.c')
-rw-r--r--lib/lz4.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/lib/lz4.c b/lib/lz4.c
index 405e977..5499547 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -516,8 +516,14 @@ static unsigned LZ4_NbCommonBytes (reg_t val)
if (LZ4_isLittleEndian()) {
if (sizeof(val) == 8) {
# if defined(_MSC_VER) && (_MSC_VER >= 1800) && defined(_M_AMD64) && !defined(LZ4_FORCE_SW_BITCOUNT)
+# if defined(__clang__) && (__clang_major__ < 10)
+ /* Avoid undefined clang-cl intrinics issue.
+ * See https://github.com/lz4/lz4/pull/1017 for details. */
+ return (unsigned)__builtin_ia32_tzcnt_u64(val) >> 3;
+# else
/* x64 CPUS without BMI support interpret `TZCNT` as `REP BSF` */
return (unsigned)_tzcnt_u64(val) >> 3;
+# endif
# elif defined(_MSC_VER) && defined(_WIN64) && !defined(LZ4_FORCE_SW_BITCOUNT)
unsigned long r = 0;
_BitScanForward64(&r, (U64)val);