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Fix a crash compiling 134.perl.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19711 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-01-20 16:50:16 +00:00
parent b1923f8dd5
commit bf52d49f36
1 changed files with 41 additions and 21 deletions
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62
lib/Target/X86/X86ISelPattern.cpp
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@ -490,6 +490,27 @@ unsigned ISel::ComputeRegPressure(SDOperand O) {
return Result;
}
/// NodeTransitivelyUsesValue - Return true if N or any of its uses uses Op.
/// The DAG cannot have cycles in it, by definition, so the visited set is not
/// needed to prevent infinite loops. The DAG CAN, however, have unbounded
/// reuse, so it prevents exponential cases.
///
static bool NodeTransitivelyUsesValue(SDOperand N, SDOperand Op,
std::set<SDNode*> &Visited) {
if (N == Op) return true; // Found it.
SDNode *Node = N.Val;
if (Node->getNumOperands() == 0) return false; // Leaf?
if (!Visited.insert(Node).second) return false; // Already visited?
// Recurse for the first N-1 operands.
for (unsigned i = 1, e = Node->getNumOperands(); i != e; ++i)
if (NodeTransitivelyUsesValue(Node->getOperand(i), Op, Visited))
return true;
// Tail recurse for the last operand.
return NodeTransitivelyUsesValue(Node->getOperand(0), Op, Visited);
}
X86AddressMode ISel::SelectAddrExprs(const X86ISelAddressMode &IAM) {
X86AddressMode Result;
@ -497,13 +518,33 @@ X86AddressMode ISel::SelectAddrExprs(const X86ISelAddressMode &IAM) {
// register pressure first.
if (IAM.BaseType == X86ISelAddressMode::RegBase &&
IAM.Base.Reg.Val && IAM.IndexReg.Val) {
bool EmitBaseThenIndex;
if (getRegPressure(IAM.Base.Reg) > getRegPressure(IAM.IndexReg)) {
std::set<SDNode*> Visited;
EmitBaseThenIndex = true;
// If Base ends up pointing to Index, we must emit index first. This is
// because of the way we fold loads, we may end up doing bad things with
// the folded add.
if (NodeTransitivelyUsesValue(IAM.Base.Reg, IAM.IndexReg, Visited))
EmitBaseThenIndex = false;
} else {
std::set<SDNode*> Visited;
EmitBaseThenIndex = false;
// If Base ends up pointing to Index, we must emit index first. This is
// because of the way we fold loads, we may end up doing bad things with
// the folded add.
if (NodeTransitivelyUsesValue(IAM.IndexReg, IAM.Base.Reg, Visited))
EmitBaseThenIndex = true;
}
if (EmitBaseThenIndex) {
Result.Base.Reg = SelectExpr(IAM.Base.Reg);
Result.IndexReg = SelectExpr(IAM.IndexReg);
} else {
Result.IndexReg = SelectExpr(IAM.IndexReg);
Result.Base.Reg = SelectExpr(IAM.Base.Reg);
}
} else if (IAM.BaseType == X86ISelAddressMode::RegBase && IAM.Base.Reg.Val) {
Result.Base.Reg = SelectExpr(IAM.Base.Reg);
} else if (IAM.IndexReg.Val) {
@ -1070,27 +1111,6 @@ void ISel::EmitCMP(SDOperand LHS, SDOperand RHS, bool HasOneUse) {
BuildMI(BB, Opc, 2).addReg(Tmp1).addReg(Tmp2);
}
/// NodeTransitivelyUsesValue - Return true if N or any of its uses uses Op.
/// The DAG cannot have cycles in it, by definition, so the visited set is not
/// needed to prevent infinite loops. The DAG CAN, however, have unbounded
/// reuse, so it prevents exponential cases.
///
static bool NodeTransitivelyUsesValue(SDOperand N, SDOperand Op,
std::set<SDNode*> &Visited) {
if (N == Op) return true; // Found it.
SDNode *Node = N.Val;
if (Node->getNumOperands() == 0) return false; // Leaf?
if (!Visited.insert(Node).second) return false; // Already visited?
// Recurse for the first N-1 operands.
for (unsigned i = 1, e = Node->getNumOperands(); i != e; ++i)
if (NodeTransitivelyUsesValue(Node->getOperand(i), Op, Visited))
return true;
// Tail recurse for the last operand.
return NodeTransitivelyUsesValue(Node->getOperand(0), Op, Visited);
}
/// isFoldableLoad - Return true if this is a load instruction that can safely
/// be folded into an operation that uses it.
bool ISel::isFoldableLoad(SDOperand Op, SDOperand OtherOp) {