[llvm-commits] [llvm] r90779 - in /llvm/trunk: include/llvm/Analysis/PHITransAddr.h lib/Analysis/PHITransAddr.cpp
Chris Lattner
sabre at nondot.org
Mon Dec 7 10:36:53 PST 2009
Author: lattner
Date: Mon Dec 7 12:36:53 2009
New Revision: 90779
URL: http://llvm.org/viewvc/llvm-project?rev=90779&view=rev
Log:
checkpoint of the new PHITransAddr code, still not done and not used by
anything.
Modified:
llvm/trunk/include/llvm/Analysis/PHITransAddr.h
llvm/trunk/lib/Analysis/PHITransAddr.cpp
Modified: llvm/trunk/include/llvm/Analysis/PHITransAddr.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/PHITransAddr.h?rev=90779&r1=90778&r2=90779&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/PHITransAddr.h (original)
+++ llvm/trunk/include/llvm/Analysis/PHITransAddr.h Mon Dec 7 12:36:53 2009
@@ -35,10 +35,13 @@
/// Addr - The actual address we're analyzing.
Value *Addr;
+ /// TD - The target data we are playing with if known, otherwise null.
+ const TargetData *TD;
+
/// InstInputs - The inputs for our symbolic address.
SmallVector<Instruction*, 4> InstInputs;
public:
- PHITransAddr(Value *addr) : Addr(addr) {
+ PHITransAddr(Value *addr, const TargetData *td) : Addr(addr), TD(td) {
// If the address is an instruction, the whole thing is considered an input.
if (Instruction *I = dyn_cast<Instruction>(Addr))
InstInputs.push_back(I);
@@ -55,35 +58,44 @@
return false;
}
- /// IsPHITranslatable - If this needs PHI translation, return true if we have
- /// some hope of doing it. This should be used as a filter to avoid calling
- /// GetPHITranslatedValue in hopeless situations.
- bool IsPHITranslatable() const;
-
- /// GetPHITranslatedValue - Given a computation that satisfied the
- /// isPHITranslatable predicate, see if we can translate the computation into
- /// the specified predecessor block. If so, return that value, otherwise
- /// return null.
- Value *GetPHITranslatedValue(Value *InVal, BasicBlock *CurBB,
- BasicBlock *Pred, const TargetData *TD) const;
-
- /// GetAvailablePHITranslatePointer - Return the value computed by
- /// PHITranslatePointer if it dominates PredBB, otherwise return null.
- Value *GetAvailablePHITranslatedValue(Value *V,
- BasicBlock *CurBB, BasicBlock *PredBB,
- const TargetData *TD,
- const DominatorTree &DT) const;
+ /// IsPotentiallyPHITranslatable - If this needs PHI translation, return true
+ /// if we have some hope of doing it. This should be used as a filter to
+ /// avoid calling PHITranslateValue in hopeless situations.
+ bool IsPotentiallyPHITranslatable() const;
+
+ /// PHITranslateValue - PHI translate the current address up the CFG from
+ /// CurBB to Pred, updating our state the reflect any needed changes. This
+ /// returns true on failure.
+ bool PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB);
+
+ /// PHITranslateWithInsertion - PHI translate this value into the specified
+ /// predecessor block, inserting a computation of the value if it is
+ /// unavailable.
+ ///
+ /// All newly created instructions are added to the NewInsts list. This
+ /// returns null on failure.
+ ///
+ Value *PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB,
+ const DominatorTree &DT,
+ SmallVectorImpl<Instruction*> &NewInsts);
+private:
+ Value *PHITranslateSubExpr(Value *V, BasicBlock *CurBB, BasicBlock *PredBB);
+
+
+ /// GetAvailablePHITranslatedSubExpr - Return the value computed by
+ /// PHITranslateSubExpr if it dominates PredBB, otherwise return null.
+ Value *GetAvailablePHITranslatedSubExpr(Value *V,
+ BasicBlock *CurBB, BasicBlock *PredBB,
+ const DominatorTree &DT);
- /// InsertPHITranslatedPointer - Insert a computation of the PHI translated
+ /// InsertPHITranslatedSubExpr - Insert a computation of the PHI translated
/// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
/// block. All newly created instructions are added to the NewInsts list.
/// This returns null on failure.
///
- Value *InsertPHITranslatedPointer(Value *InVal, BasicBlock *CurBB,
- BasicBlock *PredBB, const TargetData *TD,
- const DominatorTree &DT,
- SmallVectorImpl<Instruction*> &NewInsts) const;
-
+ Value *InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
+ BasicBlock *PredBB, const DominatorTree &DT,
+ SmallVectorImpl<Instruction*> &NewInsts);
};
} // end namespace llvm
Modified: llvm/trunk/lib/Analysis/PHITransAddr.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/PHITransAddr.cpp?rev=90779&r1=90778&r2=90779&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/PHITransAddr.cpp (original)
+++ llvm/trunk/lib/Analysis/PHITransAddr.cpp Mon Dec 7 12:36:53 2009
@@ -13,36 +13,178 @@
#include "llvm/Analysis/PHITransAddr.h"
#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/InstructionSimplify.h"
using namespace llvm;
-/// IsPHITranslatable - If this needs PHI translation, return true if we have
-/// some hope of doing it. This should be used as a filter to avoid calling
-/// GetPHITranslatedValue in hopeless situations.
-bool PHITransAddr::IsPHITranslatable() const {
- return true; // not a good filter.
+/// IsPotentiallyPHITranslatable - If this needs PHI translation, return true
+/// if we have some hope of doing it. This should be used as a filter to
+/// avoid calling PHITranslateValue in hopeless situations.
+bool PHITransAddr::IsPotentiallyPHITranslatable() const {
+ // If the input value is not an instruction, or if it is not defined in CurBB,
+ // then we don't need to phi translate it.
+ Instruction *Inst = dyn_cast<Instruction>(Addr);
+ if (isa<PHINode>(Inst) ||
+ isa<BitCastInst>(Inst) ||
+ isa<GetElementPtrInst>(Inst) ||
+ (Inst->getOpcode() == Instruction::And &&
+ isa<ConstantInt>(Inst->getOperand(1))))
+ return true;
+
+ // cerr << "MEMDEP: Could not PHI translate: " << *Pointer;
+ // if (isa<BitCastInst>(PtrInst) || isa<GetElementPtrInst>(PtrInst))
+ // cerr << "OP:\t\t\t\t" << *PtrInst->getOperand(0);
+
+ return false;
}
-/// GetPHITranslatedValue - Given a computation that satisfied the
-/// isPHITranslatable predicate, see if we can translate the computation into
-/// the specified predecessor block. If so, return that value, otherwise
-/// return null.
-Value *PHITransAddr::GetPHITranslatedValue(Value *InVal, BasicBlock *CurBB,
- BasicBlock *Pred,
- const TargetData *TD) const {
- // Not a great implementation.
- return 0;
+
+Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB,
+ BasicBlock *PredBB) {
+ // If this is a non-instruction value, it can't require PHI translation.
+ Instruction *Inst = dyn_cast<Instruction>(V);
+ if (Inst == 0) return V;
+
+ // Determine whether 'Inst' is an input to our PHI translatable expression.
+ bool isInput = std::count(InstInputs.begin(), InstInputs.end(), Inst);
+
+ // If 'Inst' is not defined in this block, it is either an input, or an
+ // intermediate result.
+ if (Inst->getParent() != CurBB) {
+ // If it is an input, then it remains an input.
+ if (isInput)
+ return Inst;
+
+ // Otherwise, it must be an intermediate result. See if its operands need
+ // to be phi translated, and if so, reconstruct it.
+
+ if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst)) {
+ Value *PHIIn = PHITranslateSubExpr(BC->getOperand(0), CurBB, PredBB);
+ if (PHIIn == 0) return 0;
+ if (PHIIn == BC->getOperand(0))
+ return BC;
+
+ // Find an available version of this cast.
+
+ // Constants are trivial to find.
+ if (Constant *C = dyn_cast<Constant>(PHIIn))
+ return ConstantExpr::getBitCast(C, BC->getType());
+
+ // Otherwise we have to see if a bitcasted version of the incoming pointer
+ // is available. If so, we can use it, otherwise we have to fail.
+ for (Value::use_iterator UI = PHIIn->use_begin(), E = PHIIn->use_end();
+ UI != E; ++UI) {
+ if (BitCastInst *BCI = dyn_cast<BitCastInst>(*UI))
+ if (BCI->getType() == BC->getType())
+ return BCI;
+ }
+ return 0;
+ }
+
+ // Handle getelementptr with at least one PHI translatable operand.
+ if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
+ SmallVector<Value*, 8> GEPOps;
+ BasicBlock *CurBB = GEP->getParent();
+ bool AnyChanged = false;
+ for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
+ Value *GEPOp = PHITranslateSubExpr(GEP->getOperand(i), CurBB, PredBB);
+ if (GEPOp == 0) return 0;
+
+ AnyChanged = GEPOp != GEP->getOperand(i);
+ GEPOps.push_back(GEPOp);
+ }
+
+ if (!AnyChanged)
+ return GEP;
+
+ // Simplify the GEP to handle 'gep x, 0' -> x etc.
+ if (Value *V = SimplifyGEPInst(&GEPOps[0], GEPOps.size(), TD))
+ return V;
+
+ // Scan to see if we have this GEP available.
+ Value *APHIOp = GEPOps[0];
+ for (Value::use_iterator UI = APHIOp->use_begin(), E = APHIOp->use_end();
+ UI != E; ++UI) {
+ if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*UI))
+ if (GEPI->getType() == GEP->getType() &&
+ GEPI->getNumOperands() == GEPOps.size() &&
+ GEPI->getParent()->getParent() == CurBB->getParent()) {
+ bool Mismatch = false;
+ for (unsigned i = 0, e = GEPOps.size(); i != e; ++i)
+ if (GEPI->getOperand(i) != GEPOps[i]) {
+ Mismatch = true;
+ break;
+ }
+ if (!Mismatch)
+ return GEPI;
+ }
+ }
+ return 0;
+ }
+
+ // Handle add with a constant RHS.
+ if (Inst->getOpcode() == Instruction::Add &&
+ isa<ConstantInt>(Inst->getOperand(1))) {
+ // PHI translate the LHS.
+ Constant *RHS = cast<ConstantInt>(Inst->getOperand(1));
+ bool isNSW = cast<BinaryOperator>(Inst)->hasNoSignedWrap();
+ bool isNUW = cast<BinaryOperator>(Inst)->hasNoUnsignedWrap();
+
+ Value *LHS = PHITranslateSubExpr(Inst->getOperand(0), CurBB, PredBB);
+ if (LHS == 0) return 0;
+
+ // If the PHI translated LHS is an add of a constant, fold the immediates.
+ if (BinaryOperator *BOp = dyn_cast<BinaryOperator>(LHS))
+ if (BOp->getOpcode() == Instruction::Add)
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(BOp->getOperand(1))) {
+ LHS = BOp->getOperand(0);
+ RHS = ConstantExpr::getAdd(RHS, CI);
+ isNSW = isNUW = false;
+ }
+
+ // See if the add simplifies away.
+ if (Value *Res = SimplifyAddInst(LHS, RHS, isNSW, isNUW, TD))
+ return Res;
+
+ // Otherwise, see if we have this add available somewhere.
+ for (Value::use_iterator UI = LHS->use_begin(), E = LHS->use_end();
+ UI != E; ++UI) {
+ if (BinaryOperator *BO = dyn_cast<BinaryOperator>(*UI))
+ if (BO->getOperand(0) == LHS && BO->getOperand(1) == RHS &&
+ BO->getParent()->getParent() == CurBB->getParent())
+ return BO;
+ }
+
+ return 0;
+ }
+
+ // Otherwise, we failed.
+ return 0;
+ }
+
+ // Otherwise, it is defined in this block. It must be an input and must be
+ // phi translated.
+ assert(isInput && "Instruction defined in block must be an input");
+
+
+ abort(); // unimplemented so far.
}
-/// GetAvailablePHITranslatePointer - Return the value computed by
-/// PHITranslatePointer if it dominates PredBB, otherwise return null.
+
+/// PHITranslateValue - PHI translate the current address up the CFG from
+/// CurBB to Pred, updating our state the reflect any needed changes. This
+/// returns true on failure.
+bool PHITransAddr::PHITranslateValue(BasicBlock *CurBB, BasicBlock *PredBB) {
+ Addr = PHITranslateSubExpr(Addr, CurBB, PredBB);
+ return Addr == 0;
+}
+
+/// GetAvailablePHITranslatedSubExpr - Return the value computed by
+/// PHITranslateSubExpr if it dominates PredBB, otherwise return null.
Value *PHITransAddr::
-GetAvailablePHITranslatedValue(Value *V,
- BasicBlock *CurBB, BasicBlock *PredBB,
- const TargetData *TD,
- const DominatorTree &DT) const {
+GetAvailablePHITranslatedSubExpr(Value *V, BasicBlock *CurBB,BasicBlock *PredBB,
+ const DominatorTree &DT) {
// See if PHI translation succeeds.
- V = GetPHITranslatedValue(V, CurBB, PredBB, TD);
- if (V == 0) return 0;
+ V = PHITranslateSubExpr(V, CurBB, PredBB);
// Make sure the value is live in the predecessor.
if (Instruction *Inst = dyn_cast_or_null<Instruction>(V))
@@ -51,21 +193,107 @@
return V;
}
+
+/// PHITranslateWithInsertion - PHI translate this value into the specified
+/// predecessor block, inserting a computation of the value if it is
+/// unavailable.
+///
+/// All newly created instructions are added to the NewInsts list. This
+/// returns null on failure.
+///
+Value *PHITransAddr::
+PHITranslateWithInsertion(BasicBlock *CurBB, BasicBlock *PredBB,
+ const DominatorTree &DT,
+ SmallVectorImpl<Instruction*> &NewInsts) {
+ unsigned NISize = NewInsts.size();
+
+ // Attempt to PHI translate with insertion.
+ Addr = InsertPHITranslatedSubExpr(Addr, CurBB, PredBB, DT, NewInsts);
+
+ // If successful, return the new value.
+ if (Addr) return Addr;
+
+ // If not, destroy any intermediate instructions inserted.
+ while (NewInsts.size() != NISize)
+ NewInsts.pop_back_val()->eraseFromParent();
+ return 0;
+}
+
+
/// InsertPHITranslatedPointer - Insert a computation of the PHI translated
/// version of 'V' for the edge PredBB->CurBB into the end of the PredBB
/// block. All newly created instructions are added to the NewInsts list.
/// This returns null on failure.
///
Value *PHITransAddr::
-InsertPHITranslatedPointer(Value *InVal, BasicBlock *CurBB,
- BasicBlock *PredBB, const TargetData *TD,
- const DominatorTree &DT,
- SmallVectorImpl<Instruction*> &NewInsts) const {
+InsertPHITranslatedSubExpr(Value *InVal, BasicBlock *CurBB,
+ BasicBlock *PredBB, const DominatorTree &DT,
+ SmallVectorImpl<Instruction*> &NewInsts) {
// See if we have a version of this value already available and dominating
- // PredBB. If so, there is no need to insert a new copy.
- if (Value *Res = GetAvailablePHITranslatedValue(InVal, CurBB, PredBB, TD, DT))
+ // PredBB. If so, there is no need to insert a new instance of it.
+ if (Value *Res = GetAvailablePHITranslatedSubExpr(InVal, CurBB, PredBB, DT))
return Res;
- // Not a great implementation.
+ // If we don't have an available version of this value, it must be an
+ // instruction.
+ Instruction *Inst = cast<Instruction>(InVal);
+
+ // Handle bitcast of PHI translatable value.
+ if (BitCastInst *BC = dyn_cast<BitCastInst>(Inst)) {
+ Value *OpVal = InsertPHITranslatedSubExpr(BC->getOperand(0),
+ CurBB, PredBB, DT, NewInsts);
+ if (OpVal == 0) return 0;
+
+ // Otherwise insert a bitcast at the end of PredBB.
+ BitCastInst *New = new BitCastInst(OpVal, InVal->getType(),
+ InVal->getName()+".phi.trans.insert",
+ PredBB->getTerminator());
+ NewInsts.push_back(New);
+ return New;
+ }
+
+ // Handle getelementptr with at least one PHI operand.
+ if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
+ SmallVector<Value*, 8> GEPOps;
+ BasicBlock *CurBB = GEP->getParent();
+ for (unsigned i = 0, e = GEP->getNumOperands(); i != e; ++i) {
+ Value *OpVal = InsertPHITranslatedSubExpr(GEP->getOperand(i),
+ CurBB, PredBB, DT, NewInsts);
+ if (OpVal == 0) return 0;
+ GEPOps.push_back(OpVal);
+ }
+
+ GetElementPtrInst *Result =
+ GetElementPtrInst::Create(GEPOps[0], GEPOps.begin()+1, GEPOps.end(),
+ InVal->getName()+".phi.trans.insert",
+ PredBB->getTerminator());
+ Result->setIsInBounds(GEP->isInBounds());
+ NewInsts.push_back(Result);
+ return Result;
+ }
+
+#if 0
+ // FIXME: This code works, but it is unclear that we actually want to insert
+ // a big chain of computation in order to make a value available in a block.
+ // This needs to be evaluated carefully to consider its cost trade offs.
+
+ // Handle add with a constant RHS.
+ if (Inst->getOpcode() == Instruction::Add &&
+ isa<ConstantInt>(Inst->getOperand(1))) {
+ // PHI translate the LHS.
+ Value *OpVal = InsertPHITranslatedSubExpr(Inst->getOperand(0),
+ CurBB, PredBB, DT, NewInsts);
+ if (OpVal == 0) return 0;
+
+ BinaryOperator *Res = BinaryOperator::CreateAdd(OpVal, Inst->getOperand(1),
+ InVal->getName()+".phi.trans.insert",
+ PredBB->getTerminator());
+ Res->setHasNoSignedWrap(cast<BinaryOperator>(Inst)->hasNoSignedWrap());
+ Res->setHasNoUnsignedWrap(cast<BinaryOperator>(Inst)->hasNoUnsignedWrap());
+ NewInsts.push_back(Res);
+ return Res;
+ }
+#endif
+
return 0;
}
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