vendor/llvm/llvm-trunk-r308421

5 files changed, 99 insertions, 80 deletions

diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 773c86e23707..fdc9c373b95e 100644
--- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1284,6 +1284,16 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
   if (Value *V = SimplifyBSwap(I, Builder))
     return replaceInstUsesWith(I, V);
 
+  if (match(Op1, m_One())) {
+    // (1 << x) & 1 --> zext(x == 0)
+    // (1 >> x) & 1 --> zext(x == 0)
+    Value *X;
+    if (match(Op0, m_OneUse(m_LogicalShift(m_One(), m_Value(X))))) {
+      Value *IsZero = Builder.CreateICmpEQ(X, ConstantInt::get(I.getType(), 0));
+      return new ZExtInst(IsZero, I.getType());
+    }
+  }
+
   if (ConstantInt *AndRHS = dyn_cast<ConstantInt>(Op1)) {
     const APInt &AndRHSMask = AndRHS->getValue();
 
@@ -1315,23 +1325,6 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
 
         break;
       }
-      case Instruction::Sub:
-        // -x & 1 -> x & 1
-        if (AndRHSMask.isOneValue() && match(Op0LHS, m_Zero()))
-          return BinaryOperator::CreateAnd(Op0RHS, AndRHS);
-
-        break;
-
-      case Instruction::Shl:
-      case Instruction::LShr:
-        // (1 << x) & 1 --> zext(x == 0)
-        // (1 >> x) & 1 --> zext(x == 0)
-        if (AndRHSMask.isOneValue() && Op0LHS == AndRHS) {
-          Value *NewICmp =
-            Builder.CreateICmpEQ(Op0RHS, Constant::getNullValue(I.getType()));
-          return new ZExtInst(NewICmp, I.getType());
-        }
-        break;
       }
 
       // ((C1 OP zext(X)) & C2) -> zext((C1-X) & C2) if C2 fits in the bitwidth
@@ -1417,12 +1410,6 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
       }
     }
 
-    // (A&((~A)|B)) -> A&B
-    if (match(Op0, m_c_Or(m_Not(m_Specific(Op1)), m_Value(A))))
-      return BinaryOperator::CreateAnd(A, Op1);
-    if (match(Op1, m_c_Or(m_Not(m_Specific(Op0)), m_Value(A))))
-      return BinaryOperator::CreateAnd(A, Op0);
-
     // (A ^ B) & ((B ^ C) ^ A) -> (A ^ B) & ~C
     if (match(Op0, m_Xor(m_Value(A), m_Value(B))))
       if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A))))
@@ -2020,18 +2007,6 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
 
   Value *A, *B;
 
-  // ((~A & B) | A) -> (A | B)
-  if (match(Op0, m_c_And(m_Not(m_Specific(Op1)), m_Value(A))))
-    return BinaryOperator::CreateOr(A, Op1);
-  if (match(Op1, m_c_And(m_Not(m_Specific(Op0)), m_Value(A))))
-    return BinaryOperator::CreateOr(Op0, A);
-
-  // ((A & B) | ~A) -> (~A | B)
-  // The NOT is guaranteed to be in the RHS by complexity ordering.
-  if (match(Op1, m_Not(m_Value(A))) &&
-      match(Op0, m_c_And(m_Specific(A), m_Value(B))))
-    return BinaryOperator::CreateOr(Op1, B);
-
   // (A & C)|(B & D)
   Value *C = nullptr, *D = nullptr;
   if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
@@ -2176,17 +2151,6 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
         return BinaryOperator::CreateOr(Not, Op0);
       }
 
-  // (A & B) | (~A ^ B) -> (~A ^ B)
-  // (A & B) | (B ^ ~A) -> (~A ^ B)
-  // (B & A) | (~A ^ B) -> (~A ^ B)
-  // (B & A) | (B ^ ~A) -> (~A ^ B)
-  // The match order is important: match the xor first because the 'not'
-  // operation defines 'A'. We do not need to match the xor as Op0 because the
-  // xor was canonicalized to Op1 above.
-  if (match(Op1, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
-      match(Op0, m_c_And(m_Specific(A), m_Specific(B))))
-    return BinaryOperator::CreateXor(Builder.CreateNot(A), B);
-
   if (SwappedForXor)
     std::swap(Op0, Op1);
 
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 60d1cde971dd..a8faaecb5c34 100644
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -1814,9 +1814,21 @@ Instruction *InstCombiner::foldICmpOrConstant(ICmpInst &Cmp, BinaryOperator *Or,
         Builder.CreateICmp(Pred, P, ConstantInt::getNullValue(P->getType()));
     Value *CmpQ =
         Builder.CreateICmp(Pred, Q, ConstantInt::getNullValue(Q->getType()));
-    auto LogicOpc = Pred == ICmpInst::Predicate::ICMP_EQ ? Instruction::And
-                                                         : Instruction::Or;
-    return BinaryOperator::Create(LogicOpc, CmpP, CmpQ);
+    auto BOpc = Pred == CmpInst::ICMP_EQ ? Instruction::And : Instruction::Or;
+    return BinaryOperator::Create(BOpc, CmpP, CmpQ);
+  }
+
+  // Are we using xors to bitwise check for a pair of (in)equalities? Convert to
+  // a shorter form that has more potential to be folded even further.
+  Value *X1, *X2, *X3, *X4;
+  if (match(Or->getOperand(0), m_OneUse(m_Xor(m_Value(X1), m_Value(X2)))) &&
+      match(Or->getOperand(1), m_OneUse(m_Xor(m_Value(X3), m_Value(X4))))) {
+    // ((X1 ^ X2) || (X3 ^ X4)) == 0 --> (X1 == X2) && (X3 == X4)
+    // ((X1 ^ X2) || (X3 ^ X4)) != 0 --> (X1 != X2) || (X3 != X4)
+    Value *Cmp12 = Builder.CreateICmp(Pred, X1, X2);
+    Value *Cmp34 = Builder.CreateICmp(Pred, X3, X4);
+    auto BOpc = Pred == CmpInst::ICMP_EQ ? Instruction::And : Instruction::Or;
+    return BinaryOperator::Create(BOpc, Cmp12, Cmp34);
   }
 
   return nullptr;
@@ -3737,6 +3749,11 @@ static Instruction *processUMulZExtIdiom(ICmpInst &I, Value *MulVal,
           const APInt &CVal = CI->getValue();
           if (CVal.getBitWidth() - CVal.countLeadingZeros() > MulWidth)
             return nullptr;
+        } else {
+          // In this case we could have the operand of the binary operation
+          // being defined in another block, and performing the replacement
+          // could break the dominance relation.
+          return nullptr;
         }
       } else {
         // Other uses prohibit this transformation.
@@ -3856,18 +3873,17 @@ static Instruction *processUMulZExtIdiom(ICmpInst &I, Value *MulVal,
       } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(U)) {
         assert(BO->getOpcode() == Instruction::And);
         // Replace (mul & mask) --> zext (mul.with.overflow & short_mask)
-        Value *ShortMask =
-            Builder.CreateTrunc(BO->getOperand(1), Builder.getIntNTy(MulWidth));
+        ConstantInt *CI = cast<ConstantInt>(BO->getOperand(1));
+        APInt ShortMask = CI->getValue().trunc(MulWidth);
         Value *ShortAnd = Builder.CreateAnd(Mul, ShortMask);
-        Value *Zext = Builder.CreateZExt(ShortAnd, BO->getType());
-        if (auto *ZextI = dyn_cast<Instruction>(Zext))
-          IC.Worklist.Add(ZextI);
+        Instruction *Zext =
+            cast<Instruction>(Builder.CreateZExt(ShortAnd, BO->getType()));
+        IC.Worklist.Add(Zext);
         IC.replaceInstUsesWith(*BO, Zext);
       } else {
         llvm_unreachable("Unexpected Binary operation");
       }
-      if (auto *UI = dyn_cast<Instruction>(U))
-        IC.Worklist.Add(UI);
+      IC.Worklist.Add(cast<Instruction>(U));
     }
   }
   if (isa<Instruction>(OtherVal))
diff --git a/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index c59e1ce69ac2..451036545741 100644
--- a/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -998,8 +998,9 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
     // that this code is not reachable.  We do this instead of inserting
     // an unreachable instruction directly because we cannot modify the
     // CFG.
-    new StoreInst(UndefValue::get(LI.getType()),
-                  Constant::getNullValue(Op->getType()), &LI);
+    StoreInst *SI = new StoreInst(UndefValue::get(LI.getType()),
+                                  Constant::getNullValue(Op->getType()), &LI);
+    SI->setDebugLoc(LI.getDebugLoc());
     return replaceInstUsesWith(LI, UndefValue::get(LI.getType()));
   }
 
diff --git a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 5689c0604239..a20f474cbf40 100644
--- a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -417,8 +417,10 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
       // the highest demanded bit, we just return the other side.
       if (DemandedFromOps.isSubsetOf(RHSKnown.Zero))
         return I->getOperand(0);
-      // We can't do this with the LHS for subtraction.
-      if (I->getOpcode() == Instruction::Add &&
+      // We can't do this with the LHS for subtraction, unless we are only
+      // demanding the LSB.
+      if ((I->getOpcode() == Instruction::Add ||
+           DemandedFromOps.isOneValue()) &&
           DemandedFromOps.isSubsetOf(LHSKnown.Zero))
         return I->getOperand(1);
     }
diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index 90e232399155..c7766568fd9d 100644
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -636,17 +636,35 @@ Value *InstCombiner::SimplifyUsingDistributiveLaws(BinaryOperator &I) {
     Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS;
     Instruction::BinaryOps InnerOpcode = Op0->getOpcode(); // op'
 
+    Value *L = SimplifyBinOp(TopLevelOpcode, A, C, SQ.getWithInstruction(&I));
+    Value *R = SimplifyBinOp(TopLevelOpcode, B, C, SQ.getWithInstruction(&I));
+
     // Do "A op C" and "B op C" both simplify?
-    if (Value *L =
-            SimplifyBinOp(TopLevelOpcode, A, C, SQ.getWithInstruction(&I)))
-      if (Value *R =
-              SimplifyBinOp(TopLevelOpcode, B, C, SQ.getWithInstruction(&I))) {
-        // They do! Return "L op' R".
-        ++NumExpand;
-        C = Builder.CreateBinOp(InnerOpcode, L, R);
-        C->takeName(&I);
-        return C;
-      }
+    if (L && R) {
+      // They do! Return "L op' R".
+      ++NumExpand;
+      C = Builder.CreateBinOp(InnerOpcode, L, R);
+      C->takeName(&I);
+      return C;
+    }
+
+    // Does "A op C" simplify to the identity value for the inner opcode?
+    if (L && L == ConstantExpr::getBinOpIdentity(InnerOpcode, L->getType())) {
+      // They do! Return "B op C".
+      ++NumExpand;
+      C = Builder.CreateBinOp(TopLevelOpcode, B, C);
+      C->takeName(&I);
+      return C;
+    }
+
+    // Does "B op C" simplify to the identity value for the inner opcode?
+    if (R && R == ConstantExpr::getBinOpIdentity(InnerOpcode, R->getType())) {
+      // They do! Return "A op C".
+      ++NumExpand;
+      C = Builder.CreateBinOp(TopLevelOpcode, A, C);
+      C->takeName(&I);
+      return C;
+    }
   }
 
   if (Op1 && LeftDistributesOverRight(TopLevelOpcode, Op1->getOpcode())) {
@@ -655,17 +673,35 @@ Value *InstCombiner::SimplifyUsingDistributiveLaws(BinaryOperator &I) {
     Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1);
     Instruction::BinaryOps InnerOpcode = Op1->getOpcode(); // op'
 
+    Value *L = SimplifyBinOp(TopLevelOpcode, A, B, SQ.getWithInstruction(&I));
+    Value *R = SimplifyBinOp(TopLevelOpcode, A, C, SQ.getWithInstruction(&I));
+
     // Do "A op B" and "A op C" both simplify?
-    if (Value *L =
-            SimplifyBinOp(TopLevelOpcode, A, B, SQ.getWithInstruction(&I)))
-      if (Value *R =
-              SimplifyBinOp(TopLevelOpcode, A, C, SQ.getWithInstruction(&I))) {
-        // They do! Return "L op' R".
-        ++NumExpand;
-        A = Builder.CreateBinOp(InnerOpcode, L, R);
-        A->takeName(&I);
-        return A;
-      }
+    if (L && R) {
+      // They do! Return "L op' R".
+      ++NumExpand;
+      A = Builder.CreateBinOp(InnerOpcode, L, R);
+      A->takeName(&I);
+      return A;
+    }
+
+    // Does "A op B" simplify to the identity value for the inner opcode?
+    if (L && L == ConstantExpr::getBinOpIdentity(InnerOpcode, L->getType())) {
+      // They do! Return "A op C".
+      ++NumExpand;
+      A = Builder.CreateBinOp(TopLevelOpcode, A, C);
+      A->takeName(&I);
+      return A;
+    }
+
+    // Does "A op C" simplify to the identity value for the inner opcode?
+    if (R && R == ConstantExpr::getBinOpIdentity(InnerOpcode, R->getType())) {
+      // They do! Return "A op B".
+      ++NumExpand;
+      A = Builder.CreateBinOp(TopLevelOpcode, A, B);
+      A->takeName(&I);
+      return A;
+    }
   }
 
   // (op (select (a, c, b)), (select (a, d, b))) -> (select (a, (op c, d), 0))