using namespace llvm;
using namespace llvm::PatternMatch;
+#define MaxRecursionDepth 3
+
+static Value *SimplifyBinOp(unsigned, Value *, Value *, const TargetData *,
+ unsigned);
+static Value *SimplifyCmpInst(unsigned, Value *, Value *, const TargetData *,
+ unsigned);
+
+/// ThreadBinOpOverSelect - In the case of a binary operation with a select
+/// instruction as an operand, try to simplify the binop by seeing whether
+/// evaluating it on both branches of the select results in the same value.
+/// Returns the common value if so, otherwise returns null.
+static Value *ThreadBinOpOverSelect(unsigned Opcode, Value *LHS, Value *RHS,
+ const TargetData *TD, unsigned MaxRecurse) {
+ SelectInst *SI;
+ if (isa<SelectInst>(LHS)) {
+ SI = cast<SelectInst>(LHS);
+ } else {
+ assert(isa<SelectInst>(RHS) && "No select instruction operand!");
+ SI = cast<SelectInst>(RHS);
+ }
+
+ // Evaluate the BinOp on the true and false branches of the select.
+ Value *TV;
+ Value *FV;
+ if (SI == LHS) {
+ TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, TD, MaxRecurse);
+ FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, TD, MaxRecurse);
+ } else {
+ TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), TD, MaxRecurse);
+ FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), TD, MaxRecurse);
+ }
+
+ // If they simplified to the same value, then return the common value.
+ // If they both failed to simplify then return null.
+ if (TV == FV)
+ return TV;
+
+ // If one branch simplified to undef, return the other one.
+ if (TV && isa<UndefValue>(TV))
+ return FV;
+ if (FV && isa<UndefValue>(FV))
+ return TV;
+
+ // If applying the operation did not change the true and false select values,
+ // then the result of the binop is the select itself.
+ if (TV == SI->getTrueValue() && FV == SI->getFalseValue())
+ return SI;
+
+ // If one branch simplified and the other did not, and the simplified
+ // value is equal to the unsimplified one, return the simplified value.
+ // For example, select (cond, X, X & Z) & Z -> X & Z.
+ if ((FV && !TV) || (TV && !FV)) {
+ // Check that the simplified value has the form "X op Y" where "op" is the
+ // same as the original operation.
+ Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV);
+ if (Simplified && Simplified->getOpcode() == Opcode) {
+ // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
+ // We already know that "op" is the same as for the simplified value. See
+ // if the operands match too. If so, return the simplified value.
+ Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue();
+ Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS;
+ Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch;
+ if (Simplified->getOperand(0) == UnsimplifiedLHS &&
+ Simplified->getOperand(1) == UnsimplifiedRHS)
+ return Simplified;
+ if (Simplified->isCommutative() &&
+ Simplified->getOperand(1) == UnsimplifiedLHS &&
+ Simplified->getOperand(0) == UnsimplifiedRHS)
+ return Simplified;
+ }
+ }
+
+ return 0;
+}
+
+/// ThreadCmpOverSelect - In the case of a comparison with a select instruction,
+/// try to simplify the comparison by seeing whether both branches of the select
+/// result in the same value. Returns the common value if so, otherwise returns
+/// null.
+static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
+ Value *RHS, const TargetData *TD,
+ unsigned MaxRecurse) {
+ // Make sure the select is on the LHS.
+ if (!isa<SelectInst>(LHS)) {
+ std::swap(LHS, RHS);
+ Pred = CmpInst::getSwappedPredicate(Pred);
+ }
+ assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
+ SelectInst *SI = cast<SelectInst>(LHS);
+
+ // Now that we have "cmp select(cond, TV, FV), RHS", analyse it.
+ // Does "cmp TV, RHS" simplify?
+ if (Value *TCmp = SimplifyCmpInst(Pred, SI->getTrueValue(), RHS, TD,
+ MaxRecurse))
+ // It does! Does "cmp FV, RHS" simplify?
+ if (Value *FCmp = SimplifyCmpInst(Pred, SI->getFalseValue(), RHS, TD,
+ MaxRecurse))
+ // It does! If they simplified to the same value, then use it as the
+ // result of the original comparison.
+ if (TCmp == FCmp)
+ return TCmp;
+ return 0;
+}
+
+/// ThreadBinOpOverPHI - In the case of a binary operation with an operand that
+/// is a PHI instruction, try to simplify the binop by seeing whether evaluating
+/// it on the incoming phi values yields the same result for every value. If so
+/// returns the common value, otherwise returns null.
+static Value *ThreadBinOpOverPHI(unsigned Opcode, Value *LHS, Value *RHS,
+ const TargetData *TD, unsigned MaxRecurse) {
+ PHINode *PI;
+ if (isa<PHINode>(LHS)) {
+ PI = cast<PHINode>(LHS);
+ } else {
+ assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
+ PI = cast<PHINode>(RHS);
+ }
+
+ // Evaluate the BinOp on the incoming phi values.
+ Value *CommonValue = 0;
+ for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
+ Value *V = PI == LHS ?
+ SimplifyBinOp(Opcode, PI->getIncomingValue(i), RHS, TD, MaxRecurse) :
+ SimplifyBinOp(Opcode, LHS, PI->getIncomingValue(i), TD, MaxRecurse);
+ // If the operation failed to simplify, or simplified to a different value
+ // to previously, then give up.
+ if (!V || (CommonValue && V != CommonValue))
+ return 0;
+ CommonValue = V;
+ }
+
+ return CommonValue;
+}
+
+/// ThreadCmpOverPHI - In the case of a comparison with a PHI instruction, try
+/// try to simplify the comparison by seeing whether comparing with all of the
+/// incoming phi values yields the same result every time. If so returns the
+/// common result, otherwise returns null.
+static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
+ const TargetData *TD, unsigned MaxRecurse) {
+ // Make sure the phi is on the LHS.
+ if (!isa<PHINode>(LHS)) {
+ std::swap(LHS, RHS);
+ Pred = CmpInst::getSwappedPredicate(Pred);
+ }
+ assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!");
+ PHINode *PI = cast<PHINode>(LHS);
+
+ // Evaluate the BinOp on the incoming phi values.
+ Value *CommonValue = 0;
+ for (unsigned i = 0, e = PI->getNumIncomingValues(); i != e; ++i) {
+ Value *V = SimplifyCmpInst(Pred, PI->getIncomingValue(i), RHS, TD,
+ MaxRecurse);
+ // If the operation failed to simplify, or simplified to a different value
+ // to previously, then give up.
+ if (!V || (CommonValue && V != CommonValue))
+ return 0;
+ CommonValue = V;
+ }
+
+ return CommonValue;
+}
+
/// SimplifyAddInst - Given operands for an Add, see if we can
/// fold the result. If not, this returns null.
Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
return ConstantFoldInstOperands(Instruction::Add, CLHS->getType(),
Ops, 2, TD);
}
-
+
// Canonicalize the constant to the RHS.
std::swap(Op0, Op1);
}
-
+
if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
// X + undef -> undef
if (isa<UndefValue>(Op1C))
return Op1C;
-
+
// X + 0 --> X
if (Op1C->isNullValue())
return Op0;
}
-
+
// FIXME: Could pull several more out of instcombine.
return 0;
}
/// SimplifyAndInst - Given operands for an And, see if we can
/// fold the result. If not, this returns null.
-Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD) {
+static Value *SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD,
+ unsigned MaxRecurse) {
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
Constant *Ops[] = { CLHS, CRHS };
return ConstantFoldInstOperands(Instruction::And, CLHS->getType(),
Ops, 2, TD);
}
-
+
// Canonicalize the constant to the RHS.
std::swap(Op0, Op1);
}
-
+
// X & undef -> 0
if (isa<UndefValue>(Op1))
return Constant::getNullValue(Op0->getType());
-
+
// X & X = X
if (Op0 == Op1)
return Op0;
-
+
// X & <0,0> = <0,0>
if (isa<ConstantAggregateZero>(Op1))
return Op1;
-
+
// X & <-1,-1> = X
if (ConstantVector *CP = dyn_cast<ConstantVector>(Op1))
if (CP->isAllOnesValue())
return Op0;
-
+
if (ConstantInt *Op1CI = dyn_cast<ConstantInt>(Op1)) {
// X & 0 = 0
if (Op1CI->isZero())
if (Op1CI->isAllOnesValue())
return Op0;
}
-
+
// A & ~A = ~A & A = 0
Value *A, *B;
if ((match(Op0, m_Not(m_Value(A))) && A == Op1) ||
(match(Op1, m_Not(m_Value(A))) && A == Op0))
return Constant::getNullValue(Op0->getType());
-
+
// (A | ?) & A = A
if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
(A == Op1 || B == Op1))
return Op1;
-
+
// A & (A | ?) = A
if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
(A == Op0 || B == Op0))
return Op0;
-
+
+ // (A & B) & A -> A & B
+ if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
+ (A == Op1 || B == Op1))
+ return Op0;
+
+ // A & (A & B) -> A & B
+ if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
+ (A == Op0 || B == Op0))
+ return Op1;
+
+ // If the operation is with the result of a select instruction, check whether
+ // operating on either branch of the select always yields the same value.
+ if (MaxRecurse && (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)))
+ if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, TD,
+ MaxRecurse-1))
+ return V;
+
+ // If the operation is with the result of a phi instruction, check whether
+ // operating on all incoming values of the phi always yields the same value.
+ if (MaxRecurse && (isa<PHINode>(Op0) || isa<PHINode>(Op1)))
+ if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, TD,
+ MaxRecurse-1))
+ return V;
+
return 0;
}
+Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD) {
+ return ::SimplifyAndInst(Op0, Op1, TD, MaxRecursionDepth);
+}
+
/// SimplifyOrInst - Given operands for an Or, see if we can
/// fold the result. If not, this returns null.
-Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD) {
+static Value *SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD,
+ unsigned MaxRecurse) {
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
Constant *Ops[] = { CLHS, CRHS };
return ConstantFoldInstOperands(Instruction::Or, CLHS->getType(),
Ops, 2, TD);
}
-
+
// Canonicalize the constant to the RHS.
std::swap(Op0, Op1);
}
-
+
// X | undef -> -1
if (isa<UndefValue>(Op1))
return Constant::getAllOnesValue(Op0->getType());
-
+
// X | X = X
if (Op0 == Op1)
return Op0;
// X | <0,0> = X
if (isa<ConstantAggregateZero>(Op1))
return Op0;
-
+
// X | <-1,-1> = <-1,-1>
if (ConstantVector *CP = dyn_cast<ConstantVector>(Op1))
- if (CP->isAllOnesValue())
+ if (CP->isAllOnesValue())
return Op1;
-
+
if (ConstantInt *Op1CI = dyn_cast<ConstantInt>(Op1)) {
// X | 0 = X
if (Op1CI->isZero())
if (Op1CI->isAllOnesValue())
return Op1CI;
}
-
+
// A | ~A = ~A | A = -1
Value *A, *B;
if ((match(Op0, m_Not(m_Value(A))) && A == Op1) ||
(match(Op1, m_Not(m_Value(A))) && A == Op0))
return Constant::getAllOnesValue(Op0->getType());
-
+
// (A & ?) | A = A
if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
(A == Op1 || B == Op1))
return Op1;
-
+
// A | (A & ?) = A
if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
(A == Op0 || B == Op0))
return Op0;
-
+
+ // (A | B) | A -> A | B
+ if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
+ (A == Op1 || B == Op1))
+ return Op0;
+
+ // A | (A | B) -> A | B
+ if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
+ (A == Op0 || B == Op0))
+ return Op1;
+
+ // If the operation is with the result of a select instruction, check whether
+ // operating on either branch of the select always yields the same value.
+ if (MaxRecurse && (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)))
+ if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, TD,
+ MaxRecurse-1))
+ return V;
+
+ // If the operation is with the result of a phi instruction, check whether
+ // operating on all incoming values of the phi always yields the same value.
+ if (MaxRecurse && (isa<PHINode>(Op0) || isa<PHINode>(Op1)))
+ if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, TD,
+ MaxRecurse-1))
+ return V;
+
return 0;
}
+Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD) {
+ return ::SimplifyOrInst(Op0, Op1, TD, MaxRecursionDepth);
+}
static const Type *GetCompareTy(Value *Op) {
return CmpInst::makeCmpResultType(Op->getType());
}
-
/// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
/// fold the result. If not, this returns null.
-Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
- const TargetData *TD) {
+static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
+ const TargetData *TD, unsigned MaxRecurse) {
CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!");
-
+
if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
if (Constant *CRHS = dyn_cast<Constant>(RHS))
return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, TD);
std::swap(LHS, RHS);
Pred = CmpInst::getSwappedPredicate(Pred);
}
-
+
// ITy - This is the return type of the compare we're considering.
const Type *ITy = GetCompareTy(LHS);
-
+
// icmp X, X -> true/false
// X icmp undef -> true/false. For example, icmp ugt %X, undef -> false
// because X could be 0.
if (LHS == RHS || isa<UndefValue>(RHS))
return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
-
+
// icmp <global/alloca*/null>, <global/alloca*/null> - Global/Stack value
// addresses never equal each other! We already know that Op0 != Op1.
- if ((isa<GlobalValue>(LHS) || isa<AllocaInst>(LHS) ||
+ if ((isa<GlobalValue>(LHS) || isa<AllocaInst>(LHS) ||
isa<ConstantPointerNull>(LHS)) &&
- (isa<GlobalValue>(RHS) || isa<AllocaInst>(RHS) ||
+ (isa<GlobalValue>(RHS) || isa<AllocaInst>(RHS) ||
isa<ConstantPointerNull>(RHS)))
return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
-
+
// See if we are doing a comparison with a constant.
if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
// If we have an icmp le or icmp ge instruction, turn it into the
break;
}
}
-
-
+
+ // If the comparison is with the result of a select instruction, check whether
+ // comparing with either branch of the select always yields the same value.
+ if (MaxRecurse && (isa<SelectInst>(LHS) || isa<SelectInst>(RHS)))
+ if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, TD, MaxRecurse-1))
+ return V;
+
+ // If the comparison is with the result of a phi instruction, check whether
+ // doing the compare with each incoming phi value yields a common result.
+ if (MaxRecurse && (isa<PHINode>(LHS) || isa<PHINode>(RHS)))
+ if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, TD, MaxRecurse-1))
+ return V;
+
return 0;
}
+Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
+ const TargetData *TD) {
+ return ::SimplifyICmpInst(Predicate, LHS, RHS, TD, MaxRecursionDepth);
+}
+
/// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
/// fold the result. If not, this returns null.
-Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
- const TargetData *TD) {
+static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
+ const TargetData *TD, unsigned MaxRecurse) {
CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!");
if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
if (Constant *CRHS = dyn_cast<Constant>(RHS))
return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, TD);
-
+
// If we have a constant, make sure it is on the RHS.
std::swap(LHS, RHS);
Pred = CmpInst::getSwappedPredicate(Pred);
}
-
+
// Fold trivial predicates.
if (Pred == FCmpInst::FCMP_FALSE)
return ConstantInt::get(GetCompareTy(LHS), 0);
if (CmpInst::isFalseWhenEqual(Pred))
return ConstantInt::get(GetCompareTy(LHS), 0);
}
-
+
// Handle fcmp with constant RHS
if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
// If the constant is a nan, see if we can fold the comparison based on it.
}
}
}
-
+
+ // If the comparison is with the result of a select instruction, check whether
+ // comparing with either branch of the select always yields the same value.
+ if (MaxRecurse && (isa<SelectInst>(LHS) || isa<SelectInst>(RHS)))
+ if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, TD, MaxRecurse-1))
+ return V;
+
+ // If the comparison is with the result of a phi instruction, check whether
+ // doing the compare with each incoming phi value yields a common result.
+ if (MaxRecurse && (isa<PHINode>(LHS) || isa<PHINode>(RHS)))
+ if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, TD, MaxRecurse-1))
+ return V;
+
return 0;
}
+Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
+ const TargetData *TD) {
+ return ::SimplifyFCmpInst(Predicate, LHS, RHS, TD, MaxRecursionDepth);
+}
+
/// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
/// the result. If not, this returns null.
Value *llvm::SimplifySelectInst(Value *CondVal, Value *TrueVal, Value *FalseVal,
// select false, X, Y -> Y
if (ConstantInt *CB = dyn_cast<ConstantInt>(CondVal))
return CB->getZExtValue() ? TrueVal : FalseVal;
-
+
// select C, X, X -> X
if (TrueVal == FalseVal)
return TrueVal;
-
+
if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X
return FalseVal;
if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
return TrueVal;
return FalseVal;
}
-
-
-
+
return 0;
}
if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1]))
if (C->isZero())
return Ops[0];
-
+
// Check to see if this is constant foldable.
for (unsigned i = 0; i != NumOps; ++i)
if (!isa<Constant>(Ops[i]))
return 0;
-
+
return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]),
(Constant *const*)Ops+1, NumOps-1);
}
/// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
/// fold the result. If not, this returns null.
-Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
- const TargetData *TD) {
+static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
+ const TargetData *TD, unsigned MaxRecurse) {
switch (Opcode) {
- case Instruction::And: return SimplifyAndInst(LHS, RHS, TD);
- case Instruction::Or: return SimplifyOrInst(LHS, RHS, TD);
+ case Instruction::And: return SimplifyAndInst(LHS, RHS, TD, MaxRecurse);
+ case Instruction::Or: return SimplifyOrInst(LHS, RHS, TD, MaxRecurse);
default:
if (Constant *CLHS = dyn_cast<Constant>(LHS))
if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
Constant *COps[] = {CLHS, CRHS};
return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, 2, TD);
}
+
+ // If the operation is with the result of a select instruction, check whether
+ // operating on either branch of the select always yields the same value.
+ if (MaxRecurse && (isa<SelectInst>(LHS) || isa<SelectInst>(RHS)))
+ if (Value *V = ThreadBinOpOverSelect(Opcode, LHS, RHS, TD, MaxRecurse-1))
+ return V;
+
+ // If the operation is with the result of a phi instruction, check whether
+ // operating on all incoming values of the phi always yields the same value.
+ if (MaxRecurse && (isa<PHINode>(LHS) || isa<PHINode>(RHS)))
+ if (Value *V = ThreadBinOpOverPHI(Opcode, LHS, RHS, TD, MaxRecurse-1))
+ return V;
+
return 0;
}
}
+Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
+ const TargetData *TD) {
+ return ::SimplifyBinOp(Opcode, LHS, RHS, TD, MaxRecursionDepth);
+}
+
/// SimplifyCmpInst - Given operands for a CmpInst, see if we can
/// fold the result.
-Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
- const TargetData *TD) {
+static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
+ const TargetData *TD, unsigned MaxRecurse) {
if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate))
- return SimplifyICmpInst(Predicate, LHS, RHS, TD);
- return SimplifyFCmpInst(Predicate, LHS, RHS, TD);
+ return SimplifyICmpInst(Predicate, LHS, RHS, TD, MaxRecurse);
+ return SimplifyFCmpInst(Predicate, LHS, RHS, TD, MaxRecurse);
}
+Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
+ const TargetData *TD) {
+ return ::SimplifyCmpInst(Predicate, LHS, RHS, TD, MaxRecursionDepth);
+}
/// SimplifyInstruction - See if we can compute a simplified version of this
/// instruction. If not, this returns null.
SmallVector<Value*, 8> Ops(I->op_begin(), I->op_end());
return SimplifyGEPInst(&Ops[0], Ops.size(), TD);
}
+ case Instruction::PHI:
+ return cast<PHINode>(I)->hasConstantValue();
}
}
void llvm::ReplaceAndSimplifyAllUses(Instruction *From, Value *To,
const TargetData *TD) {
assert(From != To && "ReplaceAndSimplifyAllUses(X,X) is not valid!");
-
- // FromHandle - This keeps a weakvh on the from value so that we can know if
- // it gets deleted out from under us in a recursive simplification.
+
+ // FromHandle/ToHandle - This keeps a WeakVH on the from/to values so that
+ // we can know if it gets deleted out from under us or replaced in a
+ // recursive simplification.
WeakVH FromHandle(From);
-
+ WeakVH ToHandle(To);
+
while (!From->use_empty()) {
// Update the instruction to use the new value.
- Use &U = From->use_begin().getUse();
- Instruction *User = cast<Instruction>(U.getUser());
- U = To;
-
- // See if we can simplify it.
- if (Value *V = SimplifyInstruction(User, TD)) {
- // Recursively simplify this.
- ReplaceAndSimplifyAllUses(User, V, TD);
-
- // If the recursive simplification ended up revisiting and deleting 'From'
- // then we're done.
- if (FromHandle == 0)
- return;
+ Use &TheUse = From->use_begin().getUse();
+ Instruction *User = cast<Instruction>(TheUse.getUser());
+ TheUse = To;
+
+ // Check to see if the instruction can be folded due to the operand
+ // replacement. For example changing (or X, Y) into (or X, -1) can replace
+ // the 'or' with -1.
+ Value *SimplifiedVal;
+ {
+ // Sanity check to make sure 'User' doesn't dangle across
+ // SimplifyInstruction.
+ AssertingVH<> UserHandle(User);
+
+ SimplifiedVal = SimplifyInstruction(User, TD);
+ if (SimplifiedVal == 0) continue;
}
+
+ // Recursively simplify this user to the new value.
+ ReplaceAndSimplifyAllUses(User, SimplifiedVal, TD);
+ From = dyn_cast_or_null<Instruction>((Value*)FromHandle);
+ To = ToHandle;
+
+ assert(ToHandle && "To value deleted by recursive simplification?");
+
+ // If the recursive simplification ended up revisiting and deleting
+ // 'From' then we're done.
+ if (From == 0)
+ return;
}
+
+ // If 'From' has value handles referring to it, do a real RAUW to update them.
+ From->replaceAllUsesWith(To);
+
From->eraseFromParent();
}
-
projects / oota-llvm.git / blobdiff