[PATCH] [OPENMP] Codegen for "omp flush" directive.

[John McCall]

Okay, that's fine by me.  Please do make sure that this change is ultimately made to the runtime, though.

One small tweak, but with that, LGTM.

================
Comment at: lib/CodeGen/CGOpenMPRuntime.cpp:670
@@ +669,3 @@
+  llvm::Value *Args[] = {EmitOpenMPUpdateLocation(CGF, Loc),
+                         llvm::Constant::getNullValue(CGM.Int32Ty)};
+  auto *RTLFn = CGF.CGM.getOpenMPRuntime().CreateRuntimeFunction(
----------------
Prefer ConstantInt::get(CGM.Int32Ty, 0).

http://reviews.llvm.org/D6292