[PATCH] CFE Knob for: Add a thread-model knob for lowering atomics on baremetal & single threaded systems

[Renato Golin]

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Comment at: lib/CodeGen/BackendUtil.cpp:431
@@ +430,3 @@
+      .Case("posix", llvm::ThreadModel::POSIX)
+      .Case("single", llvm::ThreadModel::Single);
+
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Shouldn't this have a .Default()? If so, which value?

http://reviews.llvm.org/D4985