From 5913c5f8e45d667b26f85a4d66ef9b4fab4d54f4 Mon Sep 17 00:00:00 2001
From: atdt <atdt@google.com>
Date: Thu, 13 Dec 2018 17:20:06 -0800
Subject: [PATCH] Don't use _bzhi_u32 under MSan

MSan knows that x & 0xFF only uses the lower byte from x but it isn't as
smart about _bzhi_u32(val, 8). (I'll file an upstream bug.)
---
 snappy.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/snappy.cc b/snappy.cc
index 26bef54..67e8a79 100644
--- a/snappy.cc
+++ b/snappy.cc
@@ -695,7 +695,7 @@ static inline void Report(const char *algorithm, size_t compressed_size,
 static inline uint32 ExtractLowBytes(uint32 v, int n) {
   DCHECK_GE(n, 0);
   DCHECK_LE(n, 4);
-#ifdef __BMI2__
+#if defined(__BMI2__) && !defined(MEMORY_SANITIZER)
   return _bzhi_u32(v, 8 * n);
 #else
   // This needs to be wider than uint32 otherwise `mask << 32` will be