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Implement testcase: Assembler/2003-08-20-ConstantExprGEP-Fold.llx

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llvm-svn: 7983
This commit is contained in:
Chris Lattner 2003-08-20 16:11:27 +00:00
parent 0f2fda7957
commit 6c9f00c920
1 changed files with 14 additions and 10 deletions
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24
lib/VMCore/ConstantHandling.cpp
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@ -142,23 +142,27 @@ Constant *ConstantFoldGetElementPtr(const Constant *C,
// FIXME: Implement folding of GEP constant exprs the same as instcombine does
if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
// Implement folding of:
// void ()** getelementptr (%struct..TorRec* getelementptr
// ([N x %struct..TorRec]* %llvm.global_dtors, long 0, long 0),
// long 0, ubyte 1)
// Into:
// %struct..TorRec* getelementptr ([N x %struct..TorRec]*
// %llvm.global_dtors, long 0, long 0, ubyte 1)
// Combine Indices - If the source pointer to this getelementptr instruction
// is a getelementptr instruction, combine the indices of the two
// getelementptr instructions into a single instruction.
//
if (CE->getOpcode() == Instruction::GetElementPtr)
if (IdxList[0] == Constant::getNullValue(Type::LongTy)) {
if (CE->getOpcode() == Instruction::GetElementPtr) {
if (CE->getOperand(CE->getNumOperands()-1)->getType() == Type::LongTy) {
std::vector<Constant*> NewIndices;
NewIndices.reserve(IdxList.size() + CE->getNumOperands());
for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
for (unsigned i = 1, e = CE->getNumOperands()-1; i != e; ++i)
NewIndices.push_back(cast<Constant>(CE->getOperand(i)));
// Add the last index of the source with the first index of the new GEP.
Constant *Combined =
ConstantExpr::get(Instruction::Add, IdxList[0],
CE->getOperand(CE->getNumOperands()-1));
NewIndices.push_back(Combined);
NewIndices.insert(NewIndices.end(), IdxList.begin()+1, IdxList.end());
return ConstantExpr::getGetElementPtr(CE->getOperand(0), NewIndices);
}
}
// Implement folding of:
// int* getelementptr ([2 x int]* cast ([3 x int]* %X to [2 x int]*),