commit a250dc9f111f1af6a413adf6a3749df857d668bc
author Matthew Simpson <mssimpso@codeaurora.org> Mon May 16 14:14:49 2016 +0000
committer Matthew Simpson <mssimpso@codeaurora.org> Mon May 16 14:14:49 2016 +0000
tree f50fa63bf93129a0828947e17f394ed9fb6c86f3
parent c73d559df43a0f19b0ee734cae9db2fb6c964120

[LAA] Add option to disable conflict detection (NFC)

llvm-svn: 269654

llvm/lib/Analysis/LoopAccessAnalysis.cpp

diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index 725e9b3..6eaf0ff 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -65,6 +65,13 @@
                             "loop-access analysis (default = 100)"),
                    cl::init(100));
 
+/// \brief Enable the conflict detection optimization. This option can be
+/// disabled for correctness testing.
+static cl::opt<bool> EnableConflictDetection(
+    "enable-conflict-detection", cl::Hidden,
+    cl::desc("Enable conflict detection in loop-access analysis"),
+    cl::init(true));
+
 bool VectorizerParams::isInterleaveForced() {
   return ::VectorizationInterleave.getNumOccurrences() > 0;
 }
@@ -1203,7 +1210,7 @@
   const APInt &Val = C->getAPInt();
   if (Val.isNegative()) {
     bool IsTrueDataDependence = (AIsWrite && !BIsWrite);
-    if (IsTrueDataDependence &&
+    if (IsTrueDataDependence && EnableConflictDetection &&
         (couldPreventStoreLoadForward(Val.abs().getZExtValue(), TypeByteSize) ||
          ATy != BTy)) {
       DEBUG(dbgs() << "LAA: Forward but may prevent st->ld forwarding\n");
@@ -1309,7 +1316,7 @@
       Distance < MaxSafeDepDistBytes ? Distance : MaxSafeDepDistBytes;
 
   bool IsTrueDataDependence = (!AIsWrite && BIsWrite);
-  if (IsTrueDataDependence &&
+  if (IsTrueDataDependence && EnableConflictDetection &&
       couldPreventStoreLoadForward(Distance, TypeByteSize))
     return Dependence::BackwardVectorizableButPreventsForwarding;