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//===- PtrUseVisitor.cpp - InstVisitors over a pointers uses --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
/// Implementation of the pointer use visitors.
///
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/PtrUseVisitor.h"
using namespace llvm;
void detail::PtrUseVisitorBase::enqueueUsers(Instruction &I) {
for (Value::use_iterator UI = I.use_begin(), UE = I.use_end();
UI != UE; ++UI) {
if (VisitedUses.insert(&UI.getUse())) {
UseToVisit NewU = {
UseToVisit::UseAndIsOffsetKnownPair(&UI.getUse(), IsOffsetKnown),
Offset
};
Worklist.push_back(llvm_move(NewU));
}
}
}
bool detail::PtrUseVisitorBase::adjustOffsetForGEP(GetElementPtrInst &GEPI) {
if (!IsOffsetKnown)
return false;
for (gep_type_iterator GTI = gep_type_begin(GEPI), GTE = gep_type_end(GEPI);
GTI != GTE; ++GTI) {
ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand());
if (!OpC)
return false;
if (OpC->isZero())
continue;
// Handle a struct index, which adds its field offset to the pointer.
if (StructType *STy = dyn_cast<StructType>(*GTI)) {
unsigned ElementIdx = OpC->getZExtValue();
const StructLayout *SL = DL.getStructLayout(STy);
Offset += APInt(Offset.getBitWidth(),
SL->getElementOffset(ElementIdx));
continue;
}
// For array or vector indices, scale the index by the size of the type.
APInt Index = OpC->getValue().sextOrTrunc(Offset.getBitWidth());
Offset += Index * APInt(Offset.getBitWidth(),
DL.getTypeAllocSize(GTI.getIndexedType()));
}
return true;
}
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