[EarlyCSE/CVP] Add stats for CVPs and make sure to account for any Changes.

llvm-svn: 267187

1 files changed, 9 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/Scalar/EarlyCSE.cpp b/llvm/lib/Transforms/Scalar/EarlyCSE.cpp
index 949300b94a7..f490c2b6653 100644
--- a/llvm/lib/Transforms/Scalar/EarlyCSE.cpp
+++ b/llvm/lib/Transforms/Scalar/EarlyCSE.cpp
@@ -40,6 +40,7 @@ using namespace llvm::PatternMatch;
 
 STATISTIC(NumSimplify, "Number of instructions simplified or DCE'd");
 STATISTIC(NumCSE,      "Number of instructions CSE'd");
+STATISTIC(NumCSECVP,   "Number of compare instructions CVP'd");
 STATISTIC(NumCSELoad,  "Number of load instructions CSE'd");
 STATISTIC(NumCSECall,  "Number of call instructions CSE'd");
 STATISTIC(NumDSE,      "Number of trivial dead stores removed");
@@ -482,6 +483,7 @@ private:
 }
 
 bool EarlyCSE::processNode(DomTreeNode *Node) {
+  bool Changed = false;
   BasicBlock *BB = Node->getBlock();
 
   // If this block has a single predecessor, then the predecessor is the parent
@@ -512,9 +514,13 @@ bool EarlyCSE::processNode(DomTreeNode *Node) {
             DEBUG(dbgs() << "EarlyCSE CVP: Add conditional value for '"
                   << CondInst->getName() << "' as " << *ConditionalConstant
                   << " in " << BB->getName() << "\n");
-            // Replace all dominated uses with the known value
-            replaceDominatedUsesWith(CondInst, ConditionalConstant, DT,
-                                     BasicBlockEdge(Pred, BB));
+            // Replace all dominated uses with the known value.
+            if (unsigned Count =
+                    replaceDominatedUsesWith(CondInst, ConditionalConstant, DT,
+                                             BasicBlockEdge(Pred, BB))) {
+              Changed = true;
+              NumCSECVP = NumCSECVP + Count;
+            }
           }
 
   /// LastStore - Keep track of the last non-volatile store that we saw... for
@@ -523,7 +529,6 @@ bool EarlyCSE::processNode(DomTreeNode *Node) {
   /// stores which can occur in bitfield code among other things.
   Instruction *LastStore = nullptr;
 
-  bool Changed = false;
   const DataLayout &DL = BB->getModule()->getDataLayout();
 
   // See if any instructions in the block can be eliminated.  If so, do it.  If