[llvm] 090bdaa - [Support] Use std::shared_mutex when we're not on old MacOS

[Benjamin Kramer via llvm-commits]

Author: Benjamin Kramer
Date: 2022-08-08T13:31:05+02:00
New Revision: 090bdaad34867a4aafa750cbe5bdb0d24864a121

URL: https://github.com/llvm/llvm-project/commit/090bdaad34867a4aafa750cbe5bdb0d24864a121
DIFF: https://github.com/llvm/llvm-project/commit/090bdaad34867a4aafa750cbe5bdb0d24864a121.diff

LOG: [Support] Use std::shared_mutex when we're not on old MacOS

In C++17 mode this is always available.

Added: 
    

Modified: 
    llvm/include/llvm/Support/RWMutex.h

Removed: 
    


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diff  --git a/llvm/include/llvm/Support/RWMutex.h b/llvm/include/llvm/Support/RWMutex.h
index a06a5c3e064f..984487f94c69 100644
--- a/llvm/include/llvm/Support/RWMutex.h
+++ b/llvm/include/llvm/Support/RWMutex.h
@@ -92,14 +92,8 @@ class RWMutexImpl {
 /// indicates whether this mutex should become a no-op when we're not
 /// running in multithreaded mode.
 template <bool mt_only> class SmartRWMutex {
-  // shared_mutex (C++17) is more efficient than shared_timed_mutex (C++14)
-  // on Windows and always available on MSVC except with libc++.
 #if !defined(LLVM_USE_RW_MUTEX_IMPL)
-#if (defined(_MSC_VER) && !defined(_LIBCPP_VERSION)) || __cplusplus > 201402L
   std::shared_mutex impl;
-#else
-  std::shared_timed_mutex impl;
-#endif
 #else
   RWMutexImpl impl;
 #endif