[llvm] r226993 - [PM] Add a basic doxygen comment for this pass.

[Chandler Carruth]

Author: chandlerc
Date: Sat Jan 24 04:32:53 2015
New Revision: 226993

URL: http://llvm.org/viewvc/llvm-project?rev=226993&view=rev
Log:
[PM] Add a basic doxygen comment for this pass.

Modified:
    llvm/trunk/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp?rev=226993&r1=226992&r2=226993&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp Sat Jan 24 04:32:53 2015
@@ -40,6 +40,12 @@ UnlikelyBranchWeight("unlikely-branch-we
                    cl::desc("Weight of the branch unlikely to be taken (default = 4)"));
 
 namespace {
+/// \brief Legacy pass for lowering expect intrinsics out of the IR.
+///
+/// When this pass is run over a function it uses expect intrinsics which feed
+/// branches and switches to provide branch weight metadata for those
+/// terminators. It then removes the expect intrinsics from the IR so the rest
+/// of the optimizer can ignore them.
 class LowerExpectIntrinsic : public FunctionPass {
 
   bool HandleSwitchExpect(SwitchInst *SI);