[llvm] r335788 - [X86] Make folding table checking threadsafe

[Benjamin Kramer via llvm-commits]

Author: d0k
Date: Wed Jun 27 14:01:53 2018
New Revision: 335788

URL: http://llvm.org/viewvc/llvm-project?rev=335788&view=rev
Log:
[X86] Make folding table checking threadsafe

This is a benign race, but tsan likes to complain about it. Just make it
happy.

Modified:
    llvm/trunk/lib/Target/X86/X86InstrInfo.cpp

Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.cpp?rev=335788&r1=335787&r2=335788&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86InstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86InstrInfo.cpp Wed Jun 27 14:01:53 2018
@@ -5413,8 +5413,7 @@ X86InstrInfo::X86InstrInfo(X86Subtarget
 
 #ifndef NDEBUG
   // Make sure the tables are sorted.
-  static bool FoldTablesChecked = false;
-  if (!FoldTablesChecked) {
+  static bool LLVM_ATTRIBUTE_UNUSED FoldTablesChecked = [] {
     assert(std::is_sorted(std::begin(MemoryFoldTable2Addr),
                           std::end(MemoryFoldTable2Addr)) &&
            std::adjacent_find(std::begin(MemoryFoldTable2Addr),
@@ -5451,8 +5450,8 @@ X86InstrInfo::X86InstrInfo(X86Subtarget
                               std::end(MemoryFoldTable4)) ==
            std::end(MemoryFoldTable4) &&
            "MemoryFoldTable4 is not sorted and unique!");
-    FoldTablesChecked = true;
-  }
+    return true;
+  }();
 #endif
 }