//===- InstructionCombining.cpp - Combine multiple instructions -----------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
//
// InstructionCombining - Combine instructions to form fewer, simple
// instructions. This pass does not modify the CFG This pass is where algebraic
//
// This is a simple worklist driven algorithm.
//
+// This pass guarantees that the following canonicalizations are performed on
+// the program:
+// 1. If a binary operator has a constant operand, it is moved to the RHS
+// 2. Bitwise operators with constant operands are always grouped so that
+// shifts are performed first, then or's, then and's, then xor's.
+// 3. SetCC instructions are converted from <,>,<=,>= to ==,!= if possible
+// 4. All SetCC instructions on boolean values are replaced with logical ops
+// 5. add X, X is represented as (X*2) => (X << 1)
+// 6. Multiplies with a power-of-two constant argument are transformed into
+// shifts.
+// N. This list is incomplete
+//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/ConstantHandling.h"
-#include "llvm/iMemory.h"
-#include "llvm/iOther.h"
-#include "llvm/iPHINode.h"
-#include "llvm/iOperators.h"
+#include "llvm/Instructions.h"
#include "llvm/Pass.h"
+#include "llvm/Constants.h"
+#include "llvm/ConstantHandling.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/GlobalVariable.h"
#include "llvm/Support/InstIterator.h"
#include "llvm/Support/InstVisitor.h"
+#include "llvm/Support/CallSite.h"
#include "Support/Statistic.h"
#include <algorithm>
virtual bool runOnFunction(Function &F);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.preservesCFG();
+ AU.setPreservesCFG();
}
// Visitation implementation - Implement instruction combining for different
Instruction *visitOr (BinaryOperator &I);
Instruction *visitXor(BinaryOperator &I);
Instruction *visitSetCondInst(BinaryOperator &I);
- Instruction *visitShiftInst(Instruction &I);
+ Instruction *visitShiftInst(ShiftInst &I);
Instruction *visitCastInst(CastInst &CI);
+ Instruction *visitCallInst(CallInst &CI);
+ Instruction *visitInvokeInst(InvokeInst &II);
Instruction *visitPHINode(PHINode &PN);
Instruction *visitGetElementPtrInst(GetElementPtrInst &GEP);
+ Instruction *visitAllocationInst(AllocationInst &AI);
+ Instruction *visitLoadInst(LoadInst &LI);
+ Instruction *visitBranchInst(BranchInst &BI);
// visitInstruction - Specify what to return for unhandled instructions...
Instruction *visitInstruction(Instruction &I) { return 0; }
+ private:
+ Instruction *visitCallSite(CallSite CS);
+ bool transformConstExprCastCall(CallSite CS);
+
// InsertNewInstBefore - insert an instruction New before instruction Old
// in the program. Add the new instruction to the worklist.
//
WorkList.push_back(New); // Add to worklist
}
+ public:
// ReplaceInstUsesWith - This method is to be used when an instruction is
// found to be dead, replacable with another preexisting expression. Here
// we add all uses of I to the worklist, replace all uses of I with the new
I.replaceAllUsesWith(V);
return &I;
}
+ private:
+ /// InsertOperandCastBefore - This inserts a cast of V to DestTy before the
+ /// InsertBefore instruction. This is specialized a bit to avoid inserting
+ /// casts that are known to not do anything...
+ ///
+ Value *InsertOperandCastBefore(Value *V, const Type *DestTy,
+ Instruction *InsertBefore);
+
+ // SimplifyCommutative - This performs a few simplifications for commutative
+ // operators...
+ bool SimplifyCommutative(BinaryOperator &I);
+
+ Instruction *OptAndOp(Instruction *Op, ConstantIntegral *OpRHS,
+ ConstantIntegral *AndRHS, BinaryOperator &TheAnd);
};
RegisterOpt<InstCombiner> X("instcombine", "Combine redundant instructions");
}
+// getComplexity: Assign a complexity or rank value to LLVM Values...
+// 0 -> Constant, 1 -> Other, 2 -> Argument, 2 -> Unary, 3 -> OtherInst
+static unsigned getComplexity(Value *V) {
+ if (isa<Instruction>(V)) {
+ if (BinaryOperator::isNeg(V) || BinaryOperator::isNot(V))
+ return 2;
+ return 3;
+ }
+ if (isa<Argument>(V)) return 2;
+ return isa<Constant>(V) ? 0 : 1;
+}
+
+// isOnlyUse - Return true if this instruction will be deleted if we stop using
+// it.
+static bool isOnlyUse(Value *V) {
+ return V->hasOneUse() || isa<Constant>(V);
+}
-// Make sure that this instruction has a constant on the right hand side if it
-// has any constant arguments. If not, fix it an return true.
+// SimplifyCommutative - This performs a few simplifications for commutative
+// operators:
//
-static bool SimplifyBinOp(BinaryOperator &I) {
- if (isa<Constant>(I.getOperand(0)) && !isa<Constant>(I.getOperand(1)))
- return !I.swapOperands();
- return false;
+// 1. Order operands such that they are listed from right (least complex) to
+// left (most complex). This puts constants before unary operators before
+// binary operators.
+//
+// 2. Transform: (op (op V, C1), C2) ==> (op V, (op C1, C2))
+// 3. Transform: (op (op V1, C1), (op V2, C2)) ==> (op (op V1, V2), (op C1,C2))
+//
+bool InstCombiner::SimplifyCommutative(BinaryOperator &I) {
+ bool Changed = false;
+ if (getComplexity(I.getOperand(0)) < getComplexity(I.getOperand(1)))
+ Changed = !I.swapOperands();
+
+ if (!I.isAssociative()) return Changed;
+ Instruction::BinaryOps Opcode = I.getOpcode();
+ if (BinaryOperator *Op = dyn_cast<BinaryOperator>(I.getOperand(0)))
+ if (Op->getOpcode() == Opcode && isa<Constant>(Op->getOperand(1))) {
+ if (isa<Constant>(I.getOperand(1))) {
+ Constant *Folded = ConstantExpr::get(I.getOpcode(),
+ cast<Constant>(I.getOperand(1)),
+ cast<Constant>(Op->getOperand(1)));
+ I.setOperand(0, Op->getOperand(0));
+ I.setOperand(1, Folded);
+ return true;
+ } else if (BinaryOperator *Op1=dyn_cast<BinaryOperator>(I.getOperand(1)))
+ if (Op1->getOpcode() == Opcode && isa<Constant>(Op1->getOperand(1)) &&
+ isOnlyUse(Op) && isOnlyUse(Op1)) {
+ Constant *C1 = cast<Constant>(Op->getOperand(1));
+ Constant *C2 = cast<Constant>(Op1->getOperand(1));
+
+ // Fold (op (op V1, C1), (op V2, C2)) ==> (op (op V1, V2), (op C1,C2))
+ Constant *Folded = ConstantExpr::get(I.getOpcode(), C1, C2);
+ Instruction *New = BinaryOperator::create(Opcode, Op->getOperand(0),
+ Op1->getOperand(0),
+ Op1->getName(), &I);
+ WorkList.push_back(New);
+ I.setOperand(0, New);
+ I.setOperand(1, Folded);
+ return true;
+ }
+ }
+ return Changed;
}
-// dyn_castNegInst - Given a 'sub' instruction, return the RHS of the
-// instruction if the LHS is a constant zero (which is the 'negate' form).
+// dyn_castNegVal - Given a 'sub' instruction, return the RHS of the instruction
+// if the LHS is a constant zero (which is the 'negate' form).
//
-static inline Value *dyn_castNegInst(Value *V) {
- Instruction *I = dyn_cast<Instruction>(V);
- if (!I || I->getOpcode() != Instruction::Sub) return 0;
+static inline Value *dyn_castNegVal(Value *V) {
+ if (BinaryOperator::isNeg(V))
+ return BinaryOperator::getNegArgument(cast<BinaryOperator>(V));
+
+ // Constants can be considered to be negated values if they can be folded...
+ if (Constant *C = dyn_cast<Constant>(V))
+ return ConstantExpr::get(Instruction::Sub,
+ Constant::getNullValue(V->getType()), C);
+ return 0;
+}
- if (I->getOperand(0) == Constant::getNullValue(I->getType()))
- return I->getOperand(1);
+static inline Value *dyn_castNotVal(Value *V) {
+ if (BinaryOperator::isNot(V))
+ return BinaryOperator::getNotArgument(cast<BinaryOperator>(V));
+
+ // Constants can be considered to be not'ed values...
+ if (ConstantIntegral *C = dyn_cast<ConstantIntegral>(V))
+ return ConstantExpr::get(Instruction::Xor,
+ ConstantIntegral::getAllOnesValue(C->getType()),C);
return 0;
}
-static inline Value *dyn_castNotInst(Value *V) {
- Instruction *I = dyn_cast<Instruction>(V);
- if (!I || I->getOpcode() != Instruction::Xor) return 0;
+// dyn_castFoldableMul - If this value is a multiply that can be folded into
+// other computations (because it has a constant operand), return the
+// non-constant operand of the multiply.
+//
+static inline Value *dyn_castFoldableMul(Value *V) {
+ if (V->hasOneUse() && V->getType()->isInteger())
+ if (Instruction *I = dyn_cast<Instruction>(V))
+ if (I->getOpcode() == Instruction::Mul)
+ if (isa<Constant>(I->getOperand(1)))
+ return I->getOperand(0);
+ return 0;
+}
+
+// dyn_castMaskingAnd - If this value is an And instruction masking a value with
+// a constant, return the constant being anded with.
+//
+template<class ValueType>
+static inline Constant *dyn_castMaskingAnd(ValueType *V) {
+ if (Instruction *I = dyn_cast<Instruction>(V))
+ if (I->getOpcode() == Instruction::And)
+ return dyn_cast<Constant>(I->getOperand(1));
+
+ // If this is a constant, it acts just like we were masking with it.
+ return dyn_cast<Constant>(V);
+}
+
+// Log2 - Calculate the log base 2 for the specified value if it is exactly a
+// power of 2.
+static unsigned Log2(uint64_t Val) {
+ assert(Val > 1 && "Values 0 and 1 should be handled elsewhere!");
+ unsigned Count = 0;
+ while (Val != 1) {
+ if (Val & 1) return 0; // Multiple bits set?
+ Val >>= 1;
+ ++Count;
+ }
+ return Count;
+}
+
- if (ConstantIntegral *CI = dyn_cast<ConstantIntegral>(I->getOperand(1)))
- if (CI->isAllOnesValue())
- return I->getOperand(0);
+/// AssociativeOpt - Perform an optimization on an associative operator. This
+/// function is designed to check a chain of associative operators for a
+/// potential to apply a certain optimization. Since the optimization may be
+/// applicable if the expression was reassociated, this checks the chain, then
+/// reassociates the expression as necessary to expose the optimization
+/// opportunity. This makes use of a special Functor, which must define
+/// 'shouldApply' and 'apply' methods.
+///
+template<typename Functor>
+Instruction *AssociativeOpt(BinaryOperator &Root, const Functor &F) {
+ unsigned Opcode = Root.getOpcode();
+ Value *LHS = Root.getOperand(0);
+
+ // Quick check, see if the immediate LHS matches...
+ if (F.shouldApply(LHS))
+ return F.apply(Root);
+
+ // Otherwise, if the LHS is not of the same opcode as the root, return.
+ Instruction *LHSI = dyn_cast<Instruction>(LHS);
+ while (LHSI && LHSI->getOpcode() == Opcode && LHSI->hasOneUse()) {
+ // Should we apply this transform to the RHS?
+ bool ShouldApply = F.shouldApply(LHSI->getOperand(1));
+
+ // If not to the RHS, check to see if we should apply to the LHS...
+ if (!ShouldApply && F.shouldApply(LHSI->getOperand(0))) {
+ cast<BinaryOperator>(LHSI)->swapOperands(); // Make the LHS the RHS
+ ShouldApply = true;
+ }
+
+ // If the functor wants to apply the optimization to the RHS of LHSI,
+ // reassociate the expression from ((? op A) op B) to (? op (A op B))
+ if (ShouldApply) {
+ BasicBlock *BB = Root.getParent();
+ // All of the instructions have a single use and have no side-effects,
+ // because of this, we can pull them all into the current basic block.
+ if (LHSI->getParent() != BB) {
+ // Move all of the instructions from root to LHSI into the current
+ // block.
+ Instruction *TmpLHSI = cast<Instruction>(Root.getOperand(0));
+ Instruction *LastUse = &Root;
+ while (TmpLHSI->getParent() == BB) {
+ LastUse = TmpLHSI;
+ TmpLHSI = cast<Instruction>(TmpLHSI->getOperand(0));
+ }
+
+ // Loop over all of the instructions in other blocks, moving them into
+ // the current one.
+ Value *TmpLHS = TmpLHSI;
+ do {
+ TmpLHSI = cast<Instruction>(TmpLHS);
+ // Remove from current block...
+ TmpLHSI->getParent()->getInstList().remove(TmpLHSI);
+ // Insert before the last instruction...
+ BB->getInstList().insert(LastUse, TmpLHSI);
+ TmpLHS = TmpLHSI->getOperand(0);
+ } while (TmpLHSI != LHSI);
+ }
+
+ // Now all of the instructions are in the current basic block, go ahead
+ // and perform the reassociation.
+ Instruction *TmpLHSI = cast<Instruction>(Root.getOperand(0));
+
+ // First move the selected RHS to the LHS of the root...
+ Root.setOperand(0, LHSI->getOperand(1));
+
+ // Make what used to be the LHS of the root be the user of the root...
+ Value *ExtraOperand = TmpLHSI->getOperand(1);
+ Root.replaceAllUsesWith(TmpLHSI); // Users now use TmpLHSI
+ TmpLHSI->setOperand(1, &Root); // TmpLHSI now uses the root
+ BB->getInstList().remove(&Root); // Remove root from the BB
+ BB->getInstList().insert(TmpLHSI, &Root); // Insert root before TmpLHSI
+
+ // Now propagate the ExtraOperand down the chain of instructions until we
+ // get to LHSI.
+ while (TmpLHSI != LHSI) {
+ Instruction *NextLHSI = cast<Instruction>(TmpLHSI->getOperand(0));
+ Value *NextOp = NextLHSI->getOperand(1);
+ NextLHSI->setOperand(1, ExtraOperand);
+ TmpLHSI = NextLHSI;
+ ExtraOperand = NextOp;
+ }
+
+ // Now that the instructions are reassociated, have the functor perform
+ // the transformation...
+ return F.apply(Root);
+ }
+
+ LHSI = dyn_cast<Instruction>(LHSI->getOperand(0));
+ }
return 0;
}
+
+// AddRHS - Implements: X + X --> X << 1
+struct AddRHS {
+ Value *RHS;
+ AddRHS(Value *rhs) : RHS(rhs) {}
+ bool shouldApply(Value *LHS) const { return LHS == RHS; }
+ Instruction *apply(BinaryOperator &Add) const {
+ return new ShiftInst(Instruction::Shl, Add.getOperand(0),
+ ConstantInt::get(Type::UByteTy, 1));
+ }
+};
+
+// AddMaskingAnd - Implements (A & C1)+(B & C2) --> (A & C1)|(B & C2)
+// iff C1&C2 == 0
+struct AddMaskingAnd {
+ Constant *C2;
+ AddMaskingAnd(Constant *c) : C2(c) {}
+ bool shouldApply(Value *LHS) const {
+ if (Constant *C1 = dyn_castMaskingAnd(LHS))
+ return ConstantExpr::get(Instruction::And, C1, C2)->isNullValue();
+ return false;
+ }
+ Instruction *apply(BinaryOperator &Add) const {
+ return BinaryOperator::create(Instruction::Or, Add.getOperand(0),
+ Add.getOperand(1));
+ }
+};
+
+
+
Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
- bool Changed = SimplifyBinOp(I);
+ bool Changed = SimplifyCommutative(I);
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
- // Eliminate 'add int %X, 0'
+ // X + 0 --> X
if (RHS == Constant::getNullValue(I.getType()))
return ReplaceInstUsesWith(I, LHS);
+ // X + X --> X << 1
+ if (I.getType()->isInteger())
+ if (Instruction *Result = AssociativeOpt(I, AddRHS(RHS))) return Result;
+
// -A + B --> B - A
- if (Value *V = dyn_castNegInst(LHS))
+ if (Value *V = dyn_castNegVal(LHS))
return BinaryOperator::create(Instruction::Sub, RHS, V);
// A + -B --> A - B
- if (Value *V = dyn_castNegInst(RHS))
- return BinaryOperator::create(Instruction::Sub, LHS, V);
-
- // Simplify add instructions with a constant RHS...
- if (Constant *Op2 = dyn_cast<Constant>(RHS)) {
- if (BinaryOperator *ILHS = dyn_cast<BinaryOperator>(LHS)) {
- if (ILHS->getOpcode() == Instruction::Add &&
- isa<Constant>(ILHS->getOperand(1))) {
- // Fold:
- // %Y = add int %X, 1
- // %Z = add int %Y, 1
- // into:
- // %Z = add int %X, 2
- //
- if (Constant *Val = *Op2 + *cast<Constant>(ILHS->getOperand(1))) {
- I.setOperand(0, ILHS->getOperand(0));
- I.setOperand(1, Val);
- return &I;
- }
+ if (!isa<Constant>(RHS))
+ if (Value *V = dyn_castNegVal(RHS))
+ return BinaryOperator::create(Instruction::Sub, LHS, V);
+
+ // X*C + X --> X * (C+1)
+ if (dyn_castFoldableMul(LHS) == RHS) {
+ Constant *CP1 =
+ ConstantExpr::get(Instruction::Add,
+ cast<Constant>(cast<Instruction>(LHS)->getOperand(1)),
+ ConstantInt::get(I.getType(), 1));
+ return BinaryOperator::create(Instruction::Mul, RHS, CP1);
+ }
+
+ // X + X*C --> X * (C+1)
+ if (dyn_castFoldableMul(RHS) == LHS) {
+ Constant *CP1 =
+ ConstantExpr::get(Instruction::Add,
+ cast<Constant>(cast<Instruction>(RHS)->getOperand(1)),
+ ConstantInt::get(I.getType(), 1));
+ return BinaryOperator::create(Instruction::Mul, LHS, CP1);
+ }
+
+ // (A & C1)+(B & C2) --> (A & C1)|(B & C2) iff C1&C2 == 0
+ if (Constant *C2 = dyn_castMaskingAnd(RHS))
+ if (Instruction *R = AssociativeOpt(I, AddMaskingAnd(C2))) return R;
+
+ if (ConstantInt *CRHS = dyn_cast<ConstantInt>(RHS)) {
+ if (Instruction *ILHS = dyn_cast<Instruction>(LHS)) {
+ switch (ILHS->getOpcode()) {
+ case Instruction::Xor:
+ // ~X + C --> (C-1) - X
+ if (ConstantInt *XorRHS = dyn_cast<ConstantInt>(ILHS->getOperand(1)))
+ if (XorRHS->isAllOnesValue())
+ return BinaryOperator::create(Instruction::Sub,
+ *CRHS - *ConstantInt::get(I.getType(), 1),
+ ILHS->getOperand(0));
+ break;
+ default: break;
}
}
}
return Changed ? &I : 0;
}
+// isSignBit - Return true if the value represented by the constant only has the
+// highest order bit set.
+static bool isSignBit(ConstantInt *CI) {
+ unsigned NumBits = CI->getType()->getPrimitiveSize()*8;
+ return (CI->getRawValue() & ~(-1LL << NumBits)) == (1ULL << (NumBits-1));
+}
+
+static unsigned getTypeSizeInBits(const Type *Ty) {
+ return Ty == Type::BoolTy ? 1 : Ty->getPrimitiveSize()*8;
+}
+
Instruction *InstCombiner::visitSub(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
if (Op0 == Op1) // sub X, X -> 0
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- // If this is a subtract instruction with a constant RHS, convert it to an add
- // instruction of a negative constant
- //
- if (Constant *Op2 = dyn_cast<Constant>(Op1))
- if (Constant *RHS = *Constant::getNullValue(I.getType()) - *Op2) // 0 - RHS
- return BinaryOperator::create(Instruction::Add, Op0, RHS, I.getName());
-
// If this is a 'B = x-(-A)', change to B = x+A...
- if (Value *V = dyn_castNegInst(Op1))
+ if (Value *V = dyn_castNegVal(Op1))
return BinaryOperator::create(Instruction::Add, Op0, V);
- // Replace (x - (y - z)) with (x + (z - y)) if the (y - z) subexpression is
- // not used by anyone else...
- //
+ // Replace (-1 - A) with (~A)...
+ if (ConstantInt *C = dyn_cast<ConstantInt>(Op0))
+ if (C->isAllOnesValue())
+ return BinaryOperator::createNot(Op1);
+
if (BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1))
- if (Op1I->use_size() == 1 && Op1I->getOpcode() == Instruction::Sub) {
- // Swap the two operands of the subexpr...
- Value *IIOp0 = Op1I->getOperand(0), *IIOp1 = Op1I->getOperand(1);
- Op1I->setOperand(0, IIOp1);
- Op1I->setOperand(1, IIOp0);
+ if (Op1I->hasOneUse()) {
+ // Replace (x - (y - z)) with (x + (z - y)) if the (y - z) subexpression
+ // is not used by anyone else...
+ //
+ if (Op1I->getOpcode() == Instruction::Sub) {
+ // Swap the two operands of the subexpr...
+ Value *IIOp0 = Op1I->getOperand(0), *IIOp1 = Op1I->getOperand(1);
+ Op1I->setOperand(0, IIOp1);
+ Op1I->setOperand(1, IIOp0);
+
+ // Create the new top level add instruction...
+ return BinaryOperator::create(Instruction::Add, Op0, Op1);
+ }
- // Create the new top level add instruction...
- return BinaryOperator::create(Instruction::Add, Op0, Op1);
+ // Replace (A - (A & B)) with (A & ~B) if this is the only use of (A&B)...
+ //
+ if (Op1I->getOpcode() == Instruction::And &&
+ (Op1I->getOperand(0) == Op0 || Op1I->getOperand(1) == Op0)) {
+ Value *OtherOp = Op1I->getOperand(Op1I->getOperand(0) == Op0);
+
+ Instruction *NewNot = BinaryOperator::createNot(OtherOp, "B.not", &I);
+ return BinaryOperator::create(Instruction::And, Op0, NewNot);
+ }
+
+ // X - X*C --> X * (1-C)
+ if (dyn_castFoldableMul(Op1I) == Op0) {
+ Constant *CP1 =
+ ConstantExpr::get(Instruction::Sub,
+ ConstantInt::get(I.getType(), 1),
+ cast<Constant>(cast<Instruction>(Op1)->getOperand(1)));
+ assert(CP1 && "Couldn't constant fold 1-C?");
+ return BinaryOperator::create(Instruction::Mul, Op0, CP1);
+ }
}
+
+ // X*C - X --> X * (C-1)
+ if (dyn_castFoldableMul(Op0) == Op1) {
+ Constant *CP1 =
+ ConstantExpr::get(Instruction::Sub,
+ cast<Constant>(cast<Instruction>(Op0)->getOperand(1)),
+ ConstantInt::get(I.getType(), 1));
+ assert(CP1 && "Couldn't constant fold C - 1?");
+ return BinaryOperator::create(Instruction::Mul, Op1, CP1);
+ }
+
return 0;
}
Instruction *InstCombiner::visitMul(BinaryOperator &I) {
- bool Changed = SimplifyBinOp(I);
- Value *Op1 = I.getOperand(0);
+ bool Changed = SimplifyCommutative(I);
+ Value *Op0 = I.getOperand(0);
// Simplify mul instructions with a constant RHS...
- if (Constant *Op2 = dyn_cast<Constant>(I.getOperand(1))) {
- if (I.getType()->isInteger() && cast<ConstantInt>(Op2)->equalsInt(1))
- return ReplaceInstUsesWith(I, Op1); // Eliminate 'mul int %X, 1'
-
- if (I.getType()->isInteger() && cast<ConstantInt>(Op2)->equalsInt(2))
- // Convert 'mul int %X, 2' to 'add int %X, %X'
- return BinaryOperator::create(Instruction::Add, Op1, Op1, I.getName());
-
- if (Op2->isNullValue())
- return ReplaceInstUsesWith(I, Op2); // Eliminate 'mul int %X, 0'
+ if (Constant *Op1 = dyn_cast<Constant>(I.getOperand(1))) {
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
+
+ // ((X << C1)*C2) == (X * (C2 << C1))
+ if (ShiftInst *SI = dyn_cast<ShiftInst>(Op0))
+ if (SI->getOpcode() == Instruction::Shl)
+ if (Constant *ShOp = dyn_cast<Constant>(SI->getOperand(1)))
+ return BinaryOperator::create(Instruction::Mul, SI->getOperand(0),
+ *CI << *ShOp);
+
+ if (CI->isNullValue())
+ return ReplaceInstUsesWith(I, Op1); // X * 0 == 0
+ if (CI->equalsInt(1)) // X * 1 == X
+ return ReplaceInstUsesWith(I, Op0);
+ if (CI->isAllOnesValue()) // X * -1 == 0 - X
+ return BinaryOperator::createNeg(Op0, I.getName());
+
+ int64_t Val = (int64_t)cast<ConstantInt>(CI)->getRawValue();
+ if (uint64_t C = Log2(Val)) // Replace X*(2^C) with X << C
+ return new ShiftInst(Instruction::Shl, Op0,
+ ConstantUInt::get(Type::UByteTy, C));
+ } else {
+ ConstantFP *Op1F = cast<ConstantFP>(Op1);
+ if (Op1F->isNullValue())
+ return ReplaceInstUsesWith(I, Op1);
+
+ // "In IEEE floating point, x*1 is not equivalent to x for nans. However,
+ // ANSI says we can drop signals, so we can do this anyway." (from GCC)
+ if (Op1F->getValue() == 1.0)
+ return ReplaceInstUsesWith(I, Op0); // Eliminate 'mul double %X, 1.0'
+ }
}
+ if (Value *Op0v = dyn_castNegVal(Op0)) // -X * -Y = X*Y
+ if (Value *Op1v = dyn_castNegVal(I.getOperand(1)))
+ return BinaryOperator::create(Instruction::Mul, Op0v, Op1v);
+
return Changed ? &I : 0;
}
-
Instruction *InstCombiner::visitDiv(BinaryOperator &I) {
// div X, 1 == X
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(I.getOperand(1)))
+ if (ConstantInt *RHS = dyn_cast<ConstantInt>(I.getOperand(1))) {
if (RHS->equalsInt(1))
return ReplaceInstUsesWith(I, I.getOperand(0));
+
+ // Check to see if this is an unsigned division with an exact power of 2,
+ // if so, convert to a right shift.
+ if (ConstantUInt *C = dyn_cast<ConstantUInt>(RHS))
+ if (uint64_t Val = C->getValue()) // Don't break X / 0
+ if (uint64_t C = Log2(Val))
+ return new ShiftInst(Instruction::Shr, I.getOperand(0),
+ ConstantUInt::get(Type::UByteTy, C));
+ }
+
+ // 0 / X == 0, we don't need to preserve faults!
+ if (ConstantInt *LHS = dyn_cast<ConstantInt>(I.getOperand(0)))
+ if (LHS->equalsInt(0))
+ return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
+
return 0;
}
Instruction *InstCombiner::visitRem(BinaryOperator &I) {
- // rem X, 1 == 0
- if (ConstantInt *RHS = dyn_cast<ConstantInt>(I.getOperand(1)))
- if (RHS->equalsInt(1))
+ if (ConstantInt *RHS = dyn_cast<ConstantInt>(I.getOperand(1))) {
+ if (RHS->equalsInt(1)) // X % 1 == 0
+ return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
+
+ // Check to see if this is an unsigned remainder with an exact power of 2,
+ // if so, convert to a bitwise and.
+ if (ConstantUInt *C = dyn_cast<ConstantUInt>(RHS))
+ if (uint64_t Val = C->getValue()) // Don't break X % 0 (divide by zero)
+ if (Log2(Val))
+ return BinaryOperator::create(Instruction::And, I.getOperand(0),
+ ConstantUInt::get(I.getType(), Val-1));
+ }
+
+ // 0 % X == 0, we don't need to preserve faults!
+ if (ConstantInt *LHS = dyn_cast<ConstantInt>(I.getOperand(0)))
+ if (LHS->equalsInt(0))
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
return 0;
return CS->getValue() == Val+1;
}
+/// getSetCondCode - Encode a setcc opcode into a three bit mask. These bits
+/// are carefully arranged to allow folding of expressions such as:
+///
+/// (A < B) | (A > B) --> (A != B)
+///
+/// Bit value '4' represents that the comparison is true if A > B, bit value '2'
+/// represents that the comparison is true if A == B, and bit value '1' is true
+/// if A < B.
+///
+static unsigned getSetCondCode(const SetCondInst *SCI) {
+ switch (SCI->getOpcode()) {
+ // False -> 0
+ case Instruction::SetGT: return 1;
+ case Instruction::SetEQ: return 2;
+ case Instruction::SetGE: return 3;
+ case Instruction::SetLT: return 4;
+ case Instruction::SetNE: return 5;
+ case Instruction::SetLE: return 6;
+ // True -> 7
+ default:
+ assert(0 && "Invalid SetCC opcode!");
+ return 0;
+ }
+}
+
+/// getSetCCValue - This is the complement of getSetCondCode, which turns an
+/// opcode and two operands into either a constant true or false, or a brand new
+/// SetCC instruction.
+static Value *getSetCCValue(unsigned Opcode, Value *LHS, Value *RHS) {
+ switch (Opcode) {
+ case 0: return ConstantBool::False;
+ case 1: return new SetCondInst(Instruction::SetGT, LHS, RHS);
+ case 2: return new SetCondInst(Instruction::SetEQ, LHS, RHS);
+ case 3: return new SetCondInst(Instruction::SetGE, LHS, RHS);
+ case 4: return new SetCondInst(Instruction::SetLT, LHS, RHS);
+ case 5: return new SetCondInst(Instruction::SetNE, LHS, RHS);
+ case 6: return new SetCondInst(Instruction::SetLE, LHS, RHS);
+ case 7: return ConstantBool::True;
+ default: assert(0 && "Illegal SetCCCode!"); return 0;
+ }
+}
+
+// FoldSetCCLogical - Implements (setcc1 A, B) & (setcc2 A, B) --> (setcc3 A, B)
+struct FoldSetCCLogical {
+ InstCombiner &IC;
+ Value *LHS, *RHS;
+ FoldSetCCLogical(InstCombiner &ic, SetCondInst *SCI)
+ : IC(ic), LHS(SCI->getOperand(0)), RHS(SCI->getOperand(1)) {}
+ bool shouldApply(Value *V) const {
+ if (SetCondInst *SCI = dyn_cast<SetCondInst>(V))
+ return (SCI->getOperand(0) == LHS && SCI->getOperand(1) == RHS ||
+ SCI->getOperand(0) == RHS && SCI->getOperand(1) == LHS);
+ return false;
+ }
+ Instruction *apply(BinaryOperator &Log) const {
+ SetCondInst *SCI = cast<SetCondInst>(Log.getOperand(0));
+ if (SCI->getOperand(0) != LHS) {
+ assert(SCI->getOperand(1) == LHS);
+ SCI->swapOperands(); // Swap the LHS and RHS of the SetCC
+ }
+
+ unsigned LHSCode = getSetCondCode(SCI);
+ unsigned RHSCode = getSetCondCode(cast<SetCondInst>(Log.getOperand(1)));
+ unsigned Code;
+ switch (Log.getOpcode()) {
+ case Instruction::And: Code = LHSCode & RHSCode; break;
+ case Instruction::Or: Code = LHSCode | RHSCode; break;
+ case Instruction::Xor: Code = LHSCode ^ RHSCode; break;
+ default: assert(0 && "Illegal logical opcode!"); return 0;
+ }
+
+ Value *RV = getSetCCValue(Code, LHS, RHS);
+ if (Instruction *I = dyn_cast<Instruction>(RV))
+ return I;
+ // Otherwise, it's a constant boolean value...
+ return IC.ReplaceInstUsesWith(Log, RV);
+ }
+};
+
+
+// OptAndOp - This handles expressions of the form ((val OP C1) & C2). Where
+// the Op parameter is 'OP', OpRHS is 'C1', and AndRHS is 'C2'. Op is
+// guaranteed to be either a shift instruction or a binary operator.
+Instruction *InstCombiner::OptAndOp(Instruction *Op,
+ ConstantIntegral *OpRHS,
+ ConstantIntegral *AndRHS,
+ BinaryOperator &TheAnd) {
+ Value *X = Op->getOperand(0);
+ switch (Op->getOpcode()) {
+ case Instruction::Xor:
+ if ((*AndRHS & *OpRHS)->isNullValue()) {
+ // (X ^ C1) & C2 --> (X & C2) iff (C1&C2) == 0
+ return BinaryOperator::create(Instruction::And, X, AndRHS);
+ } else if (Op->hasOneUse()) {
+ // (X ^ C1) & C2 --> (X & C2) ^ (C1&C2)
+ std::string OpName = Op->getName(); Op->setName("");
+ Instruction *And = BinaryOperator::create(Instruction::And,
+ X, AndRHS, OpName);
+ InsertNewInstBefore(And, TheAnd);
+ return BinaryOperator::create(Instruction::Xor, And, *AndRHS & *OpRHS);
+ }
+ break;
+ case Instruction::Or:
+ // (X | C1) & C2 --> X & C2 iff C1 & C1 == 0
+ if ((*AndRHS & *OpRHS)->isNullValue())
+ return BinaryOperator::create(Instruction::And, X, AndRHS);
+ else {
+ Constant *Together = *AndRHS & *OpRHS;
+ if (Together == AndRHS) // (X | C) & C --> C
+ return ReplaceInstUsesWith(TheAnd, AndRHS);
+
+ if (Op->hasOneUse() && Together != OpRHS) {
+ // (X | C1) & C2 --> (X | (C1&C2)) & C2
+ std::string Op0Name = Op->getName(); Op->setName("");
+ Instruction *Or = BinaryOperator::create(Instruction::Or, X,
+ Together, Op0Name);
+ InsertNewInstBefore(Or, TheAnd);
+ return BinaryOperator::create(Instruction::And, Or, AndRHS);
+ }
+ }
+ break;
+ case Instruction::Add:
+ if (Op->hasOneUse()) {
+ // Adding a one to a single bit bit-field should be turned into an XOR
+ // of the bit. First thing to check is to see if this AND is with a
+ // single bit constant.
+ unsigned long long AndRHSV = cast<ConstantInt>(AndRHS)->getRawValue();
+
+ // Clear bits that are not part of the constant.
+ AndRHSV &= (1ULL << AndRHS->getType()->getPrimitiveSize()*8)-1;
+
+ // If there is only one bit set...
+ if ((AndRHSV & (AndRHSV-1)) == 0) {
+ // Ok, at this point, we know that we are masking the result of the
+ // ADD down to exactly one bit. If the constant we are adding has
+ // no bits set below this bit, then we can eliminate the ADD.
+ unsigned long long AddRHS = cast<ConstantInt>(OpRHS)->getRawValue();
+
+ // Check to see if any bits below the one bit set in AndRHSV are set.
+ if ((AddRHS & (AndRHSV-1)) == 0) {
+ // If not, the only thing that can effect the output of the AND is
+ // the bit specified by AndRHSV. If that bit is set, the effect of
+ // the XOR is to toggle the bit. If it is clear, then the ADD has
+ // no effect.
+ if ((AddRHS & AndRHSV) == 0) { // Bit is not set, noop
+ TheAnd.setOperand(0, X);
+ return &TheAnd;
+ } else {
+ std::string Name = Op->getName(); Op->setName("");
+ // Pull the XOR out of the AND.
+ Instruction *NewAnd =
+ BinaryOperator::create(Instruction::And, X, AndRHS, Name);
+ InsertNewInstBefore(NewAnd, TheAnd);
+ return BinaryOperator::create(Instruction::Xor, NewAnd, AndRHS);
+ }
+ }
+ }
+ }
+ break;
+
+ case Instruction::Shl: {
+ // We know that the AND will not produce any of the bits shifted in, so if
+ // the anded constant includes them, clear them now!
+ //
+ Constant *AllOne = ConstantIntegral::getAllOnesValue(AndRHS->getType());
+ Constant *CI = *AndRHS & *(*AllOne << *OpRHS);
+ if (CI != AndRHS) {
+ TheAnd.setOperand(1, CI);
+ return &TheAnd;
+ }
+ break;
+ }
+ case Instruction::Shr:
+ // We know that the AND will not produce any of the bits shifted in, so if
+ // the anded constant includes them, clear them now! This only applies to
+ // unsigned shifts, because a signed shr may bring in set bits!
+ //
+ if (AndRHS->getType()->isUnsigned()) {
+ Constant *AllOne = ConstantIntegral::getAllOnesValue(AndRHS->getType());
+ Constant *CI = *AndRHS & *(*AllOne >> *OpRHS);
+ if (CI != AndRHS) {
+ TheAnd.setOperand(1, CI);
+ return &TheAnd;
+ }
+ }
+ break;
+ }
+ return 0;
+}
+
Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
- bool Changed = SimplifyBinOp(I);
+ bool Changed = SimplifyCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
// and X, X = X and X, 0 == 0
return ReplaceInstUsesWith(I, Op1);
// and X, -1 == X
- if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1))
+ if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1)) {
if (RHS->isAllOnesValue())
return ReplaceInstUsesWith(I, Op0);
- // and (not A), (not B) == not (or A, B)
- if (Op0->use_size() == 1 && Op1->use_size() == 1)
- if (Value *A = dyn_castNotInst(Op0))
- if (Value *B = dyn_castNotInst(Op1)) {
- Instruction *Or = BinaryOperator::create(Instruction::Or, A, B,
- I.getName()+".demorgan");
- InsertNewInstBefore(Or, I);
- return BinaryOperator::createNot(Or, I.getName());
- }
+ // Optimize a variety of ((val OP C1) & C2) combinations...
+ if (isa<BinaryOperator>(Op0) || isa<ShiftInst>(Op0)) {
+ Instruction *Op0I = cast<Instruction>(Op0);
+ Value *X = Op0I->getOperand(0);
+ if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1)))
+ if (Instruction *Res = OptAndOp(Op0I, Op0CI, RHS, I))
+ return Res;
+ }
+ }
+
+ Value *Op0NotVal = dyn_castNotVal(Op0);
+ Value *Op1NotVal = dyn_castNotVal(Op1);
+
+ // (~A & ~B) == (~(A | B)) - Demorgan's Law
+ if (Op0NotVal && Op1NotVal && isOnlyUse(Op0) && isOnlyUse(Op1)) {
+ Instruction *Or = BinaryOperator::create(Instruction::Or, Op0NotVal,
+ Op1NotVal,I.getName()+".demorgan");
+ InsertNewInstBefore(Or, I);
+ return BinaryOperator::createNot(Or);
+ }
+
+ if (Op0NotVal == Op1 || Op1NotVal == Op0) // A & ~A == ~A & A == 0
+ return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
+
+ // (setcc1 A, B) & (setcc2 A, B) --> (setcc3 A, B)
+ if (SetCondInst *RHS = dyn_cast<SetCondInst>(I.getOperand(1)))
+ if (Instruction *R = AssociativeOpt(I, FoldSetCCLogical(*this, RHS)))
+ return R;
return Changed ? &I : 0;
}
Instruction *InstCombiner::visitOr(BinaryOperator &I) {
- bool Changed = SimplifyBinOp(I);
+ bool Changed = SimplifyCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
// or X, X = X or X, 0 == X
return ReplaceInstUsesWith(I, Op0);
// or X, -1 == -1
- if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1))
+ if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1)) {
if (RHS->isAllOnesValue())
return ReplaceInstUsesWith(I, Op1);
+ if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) {
+ // (X & C1) | C2 --> (X | C2) & (C1|C2)
+ if (Op0I->getOpcode() == Instruction::And && isOnlyUse(Op0))
+ if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
+ std::string Op0Name = Op0I->getName(); Op0I->setName("");
+ Instruction *Or = BinaryOperator::create(Instruction::Or,
+ Op0I->getOperand(0), RHS,
+ Op0Name);
+ InsertNewInstBefore(Or, I);
+ return BinaryOperator::create(Instruction::And, Or, *RHS | *Op0CI);
+ }
+
+ // (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2)
+ if (Op0I->getOpcode() == Instruction::Xor && isOnlyUse(Op0))
+ if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
+ std::string Op0Name = Op0I->getName(); Op0I->setName("");
+ Instruction *Or = BinaryOperator::create(Instruction::Or,
+ Op0I->getOperand(0), RHS,
+ Op0Name);
+ InsertNewInstBefore(Or, I);
+ return BinaryOperator::create(Instruction::Xor, Or, *Op0CI & *~*RHS);
+ }
+ }
+ }
+
+ // (A & C1)|(A & C2) == A & (C1|C2)
+ if (Instruction *LHS = dyn_cast<BinaryOperator>(Op0))
+ if (Instruction *RHS = dyn_cast<BinaryOperator>(Op1))
+ if (LHS->getOperand(0) == RHS->getOperand(0))
+ if (Constant *C0 = dyn_castMaskingAnd(LHS))
+ if (Constant *C1 = dyn_castMaskingAnd(RHS))
+ return BinaryOperator::create(Instruction::And, LHS->getOperand(0),
+ *C0 | *C1);
+
+ Value *Op0NotVal = dyn_castNotVal(Op0);
+ Value *Op1NotVal = dyn_castNotVal(Op1);
+
+ if (Op1 == Op0NotVal) // ~A | A == -1
+ return ReplaceInstUsesWith(I,
+ ConstantIntegral::getAllOnesValue(I.getType()));
+
+ if (Op0 == Op1NotVal) // A | ~A == -1
+ return ReplaceInstUsesWith(I,
+ ConstantIntegral::getAllOnesValue(I.getType()));
+
+ // (~A | ~B) == (~(A & B)) - Demorgan's Law
+ if (Op0NotVal && Op1NotVal && isOnlyUse(Op0) && isOnlyUse(Op1)) {
+ Instruction *And = BinaryOperator::create(Instruction::And, Op0NotVal,
+ Op1NotVal,I.getName()+".demorgan",
+ &I);
+ WorkList.push_back(And);
+ return BinaryOperator::createNot(And);
+ }
+
+ // (setcc1 A, B) | (setcc2 A, B) --> (setcc3 A, B)
+ if (SetCondInst *RHS = dyn_cast<SetCondInst>(I.getOperand(1)))
+ if (Instruction *R = AssociativeOpt(I, FoldSetCCLogical(*this, RHS)))
+ return R;
+
return Changed ? &I : 0;
}
Instruction *InstCombiner::visitXor(BinaryOperator &I) {
- bool Changed = SimplifyBinOp(I);
+ bool Changed = SimplifyCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
// xor X, X = 0
if (Op0 == Op1)
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- if (ConstantIntegral *Op1C = dyn_cast<ConstantIntegral>(Op1)) {
+ if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1)) {
// xor X, 0 == X
- if (Op1C->isNullValue())
+ if (RHS->isNullValue())
return ReplaceInstUsesWith(I, Op0);
- // Is this a "NOT" instruction?
- if (Op1C->isAllOnesValue()) {
- // xor (xor X, -1), -1 = not (not X) = X
- if (Value *X = dyn_castNotInst(Op0))
- return ReplaceInstUsesWith(I, X);
-
+ if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
// xor (setcc A, B), true = not (setcc A, B) = setncc A, B
- if (SetCondInst *SCI = dyn_cast<SetCondInst>(Op0))
- if (SCI->use_size() == 1)
+ if (SetCondInst *SCI = dyn_cast<SetCondInst>(Op0I))
+ if (RHS == ConstantBool::True && SCI->hasOneUse())
return new SetCondInst(SCI->getInverseCondition(),
SCI->getOperand(0), SCI->getOperand(1));
+
+ if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1)))
+ if (Op0I->getOpcode() == Instruction::And) {
+ // (X & C1) ^ C2 --> (X & C1) | C2 iff (C1&C2) == 0
+ if ((*RHS & *Op0CI)->isNullValue())
+ return BinaryOperator::create(Instruction::Or, Op0, RHS);
+ } else if (Op0I->getOpcode() == Instruction::Or) {
+ // (X | C1) ^ C2 --> (X | C1) & ~C2 iff (C1&C2) == C2
+ if ((*RHS & *Op0CI) == RHS)
+ return BinaryOperator::create(Instruction::And, Op0, ~*RHS);
+ }
}
}
+ if (Value *X = dyn_castNotVal(Op0)) // ~A ^ A == -1
+ if (X == Op1)
+ return ReplaceInstUsesWith(I,
+ ConstantIntegral::getAllOnesValue(I.getType()));
+
+ if (Value *X = dyn_castNotVal(Op1)) // A ^ ~A == -1
+ if (X == Op0)
+ return ReplaceInstUsesWith(I,
+ ConstantIntegral::getAllOnesValue(I.getType()));
+
+ if (Instruction *Op1I = dyn_cast<Instruction>(Op1))
+ if (Op1I->getOpcode() == Instruction::Or)
+ if (Op1I->getOperand(0) == Op0) { // B^(B|A) == (A|B)^B
+ cast<BinaryOperator>(Op1I)->swapOperands();
+ I.swapOperands();
+ std::swap(Op0, Op1);
+ } else if (Op1I->getOperand(1) == Op0) { // B^(A|B) == (A|B)^B
+ I.swapOperands();
+ std::swap(Op0, Op1);
+ }
+
+ if (Instruction *Op0I = dyn_cast<Instruction>(Op0))
+ if (Op0I->getOpcode() == Instruction::Or && Op0I->hasOneUse()) {
+ if (Op0I->getOperand(0) == Op1) // (B|A)^B == (A|B)^B
+ cast<BinaryOperator>(Op0I)->swapOperands();
+ if (Op0I->getOperand(1) == Op1) { // (A|B)^B == A & ~B
+ Value *NotB = BinaryOperator::createNot(Op1, Op1->getName()+".not", &I);
+ WorkList.push_back(cast<Instruction>(NotB));
+ return BinaryOperator::create(Instruction::And, Op0I->getOperand(0),
+ NotB);
+ }
+ }
+
+ // (A & C1)^(B & C2) -> (A & C1)|(B & C2) iff C1^C2 == 0
+ if (Constant *C1 = dyn_castMaskingAnd(Op0))
+ if (Constant *C2 = dyn_castMaskingAnd(Op1))
+ if (ConstantExpr::get(Instruction::And, C1, C2)->isNullValue())
+ return BinaryOperator::create(Instruction::Or, Op0, Op1);
+
+ // (setcc1 A, B) ^ (setcc2 A, B) --> (setcc3 A, B)
+ if (SetCondInst *RHS = dyn_cast<SetCondInst>(I.getOperand(1)))
+ if (Instruction *R = AssociativeOpt(I, FoldSetCCLogical(*this, RHS)))
+ return R;
+
return Changed ? &I : 0;
}
// AddOne, SubOne - Add or subtract a constant one from an integer constant...
static Constant *AddOne(ConstantInt *C) {
- Constant *Result = *C + *ConstantInt::get(C->getType(), 1);
+ Constant *Result = ConstantExpr::get(Instruction::Add, C,
+ ConstantInt::get(C->getType(), 1));
assert(Result && "Constant folding integer addition failed!");
return Result;
}
static Constant *SubOne(ConstantInt *C) {
- Constant *Result = *C - *ConstantInt::get(C->getType(), 1);
+ Constant *Result = ConstantExpr::get(Instruction::Sub, C,
+ ConstantInt::get(C->getType(), 1));
assert(Result && "Constant folding integer addition failed!");
return Result;
}
}
Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) {
- bool Changed = SimplifyBinOp(I);
+ bool Changed = SimplifyCommutative(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
const Type *Ty = Op0->getType();
if (Op0 == Op1)
return ReplaceInstUsesWith(I, ConstantBool::get(isTrueWhenEqual(I)));
- // setcc <global*>, 0 - Global value addresses are never null!
- if (isa<GlobalValue>(Op0) && isa<ConstantPointerNull>(Op1))
+ // setcc <global/alloca*>, 0 - Global/Stack value addresses are never null!
+ if (isa<ConstantPointerNull>(Op1) &&
+ (isa<GlobalValue>(Op0) || isa<AllocaInst>(Op0)))
return ReplaceInstUsesWith(I, ConstantBool::get(!isTrueWhenEqual(I)));
+
// setcc's with boolean values can always be turned into bitwise operations
if (Ty == Type::BoolTy) {
// If this is <, >, or !=, we can change this into a simple xor instruction
// integers at the end of their ranges...
//
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
+ // Simplify seteq and setne instructions...
+ if (I.getOpcode() == Instruction::SetEQ ||
+ I.getOpcode() == Instruction::SetNE) {
+ bool isSetNE = I.getOpcode() == Instruction::SetNE;
+
+ // If the first operand is (and|or|xor) with a constant, and the second
+ // operand is a constant, simplify a bit.
+ if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0)) {
+ switch (BO->getOpcode()) {
+ case Instruction::Add:
+ if (CI->isNullValue()) {
+ // Replace ((add A, B) != 0) with (A != -B) if A or B is
+ // efficiently invertible, or if the add has just this one use.
+ Value *BOp0 = BO->getOperand(0), *BOp1 = BO->getOperand(1);
+ if (Value *NegVal = dyn_castNegVal(BOp1))
+ return new SetCondInst(I.getOpcode(), BOp0, NegVal);
+ else if (Value *NegVal = dyn_castNegVal(BOp0))
+ return new SetCondInst(I.getOpcode(), NegVal, BOp1);
+ else if (BO->hasOneUse()) {
+ Instruction *Neg = BinaryOperator::createNeg(BOp1, BO->getName());
+ BO->setName("");
+ InsertNewInstBefore(Neg, I);
+ return new SetCondInst(I.getOpcode(), BOp0, Neg);
+ }
+ }
+ break;
+ case Instruction::Xor:
+ // For the xor case, we can xor two constants together, eliminating
+ // the explicit xor.
+ if (Constant *BOC = dyn_cast<Constant>(BO->getOperand(1)))
+ return BinaryOperator::create(I.getOpcode(), BO->getOperand(0),
+ *CI ^ *BOC);
+
+ // FALLTHROUGH
+ case Instruction::Sub:
+ // Replace (([sub|xor] A, B) != 0) with (A != B)
+ if (CI->isNullValue())
+ return new SetCondInst(I.getOpcode(), BO->getOperand(0),
+ BO->getOperand(1));
+ break;
+
+ case Instruction::Or:
+ // If bits are being or'd in that are not present in the constant we
+ // are comparing against, then the comparison could never succeed!
+ if (Constant *BOC = dyn_cast<Constant>(BO->getOperand(1)))
+ if (!(*BOC & *~*CI)->isNullValue())
+ return ReplaceInstUsesWith(I, ConstantBool::get(isSetNE));
+ break;
+
+ case Instruction::And:
+ if (ConstantInt *BOC = dyn_cast<ConstantInt>(BO->getOperand(1))) {
+ // If bits are being compared against that are and'd out, then the
+ // comparison can never succeed!
+ if (!(*CI & *~*BOC)->isNullValue())
+ return ReplaceInstUsesWith(I, ConstantBool::get(isSetNE));
+
+ // Replace (and X, (1 << size(X)-1) != 0) with x < 0, converting X
+ // to be a signed value as appropriate.
+ if (isSignBit(BOC)) {
+ Value *X = BO->getOperand(0);
+ // If 'X' is not signed, insert a cast now...
+ if (!BOC->getType()->isSigned()) {
+ const Type *DestTy;
+ switch (BOC->getType()->getPrimitiveID()) {
+ case Type::UByteTyID: DestTy = Type::SByteTy; break;
+ case Type::UShortTyID: DestTy = Type::ShortTy; break;
+ case Type::UIntTyID: DestTy = Type::IntTy; break;
+ case Type::ULongTyID: DestTy = Type::LongTy; break;
+ default: assert(0 && "Invalid unsigned integer type!"); abort();
+ }
+ CastInst *NewCI = new CastInst(X,DestTy,X->getName()+".signed");
+ InsertNewInstBefore(NewCI, I);
+ X = NewCI;
+ }
+ return new SetCondInst(isSetNE ? Instruction::SetLT :
+ Instruction::SetGE, X,
+ Constant::getNullValue(X->getType()));
+ }
+ }
+ default: break;
+ }
+ }
+ }
+
// Check to see if we are comparing against the minimum or maximum value...
if (CI->isMinValue()) {
if (I.getOpcode() == Instruction::SetLT) // A < MIN -> FALSE
-Instruction *InstCombiner::visitShiftInst(Instruction &I) {
+Instruction *InstCombiner::visitShiftInst(ShiftInst &I) {
assert(I.getOperand(1)->getType() == Type::UByteTy);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+ bool isLeftShift = I.getOpcode() == Instruction::Shl;
// shl X, 0 == X and shr X, 0 == X
// shl 0, X == 0 and shr 0, X == 0
Op0 == Constant::getNullValue(Op0->getType()))
return ReplaceInstUsesWith(I, Op0);
- // shl uint X, 32 = 0 and shr ubyte Y, 9 = 0, ... just don't eliminate shr of
- // a signed value.
- //
+ // shr int -1, X = -1 (for any arithmetic shift rights of ~0)
+ if (!isLeftShift)
+ if (ConstantSInt *CSI = dyn_cast<ConstantSInt>(Op0))
+ if (CSI->isAllOnesValue())
+ return ReplaceInstUsesWith(I, CSI);
+
if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(Op1)) {
- if (I.getOpcode() == Instruction::Shr) {
- unsigned TypeBits = Op0->getType()->getPrimitiveSize()*8;
- if (CUI->getValue() >= TypeBits && !(Op0->getType()->isSigned()))
- return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType()));
- }
+ // shl uint X, 32 = 0 and shr ubyte Y, 9 = 0, ... just don't eliminate shr
+ // of a signed value.
+ //
+ unsigned TypeBits = Op0->getType()->getPrimitiveSize()*8;
+ if (CUI->getValue() >= TypeBits &&
+ (!Op0->getType()->isSigned() || isLeftShift))
+ return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType()));
+
+ // ((X*C1) << C2) == (X * (C1 << C2))
+ if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0))
+ if (BO->getOpcode() == Instruction::Mul && isLeftShift)
+ if (Constant *BOOp = dyn_cast<Constant>(BO->getOperand(1)))
+ return BinaryOperator::create(Instruction::Mul, BO->getOperand(0),
+ *BOOp << *CUI);
+
- // Check to see if we are shifting left by 1. If so, turn it into an add
- // instruction.
- if (I.getOpcode() == Instruction::Shl && CUI->equalsInt(1))
- // Convert 'shl int %X, 2' to 'add int %X, %X'
- return BinaryOperator::create(Instruction::Add, Op0, Op0, I.getName());
+ // If the operand is an bitwise operator with a constant RHS, and the
+ // shift is the only use, we can pull it out of the shift.
+ if (Op0->hasOneUse())
+ if (BinaryOperator *Op0BO = dyn_cast<BinaryOperator>(Op0))
+ if (ConstantInt *Op0C = dyn_cast<ConstantInt>(Op0BO->getOperand(1))) {
+ bool isValid = true; // Valid only for And, Or, Xor
+ bool highBitSet = false; // Transform if high bit of constant set?
+
+ switch (Op0BO->getOpcode()) {
+ default: isValid = false; break; // Do not perform transform!
+ case Instruction::Or:
+ case Instruction::Xor:
+ highBitSet = false;
+ break;
+ case Instruction::And:
+ highBitSet = true;
+ break;
+ }
+
+ // If this is a signed shift right, and the high bit is modified
+ // by the logical operation, do not perform the transformation.
+ // The highBitSet boolean indicates the value of the high bit of
+ // the constant which would cause it to be modified for this
+ // operation.
+ //
+ if (isValid && !isLeftShift && !I.getType()->isUnsigned()) {
+ uint64_t Val = Op0C->getRawValue();
+ isValid = ((Val & (1 << (TypeBits-1))) != 0) == highBitSet;
+ }
+
+ if (isValid) {
+ Constant *NewRHS =
+ ConstantFoldShiftInstruction(I.getOpcode(), Op0C, CUI);
+
+ Instruction *NewShift =
+ new ShiftInst(I.getOpcode(), Op0BO->getOperand(0), CUI,
+ Op0BO->getName());
+ Op0BO->setName("");
+ InsertNewInstBefore(NewShift, I);
+
+ return BinaryOperator::create(Op0BO->getOpcode(), NewShift,
+ NewRHS);
+ }
+ }
+ // If this is a shift of a shift, see if we can fold the two together...
+ if (ShiftInst *Op0SI = dyn_cast<ShiftInst>(Op0))
+ if (ConstantUInt *ShiftAmt1C =
+ dyn_cast<ConstantUInt>(Op0SI->getOperand(1))) {
+ unsigned ShiftAmt1 = ShiftAmt1C->getValue();
+ unsigned ShiftAmt2 = CUI->getValue();
+
+ // Check for (A << c1) << c2 and (A >> c1) >> c2
+ if (I.getOpcode() == Op0SI->getOpcode()) {
+ unsigned Amt = ShiftAmt1+ShiftAmt2; // Fold into one big shift...
+ return new ShiftInst(I.getOpcode(), Op0SI->getOperand(0),
+ ConstantUInt::get(Type::UByteTy, Amt));
+ }
+
+ // Check for (A << c1) >> c2 or visaversa. If we are dealing with
+ // signed types, we can only support the (A >> c1) << c2 configuration,
+ // because it can not turn an arbitrary bit of A into a sign bit.
+ if (I.getType()->isUnsigned() || isLeftShift) {
+ // Calculate bitmask for what gets shifted off the edge...
+ Constant *C = ConstantIntegral::getAllOnesValue(I.getType());
+ if (isLeftShift)
+ C = ConstantExpr::getShift(Instruction::Shl, C, ShiftAmt1C);
+ else
+ C = ConstantExpr::getShift(Instruction::Shr, C, ShiftAmt1C);
+
+ Instruction *Mask =
+ BinaryOperator::create(Instruction::And, Op0SI->getOperand(0),
+ C, Op0SI->getOperand(0)->getName()+".mask");
+ InsertNewInstBefore(Mask, I);
+
+ // Figure out what flavor of shift we should use...
+ if (ShiftAmt1 == ShiftAmt2)
+ return ReplaceInstUsesWith(I, Mask); // (A << c) >> c === A & c2
+ else if (ShiftAmt1 < ShiftAmt2) {
+ return new ShiftInst(I.getOpcode(), Mask,
+ ConstantUInt::get(Type::UByteTy, ShiftAmt2-ShiftAmt1));
+ } else {
+ return new ShiftInst(Op0SI->getOpcode(), Mask,
+ ConstantUInt::get(Type::UByteTy, ShiftAmt1-ShiftAmt2));
+ }
+ }
+ }
}
+
return 0;
}
// isEliminableCastOfCast - Return true if it is valid to eliminate the CI
// instruction.
//
-static inline bool isEliminableCastOfCast(const CastInst &CI,
- const CastInst *CSrc) {
- assert(CI.getOperand(0) == CSrc);
- const Type *SrcTy = CSrc->getOperand(0)->getType();
- const Type *MidTy = CSrc->getType();
- const Type *DstTy = CI.getType();
+static inline bool isEliminableCastOfCast(const Type *SrcTy, const Type *MidTy,
+ const Type *DstTy) {
// It is legal to eliminate the instruction if casting A->B->A if the sizes
// are identical and the bits don't get reinterpreted (for example
// int->float->int would not be allowed)
- if (SrcTy == DstTy && SrcTy->isLosslesslyConvertableTo(MidTy))
+ if (SrcTy == DstTy && SrcTy->isLosslesslyConvertibleTo(MidTy))
return true;
// Allow free casting and conversion of sizes as long as the sign doesn't
return false;
}
+static bool ValueRequiresCast(const Value *V, const Type *Ty) {
+ if (V->getType() == Ty || isa<Constant>(V)) return false;
+ if (const CastInst *CI = dyn_cast<CastInst>(V))
+ if (isEliminableCastOfCast(CI->getOperand(0)->getType(), CI->getType(), Ty))
+ return false;
+ return true;
+}
+
+/// InsertOperandCastBefore - This inserts a cast of V to DestTy before the
+/// InsertBefore instruction. This is specialized a bit to avoid inserting
+/// casts that are known to not do anything...
+///
+Value *InstCombiner::InsertOperandCastBefore(Value *V, const Type *DestTy,
+ Instruction *InsertBefore) {
+ if (V->getType() == DestTy) return V;
+ if (Constant *C = dyn_cast<Constant>(V))
+ return ConstantExpr::getCast(C, DestTy);
+
+ CastInst *CI = new CastInst(V, DestTy, V->getName());
+ InsertNewInstBefore(CI, *InsertBefore);
+ return CI;
+}
// CastInst simplification
//
Instruction *InstCombiner::visitCastInst(CastInst &CI) {
+ Value *Src = CI.getOperand(0);
+
// If the user is casting a value to the same type, eliminate this cast
// instruction...
- if (CI.getType() == CI.getOperand(0)->getType())
- return ReplaceInstUsesWith(CI, CI.getOperand(0));
+ if (CI.getType() == Src->getType())
+ return ReplaceInstUsesWith(CI, Src);
// If casting the result of another cast instruction, try to eliminate this
// one!
//
- if (CastInst *CSrc = dyn_cast<CastInst>(CI.getOperand(0))) {
- if (isEliminableCastOfCast(CI, CSrc)) {
+ if (CastInst *CSrc = dyn_cast<CastInst>(Src)) {
+ if (isEliminableCastOfCast(CSrc->getOperand(0)->getType(),
+ CSrc->getType(), CI.getType())) {
// This instruction now refers directly to the cast's src operand. This
// has a good chance of making CSrc dead.
CI.setOperand(0, CSrc->getOperand(0));
CSrc->getType()->getPrimitiveSize() < CI.getType()->getPrimitiveSize()){
assert(CSrc->getType() != Type::ULongTy &&
"Cannot have type bigger than ulong!");
- unsigned AndValue = (1U << CSrc->getType()->getPrimitiveSize()*8)-1;
+ uint64_t AndValue = (1ULL << CSrc->getType()->getPrimitiveSize()*8)-1;
Constant *AndOp = ConstantUInt::get(CI.getType(), AndValue);
return BinaryOperator::create(Instruction::And, CSrc->getOperand(0),
AndOp);
}
}
+ // If casting the result of a getelementptr instruction with no offset, turn
+ // this into a cast of the original pointer!
+ //
+ if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Src)) {
+ bool AllZeroOperands = true;
+ for (unsigned i = 1, e = GEP->getNumOperands(); i != e; ++i)
+ if (!isa<Constant>(GEP->getOperand(i)) ||
+ !cast<Constant>(GEP->getOperand(i))->isNullValue()) {
+ AllZeroOperands = false;
+ break;
+ }
+ if (AllZeroOperands) {
+ CI.setOperand(0, GEP->getOperand(0));
+ return &CI;
+ }
+ }
+
+ // If the source value is an instruction with only this use, we can attempt to
+ // propagate the cast into the instruction. Also, only handle integral types
+ // for now.
+ if (Instruction *SrcI = dyn_cast<Instruction>(Src))
+ if (SrcI->hasOneUse() && Src->getType()->isIntegral() &&
+ CI.getType()->isInteger()) { // Don't mess with casts to bool here
+ const Type *DestTy = CI.getType();
+ unsigned SrcBitSize = getTypeSizeInBits(Src->getType());
+ unsigned DestBitSize = getTypeSizeInBits(DestTy);
+
+ Value *Op0 = SrcI->getNumOperands() > 0 ? SrcI->getOperand(0) : 0;
+ Value *Op1 = SrcI->getNumOperands() > 1 ? SrcI->getOperand(1) : 0;
+
+ switch (SrcI->getOpcode()) {
+ case Instruction::Add:
+ case Instruction::Mul:
+ case Instruction::And:
+ case Instruction::Or:
+ case Instruction::Xor:
+ // If we are discarding information, or just changing the sign, rewrite.
+ if (DestBitSize <= SrcBitSize && DestBitSize != 1) {
+ // Don't insert two casts if they cannot be eliminated. We allow two
+ // casts to be inserted if the sizes are the same. This could only be
+ // converting signedness, which is a noop.
+ if (DestBitSize == SrcBitSize || !ValueRequiresCast(Op1, DestTy) ||
+ !ValueRequiresCast(Op0, DestTy)) {
+ Value *Op0c = InsertOperandCastBefore(Op0, DestTy, SrcI);
+ Value *Op1c = InsertOperandCastBefore(Op1, DestTy, SrcI);
+ return BinaryOperator::create(cast<BinaryOperator>(SrcI)
+ ->getOpcode(), Op0c, Op1c);
+ }
+ }
+ break;
+ case Instruction::Shl:
+ // Allow changing the sign of the source operand. Do not allow changing
+ // the size of the shift, UNLESS the shift amount is a constant. We
+ // mush not change variable sized shifts to a smaller size, because it
+ // is undefined to shift more bits out than exist in the value.
+ if (DestBitSize == SrcBitSize ||
+ (DestBitSize < SrcBitSize && isa<Constant>(Op1))) {
+ Value *Op0c = InsertOperandCastBefore(Op0, DestTy, SrcI);
+ return new ShiftInst(Instruction::Shl, Op0c, Op1);
+ }
+ break;
+ }
+ }
+
return 0;
}
+// CallInst simplification
+//
+Instruction *InstCombiner::visitCallInst(CallInst &CI) {
+ return visitCallSite(&CI);
+}
+
+// InvokeInst simplification
+//
+Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) {
+ return visitCallSite(&II);
+}
+
+// getPromotedType - Return the specified type promoted as it would be to pass
+// though a va_arg area...
+static const Type *getPromotedType(const Type *Ty) {
+ switch (Ty->getPrimitiveID()) {
+ case Type::SByteTyID:
+ case Type::ShortTyID: return Type::IntTy;
+ case Type::UByteTyID:
+ case Type::UShortTyID: return Type::UIntTy;
+ case Type::FloatTyID: return Type::DoubleTy;
+ default: return Ty;
+ }
+}
+
+// visitCallSite - Improvements for call and invoke instructions.
+//
+Instruction *InstCombiner::visitCallSite(CallSite CS) {
+ bool Changed = false;
+
+ // If the callee is a constexpr cast of a function, attempt to move the cast
+ // to the arguments of the call/invoke.
+ if (transformConstExprCastCall(CS)) return 0;
+
+ Value *Callee = CS.getCalledValue();
+ const PointerType *PTy = cast<PointerType>(Callee->getType());
+ const FunctionType *FTy = cast<FunctionType>(PTy->getElementType());
+ if (FTy->isVarArg()) {
+ // See if we can optimize any arguments passed through the varargs area of
+ // the call.
+ for (CallSite::arg_iterator I = CS.arg_begin()+FTy->getNumParams(),
+ E = CS.arg_end(); I != E; ++I)
+ if (CastInst *CI = dyn_cast<CastInst>(*I)) {
+ // If this cast does not effect the value passed through the varargs
+ // area, we can eliminate the use of the cast.
+ Value *Op = CI->getOperand(0);
+ if (CI->getType()->isLosslesslyConvertibleTo(Op->getType())) {
+ *I = Op;
+ Changed = true;
+ }
+ }
+ }
+
+ return Changed ? CS.getInstruction() : 0;
+}
+
+// transformConstExprCastCall - If the callee is a constexpr cast of a function,
+// attempt to move the cast to the arguments of the call/invoke.
+//
+bool InstCombiner::transformConstExprCastCall(CallSite CS) {
+ if (!isa<ConstantExpr>(CS.getCalledValue())) return false;
+ ConstantExpr *CE = cast<ConstantExpr>(CS.getCalledValue());
+ if (CE->getOpcode() != Instruction::Cast ||
+ !isa<ConstantPointerRef>(CE->getOperand(0)))
+ return false;
+ ConstantPointerRef *CPR = cast<ConstantPointerRef>(CE->getOperand(0));
+ if (!isa<Function>(CPR->getValue())) return false;
+ Function *Callee = cast<Function>(CPR->getValue());
+ Instruction *Caller = CS.getInstruction();
+
+ // Okay, this is a cast from a function to a different type. Unless doing so
+ // would cause a type conversion of one of our arguments, change this call to
+ // be a direct call with arguments casted to the appropriate types.
+ //
+ const FunctionType *FT = Callee->getFunctionType();
+ const Type *OldRetTy = Caller->getType();
+
+ if (Callee->isExternal() &&
+ !OldRetTy->isLosslesslyConvertibleTo(FT->getReturnType()))
+ return false; // Cannot transform this return value...
+
+ unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin());
+ unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs);
+
+ CallSite::arg_iterator AI = CS.arg_begin();
+ for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) {
+ const Type *ParamTy = FT->getParamType(i);
+ bool isConvertible = (*AI)->getType()->isLosslesslyConvertibleTo(ParamTy);
+ if (Callee->isExternal() && !isConvertible) return false;
+ }
+
+ if (FT->getNumParams() < NumActualArgs && !FT->isVarArg() &&
+ Callee->isExternal())
+ return false; // Do not delete arguments unless we have a function body...
+
+ // Okay, we decided that this is a safe thing to do: go ahead and start
+ // inserting cast instructions as necessary...
+ std::vector<Value*> Args;
+ Args.reserve(NumActualArgs);
+
+ AI = CS.arg_begin();
+ for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) {
+ const Type *ParamTy = FT->getParamType(i);
+ if ((*AI)->getType() == ParamTy) {
+ Args.push_back(*AI);
+ } else {
+ Instruction *Cast = new CastInst(*AI, ParamTy, "tmp");
+ InsertNewInstBefore(Cast, *Caller);
+ Args.push_back(Cast);
+ }
+ }
+
+ // If the function takes more arguments than the call was taking, add them
+ // now...
+ for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i)
+ Args.push_back(Constant::getNullValue(FT->getParamType(i)));
+
+ // If we are removing arguments to the function, emit an obnoxious warning...
+ if (FT->getNumParams() < NumActualArgs)
+ if (!FT->isVarArg()) {
+ std::cerr << "WARNING: While resolving call to function '"
+ << Callee->getName() << "' arguments were dropped!\n";
+ } else {
+ // Add all of the arguments in their promoted form to the arg list...
+ for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) {
+ const Type *PTy = getPromotedType((*AI)->getType());
+ if (PTy != (*AI)->getType()) {
+ // Must promote to pass through va_arg area!
+ Instruction *Cast = new CastInst(*AI, PTy, "tmp");
+ InsertNewInstBefore(Cast, *Caller);
+ Args.push_back(Cast);
+ } else {
+ Args.push_back(*AI);
+ }
+ }
+ }
+
+ if (FT->getReturnType() == Type::VoidTy)
+ Caller->setName(""); // Void type should not have a name...
+
+ Instruction *NC;
+ if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) {
+ NC = new InvokeInst(Callee, II->getNormalDest(), II->getExceptionalDest(),
+ Args, Caller->getName(), Caller);
+ } else {
+ NC = new CallInst(Callee, Args, Caller->getName(), Caller);
+ }
+
+ // Insert a cast of the return type as necessary...
+ Value *NV = NC;
+ if (Caller->getType() != NV->getType() && !Caller->use_empty()) {
+ if (NV->getType() != Type::VoidTy) {
+ NV = NC = new CastInst(NC, Caller->getType(), "tmp");
+ InsertNewInstBefore(NC, *Caller);
+ AddUsesToWorkList(*Caller);
+ } else {
+ NV = Constant::getNullValue(Caller->getType());
+ }
+ }
+
+ if (Caller->getType() != Type::VoidTy && !Caller->use_empty())
+ Caller->replaceAllUsesWith(NV);
+ Caller->getParent()->getInstList().erase(Caller);
+ removeFromWorkList(Caller);
+ return true;
+}
+
+
// PHINode simplification
//
Instruction *InstCombiner::visitPHINode(PHINode &PN) {
// If the PHI node only has one incoming value, eliminate the PHI node...
- if (PN.getNumIncomingValues() == 0)
- return ReplaceInstUsesWith(PN, Constant::getNullValue(PN.getType()));
if (PN.getNumIncomingValues() == 1)
return ReplaceInstUsesWith(PN, PN.getIncomingValue(0));
Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
- // Is it 'getelementptr %P, uint 0' or 'getelementptr %P'
+ // Is it 'getelementptr %P, long 0' or 'getelementptr %P'
// If so, eliminate the noop.
if ((GEP.getNumOperands() == 2 &&
GEP.getOperand(1) == Constant::getNullValue(Type::LongTy)) ||
// Can we combine the two pointer arithmetics offsets?
if (Src->getNumOperands() == 2 && isa<Constant>(Src->getOperand(1)) &&
isa<Constant>(GEP.getOperand(1))) {
- // Replace the index list on this GEP with the index on the getelementptr
- Indices.insert(Indices.end(), GEP.idx_begin(), GEP.idx_end());
- Indices[0] = *cast<Constant>(Src->getOperand(1)) +
- *cast<Constant>(GEP.getOperand(1));
- assert(Indices[0] != 0 && "Constant folding of uint's failed!?");
-
- } else if (*GEP.idx_begin() == ConstantUInt::getNullValue(Type::LongTy) &&
+ // Replace: gep (gep %P, long C1), long C2, ...
+ // With: gep %P, long (C1+C2), ...
+ Value *Sum = ConstantExpr::get(Instruction::Add,
+ cast<Constant>(Src->getOperand(1)),
+ cast<Constant>(GEP.getOperand(1)));
+ assert(Sum && "Constant folding of longs failed!?");
+ GEP.setOperand(0, Src->getOperand(0));
+ GEP.setOperand(1, Sum);
+ AddUsesToWorkList(*Src); // Reduce use count of Src
+ return &GEP;
+ } else if (Src->getNumOperands() == 2) {
+ // Replace: gep (gep %P, long B), long A, ...
+ // With: T = long A+B; gep %P, T, ...
+ //
+ Value *Sum = BinaryOperator::create(Instruction::Add, Src->getOperand(1),
+ GEP.getOperand(1),
+ Src->getName()+".sum", &GEP);
+ GEP.setOperand(0, Src->getOperand(0));
+ GEP.setOperand(1, Sum);
+ WorkList.push_back(cast<Instruction>(Sum));
+ return &GEP;
+ } else if (*GEP.idx_begin() == Constant::getNullValue(Type::LongTy) &&
Src->getNumOperands() != 1) {
// Otherwise we can do the fold if the first index of the GEP is a zero
Indices.insert(Indices.end(), Src->idx_begin(), Src->idx_end());
Indices.insert(Indices.end(), GEP.idx_begin()+1, GEP.idx_end());
+ } else if (Src->getOperand(Src->getNumOperands()-1) ==
+ Constant::getNullValue(Type::LongTy)) {
+ // If the src gep ends with a constant array index, merge this get into
+ // it, even if we have a non-zero array index.
+ Indices.insert(Indices.end(), Src->idx_begin(), Src->idx_end()-1);
+ Indices.insert(Indices.end(), GEP.idx_begin(), GEP.idx_end());
}
if (!Indices.empty())
Indices.push_back(cast<Constant>(*I));
if (I == E) { // If they are all constants...
- ConstantExpr *CE =
+ Constant *CE =
ConstantExpr::getGetElementPtr(ConstantPointerRef::get(GV), Indices);
// Replace all uses of the GEP with the new constexpr...
return 0;
}
+Instruction *InstCombiner::visitAllocationInst(AllocationInst &AI) {
+ // Convert: malloc Ty, C - where C is a constant != 1 into: malloc [C x Ty], 1
+ if (AI.isArrayAllocation()) // Check C != 1
+ if (const ConstantUInt *C = dyn_cast<ConstantUInt>(AI.getArraySize())) {
+ const Type *NewTy = ArrayType::get(AI.getAllocatedType(), C->getValue());
+ AllocationInst *New = 0;
+
+ // Create and insert the replacement instruction...
+ if (isa<MallocInst>(AI))
+ New = new MallocInst(NewTy, 0, AI.getName(), &AI);
+ else {
+ assert(isa<AllocaInst>(AI) && "Unknown type of allocation inst!");
+ New = new AllocaInst(NewTy, 0, AI.getName(), &AI);
+ }
+
+ // Scan to the end of the allocation instructions, to skip over a block of
+ // allocas if possible...
+ //
+ BasicBlock::iterator It = New;
+ while (isa<AllocationInst>(*It)) ++It;
+
+ // Now that I is pointing to the first non-allocation-inst in the block,
+ // insert our getelementptr instruction...
+ //
+ std::vector<Value*> Idx(2, Constant::getNullValue(Type::LongTy));
+ Value *V = new GetElementPtrInst(New, Idx, New->getName()+".sub", It);
+
+ // Now make everything use the getelementptr instead of the original
+ // allocation.
+ ReplaceInstUsesWith(AI, V);
+ return &AI;
+ }
+ return 0;
+}
+
+/// GetGEPGlobalInitializer - Given a constant, and a getelementptr
+/// constantexpr, return the constant value being addressed by the constant
+/// expression, or null if something is funny.
+///
+static Constant *GetGEPGlobalInitializer(Constant *C, ConstantExpr *CE) {
+ if (CE->getOperand(1) != Constant::getNullValue(Type::LongTy))
+ return 0; // Do not allow stepping over the value!
+
+ // Loop over all of the operands, tracking down which value we are
+ // addressing...
+ for (unsigned i = 2, e = CE->getNumOperands(); i != e; ++i)
+ if (ConstantUInt *CU = dyn_cast<ConstantUInt>(CE->getOperand(i))) {
+ ConstantStruct *CS = cast<ConstantStruct>(C);
+ if (CU->getValue() >= CS->getValues().size()) return 0;
+ C = cast<Constant>(CS->getValues()[CU->getValue()]);
+ } else if (ConstantSInt *CS = dyn_cast<ConstantSInt>(CE->getOperand(i))) {
+ ConstantArray *CA = cast<ConstantArray>(C);
+ if ((uint64_t)CS->getValue() >= CA->getValues().size()) return 0;
+ C = cast<Constant>(CA->getValues()[CS->getValue()]);
+ } else
+ return 0;
+ return C;
+}
+
+Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
+ Value *Op = LI.getOperand(0);
+ if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(Op))
+ Op = CPR->getValue();
+
+ // Instcombine load (constant global) into the value loaded...
+ if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Op))
+ if (GV->isConstant() && !GV->isExternal())
+ return ReplaceInstUsesWith(LI, GV->getInitializer());
+
+ // Instcombine load (constantexpr_GEP global, 0, ...) into the value loaded...
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Op))
+ if (CE->getOpcode() == Instruction::GetElementPtr)
+ if (ConstantPointerRef *G=dyn_cast<ConstantPointerRef>(CE->getOperand(0)))
+ if (GlobalVariable *GV = dyn_cast<GlobalVariable>(G->getValue()))
+ if (GV->isConstant() && !GV->isExternal())
+ if (Constant *V = GetGEPGlobalInitializer(GV->getInitializer(), CE))
+ return ReplaceInstUsesWith(LI, V);
+ return 0;
+}
+
+
+Instruction *InstCombiner::visitBranchInst(BranchInst &BI) {
+ // Change br (not X), label True, label False to: br X, label False, True
+ if (BI.isConditional() && !isa<Constant>(BI.getCondition()))
+ if (Value *V = dyn_castNotVal(BI.getCondition())) {
+ BasicBlock *TrueDest = BI.getSuccessor(0);
+ BasicBlock *FalseDest = BI.getSuccessor(1);
+ // Swap Destinations and condition...
+ BI.setCondition(V);
+ BI.setSuccessor(0, FalseDest);
+ BI.setSuccessor(1, TrueDest);
+ return &BI;
+ }
+ return 0;
+}
+
void InstCombiner::removeFromWorkList(Instruction *I) {
WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), I),
Instruction *I = WorkList.back(); // Get an instruction from the worklist
WorkList.pop_back();
- // Check to see if we can DCE or ConstantPropogate the instruction...
+ // Check to see if we can DCE or ConstantPropagate the instruction...
// Check to see if we can DIE the instruction...
if (isInstructionTriviallyDead(I)) {
// Add operands to the worklist...
- for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
- if (Instruction *Op = dyn_cast<Instruction>(I->getOperand(i)))
- WorkList.push_back(Op);
-
+ if (I->getNumOperands() < 4)
+ for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
+ if (Instruction *Op = dyn_cast<Instruction>(I->getOperand(i)))
+ WorkList.push_back(Op);
++NumDeadInst;
- BasicBlock::iterator BBI = I;
- if (dceInstruction(BBI)) {
- removeFromWorkList(I);
- continue;
- }
- }
- // Instruction isn't dead, see if we can constant propogate it...
+ I->getParent()->getInstList().erase(I);
+ removeFromWorkList(I);
+ continue;
+ }
+
+ // Instruction isn't dead, see if we can constant propagate it...
if (Constant *C = ConstantFoldInstruction(I)) {
// Add operands to the worklist...
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
if (Instruction *Op = dyn_cast<Instruction>(I->getOperand(i)))
WorkList.push_back(Op);
- I->replaceAllUsesWith(C);
+ ReplaceInstUsesWith(*I, C);
+
++NumConstProp;
- BasicBlock::iterator BBI = I;
- if (dceInstruction(BBI)) {
- removeFromWorkList(I);
- continue;
- }
+ I->getParent()->getInstList().erase(I);
+ removeFromWorkList(I);
+ continue;
}
-
+
// Now that we have an instruction, try combining it to simplify it...
if (Instruction *Result = visit(*I)) {
++NumCombined;
// Instructions can end up on the worklist more than once. Make sure
// we do not process an instruction that has been deleted.
removeFromWorkList(I);
- ReplaceInstWithInst(I, Result);
+
+ // Move the name to the new instruction first...
+ std::string OldName = I->getName(); I->setName("");
+ Result->setName(OldName);
+
+ // Insert the new instruction into the basic block...
+ BasicBlock *InstParent = I->getParent();
+ InstParent->getInstList().insert(I, Result);
+
+ // Everything uses the new instruction now...
+ I->replaceAllUsesWith(Result);
+
+ // Erase the old instruction.
+ InstParent->getInstList().erase(I);
} else {
BasicBlock::iterator II = I;
projects / oota-llvm.git / blobdiff