InstSimplify: Simplify trivial pointer expressions like b + (e - b)

[oota-llvm.git] / lib / Analysis / CostModel.cpp

diff --git a/lib/Analysis/CostModel.cpp b/lib/Analysis/CostModel.cpp
index 9fe0bfa267ee4d2c3875088fb7c88f098349f828..1b74f8c19c51636ab651be39ecf6021a59bda80c 100644 (file)
--- a/lib/Analysis/CostModel.cpp
+++ b/lib/Analysis/CostModel.cpp
@@ -17,8 +17,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define CM_NAME "cost-model"
-#define DEBUG_TYPE CM_NAME
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Analysis/Passes.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
@@ -32,6 +30,9 @@
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
+#define CM_NAME "cost-model"
+#define DEBUG_TYPE CM_NAME
+
 static cl::opt<bool> EnableReduxCost("costmodel-reduxcost", cl::init(false),
                                      cl::Hidden,
                                      cl::desc("Recognize reduction patterns."));
@@ -94,6 +95,31 @@ static bool isReverseVectorMask(SmallVectorImpl<int> &Mask) {
   return true;
 }
 
+static bool isAlternateVectorMask(SmallVectorImpl<int> &Mask) {
+  bool isAlternate = true;
+  unsigned MaskSize = Mask.size();
+
+  // Example: shufflevector A, B, <0,5,2,7>
+  for (unsigned i = 0; i < MaskSize && isAlternate; ++i) {
+    if (Mask[i] < 0)
+      continue;
+    isAlternate = Mask[i] == (int)((i & 1) ? MaskSize + i : i);
+  }
+
+  if (isAlternate)
+    return true;
+
+  isAlternate = true;
+  // Example: shufflevector A, B, <4,1,6,3>
+  for (unsigned i = 0; i < MaskSize && isAlternate; ++i) {
+    if (Mask[i] < 0)
+      continue;
+    isAlternate = Mask[i] == (int)((i & 1) ? i : MaskSize + i);
+  }
+
+  return isAlternate;
+}
+
 static TargetTransformInfo::OperandValueKind getOperandInfo(Value *V) {
   TargetTransformInfo::OperandValueKind OpInfo =
     TargetTransformInfo::OK_AnyValue;
@@ -108,17 +134,6 @@ static TargetTransformInfo::OperandValueKind getOperandInfo(Value *V) {
   return OpInfo;
 }
 
-static bool matchMask(SmallVectorImpl<int> &M1, SmallVectorImpl<int> &M2) {
-  if (M1.size() != M2.size())
-    return false;
-
-  for (unsigned i = 0, e = M1.size(); i != e; ++i)
-    if (M1[i] != M2[i])
-      return false;
-
-  return true;
-}
-
 static bool matchPairwiseShuffleMask(ShuffleVectorInst *SI, bool IsLeft,
                                      unsigned Level) {
   // We don't need a shuffle if we just want to have element 0 in position 0 of
@@ -136,7 +151,7 @@ static bool matchPairwiseShuffleMask(ShuffleVectorInst *SI, bool IsLeft,
     Mask[i] = val;
 
   SmallVector<int, 16> ActualMask = SI->getShuffleMask();
-  if (!matchMask(Mask, ActualMask))
+  if (Mask != ActualMask)
     return false;
 
   return true;
@@ -349,7 +364,7 @@ static bool matchVectorSplittingReduction(const ExtractElementInst *ReduxRoot,
     std::fill(&ShuffleMask[MaskStart], ShuffleMask.end(), -1);
 
     SmallVector<int, 16> Mask = Shuffle->getShuffleMask();
-    if (!matchMask(ShuffleMask, Mask))
+    if (ShuffleMask != Mask)
       return false;
 
     RdxOp = NextRdxOp;
@@ -476,9 +491,15 @@ unsigned CostModelAnalysis::getInstructionCost(const Instruction *I) const {
     unsigned NumVecElems = VecTypOp0->getVectorNumElements();
     SmallVector<int, 16> Mask = Shuffle->getShuffleMask();
 
-    if (NumVecElems == Mask.size() && isReverseVectorMask(Mask))
-      return TTI->getShuffleCost(TargetTransformInfo::SK_Reverse, VecTypOp0, 0,
-                                 nullptr);
+    if (NumVecElems == Mask.size()) {
+      if (isReverseVectorMask(Mask))
+        return TTI->getShuffleCost(TargetTransformInfo::SK_Reverse, VecTypOp0,
+                                   0, nullptr);
+      if (isAlternateVectorMask(Mask))
+        return TTI->getShuffleCost(TargetTransformInfo::SK_Alternate,
+                                   VecTypOp0, 0, nullptr);
+    }
+
     return -1;
   }
   case Instruction::Call: