BBVectorize: Simplify how input swapping is handled.

Stop propagating the FlipMemInputs variable into the routines that
create the replacement instructions. Instead, just flip the arguments
of those routines. This allows for some associated cleanup (not all
of which is done here). No functionality change is intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167042 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Vectorize/BBVectorize.cpp

@@ -296,7 +296,7 @@ namespace {
                       bool UseCycleCheck);
 
     Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I,
-                     Instruction *J, unsigned o, bool FlipMemInputs);
+                     Instruction *J, unsigned o);
 
     void fillNewShuffleMask(LLVMContext& Context, Instruction *J,
                      unsigned MaskOffset, unsigned NumInElem,
@@ -312,16 +312,15 @@ namespace {
                        unsigned IdxOff = 0);
 
     Value *getReplacementInput(LLVMContext& Context, Instruction *I,
-                     Instruction *J, unsigned o, bool FlipMemInputs);
+                     Instruction *J, unsigned o);
 
     void getReplacementInputsForPair(LLVMContext& Context, Instruction *I,
-                     Instruction *J, SmallVector<Value *, 3> &ReplacedOperands,
+                     Instruction *J, SmallVector<Value *, 3> &ReplacedOperands);
-                     bool FlipMemInputs);
 
     void replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
                      Instruction *J, Instruction *K,
                      Instruction *&InsertionPt, Instruction *&K1,
-                     Instruction *&K2, bool FlipMemInputs);
+                     Instruction *&K2);
 
     void collectPairLoadMoveSet(BasicBlock &BB,
                      DenseMap<Value *, Value *> &ChosenPairs,
@@ -1670,25 +1669,19 @@ namespace {
   // Returns the value that is to be used as the pointer input to the vector
   // instruction that fuses I with J.
   Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context,
-                     Instruction *I, Instruction *J, unsigned o,
+                     Instruction *I, Instruction *J, unsigned o) {
-                     bool FlipMemInputs) {
     Value *IPtr, *JPtr;
     unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace;
     int64_t OffsetInElmts;
 
-    // Note: the analysis might fail here, that is why FlipMemInputs has
+    // Note: the analysis might fail here, that is why the pair order has
     // been precomputed (OffsetInElmts must be unused here).
     (void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
                           IAddressSpace, JAddressSpace,
                           OffsetInElmts, false);
 
     // The pointer value is taken to be the one with the lowest offset.
-    Value *VPtr;
+    Value *VPtr = IPtr;
-    if (!FlipMemInputs) {
-      VPtr = IPtr;
-    } else {
-      VPtr = JPtr;
-    }
 
     Type *ArgTypeI = cast<PointerType>(IPtr->getType())->getElementType();
     Type *ArgTypeJ = cast<PointerType>(JPtr->getType())->getElementType();
@@ -1696,7 +1689,7 @@ namespace {
     Type *VArgPtrType = PointerType::get(VArgType,
       cast<PointerType>(IPtr->getType())->getAddressSpace());
     return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o),
-                        /* insert before */ FlipMemInputs ? J : I);
+                        /* insert before */ I);
   }
 
   void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J,
@@ -1816,7 +1809,7 @@ namespace {
   // Returns the value to be used as the specified operand of the vector
   // instruction that fuses I with J.
   Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I,
-                     Instruction *J, unsigned o, bool FlipMemInputs) {
+                     Instruction *J, unsigned o) {
     Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
     Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1);
 
@@ -1827,12 +1820,6 @@ namespace {
 
     Instruction *L = I, *H = J;
     Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ;
-    if (FlipMemInputs) {
-      L = J;
-      H = I;
-      ArgTypeL = ArgTypeJ;
-      ArgTypeH = ArgTypeI;
-    }
 
     unsigned numElemL;
     if (ArgTypeL->isVectorTy())
@@ -2156,8 +2143,7 @@ namespace {
   // to the vector instruction that fuses I with J.
   void BBVectorize::getReplacementInputsForPair(LLVMContext& Context,
                      Instruction *I, Instruction *J,
-                     SmallVector<Value *, 3> &ReplacedOperands,
+                     SmallVector<Value *, 3> &ReplacedOperands) {
-                     bool FlipMemInputs) {
     unsigned NumOperands = I->getNumOperands();
 
     for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) {
@@ -2166,8 +2152,7 @@ namespace {
 
       if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) {
         // This is the pointer for a load/store instruction.
-        ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o,
+        ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o);
-                                FlipMemInputs);
         continue;
       } else if (isa<CallInst>(I)) {
         Function *F = cast<CallInst>(I)->getCalledFunction();
@@ -2195,8 +2180,7 @@ namespace {
         continue;
       }
 
-      ReplacedOperands[o] =
+      ReplacedOperands[o] = getReplacementInput(Context, I, J, o);
-        getReplacementInput(Context, I, J, o, FlipMemInputs);
     }
   }
 
@@ -2207,8 +2191,7 @@ namespace {
   void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
                      Instruction *J, Instruction *K,
                      Instruction *&InsertionPt,
-                     Instruction *&K1, Instruction *&K2,
+                     Instruction *&K1, Instruction *&K2) {
-                     bool FlipMemInputs) {
     if (isa<StoreInst>(I)) {
       AA->replaceWithNewValue(I, K);
       AA->replaceWithNewValue(J, K);
@@ -2238,13 +2221,11 @@ namespace {
         }
 
         K1 = new ShuffleVectorInst(K, UndefValue::get(VType),
-                                   ConstantVector::get(
+                                   ConstantVector::get( Mask1),
-                                     FlipMemInputs ? Mask2 : Mask1),
                                    getReplacementName(K, false, 1));
       } else {
         Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
-        Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1);
+        K1 = ExtractElementInst::Create(K, CV0,
-        K1 = ExtractElementInst::Create(K, FlipMemInputs ? CV1 : CV0,
                                           getReplacementName(K, false, 1));
       }
 
@@ -2256,13 +2237,11 @@ namespace {
         }
 
         K2 = new ShuffleVectorInst(K, UndefValue::get(VType),
-                                   ConstantVector::get(
+                                   ConstantVector::get( Mask2),
-                                     FlipMemInputs ? Mask1 : Mask2),
                                    getReplacementName(K, false, 2));
       } else {
-        Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
         Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1);
-        K2 = ExtractElementInst::Create(K, FlipMemInputs ? CV0 : CV1,
+        K2 = ExtractElementInst::Create(K, CV1,
                                           getReplacementName(K, false, 2));
       }
 
@@ -2490,10 +2469,14 @@ namespace {
       if (isa<LoadInst>(I) || isa<StoreInst>(I))
         FlipMemInputs = (LowPtrInsts.find(I) == LowPtrInsts.end());
 
+      Instruction *L = I, *H = J;
+      if (FlipMemInputs)
+        std::swap(H, L);
+      FlipMemInputs = false;
+
       unsigned NumOperands = I->getNumOperands();
       SmallVector<Value *, 3> ReplacedOperands(NumOperands);
-      getReplacementInputsForPair(Context, I, J, ReplacedOperands,
+      getReplacementInputsForPair(Context, L, H, ReplacedOperands);
-        FlipMemInputs);
 
       // Make a copy of the original operation, change its type to the vector
       // type and replace its operands with the vector operands.
@@ -2501,7 +2484,7 @@ namespace {
       if (I->hasName()) K->takeName(I);
 
       if (!isa<StoreInst>(K))
-        K->mutateType(getVecTypeForPair(I->getType(), J->getType()));
+        K->mutateType(getVecTypeForPair(L->getType(), H->getType()));
 
       combineMetadata(K, J);
 
@@ -2522,8 +2505,7 @@ namespace {
       // Instruction insertion point:
       Instruction *InsertionPt = K;
       Instruction *K1 = 0, *K2 = 0;
-      replaceOutputsOfPair(Context, I, J, K, InsertionPt, K1, K2,
+      replaceOutputsOfPair(Context, L, H, K, InsertionPt, K1, K2);
-        FlipMemInputs);
 
       // The use tree of the first original instruction must be moved to after
       // the location of the second instruction. The entire use tree of the