Remove \brief commands from doxygen comments.

We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

  for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46290

llvm-svn: 331272
diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
index a1b25a2..822f880 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -286,17 +286,17 @@
 };
 
 struct EstimatedUnrollCost {
-  /// \brief The estimated cost after unrolling.
+  /// The estimated cost after unrolling.
   unsigned UnrolledCost;
 
-  /// \brief The estimated dynamic cost of executing the instructions in the
+  /// The estimated dynamic cost of executing the instructions in the
   /// rolled form.
   unsigned RolledDynamicCost;
 };
 
 } // end anonymous namespace
 
-/// \brief Figure out if the loop is worth full unrolling.
+/// Figure out if the loop is worth full unrolling.
 ///
 /// Complete loop unrolling can make some loads constant, and we need to know
 /// if that would expose any further optimization opportunities.  This routine