Refactor creation of overflow result tuples in InstCombineCalls.

Extract the creation of overflow result tuples in a separate function. NFC.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224006 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/InstCombine/InstCombine.h

@@ -331,6 +331,20 @@ public:
     return &I;
   }
 
+  /// Creates a result tuple for an overflow intrinsic \p II with a given
+  /// \p Result and a constant \p Overflow value. If \p ReUseName is true the
+  /// \p Result's name is taken from \p II.
+  Instruction *CreateOverflowTuple(IntrinsicInst *II, Value *Result,
+                                    bool Overflow, bool ReUseName = true) {
+    if (ReUseName)
+      Result->takeName(II);
+    Constant *V[] = { UndefValue::get(Result->getType()),
+                      Overflow ? Builder->getTrue() : Builder->getFalse() };
+    StructType *ST = cast<StructType>(II->getType());
+    Constant *Struct = ConstantStruct::get(ST, V);
+    return InsertValueInst::Create(Struct, Result, 0);
+  }
+        
   // EraseInstFromFunction - When dealing with an instruction that has side
   // effects or produces a void value, we can't rely on DCE to delete the
   // instruction.  Instead, visit methods should return the value returned by

lib/Transforms/InstCombine/InstCombineCalls.cpp

@@ -369,29 +369,14 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
       if (LHSKnownNegative && RHSKnownNegative) {
         // The sign bit is set in both cases: this MUST overflow.
         // Create a simple add instruction, and insert it into the struct.
-        Value *Add = Builder->CreateAdd(LHS, RHS);
+        return CreateOverflowTuple(II, Builder->CreateAdd(LHS, RHS), true,
-        Add->takeName(&CI);
+                                    /*ReUseName*/true);
-        Constant *V[] = {
-          UndefValue::get(LHS->getType()),
-          ConstantInt::getTrue(II->getContext())
-        };
-        StructType *ST = cast<StructType>(II->getType());
-        Constant *Struct = ConstantStruct::get(ST, V);
-        return InsertValueInst::Create(Struct, Add, 0);
       }
 
       if (LHSKnownPositive && RHSKnownPositive) {
         // The sign bit is clear in both cases: this CANNOT overflow.
         // Create a simple add instruction, and insert it into the struct.
-        Value *Add = Builder->CreateNUWAdd(LHS, RHS);
+        return CreateOverflowTuple(II, Builder->CreateNUWAdd(LHS, RHS), false);
-        Add->takeName(&CI);
-        Constant *V[] = {
-          UndefValue::get(LHS->getType()),
-          ConstantInt::getFalse(II->getContext())
-        };
-        StructType *ST = cast<StructType>(II->getType());
-        Constant *Struct = ConstantStruct::get(ST, V);
-        return InsertValueInst::Create(Struct, Add, 0);
       }
     }
   }
@@ -413,13 +398,8 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
     if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
       // X + 0 -> {X, false}
       if (RHS->isZero()) {
-        Constant *V[] = {
+        return CreateOverflowTuple(II, II->getArgOperand(0), false,
-          UndefValue::get(II->getArgOperand(0)->getType()),
+                                    /*ReUseName*/false);
-          ConstantInt::getFalse(II->getContext())
-        };
-        Constant *Struct =
-          ConstantStruct::get(cast<StructType>(II->getType()), V);
-        return InsertValueInst::Create(Struct, II->getArgOperand(0), 0);
       }
     }
 
@@ -428,37 +408,27 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
     if (II->getIntrinsicID() == Intrinsic::sadd_with_overflow) {
       Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1);
       if (WillNotOverflowSignedAdd(LHS, RHS, II)) {
-        Value *Add = Builder->CreateNSWAdd(LHS, RHS);
+        return CreateOverflowTuple(II, Builder->CreateNSWAdd(LHS, RHS), false);
-        Add->takeName(&CI);
-        Constant *V[] = {UndefValue::get(Add->getType()), Builder->getFalse()};
-        StructType *ST = cast<StructType>(II->getType());
-        Constant *Struct = ConstantStruct::get(ST, V);
-        return InsertValueInst::Create(Struct, Add, 0);
       }
     }
 
     break;
   case Intrinsic::usub_with_overflow:
-  case Intrinsic::ssub_with_overflow:
+  case Intrinsic::ssub_with_overflow: {
+    Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1);
     // undef - X -> undef
     // X - undef -> undef
-    if (isa<UndefValue>(II->getArgOperand(0)) ||
+    if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
-        isa<UndefValue>(II->getArgOperand(1)))
       return ReplaceInstUsesWith(CI, UndefValue::get(II->getType()));
 
-    if (ConstantInt *RHS = dyn_cast<ConstantInt>(II->getArgOperand(1))) {
+    if (ConstantInt *ConstRHS = dyn_cast<ConstantInt>(RHS)) {
       // X - 0 -> {X, false}
-      if (RHS->isZero()) {
+      if (ConstRHS->isZero()) {
-        Constant *V[] = {
+        return CreateOverflowTuple(II, LHS, false, /*ReUseName*/false);
-          UndefValue::get(II->getArgOperand(0)->getType()),
-          ConstantInt::getFalse(II->getContext())
-        };
-        Constant *Struct =
-          ConstantStruct::get(cast<StructType>(II->getType()), V);
-        return InsertValueInst::Create(Struct, II->getArgOperand(0), 0);
       }
     }
     break;
+  }
   case Intrinsic::umul_with_overflow: {
     Value *LHS = II->getArgOperand(0), *RHS = II->getArgOperand(1);
     unsigned BitWidth = cast<IntegerType>(LHS->getType())->getBitWidth();
@@ -479,13 +449,7 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
     bool Overflow;
     LHSMax.umul_ov(RHSMax, Overflow);
     if (!Overflow) {
-      Value *Mul = Builder->CreateNUWMul(LHS, RHS, "umul_with_overflow");
+      return CreateOverflowTuple(II, Builder->CreateNUWMul(LHS, RHS), false);
-      Constant *V[] = {
-        UndefValue::get(LHS->getType()),
-        Builder->getFalse()
-      };
-      Constant *Struct = ConstantStruct::get(cast<StructType>(II->getType()),V);
-      return InsertValueInst::Create(Struct, Mul, 0);
     }
   } // FALL THROUGH
   case Intrinsic::smul_with_overflow:
@@ -509,13 +473,8 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
 
       // X * 1 -> {X, false}
       if (RHSI->equalsInt(1)) {
-        Constant *V[] = {
+        return CreateOverflowTuple(II, II->getArgOperand(0), false,
-          UndefValue::get(II->getArgOperand(0)->getType()),
+                                    /*ReUseName*/false);
-          ConstantInt::getFalse(II->getContext())
-        };
-        Constant *Struct =
-          ConstantStruct::get(cast<StructType>(II->getType()), V);
-        return InsertValueInst::Create(Struct, II->getArgOperand(0), 0);
       }
     }
     break;