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Move llvm::ConstantFoldInstruction from here to Transforms/Utils

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10784 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-01-12 18:25:03 +00:00
parent ccd3a878d0
commit 28aabc34f7
1 changed files with 0 additions and 58 deletions
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58
lib/VMCore/ConstantFold.cpp
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@ -19,64 +19,6 @@
#include <cmath>
using namespace llvm;
// ConstantFoldInstruction - Attempt to constant fold the specified instruction.
// If successful, the constant result is returned, if not, null is returned.
//
Constant *llvm::ConstantFoldInstruction(Instruction *I) {
if (PHINode *PN = dyn_cast<PHINode>(I)) {
if (PN->getNumIncomingValues() == 0)
return Constant::getNullValue(PN->getType());
Constant *Result = dyn_cast<Constant>(PN->getIncomingValue(0));
if (Result == 0) return 0;
// Handle PHI nodes specially here...
for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i)
if (PN->getIncomingValue(i) != Result)
return 0; // Not all the same incoming constants...
// If we reach here, all incoming values are the same constant.
return Result;
}
Constant *Op0 = 0;
Constant *Op1 = 0;
if (I->getNumOperands() != 0) { // Get first operand if it's a constant...
Op0 = dyn_cast<Constant>(I->getOperand(0));
if (Op0 == 0) return 0; // Not a constant?, can't fold
if (I->getNumOperands() != 1) { // Get second operand if it's a constant...
Op1 = dyn_cast<Constant>(I->getOperand(1));
if (Op1 == 0) return 0; // Not a constant?, can't fold
}
}
if (isa<BinaryOperator>(I))
return ConstantExpr::get(I->getOpcode(), Op0, Op1);
switch (I->getOpcode()) {
case Instruction::Cast:
return ConstantExpr::getCast(Op0, I->getType());
case Instruction::Shl:
case Instruction::Shr:
return ConstantExpr::getShift(I->getOpcode(), Op0, Op1);
case Instruction::GetElementPtr: {
std::vector<Constant*> IdxList;
IdxList.reserve(I->getNumOperands()-1);
if (Op1) IdxList.push_back(Op1);
for (unsigned i = 2, e = I->getNumOperands(); i != e; ++i)
if (Constant *C = dyn_cast<Constant>(I->getOperand(i)))
IdxList.push_back(C);
else
return 0; // Non-constant operand
return ConstantExpr::getGetElementPtr(Op0, IdxList);
}
default:
return 0;
}
}
static unsigned getSize(const Type *Ty) {
unsigned S = Ty->getPrimitiveSize();
return S ? S : 8; // Treat pointers at 8 bytes