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210e45af3a
gvn (this is just a skeleton so far). This will ultimately be used to fix a nasty miscompilation with GVN. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90518 91177308-0d34-0410-b5e6-96231b3b80d8
92 lines
3.6 KiB
C++
92 lines
3.6 KiB
C++
//===- PHITransAddr.h - PHI Translation for Addresses -----------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file declares the PHITransAddr class.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_PHITRANSADDR_H
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#define LLVM_ANALYSIS_PHITRANSADDR_H
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#include "llvm/Instruction.h"
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#include "llvm/ADT/SmallVector.h"
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namespace llvm {
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class DominatorTree;
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class TargetData;
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/// PHITransAddr - An address value which tracks and handles phi translation.
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/// As we walk "up" the CFG through predecessors, we need to ensure that the
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/// address we're tracking is kept up to date. For example, if we're analyzing
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/// an address of "&A[i]" and walk through the definition of 'i' which is a PHI
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/// node, we *must* phi translate i to get "&A[j]" or else we will analyze an
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/// incorrect pointer in the predecessor block.
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///
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/// This is designed to be a relatively small object that lives on the stack and
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/// is copyable.
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///
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class PHITransAddr {
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/// Addr - The actual address we're analyzing.
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Value *Addr;
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/// InstInputs - The inputs for our symbolic address.
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SmallVector<Instruction*, 4> InstInputs;
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public:
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PHITransAddr(Value *addr) : Addr(addr) {
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// If the address is an instruction, the whole thing is considered an input.
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if (Instruction *I = dyn_cast<Instruction>(Addr))
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InstInputs.push_back(I);
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}
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/// NeedsPHITranslationFromBlock - Return true if moving from the specified
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/// BasicBlock to its predecessors requires PHI translation.
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bool NeedsPHITranslationFromBlock(BasicBlock *BB) const {
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// We do need translation if one of our input instructions is defined in
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// this block.
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for (unsigned i = 0, e = InstInputs.size(); i != e; ++i)
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if (InstInputs[i]->getParent() == BB)
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return true;
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return false;
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}
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/// IsPHITranslatable - If this needs PHI translation, return true if we have
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/// some hope of doing it. This should be used as a filter to avoid calling
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/// GetPHITranslatedValue in hopeless situations.
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bool IsPHITranslatable() const;
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/// GetPHITranslatedValue - Given a computation that satisfied the
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/// isPHITranslatable predicate, see if we can translate the computation into
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/// the specified predecessor block. If so, return that value, otherwise
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/// return null.
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Value *GetPHITranslatedValue(Value *InVal, BasicBlock *CurBB,
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BasicBlock *Pred, const TargetData *TD) const;
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/// GetAvailablePHITranslatePointer - Return the value computed by
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/// PHITranslatePointer if it dominates PredBB, otherwise return null.
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Value *GetAvailablePHITranslatedValue(Value *V,
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BasicBlock *CurBB, BasicBlock *PredBB,
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const TargetData *TD,
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const DominatorTree &DT) const;
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/// InsertPHITranslatedPointer - Insert a computation of the PHI translated
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/// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
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/// block. All newly created instructions are added to the NewInsts list.
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/// This returns null on failure.
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///
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Value *InsertPHITranslatedPointer(Value *InVal, BasicBlock *CurBB,
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BasicBlock *PredBB, const TargetData *TD,
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const DominatorTree &DT,
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SmallVectorImpl<Instruction*> &NewInsts) const;
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};
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} // end namespace llvm
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#endif
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