mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2025-01-12 17:32:19 +00:00
checkpoint of the new PHITransAddr code, still not done and not used by
anything. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90779 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
parent
abf31b9d09
commit
9a8641201b
@ -35,10 +35,13 @@ class PHITransAddr {
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/// Addr - The actual address we're analyzing.
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Value *Addr;
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/// TD - The target data we are playing with if known, otherwise null.
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const TargetData *TD;
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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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PHITransAddr(Value *addr, const TargetData *td) : Addr(addr), TD(td) {
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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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@ -55,35 +58,44 @@ public:
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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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/// IsPotentiallyPHITranslatable - If this needs PHI translation, return true
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/// if we have some hope of doing it. This should be used as a filter to
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/// avoid calling PHITranslateValue in hopeless situations.
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bool IsPotentiallyPHITranslatable() 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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/// PHITranslateValue - PHI translate the current address up the CFG from
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/// CurBB to Pred, updating our state the reflect any needed changes. This
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/// returns true on failure.
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bool PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB);
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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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/// PHITranslateWithInsertion - PHI translate this value into the specified
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/// predecessor block, inserting a computation of the value if it is
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/// unavailable.
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///
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/// All newly created instructions are added to the NewInsts list. This
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/// returns null on failure.
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///
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Value *PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB,
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const DominatorTree &DT,
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SmallVectorImpl<Instruction*> &NewInsts);
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private:
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Value *PHITranslateSubExpr(Value *V, BasicBlock *CurBB, BasicBlock *PredBB);
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/// InsertPHITranslatedPointer - Insert a computation of the PHI translated
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/// GetAvailablePHITranslatedSubExpr - Return the value computed by
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/// PHITranslateSubExpr if it dominates PredBB, otherwise return null.
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Value *GetAvailablePHITranslatedSubExpr(Value *V,
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BasicBlock *CurBB, BasicBlock *PredBB,
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const DominatorTree &DT);
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/// InsertPHITranslatedSubExpr - 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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Value *InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
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BasicBlock *PredBB, const DominatorTree &DT,
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SmallVectorImpl<Instruction*> &NewInsts);
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};
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} // end namespace llvm
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@ -13,36 +13,178 @@
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#include "llvm/Analysis/PHITransAddr.h"
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Analysis/InstructionSimplify.h"
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using namespace llvm;
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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 PHITransAddr::IsPHITranslatable() const {
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return true; // not a good filter.
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/// IsPotentiallyPHITranslatable - If this needs PHI translation, return true
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/// if we have some hope of doing it. This should be used as a filter to
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/// avoid calling PHITranslateValue in hopeless situations.
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bool PHITransAddr::IsPotentiallyPHITranslatable() const {
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// If the input value is not an instruction, or if it is not defined in CurBB,
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// then we don't need to phi translate it.
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Instruction *Inst = dyn_cast<Instruction>(Addr);
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if (isa<PHINode>(Inst) ||
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isa<BitCastInst>(Inst) ||
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isa<GetElementPtrInst>(Inst) ||
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(Inst->getOpcode() == Instruction::And &&
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isa<ConstantInt>(Inst->getOperand(1))))
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return true;
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// cerr << "MEMDEP: Could not PHI translate: " << *Pointer;
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// if (isa<BitCastInst>(PtrInst) || isa<GetElementPtrInst>(PtrInst))
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// cerr << "OP:\t\t\t\t" << *PtrInst->getOperand(0);
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return false;
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}
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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 *PHITransAddr::GetPHITranslatedValue(Value *InVal, BasicBlock *CurBB,
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BasicBlock *Pred,
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const TargetData *TD) const {
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// Not a great implementation.
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return 0;
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Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB,
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BasicBlock *PredBB) {
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// If this is a non-instruction value, it can't require PHI translation.
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Instruction *Inst = dyn_cast<Instruction>(V);
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if (Inst == 0) return V;
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// Determine whether 'Inst' is an input to our PHI translatable expression.
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bool isInput = std::count(InstInputs.begin(), InstInputs.end(), Inst);
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// If 'Inst' is not defined in this block, it is either an input, or an
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// intermediate result.
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if (Inst->getParent() != CurBB) {
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// If it is an input, then it remains an input.
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if (isInput)
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return Inst;
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// Otherwise, it must be an intermediate result. See if its operands need
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// to be phi translated, and if so, reconstruct it.
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if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst)) {
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Value *PHIIn = PHITranslateSubExpr(BC->getOperand(0), CurBB, PredBB);
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if (PHIIn == 0) return 0;
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if (PHIIn == BC->getOperand(0))
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return BC;
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// Find an available version of this cast.
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// Constants are trivial to find.
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if (Constant *C = dyn_cast<Constant>(PHIIn))
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return ConstantExpr::getBitCast(C, BC->getType());
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// Otherwise we have to see if a bitcasted version of the incoming pointer
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// is available. If so, we can use it, otherwise we have to fail.
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for (Value::use_iterator UI = PHIIn->use_begin(), E = PHIIn->use_end();
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UI != E; ++UI) {
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if (BitCastInst *BCI = dyn_cast<BitCastInst>(*UI))
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if (BCI->getType() == BC->getType())
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return BCI;
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}
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return 0;
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}
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// Handle getelementptr with at least one PHI translatable operand.
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if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
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SmallVector<Value*, 8> GEPOps;
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BasicBlock *CurBB = GEP->getParent();
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bool AnyChanged = false;
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for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
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Value *GEPOp = PHITranslateSubExpr(GEP->getOperand(i), CurBB, PredBB);
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if (GEPOp == 0) return 0;
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AnyChanged = GEPOp != GEP->getOperand(i);
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GEPOps.push_back(GEPOp);
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}
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if (!AnyChanged)
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return GEP;
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// Simplify the GEP to handle 'gep x, 0' -> x etc.
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if (Value *V = SimplifyGEPInst(&GEPOps[0], GEPOps.size(), TD))
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return V;
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// Scan to see if we have this GEP available.
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Value *APHIOp = GEPOps[0];
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for (Value::use_iterator UI = APHIOp->use_begin(), E = APHIOp->use_end();
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UI != E; ++UI) {
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if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*UI))
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if (GEPI->getType() == GEP->getType() &&
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GEPI->getNumOperands() == GEPOps.size() &&
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GEPI->getParent()->getParent() == CurBB->getParent()) {
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bool Mismatch = false;
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for (unsigned i = 0, e = GEPOps.size(); i != e; ++i)
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if (GEPI->getOperand(i) != GEPOps[i]) {
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Mismatch = true;
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break;
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}
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if (!Mismatch)
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return GEPI;
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}
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}
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return 0;
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}
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// Handle add with a constant RHS.
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if (Inst->getOpcode() == Instruction::Add &&
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isa<ConstantInt>(Inst->getOperand(1))) {
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// PHI translate the LHS.
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Constant *RHS = cast<ConstantInt>(Inst->getOperand(1));
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bool isNSW = cast<BinaryOperator>(Inst)->hasNoSignedWrap();
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bool isNUW = cast<BinaryOperator>(Inst)->hasNoUnsignedWrap();
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Value *LHS = PHITranslateSubExpr(Inst->getOperand(0), CurBB, PredBB);
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if (LHS == 0) return 0;
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// If the PHI translated LHS is an add of a constant, fold the immediates.
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if (BinaryOperator *BOp = dyn_cast<BinaryOperator>(LHS))
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if (BOp->getOpcode() == Instruction::Add)
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if (ConstantInt *CI = dyn_cast<ConstantInt>(BOp->getOperand(1))) {
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LHS = BOp->getOperand(0);
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RHS = ConstantExpr::getAdd(RHS, CI);
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isNSW = isNUW = false;
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}
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// See if the add simplifies away.
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if (Value *Res = SimplifyAddInst(LHS, RHS, isNSW, isNUW, TD))
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return Res;
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// Otherwise, see if we have this add available somewhere.
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for (Value::use_iterator UI = LHS->use_begin(), E = LHS->use_end();
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UI != E; ++UI) {
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if (BinaryOperator *BO = dyn_cast<BinaryOperator>(*UI))
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if (BO->getOperand(0) == LHS && BO->getOperand(1) == RHS &&
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BO->getParent()->getParent() == CurBB->getParent())
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return BO;
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}
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return 0;
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}
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// Otherwise, we failed.
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return 0;
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}
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// Otherwise, it is defined in this block. It must be an input and must be
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// phi translated.
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assert(isInput && "Instruction defined in block must be an input");
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abort(); // unimplemented so far.
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}
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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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/// PHITranslateValue - PHI translate the current address up the CFG from
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/// CurBB to Pred, updating our state the reflect any needed changes. This
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/// returns true on failure.
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bool PHITransAddr::PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB) {
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Addr = PHITranslateSubExpr(Addr, CurBB, PredBB);
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return Addr == 0;
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}
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/// GetAvailablePHITranslatedSubExpr - Return the value computed by
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/// PHITranslateSubExpr if it dominates PredBB, otherwise return null.
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Value *PHITransAddr::
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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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GetAvailablePHITranslatedSubExpr(Value *V, BasicBlock *CurBB,BasicBlock *PredBB,
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const DominatorTree &DT) {
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// See if PHI translation succeeds.
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V = GetPHITranslatedValue(V, CurBB, PredBB, TD);
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if (V == 0) return 0;
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V = PHITranslateSubExpr(V, CurBB, PredBB);
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// Make sure the value is live in the predecessor.
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if (Instruction *Inst = dyn_cast_or_null<Instruction>(V))
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@ -51,21 +193,107 @@ GetAvailablePHITranslatedValue(Value *V,
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return V;
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}
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/// PHITranslateWithInsertion - PHI translate this value into the specified
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/// predecessor block, inserting a computation of the value if it is
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/// unavailable.
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///
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/// All newly created instructions are added to the NewInsts list. This
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/// returns null on failure.
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///
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Value *PHITransAddr::
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PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB,
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const DominatorTree &DT,
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SmallVectorImpl<Instruction*> &NewInsts) {
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unsigned NISize = NewInsts.size();
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// Attempt to PHI translate with insertion.
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Addr = InsertPHITranslatedSubExpr(Addr, CurBB, PredBB, DT, NewInsts);
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// If successful, return the new value.
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if (Addr) return Addr;
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// If not, destroy any intermediate instructions inserted.
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while (NewInsts.size() != NISize)
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NewInsts.pop_back_val()->eraseFromParent();
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return 0;
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}
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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 *PHITransAddr::
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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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InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
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BasicBlock *PredBB, const DominatorTree &DT,
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SmallVectorImpl<Instruction*> &NewInsts) {
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// See if we have a version of this value already available and dominating
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// PredBB. If so, there is no need to insert a new copy.
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if (Value *Res = GetAvailablePHITranslatedValue(InVal, CurBB, PredBB, TD, DT))
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// PredBB. If so, there is no need to insert a new instance of it.
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if (Value *Res = GetAvailablePHITranslatedSubExpr(InVal, CurBB, PredBB, DT))
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return Res;
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// Not a great implementation.
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// If we don't have an available version of this value, it must be an
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// instruction.
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Instruction *Inst = cast<Instruction>(InVal);
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// Handle bitcast of PHI translatable value.
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if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst)) {
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Value *OpVal = InsertPHITranslatedSubExpr(BC->getOperand(0),
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CurBB, PredBB, DT, NewInsts);
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if (OpVal == 0) return 0;
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// Otherwise insert a bitcast at the end of PredBB.
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BitCastInst *New = new BitCastInst(OpVal, InVal->getType(),
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InVal->getName()+".phi.trans.insert",
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PredBB->getTerminator());
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NewInsts.push_back(New);
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return New;
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}
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// Handle getelementptr with at least one PHI operand.
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if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
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SmallVector<Value*, 8> GEPOps;
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BasicBlock *CurBB = GEP->getParent();
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for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
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Value *OpVal = InsertPHITranslatedSubExpr(GEP->getOperand(i),
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CurBB, PredBB, DT, NewInsts);
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if (OpVal == 0) return 0;
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GEPOps.push_back(OpVal);
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}
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GetElementPtrInst *Result =
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GetElementPtrInst::Create(GEPOps[0], GEPOps.begin()+1, GEPOps.end(),
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InVal->getName()+".phi.trans.insert",
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PredBB->getTerminator());
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Result->setIsInBounds(GEP->isInBounds());
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NewInsts.push_back(Result);
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return Result;
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}
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#if 0
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// FIXME: This code works, but it is unclear that we actually want to insert
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// a big chain of computation in order to make a value available in a block.
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// This needs to be evaluated carefully to consider its cost trade offs.
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// Handle add with a constant RHS.
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if (Inst->getOpcode() == Instruction::Add &&
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isa<ConstantInt>(Inst->getOperand(1))) {
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// PHI translate the LHS.
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Value *OpVal = InsertPHITranslatedSubExpr(Inst->getOperand(0),
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CurBB, PredBB, DT, NewInsts);
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if (OpVal == 0) return 0;
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BinaryOperator *Res = BinaryOperator::CreateAdd(OpVal, Inst->getOperand(1),
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InVal->getName()+".phi.trans.insert",
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PredBB->getTerminator());
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Res->setHasNoSignedWrap(cast<BinaryOperator>(Inst)->hasNoSignedWrap());
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Res->setHasNoUnsignedWrap(cast<BinaryOperator>(Inst)->hasNoUnsignedWrap());
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NewInsts.push_back(Res);
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return Res;
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}
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#endif
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return 0;
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}
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