1 files changed, 68 insertions, 34 deletions

diff --git a/lib/Transforms/InstCombine/InstCombineCasts.cpp b/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 2c9ba203fbf3..65aaef28d87a 100644
--- a/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -140,7 +140,7 @@ Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI,
   }
 
   AllocaInst *New = AllocaBuilder.CreateAlloca(CastElTy, Amt);
-  New->setAlignment(AI.getAlignment());
+  New->setAlignment(MaybeAlign(AI.getAlignment()));
   New->takeName(&AI);
   New->setUsedWithInAlloca(AI.isUsedWithInAlloca());
 
@@ -1531,16 +1531,16 @@ Instruction *InstCombiner::visitFPTrunc(FPTruncInst &FPT) {
   // what we can and cannot do safely varies from operation to operation, and
   // is explained below in the various case statements.
   Type *Ty = FPT.getType();
-  BinaryOperator *OpI = dyn_cast<BinaryOperator>(FPT.getOperand(0));
-  if (OpI && OpI->hasOneUse()) {
-    Type *LHSMinType = getMinimumFPType(OpI->getOperand(0));
-    Type *RHSMinType = getMinimumFPType(OpI->getOperand(1));
-    unsigned OpWidth = OpI->getType()->getFPMantissaWidth();
+  auto *BO = dyn_cast<BinaryOperator>(FPT.getOperand(0));
+  if (BO && BO->hasOneUse()) {
+    Type *LHSMinType = getMinimumFPType(BO->getOperand(0));
+    Type *RHSMinType = getMinimumFPType(BO->getOperand(1));
+    unsigned OpWidth = BO->getType()->getFPMantissaWidth();
     unsigned LHSWidth = LHSMinType->getFPMantissaWidth();
     unsigned RHSWidth = RHSMinType->getFPMantissaWidth();
     unsigned SrcWidth = std::max(LHSWidth, RHSWidth);
     unsigned DstWidth = Ty->getFPMantissaWidth();
-    switch (OpI->getOpcode()) {
+    switch (BO->getOpcode()) {
       default: break;
       case Instruction::FAdd:
       case Instruction::FSub:
@@ -1563,10 +1563,10 @@ Instruction *InstCombiner::visitFPTrunc(FPTruncInst &FPT) {
         // could be tightened for those cases, but they are rare (the main
         // case of interest here is (float)((double)float + float)).
         if (OpWidth >= 2*DstWidth+1 && DstWidth >= SrcWidth) {
-          Value *LHS = Builder.CreateFPTrunc(OpI->getOperand(0), Ty);
-          Value *RHS = Builder.CreateFPTrunc(OpI->getOperand(1), Ty);
-          Instruction *RI = BinaryOperator::Create(OpI->getOpcode(), LHS, RHS);
-          RI->copyFastMathFlags(OpI);
+          Value *LHS = Builder.CreateFPTrunc(BO->getOperand(0), Ty);
+          Value *RHS = Builder.CreateFPTrunc(BO->getOperand(1), Ty);
+          Instruction *RI = BinaryOperator::Create(BO->getOpcode(), LHS, RHS);
+          RI->copyFastMathFlags(BO);
           return RI;
         }
         break;
@@ -1577,9 +1577,9 @@ Instruction *InstCombiner::visitFPTrunc(FPTruncInst &FPT) {
         // rounding can possibly occur; we can safely perform the operation
         // in the destination format if it can represent both sources.
         if (OpWidth >= LHSWidth + RHSWidth && DstWidth >= SrcWidth) {
-          Value *LHS = Builder.CreateFPTrunc(OpI->getOperand(0), Ty);
-          Value *RHS = Builder.CreateFPTrunc(OpI->getOperand(1), Ty);
-          return BinaryOperator::CreateFMulFMF(LHS, RHS, OpI);
+          Value *LHS = Builder.CreateFPTrunc(BO->getOperand(0), Ty);
+          Value *RHS = Builder.CreateFPTrunc(BO->getOperand(1), Ty);
+          return BinaryOperator::CreateFMulFMF(LHS, RHS, BO);
         }
         break;
       case Instruction::FDiv:
@@ -1590,9 +1590,9 @@ Instruction *InstCombiner::visitFPTrunc(FPTruncInst &FPT) {
         // condition used here is a good conservative first pass.
         // TODO: Tighten bound via rigorous analysis of the unbalanced case.
         if (OpWidth >= 2*DstWidth && DstWidth >= SrcWidth) {
-          Value *LHS = Builder.CreateFPTrunc(OpI->getOperand(0), Ty);
-          Value *RHS = Builder.CreateFPTrunc(OpI->getOperand(1), Ty);
-          return BinaryOperator::CreateFDivFMF(LHS, RHS, OpI);
+          Value *LHS = Builder.CreateFPTrunc(BO->getOperand(0), Ty);
+          Value *RHS = Builder.CreateFPTrunc(BO->getOperand(1), Ty);
+          return BinaryOperator::CreateFDivFMF(LHS, RHS, BO);
         }
         break;
       case Instruction::FRem: {
@@ -1604,14 +1604,14 @@ Instruction *InstCombiner::visitFPTrunc(FPTruncInst &FPT) {
           break;
         Value *LHS, *RHS;
         if (LHSWidth == SrcWidth) {
-           LHS = Builder.CreateFPTrunc(OpI->getOperand(0), LHSMinType);
-           RHS = Builder.CreateFPTrunc(OpI->getOperand(1), LHSMinType);
+           LHS = Builder.CreateFPTrunc(BO->getOperand(0), LHSMinType);
+           RHS = Builder.CreateFPTrunc(BO->getOperand(1), LHSMinType);
         } else {
-           LHS = Builder.CreateFPTrunc(OpI->getOperand(0), RHSMinType);
-           RHS = Builder.CreateFPTrunc(OpI->getOperand(1), RHSMinType);
+           LHS = Builder.CreateFPTrunc(BO->getOperand(0), RHSMinType);
+           RHS = Builder.CreateFPTrunc(BO->getOperand(1), RHSMinType);
         }
 
-        Value *ExactResult = Builder.CreateFRemFMF(LHS, RHS, OpI);
+        Value *ExactResult = Builder.CreateFRemFMF(LHS, RHS, BO);
         return CastInst::CreateFPCast(ExactResult, Ty);
       }
     }
@@ -2338,8 +2338,23 @@ Instruction *InstCombiner::visitBitCast(BitCastInst &CI) {
     // If we found a path from the src to dest, create the getelementptr now.
     if (SrcElTy == DstElTy) {
       SmallVector<Value *, 8> Idxs(NumZeros + 1, Builder.getInt32(0));
-      return GetElementPtrInst::CreateInBounds(SrcPTy->getElementType(), Src,
-                                               Idxs);
+      GetElementPtrInst *GEP =
+          GetElementPtrInst::Create(SrcPTy->getElementType(), Src, Idxs);
+
+      // If the source pointer is dereferenceable, then assume it points to an
+      // allocated object and apply "inbounds" to the GEP.
+      bool CanBeNull;
+      if (Src->getPointerDereferenceableBytes(DL, CanBeNull)) {
+        // In a non-default address space (not 0), a null pointer can not be
+        // assumed inbounds, so ignore that case (dereferenceable_or_null).
+        // The reason is that 'null' is not treated differently in these address
+        // spaces, and we consequently ignore the 'gep inbounds' special case
+        // for 'null' which allows 'inbounds' on 'null' if the indices are
+        // zeros.
+        if (SrcPTy->getAddressSpace() == 0 || !CanBeNull)
+          GEP->setIsInBounds();
+      }
+      return GEP;
     }
   }
 
@@ -2391,28 +2406,47 @@ Instruction *InstCombiner::visitBitCast(BitCastInst &CI) {
     }
   }
 
-  if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(Src)) {
+  if (auto *Shuf = dyn_cast<ShuffleVectorInst>(Src)) {
     // Okay, we have (bitcast (shuffle ..)).  Check to see if this is
     // a bitcast to a vector with the same # elts.
-    if (SVI->hasOneUse() && DestTy->isVectorTy() &&
-        DestTy->getVectorNumElements() == SVI->getType()->getNumElements() &&
-        SVI->getType()->getNumElements() ==
-        SVI->getOperand(0)->getType()->getVectorNumElements()) {
+    Value *ShufOp0 = Shuf->getOperand(0);
+    Value *ShufOp1 = Shuf->getOperand(1);
+    unsigned NumShufElts = Shuf->getType()->getVectorNumElements();
+    unsigned NumSrcVecElts = ShufOp0->getType()->getVectorNumElements();
+    if (Shuf->hasOneUse() && DestTy->isVectorTy() &&
+        DestTy->getVectorNumElements() == NumShufElts &&
+        NumShufElts == NumSrcVecElts) {
       BitCastInst *Tmp;
       // If either of the operands is a cast from CI.getType(), then
       // evaluating the shuffle in the casted destination's type will allow
       // us to eliminate at least one cast.
-      if (((Tmp = dyn_cast<BitCastInst>(SVI->getOperand(0))) &&
+      if (((Tmp = dyn_cast<BitCastInst>(ShufOp0)) &&
            Tmp->getOperand(0)->getType() == DestTy) ||
-          ((Tmp = dyn_cast<BitCastInst>(SVI->getOperand(1))) &&
+          ((Tmp = dyn_cast<BitCastInst>(ShufOp1)) &&
            Tmp->getOperand(0)->getType() == DestTy)) {
-        Value *LHS = Builder.CreateBitCast(SVI->getOperand(0), DestTy);
-        Value *RHS = Builder.CreateBitCast(SVI->getOperand(1), DestTy);
+        Value *LHS = Builder.CreateBitCast(ShufOp0, DestTy);
+        Value *RHS = Builder.CreateBitCast(ShufOp1, DestTy);
         // Return a new shuffle vector.  Use the same element ID's, as we
         // know the vector types match #elts.
-        return new ShuffleVectorInst(LHS, RHS, SVI->getOperand(2));
+        return new ShuffleVectorInst(LHS, RHS, Shuf->getOperand(2));
       }
     }
+
+    // A bitcasted-to-scalar and byte-reversing shuffle is better recognized as
+    // a byte-swap:
+    // bitcast <N x i8> (shuf X, undef, <N, N-1,...0>) --> bswap (bitcast X)
+    // TODO: We should match the related pattern for bitreverse.
+    if (DestTy->isIntegerTy() &&
+        DL.isLegalInteger(DestTy->getScalarSizeInBits()) &&
+        SrcTy->getScalarSizeInBits() == 8 && NumShufElts % 2 == 0 &&
+        Shuf->hasOneUse() && Shuf->isReverse()) {
+      assert(ShufOp0->getType() == SrcTy && "Unexpected shuffle mask");
+      assert(isa<UndefValue>(ShufOp1) && "Unexpected shuffle op");
+      Function *Bswap =
+          Intrinsic::getDeclaration(CI.getModule(), Intrinsic::bswap, DestTy);
+      Value *ScalarX = Builder.CreateBitCast(ShufOp0, DestTy);
+      return IntrinsicInst::Create(Bswap, { ScalarX });
+    }
   }
 
   // Handle the A->B->A cast, and there is an intervening PHI node.