Drop '@brief' from doxygen comments

LLVM's coding guideline suggests to not use @brief for one-sentence doxygen
comments to improve readability. Switch this once and for all to ensure people
do not copy @brief comments from other parts of Polly, when writing new code.

llvm-svn: 280468
diff --git a/polly/lib/Analysis/ScopDetection.cpp b/polly/lib/Analysis/ScopDetection.cpp
index eda988d..586beaf 100644
--- a/polly/lib/Analysis/ScopDetection.cpp
+++ b/polly/lib/Analysis/ScopDetection.cpp
@@ -178,7 +178,7 @@
     cl::location(PollyInvariantLoadHoisting), cl::Hidden, cl::ZeroOrMore,
     cl::init(false), cl::cat(PollyCategory));
 
-/// @brief The minimal trip count under which loops are considered unprofitable.
+/// The minimal trip count under which loops are considered unprofitable.
 static const unsigned MIN_LOOP_TRIP_COUNT = 8;
 
 bool polly::PollyTrackFailures = false;
@@ -621,7 +621,7 @@
   return true;
 }
 
-/// @brief Remove smax of smax(0, size) expressions from a SCEV expression and
+/// Remove smax of smax(0, size) expressions from a SCEV expression and
 /// register the '...' components.
 ///
 /// Array access expressions as they are generated by gfortran contain smax(0,
@@ -1096,7 +1096,7 @@
   return invalid<ReportLoopBound>(Context, /*Assert=*/true, L, LoopCount);
 }
 
-/// @brief Return the number of loops in @p L (incl. @p L) that have a trip
+/// Return the number of loops in @p L (incl. @p L) that have a trip
 ///        count that is not known to be less than MIN_LOOP_TRIP_COUNT.
 static int countBeneficialSubLoops(Loop *L, ScalarEvolution &SE) {
   auto *TripCount = SE.getBackedgeTakenCount(L);
@@ -1435,7 +1435,7 @@
 }
 
 bool ScopDetection::isReducibleRegion(Region &R, DebugLoc &DbgLoc) const {
-  /// @brief Enum for coloring BBs in Region.
+  /// Enum for coloring BBs in Region.
   ///
   /// WHITE - Unvisited BB in DFS walk.
   /// GREY - BBs which are currently on the DFS stack for processing.