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-rw-r--r--llvm/lib/Transforms/Scalar/InstructionCombining.cpp214
1 files changed, 51 insertions, 163 deletions
diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
index ba97be63034..20c7dbe8d3f 100644
--- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -1,4 +1,4 @@
-//===- InstructionCombining.cpp - Combine multiple instructions -------------=//
+//===- InstructionCombining.cpp - Combine multiple instructions -----------===//
//
// InstructionCombining - Combine instructions to form fewer, simple
// instructions. This pass does not modify the CFG, and has a tendancy to
@@ -57,7 +57,7 @@ namespace {
// instruction types. The semantics are as follows:
// Return Value:
// null - No change was made
- // I - Change was made, I is still valid
+ // I - Change was made, I is still valid, I may be dead though
// otherwise - Change was made, replace I with returned instruction
//
Instruction *visitNot(UnaryOperator &I);
@@ -107,11 +107,8 @@ namespace {
Instruction *InstCombiner::visitNot(UnaryOperator &I) {
// not (not X) = X
if (Instruction *Op = dyn_cast<Instruction>(I.getOperand(0)))
- if (Op->getOpcode() == Instruction::Not) {
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Op->getOperand(0));
- return &I;
- }
+ if (Op->getOpcode() == Instruction::Not)
+ return ReplaceInstUsesWith(I, Op->getOperand(0));
return 0;
}
@@ -142,11 +139,8 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
// Eliminate 'add int %X, 0'
- if (RHS == Constant::getNullValue(I.getType())) {
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(LHS);
- return &I;
- }
+ if (RHS == Constant::getNullValue(I.getType()))
+ return ReplaceInstUsesWith(I, LHS);
// -A + B --> B - A
if (Value *V = dyn_castNegInst(LHS))
@@ -182,11 +176,8 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
Instruction *InstCombiner::visitSub(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
- if (Op0 == Op1) { // sub X, X -> 0
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Constant::getNullValue(I.getType()));
- return &I;
- }
+ 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
@@ -195,7 +186,7 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) {
if (Constant *RHS = *Constant::getNullValue(I.getType()) - *Op2) // 0 - RHS
return BinaryOperator::create(Instruction::Add, Op0, RHS, I.getName());
- // If this is a 'C = x-B', check to see if 'B = -A', so that C = x+A...
+ // If this is a 'B = x-(-A)', change to B = x+A...
if (Value *V = dyn_castNegInst(Op1))
return BinaryOperator::create(Instruction::Add, Op0, V);
@@ -219,25 +210,17 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
bool Changed = SimplifyBinOp(I);
Value *Op1 = I.getOperand(0);
- // Simplify add instructions with a constant RHS...
+ // Simplify mul instructions with a constant RHS...
if (Constant *Op2 = dyn_cast<Constant>(I.getOperand(1))) {
- if (I.getType()->isIntegral() && cast<ConstantInt>(Op2)->equalsInt(1)){
- // Eliminate 'mul int %X, 1'
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Op1);
- return &I;
+ if (I.getType()->isIntegral() && cast<ConstantInt>(Op2)->equalsInt(1))
+ return ReplaceInstUsesWith(I, Op1); // Eliminate 'mul int %X, 1'
- } else if (I.getType()->isIntegral() &&
- cast<ConstantInt>(Op2)->equalsInt(2)) {
+ if (I.getType()->isIntegral() && cast<ConstantInt>(Op2)->equalsInt(2))
// Convert 'mul int %X, 2' to 'add int %X, %X'
return BinaryOperator::create(Instruction::Add, Op1, Op1, I.getName());
- } else if (Op2->isNullValue()) {
- // Eliminate 'mul int %X, 0'
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Op2); // Set this value to zero directly
- return &I;
- }
+ if (Op2->isNullValue())
+ return ReplaceInstUsesWith(I, Op2); // Eliminate 'mul int %X, 0'
}
return Changed ? &I : 0;
@@ -247,11 +230,8 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
Instruction *InstCombiner::visitDiv(BinaryOperator &I) {
// div X, 1 == X
if (ConstantInt *RHS = dyn_cast<ConstantInt>(I.getOperand(1)))
- if (RHS->equalsInt(1)) {
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(I.getOperand(0));
- return &I;
- }
+ if (RHS->equalsInt(1))
+ return ReplaceInstUsesWith(I, I.getOperand(0));
return 0;
}
@@ -259,70 +239,14 @@ Instruction *InstCombiner::visitDiv(BinaryOperator &I) {
Instruction *InstCombiner::visitRem(BinaryOperator &I) {
// rem X, 1 == 0
if (ConstantInt *RHS = dyn_cast<ConstantInt>(I.getOperand(1)))
- if (RHS->equalsInt(1)) {
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Constant::getNullValue(I.getType()));
- return &I;
- }
- return 0;
-}
-
-// FIXME: These should be moved to Constants.h
-
-// isAllOnesValue - Return true if integral or boolean value is all ones.
-static bool isAllOnesValue(const Constant *C) {
- if (const ConstantBool *CB = dyn_cast<ConstantBool>(C))
- return CB == ConstantBool::True;
- else if (const ConstantSInt *CS = dyn_cast<ConstantSInt>(C))
- return CS->getValue() == -1;
- else if (const ConstantUInt *CU = dyn_cast<ConstantUInt>(C)) {
- // Calculate -1 casted to the right type...
- unsigned TypeBits = C->getType()->getPrimitiveSize()*8;
- uint64_t Val = ~0ULL; // All ones
- Val >>= 64-TypeBits; // Shift out unwanted 1 bits...
- return CU->getValue() == Val;
- }
-
- return false;
-}
-
-// isMaxValue - Return true if this is the maximum value for this type.
-static bool isMaxValue(const Constant *C) {
- if (const ConstantBool *CB = dyn_cast<ConstantBool>(C))
- return CB == ConstantBool::True;
- else if (const ConstantUInt *CU = dyn_cast<ConstantUInt>(C))
- return isAllOnesValue(C);
- else if (const ConstantSInt *CS = dyn_cast<ConstantSInt>(C)) {
- // Calculate 011111111111111...
- unsigned TypeBits = C->getType()->getPrimitiveSize()*8;
- int64_t Val = INT64_MAX; // All ones
- Val >>= 64-TypeBits; // Shift out unwanted 1 bits...
- return CS->getValue() == Val;
- }
+ if (RHS->equalsInt(1))
+ return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- return false;
-}
-
-// isMinValue - Return true if this is the minimum value for this type.
-static bool isMinValue(const Constant *C) {
- if (const ConstantBool *CB = dyn_cast<ConstantBool>(C))
- return CB == ConstantBool::False;
- else if (const ConstantUInt *CU = dyn_cast<ConstantUInt>(C))
- return CU->getValue() == 0;
- else if (const ConstantSInt *CS = dyn_cast<ConstantSInt>(C)) {
- // Calculate 1111111111000000000000
- unsigned TypeBits = C->getType()->getPrimitiveSize()*8;
- int64_t Val = -1; // All ones
- Val <<= TypeBits-1; // Shift over to the right spot
- return CS->getValue() == Val;
- }
- return false;
+ return 0;
}
// isMaxValueMinusOne - return true if this is Max-1
-static bool isMaxValueMinusOne(const Constant *C) {
- if (!isa<ConstantInt>(C)) return false;
-
+static bool isMaxValueMinusOne(const ConstantInt *C) {
if (const ConstantUInt *CU = dyn_cast<ConstantUInt>(C)) {
// Calculate -1 casted to the right type...
unsigned TypeBits = C->getType()->getPrimitiveSize()*8;
@@ -341,9 +265,7 @@ static bool isMaxValueMinusOne(const Constant *C) {
}
// isMinValuePlusOne - return true if this is Min+1
-static bool isMinValuePlusOne(const Constant *C) {
- if (!isa<ConstantInt>(C)) return false;
-
+static bool isMinValuePlusOne(const ConstantInt *C) {
if (const ConstantUInt *CU = dyn_cast<ConstantUInt>(C))
return CU->getValue() == 1;
@@ -357,25 +279,18 @@ static bool isMinValuePlusOne(const Constant *C) {
}
-
Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
bool Changed = SimplifyBinOp(I);
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
// and X, X = X and X, 0 == 0
- if (Op0 == Op1 || Op1 == Constant::getNullValue(I.getType())) {
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Op1);
- return &I;
- }
+ if (Op0 == Op1 || Op1 == Constant::getNullValue(I.getType()))
+ return ReplaceInstUsesWith(I, Op1);
// and X, -1 == X
- if (Constant *RHS = dyn_cast<Constant>(Op1))
- if (isAllOnesValue(RHS)) {
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Op0);
- return &I;
- }
+ if (ConstantGenericIntegral *RHS = dyn_cast<ConstantGenericIntegral>(Op1))
+ if (RHS->isAllOnesValue())
+ return ReplaceInstUsesWith(I, Op0);
return Changed ? &I : 0;
}
@@ -387,19 +302,13 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
// or X, X = X or X, 0 == X
- if (Op0 == Op1 || Op1 == Constant::getNullValue(I.getType())) {
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Op0);
- return &I;
- }
+ if (Op0 == Op1 || Op1 == Constant::getNullValue(I.getType()))
+ return ReplaceInstUsesWith(I, Op0);
// or X, -1 == -1
- if (Constant *RHS = dyn_cast<Constant>(Op1))
- if (isAllOnesValue(RHS)) {
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Op1);
- return &I;
- }
+ if (ConstantGenericIntegral *RHS = dyn_cast<ConstantGenericIntegral>(Op1))
+ if (RHS->isAllOnesValue())
+ return ReplaceInstUsesWith(I, Op1);
return Changed ? &I : 0;
}
@@ -411,22 +320,16 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
// xor X, X = 0
- if (Op0 == Op1) {
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Constant::getNullValue(I.getType()));
- return &I;
- }
+ if (Op0 == Op1)
+ return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
- if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
+ if (ConstantGenericIntegral *Op1C = dyn_cast<ConstantGenericIntegral>(Op1)) {
// xor X, 0 == X
- if (Op1C->isNullValue()) {
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Op0);
- return &I;
- }
+ if (Op1C->isNullValue())
+ return ReplaceInstUsesWith(I, Op0);
// xor X, -1 = not X
- if (isAllOnesValue(Op1C))
+ if (Op1C->isAllOnesValue())
return UnaryOperator::create(Instruction::Not, Op0, I.getName());
}
@@ -506,7 +409,7 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) {
//
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
// Check to see if we are comparing against the minimum or maximum value...
- if (isMinValue(CI)) {
+ if (CI->isMinValue()) {
if (I.getOpcode() == Instruction::SetLT) // A < MIN -> FALSE
return ReplaceInstUsesWith(I, ConstantBool::False);
if (I.getOpcode() == Instruction::SetGE) // A >= MIN -> TRUE
@@ -516,7 +419,7 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) {
if (I.getOpcode() == Instruction::SetGT) // A > MIN -> A != MIN
return BinaryOperator::create(Instruction::SetNE, Op0,Op1, I.getName());
- } else if (isMaxValue(CI)) {
+ } else if (CI->isMaxValue()) {
if (I.getOpcode() == Instruction::SetGT) // A > MAX -> FALSE
return ReplaceInstUsesWith(I, ConstantBool::False);
if (I.getOpcode() == Instruction::SetLE) // A <= MAX -> TRUE
@@ -557,23 +460,17 @@ Instruction *InstCombiner::visitShiftInst(Instruction &I) {
// shl X, 0 == X and shr X, 0 == X
// shl 0, X == 0 and shr 0, X == 0
if (Op1 == Constant::getNullValue(Type::UByteTy) ||
- Op0 == Constant::getNullValue(Op0->getType())) {
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Op0);
- return &I;
- }
+ Op0 == Constant::getNullValue(Op0->getType()))
+ return ReplaceInstUsesWith(I, Op0);
- // shl int X, 32 = 0 and shr sbyte Y, 9 = 0, ... just don't eliminate shr of
+ // shl uint X, 32 = 0 and shr ubyte Y, 9 = 0, ... just don't eliminate shr of
// a signed value.
//
if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(Op1)) {
unsigned TypeBits = Op0->getType()->getPrimitiveSize()*8;
if (CUI->getValue() >= TypeBits &&
- !(Op0->getType()->isSigned() && I.getOpcode() == Instruction::Shr)) {
- AddUsesToWorkList(I); // Add all modified instrs to worklist
- I.replaceAllUsesWith(Constant::getNullValue(Op0->getType()));
- return &I;
- }
+ !(Op0->getType()->isSigned() && I.getOpcode() == Instruction::Shr))
+ return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType()));
}
return 0;
}
@@ -626,11 +523,8 @@ static inline bool isEliminableCastOfCast(const CastInst &CI,
Instruction *InstCombiner::visitCastInst(CastInst &CI) {
// If the user is casting a value to the same type, eliminate this cast
// instruction...
- if (CI.getType() == CI.getOperand(0)->getType()) {
- AddUsesToWorkList(CI); // Add all modified instrs to worklist
- CI.replaceAllUsesWith(CI.getOperand(0));
- return &CI;
- }
+ if (CI.getType() == CI.getOperand(0)->getType())
+ return ReplaceInstUsesWith(CI, CI.getOperand(0));
// If casting the result of another cast instruction, try to eliminate this
// one!
@@ -667,11 +561,8 @@ Instruction *InstCombiner::visitCastInst(CastInst &CI) {
//
Instruction *InstCombiner::visitPHINode(PHINode &PN) {
// If the PHI node only has one incoming value, eliminate the PHI node...
- if (PN.getNumIncomingValues() == 1) {
- AddUsesToWorkList(PN); // Add all modified instrs to worklist
- PN.replaceAllUsesWith(PN.getIncomingValue(0));
- return &PN;
- }
+ if (PN.getNumIncomingValues() == 1)
+ return ReplaceInstUsesWith(PN, PN.getIncomingValue(0));
return 0;
}
@@ -682,11 +573,8 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
// If so, eliminate the noop.
if ((GEP.getNumOperands() == 2 &&
GEP.getOperand(1) == Constant::getNullValue(Type::UIntTy)) ||
- GEP.getNumOperands() == 1) {
- AddUsesToWorkList(GEP); // Add all modified instrs to worklist
- GEP.replaceAllUsesWith(GEP.getOperand(0));
- return &GEP;
- }
+ GEP.getNumOperands() == 1)
+ return ReplaceInstUsesWith(GEP, GEP.getOperand(0));
// Combine Indices - If the source pointer to this getelementptr instruction
// is a getelementptr instruction, combine the indices of the two
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