[msan] Make -msan-check-constant-shadow a bit stronger.

[oota-llvm.git] / lib / Transforms / Instrumentation / MaximumSpanningTree.h

diff --git a/lib/Transforms/Instrumentation/MaximumSpanningTree.h b/lib/Transforms/Instrumentation/MaximumSpanningTree.h
index 2951dbcea9a185a39caa0271ba235e341147582d..363539b2886f3998bbfa56b8c06baae79c85ffca 100644 (file)
--- a/lib/Transforms/Instrumentation/MaximumSpanningTree.h
+++ b/lib/Transforms/Instrumentation/MaximumSpanningTree.h
@@ -7,7 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This module privides means for calculating a maximum spanning tree for a
+// This module provides means for calculating a maximum spanning tree for a
 // given set of weighted edges. The type parameter T is the type of a node.
 //
 //===----------------------------------------------------------------------===//
@@ -16,8 +16,9 @@
 #define LLVM_ANALYSIS_MAXIMUMSPANNINGTREE_H
 
 #include "llvm/ADT/EquivalenceClasses.h"
-#include <vector>
+#include "llvm/IR/BasicBlock.h"
 #include <algorithm>
+#include <vector>
 
 namespace llvm {
 
@@ -25,18 +26,6 @@ namespace llvm {
   /// The type parameter T determines the type of the nodes of the graph.
   template <typename T>
   class MaximumSpanningTree {
-
-    // A comparing class for comparing weighted edges.
-    template <typename CT>
-    struct EdgeWeightCompare {
-      bool operator()(typename MaximumSpanningTree<CT>::EdgeWeight X, 
-                      typename MaximumSpanningTree<CT>::EdgeWeight Y) const {
-        if (X.second > Y.second) return true;
-        if (X.second < Y.second) return false;
-        return false;
-      }
-    };
-
   public:
     typedef std::pair<const T*, const T*> Edge;
     typedef std::pair<Edge, double> EdgeWeight;
@@ -46,6 +35,33 @@ namespace llvm {
 
     MaxSpanTree MST;
 
+  private:
+    // A comparing class for comparing weighted edges.
+    struct EdgeWeightCompare {
+      static bool getBlockSize(const T *X) {
+        const BasicBlock *BB = dyn_cast_or_null<BasicBlock>(X);
+        return BB ? BB->size() : 0;
+      }
+
+      bool operator()(EdgeWeight X, EdgeWeight Y) const {
+        if (X.second > Y.second) return true;
+        if (X.second < Y.second) return false;
+
+        // Equal edge weights: break ties by comparing block sizes.
+        size_t XSizeA = getBlockSize(X.first.first);
+        size_t YSizeA = getBlockSize(Y.first.first);
+        if (XSizeA > YSizeA) return true;
+        if (XSizeA < YSizeA) return false;
+
+        size_t XSizeB = getBlockSize(X.first.second);
+        size_t YSizeB = getBlockSize(Y.first.second);
+        if (XSizeB > YSizeB) return true;
+        if (XSizeB < YSizeB) return false;
+
+        return false;
+      }
+    };
+
   public:
     static char ID; // Class identification, replacement for typeinfo
 
@@ -53,7 +69,7 @@ namespace llvm {
     /// spanning tree.
     MaximumSpanningTree(EdgeWeights &EdgeVector) {
 
-      std::stable_sort(EdgeVector.begin(), EdgeVector.end(), EdgeWeightCompare<T>());
+      std::stable_sort(EdgeVector.begin(), EdgeVector.end(), EdgeWeightCompare());
 
       // Create spanning tree, Forest contains a special data structure
       // that makes checking if two nodes are already in a common (sub-)tree