Add a hidden -disable-pre flag for testing purposes. This should be removed

once benchmarking is completed.

llvm-svn: 52506

1 files changed, 8 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index cbc24eda56f..88377d51ce7 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -32,6 +32,7 @@
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/MemoryDependenceAnalysis.h"
 #include "llvm/Support/CFG.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
@@ -41,6 +42,9 @@ STATISTIC(NumGVNInstr, "Number of instructions deleted");
 STATISTIC(NumGVNLoad, "Number of loads deleted");
 STATISTIC(NumGVNPRE, "Number of instructions PRE'd");
 
+static cl::opt<bool> DisablePRE("disable-pre",
+                                cl::init(false), cl::Hidden);
+
 //===----------------------------------------------------------------------===//
 //                         ValueTable Class
 //===----------------------------------------------------------------------===//
@@ -1285,7 +1289,9 @@ bool GVN::iterateOnFunction(Function &F) {
   for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
        DE = df_end(DT.getRootNode()); DI != DE; ++DI)
     changed |= processBlock(*DI);
-    
-  changed |= performPRE(F);
+  
+  if (!DisablePRE)
+    changed |= performPRE(F);
+  
   return changed;
 }