//
// The LLVM Compiler Infrastructure
//
-// This file was developed by Chris Lattner and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
+#include "llvm/InlineAsm.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
-#include "llvm/Support/Compiler.h"
#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallSet.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/GetElementPtrTypeIterator.h"
using namespace llvm;
+namespace {
+ cl::opt<bool> OptExtUses("optimize-ext-uses",
+ cl::init(true), cl::Hidden);
+}
+
namespace {
class VISIBILITY_HIDDEN CodeGenPrepare : public FunctionPass {
/// TLI - Keep a pointer of a TargetLowering to consult for determining
/// transformation profitability.
const TargetLowering *TLI;
public:
- CodeGenPrepare(const TargetLowering *tli = 0) : TLI(tli) {}
+ static char ID; // Pass identification, replacement for typeid
+ explicit CodeGenPrepare(const TargetLowering *tli = 0)
+ : FunctionPass((intptr_t)&ID), TLI(tli) {}
bool runOnFunction(Function &F);
private:
+ bool EliminateMostlyEmptyBlocks(Function &F);
+ bool CanMergeBlocks(const BasicBlock *BB, const BasicBlock *DestBB) const;
+ void EliminateMostlyEmptyBlock(BasicBlock *BB);
bool OptimizeBlock(BasicBlock &BB);
- bool OptimizeGEPExpression(GetElementPtrInst *GEPI);
+ bool OptimizeLoadStoreInst(Instruction *I, Value *Addr,
+ const Type *AccessTy,
+ DenseMap<Value*,Value*> &SunkAddrs);
+ bool OptimizeInlineAsmInst(Instruction *I, CallSite CS,
+ DenseMap<Value*,Value*> &SunkAddrs);
+ bool OptimizeExtUses(Instruction *I);
};
}
+
+char CodeGenPrepare::ID = 0;
static RegisterPass<CodeGenPrepare> X("codegenprepare",
"Optimize for code generation");
bool CodeGenPrepare::runOnFunction(Function &F) {
- bool MadeChange = true;
bool EverMadeChange = false;
+
+ // First pass, eliminate blocks that contain only PHI nodes and an
+ // unconditional branch.
+ EverMadeChange |= EliminateMostlyEmptyBlocks(F);
+
+ bool MadeChange = true;
while (MadeChange) {
MadeChange = false;
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
return EverMadeChange;
}
-/// SplitEdgeNicely - Split the critical edge from TI to it's specified
+/// EliminateMostlyEmptyBlocks - eliminate blocks that contain only PHI nodes
+/// and an unconditional branch. Passes before isel (e.g. LSR/loopsimplify)
+/// often split edges in ways that are non-optimal for isel. Start by
+/// eliminating these blocks so we can split them the way we want them.
+bool CodeGenPrepare::EliminateMostlyEmptyBlocks(Function &F) {
+ bool MadeChange = false;
+ // Note that this intentionally skips the entry block.
+ for (Function::iterator I = ++F.begin(), E = F.end(); I != E; ) {
+ BasicBlock *BB = I++;
+
+ // If this block doesn't end with an uncond branch, ignore it.
+ BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
+ if (!BI || !BI->isUnconditional())
+ continue;
+
+ // If the instruction before the branch isn't a phi node, then other stuff
+ // is happening here.
+ BasicBlock::iterator BBI = BI;
+ if (BBI != BB->begin()) {
+ --BBI;
+ if (!isa<PHINode>(BBI)) continue;
+ }
+
+ // Do not break infinite loops.
+ BasicBlock *DestBB = BI->getSuccessor(0);
+ if (DestBB == BB)
+ continue;
+
+ if (!CanMergeBlocks(BB, DestBB))
+ continue;
+
+ EliminateMostlyEmptyBlock(BB);
+ MadeChange = true;
+ }
+ return MadeChange;
+}
+
+/// CanMergeBlocks - Return true if we can merge BB into DestBB if there is a
+/// single uncond branch between them, and BB contains no other non-phi
+/// instructions.
+bool CodeGenPrepare::CanMergeBlocks(const BasicBlock *BB,
+ const BasicBlock *DestBB) const {
+ // We only want to eliminate blocks whose phi nodes are used by phi nodes in
+ // the successor. If there are more complex condition (e.g. preheaders),
+ // don't mess around with them.
+ BasicBlock::const_iterator BBI = BB->begin();
+ while (const PHINode *PN = dyn_cast<PHINode>(BBI++)) {
+ for (Value::use_const_iterator UI = PN->use_begin(), E = PN->use_end();
+ UI != E; ++UI) {
+ const Instruction *User = cast<Instruction>(*UI);
+ if (User->getParent() != DestBB || !isa<PHINode>(User))
+ return false;
+ // If User is inside DestBB block and it is a PHINode then check
+ // incoming value. If incoming value is not from BB then this is
+ // a complex condition (e.g. preheaders) we want to avoid here.
+ if (User->getParent() == DestBB) {
+ if (const PHINode *UPN = dyn_cast<PHINode>(User))
+ for (unsigned I = 0, E = UPN->getNumIncomingValues(); I != E; ++I) {
+ Instruction *Insn = dyn_cast<Instruction>(UPN->getIncomingValue(I));
+ if (Insn && Insn->getParent() == BB &&
+ Insn->getParent() != UPN->getIncomingBlock(I))
+ return false;
+ }
+ }
+ }
+ }
+
+ // If BB and DestBB contain any common predecessors, then the phi nodes in BB
+ // and DestBB may have conflicting incoming values for the block. If so, we
+ // can't merge the block.
+ const PHINode *DestBBPN = dyn_cast<PHINode>(DestBB->begin());
+ if (!DestBBPN) return true; // no conflict.
+
+ // Collect the preds of BB.
+ SmallPtrSet<const BasicBlock*, 16> BBPreds;
+ if (const PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
+ // It is faster to get preds from a PHI than with pred_iterator.
+ for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
+ BBPreds.insert(BBPN->getIncomingBlock(i));
+ } else {
+ BBPreds.insert(pred_begin(BB), pred_end(BB));
+ }
+
+ // Walk the preds of DestBB.
+ for (unsigned i = 0, e = DestBBPN->getNumIncomingValues(); i != e; ++i) {
+ BasicBlock *Pred = DestBBPN->getIncomingBlock(i);
+ if (BBPreds.count(Pred)) { // Common predecessor?
+ BBI = DestBB->begin();
+ while (const PHINode *PN = dyn_cast<PHINode>(BBI++)) {
+ const Value *V1 = PN->getIncomingValueForBlock(Pred);
+ const Value *V2 = PN->getIncomingValueForBlock(BB);
+
+ // If V2 is a phi node in BB, look up what the mapped value will be.
+ if (const PHINode *V2PN = dyn_cast<PHINode>(V2))
+ if (V2PN->getParent() == BB)
+ V2 = V2PN->getIncomingValueForBlock(Pred);
+
+ // If there is a conflict, bail out.
+ if (V1 != V2) return false;
+ }
+ }
+ }
+
+ return true;
+}
+
+
+/// EliminateMostlyEmptyBlock - Eliminate a basic block that have only phi's and
+/// an unconditional branch in it.
+void CodeGenPrepare::EliminateMostlyEmptyBlock(BasicBlock *BB) {
+ BranchInst *BI = cast<BranchInst>(BB->getTerminator());
+ BasicBlock *DestBB = BI->getSuccessor(0);
+
+ DOUT << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n" << *BB << *DestBB;
+
+ // If the destination block has a single pred, then this is a trivial edge,
+ // just collapse it.
+ if (DestBB->getSinglePredecessor()) {
+ // If DestBB has single-entry PHI nodes, fold them.
+ while (PHINode *PN = dyn_cast<PHINode>(DestBB->begin())) {
+ PN->replaceAllUsesWith(PN->getIncomingValue(0));
+ PN->eraseFromParent();
+ }
+
+ // Splice all the PHI nodes from BB over to DestBB.
+ DestBB->getInstList().splice(DestBB->begin(), BB->getInstList(),
+ BB->begin(), BI);
+
+ // Anything that branched to BB now branches to DestBB.
+ BB->replaceAllUsesWith(DestBB);
+
+ // Nuke BB.
+ BB->eraseFromParent();
+
+ DOUT << "AFTER:\n" << *DestBB << "\n\n\n";
+ return;
+ }
+
+ // Otherwise, we have multiple predecessors of BB. Update the PHIs in DestBB
+ // to handle the new incoming edges it is about to have.
+ PHINode *PN;
+ for (BasicBlock::iterator BBI = DestBB->begin();
+ (PN = dyn_cast<PHINode>(BBI)); ++BBI) {
+ // Remove the incoming value for BB, and remember it.
+ Value *InVal = PN->removeIncomingValue(BB, false);
+
+ // Two options: either the InVal is a phi node defined in BB or it is some
+ // value that dominates BB.
+ PHINode *InValPhi = dyn_cast<PHINode>(InVal);
+ if (InValPhi && InValPhi->getParent() == BB) {
+ // Add all of the input values of the input PHI as inputs of this phi.
+ for (unsigned i = 0, e = InValPhi->getNumIncomingValues(); i != e; ++i)
+ PN->addIncoming(InValPhi->getIncomingValue(i),
+ InValPhi->getIncomingBlock(i));
+ } else {
+ // Otherwise, add one instance of the dominating value for each edge that
+ // we will be adding.
+ if (PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
+ for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
+ PN->addIncoming(InVal, BBPN->getIncomingBlock(i));
+ } else {
+ for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
+ PN->addIncoming(InVal, *PI);
+ }
+ }
+ }
+
+ // The PHIs are now updated, change everything that refers to BB to use
+ // DestBB and remove BB.
+ BB->replaceAllUsesWith(DestBB);
+ BB->eraseFromParent();
+
+ DOUT << "AFTER:\n" << *DestBB << "\n\n\n";
+}
+
+
+/// SplitEdgeNicely - Split the critical edge from TI to its specified
/// successor if it will improve codegen. We only do this if the successor has
/// phi nodes (otherwise critical edges are ok). If there is already another
/// predecessor of the succ that is empty (and thus has no phi nodes), use it
assert(isa<PHINode>(Dest->begin()) &&
"This should only be called if Dest has a PHI!");
+ // As a hack, never split backedges of loops. Even though the copy for any
+ // PHIs inserted on the backedge would be dead for exits from the loop, we
+ // assume that the cost of *splitting* the backedge would be too high.
+ if (Dest == TIBB)
+ return;
+
/// TIPHIValues - This array is lazily computed to determine the values of
/// PHIs in Dest that TI would provide.
- std::vector<Value*> TIPHIValues;
+ SmallVector<Value*, 32> TIPHIValues;
// Check to see if Dest has any blocks that can be used as a split edge for
// this terminator.
BranchInst *PredBr = dyn_cast<BranchInst>(Pred->getTerminator());
if (!PredBr || !PredBr->isUnconditional() ||
// Must be empty other than the branch.
- &Pred->front() != PredBr)
+ &Pred->front() != PredBr ||
+ // Cannot be the entry block; its label does not get emitted.
+ Pred == &(Dest->getParent()->getEntryBlock()))
continue;
// Finally, since we know that Dest has phi nodes in it, we have to make
SplitCriticalEdge(TI, SuccNum, P, true);
}
+/// OptimizeNoopCopyExpression - If the specified cast instruction is a noop
+/// copy (e.g. it's casting from one pointer type to another, int->uint, or
+/// int->sbyte on PPC), sink it into user blocks to reduce the number of virtual
+/// registers that must be created and coalesced.
+///
+/// Return true if any changes are made.
+static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI){
+ // If this is a noop copy,
+ MVT::ValueType SrcVT = TLI.getValueType(CI->getOperand(0)->getType());
+ MVT::ValueType DstVT = TLI.getValueType(CI->getType());
+
+ // This is an fp<->int conversion?
+ if (MVT::isInteger(SrcVT) != MVT::isInteger(DstVT))
+ return false;
+
+ // If this is an extension, it will be a zero or sign extension, which
+ // isn't a noop.
+ if (SrcVT < DstVT) return false;
+
+ // If these values will be promoted, find out what they will be promoted
+ // to. This helps us consider truncates on PPC as noop copies when they
+ // are.
+ if (TLI.getTypeAction(SrcVT) == TargetLowering::Promote)
+ SrcVT = TLI.getTypeToTransformTo(SrcVT);
+ if (TLI.getTypeAction(DstVT) == TargetLowering::Promote)
+ DstVT = TLI.getTypeToTransformTo(DstVT);
+
+ // If, after promotion, these are the same types, this is a noop copy.
+ if (SrcVT != DstVT)
+ return false;
+
+ BasicBlock *DefBB = CI->getParent();
+
+ /// InsertedCasts - Only insert a cast in each block once.
+ DenseMap<BasicBlock*, CastInst*> InsertedCasts;
+
+ bool MadeChange = false;
+ for (Value::use_iterator UI = CI->use_begin(), E = CI->use_end();
+ UI != E; ) {
+ Use &TheUse = UI.getUse();
+ Instruction *User = cast<Instruction>(*UI);
+
+ // Figure out which BB this cast is used in. For PHI's this is the
+ // appropriate predecessor block.
+ BasicBlock *UserBB = User->getParent();
+ if (PHINode *PN = dyn_cast<PHINode>(User)) {
+ unsigned OpVal = UI.getOperandNo()/2;
+ UserBB = PN->getIncomingBlock(OpVal);
+ }
+
+ // Preincrement use iterator so we don't invalidate it.
+ ++UI;
+
+ // If this user is in the same block as the cast, don't change the cast.
+ if (UserBB == DefBB) continue;
+
+ // If we have already inserted a cast into this block, use it.
+ CastInst *&InsertedCast = InsertedCasts[UserBB];
-/// InsertGEPComputeCode - Insert code into BB to compute Ptr+PtrOffset,
-/// casting to the type of GEPI.
-static Instruction *InsertGEPComputeCode(Instruction *&V, BasicBlock *BB,
- Instruction *GEPI, Value *Ptr,
- Value *PtrOffset) {
- if (V) return V; // Already computed.
+ if (!InsertedCast) {
+ BasicBlock::iterator InsertPt = UserBB->begin();
+ while (isa<PHINode>(InsertPt)) ++InsertPt;
+
+ InsertedCast =
+ CastInst::create(CI->getOpcode(), CI->getOperand(0), CI->getType(), "",
+ InsertPt);
+ MadeChange = true;
+ }
+
+ // Replace a use of the cast with a use of the new cast.
+ TheUse = InsertedCast;
+ }
- // Figure out the insertion point
- BasicBlock::iterator InsertPt;
- if (BB == GEPI->getParent()) {
- // If GEP is already inserted into BB, insert right after the GEP.
- InsertPt = GEPI;
- ++InsertPt;
- } else {
- // Otherwise, insert at the top of BB, after any PHI nodes
- InsertPt = BB->begin();
- while (isa<PHINode>(InsertPt)) ++InsertPt;
- }
-
- // If Ptr is itself a cast, but in some other BB, emit a copy of the cast into
- // BB so that there is only one value live across basic blocks (the cast
- // operand).
- if (CastInst *CI = dyn_cast<CastInst>(Ptr))
- if (CI->getParent() != BB && isa<PointerType>(CI->getOperand(0)->getType()))
- Ptr = CastInst::create(CI->getOpcode(), CI->getOperand(0), CI->getType(),
- "", InsertPt);
-
- // Add the offset, cast it to the right type.
- Ptr = BinaryOperator::createAdd(Ptr, PtrOffset, "", InsertPt);
- // Ptr is an integer type, GEPI is pointer type ==> IntToPtr
- return V = CastInst::create(Instruction::IntToPtr, Ptr, GEPI->getType(),
- "", InsertPt);
+ // If we removed all uses, nuke the cast.
+ if (CI->use_empty()) {
+ CI->eraseFromParent();
+ MadeChange = true;
+ }
+
+ return MadeChange;
}
-/// ReplaceUsesOfGEPInst - Replace all uses of RepPtr with inserted code to
-/// compute its value. The RepPtr value can be computed with Ptr+PtrOffset. One
-/// trivial way of doing this would be to evaluate Ptr+PtrOffset in RepPtr's
-/// block, then ReplaceAllUsesWith'ing everything. However, we would prefer to
-/// sink PtrOffset into user blocks where doing so will likely allow us to fold
-/// the constant add into a load or store instruction. Additionally, if a user
-/// is a pointer-pointer cast, we look through it to find its users.
-static void ReplaceUsesOfGEPInst(Instruction *RepPtr, Value *Ptr,
- Constant *PtrOffset, BasicBlock *DefBB,
- GetElementPtrInst *GEPI,
- std::map<BasicBlock*,Instruction*> &InsertedExprs) {
- while (!RepPtr->use_empty()) {
- Instruction *User = cast<Instruction>(RepPtr->use_back());
+/// OptimizeCmpExpression - sink the given CmpInst into user blocks to reduce
+/// the number of virtual registers that must be created and coalesced. This is
+/// a clear win except on targets with multiple condition code registers
+/// (PowerPC), where it might lose; some adjustment may be wanted there.
+///
+/// Return true if any changes are made.
+static bool OptimizeCmpExpression(CmpInst *CI){
+
+ BasicBlock *DefBB = CI->getParent();
+
+ /// InsertedCmp - Only insert a cmp in each block once.
+ DenseMap<BasicBlock*, CmpInst*> InsertedCmps;
+
+ bool MadeChange = false;
+ for (Value::use_iterator UI = CI->use_begin(), E = CI->use_end();
+ UI != E; ) {
+ Use &TheUse = UI.getUse();
+ Instruction *User = cast<Instruction>(*UI);
- // If the user is a Pointer-Pointer cast, recurse. Only BitCast can be
- // used for a Pointer-Pointer cast.
- if (isa<BitCastInst>(User)) {
- ReplaceUsesOfGEPInst(User, Ptr, PtrOffset, DefBB, GEPI, InsertedExprs);
-
- // Drop the use of RepPtr. The cast is dead. Don't delete it now, else we
- // could invalidate an iterator.
- User->setOperand(0, UndefValue::get(RepPtr->getType()));
+ // Preincrement use iterator so we don't invalidate it.
+ ++UI;
+
+ // Don't bother for PHI nodes.
+ if (isa<PHINode>(User))
continue;
- }
+
+ // Figure out which BB this cmp is used in.
+ BasicBlock *UserBB = User->getParent();
- // If this is a load of the pointer, or a store through the pointer, emit
- // the increment into the load/store block.
- Instruction *NewVal;
- if (isa<LoadInst>(User) ||
- (isa<StoreInst>(User) && User->getOperand(0) != RepPtr)) {
- NewVal = InsertGEPComputeCode(InsertedExprs[User->getParent()],
- User->getParent(), GEPI,
- Ptr, PtrOffset);
- } else {
- // If this use is not foldable into the addressing mode, use a version
- // emitted in the GEP block.
- NewVal = InsertGEPComputeCode(InsertedExprs[DefBB], DefBB, GEPI,
- Ptr, PtrOffset);
+ // If this user is in the same block as the cmp, don't change the cmp.
+ if (UserBB == DefBB) continue;
+
+ // If we have already inserted a cmp into this block, use it.
+ CmpInst *&InsertedCmp = InsertedCmps[UserBB];
+
+ if (!InsertedCmp) {
+ BasicBlock::iterator InsertPt = UserBB->begin();
+ while (isa<PHINode>(InsertPt)) ++InsertPt;
+
+ InsertedCmp =
+ CmpInst::create(CI->getOpcode(), CI->getPredicate(), CI->getOperand(0),
+ CI->getOperand(1), "", InsertPt);
+ MadeChange = true;
}
- if (GEPI->getType() != RepPtr->getType()) {
- BasicBlock::iterator IP = NewVal;
- ++IP;
- // NewVal must be a GEP which must be pointer type, so BitCast
- NewVal = new BitCastInst(NewVal, RepPtr->getType(), "", IP);
+ // Replace a use of the cmp with a use of the new cmp.
+ TheUse = InsertedCmp;
+ }
+
+ // If we removed all uses, nuke the cmp.
+ if (CI->use_empty())
+ CI->eraseFromParent();
+
+ return MadeChange;
+}
+
+/// EraseDeadInstructions - Erase any dead instructions
+static void EraseDeadInstructions(Value *V) {
+ Instruction *I = dyn_cast<Instruction>(V);
+ if (!I || !I->use_empty()) return;
+
+ SmallPtrSet<Instruction*, 16> Insts;
+ Insts.insert(I);
+
+ while (!Insts.empty()) {
+ I = *Insts.begin();
+ Insts.erase(I);
+ if (isInstructionTriviallyDead(I)) {
+ for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
+ if (Instruction *U = dyn_cast<Instruction>(I->getOperand(i)))
+ Insts.insert(U);
+ I->eraseFromParent();
}
- User->replaceUsesOfWith(RepPtr, NewVal);
}
}
-/// OptimizeGEPExpression - Since we are doing basic-block-at-a-time instruction
-/// selection, we want to be a bit careful about some things. In particular, if
-/// we have a GEP instruction that is used in a different block than it is
-/// defined, the addressing expression of the GEP cannot be folded into loads or
-/// stores that use it. In this case, decompose the GEP and move constant
-/// indices into blocks that use it.
-bool CodeGenPrepare::OptimizeGEPExpression(GetElementPtrInst *GEPI) {
- // If this GEP is only used inside the block it is defined in, there is no
- // need to rewrite it.
- bool isUsedOutsideDefBB = false;
- BasicBlock *DefBB = GEPI->getParent();
- for (Value::use_iterator UI = GEPI->use_begin(), E = GEPI->use_end();
- UI != E; ++UI) {
- if (cast<Instruction>(*UI)->getParent() != DefBB) {
- isUsedOutsideDefBB = true;
- break;
+
+/// ExtAddrMode - This is an extended version of TargetLowering::AddrMode which
+/// holds actual Value*'s for register values.
+struct ExtAddrMode : public TargetLowering::AddrMode {
+ Value *BaseReg;
+ Value *ScaledReg;
+ ExtAddrMode() : BaseReg(0), ScaledReg(0) {}
+ void dump() const;
+};
+
+static std::ostream &operator<<(std::ostream &OS, const ExtAddrMode &AM) {
+ bool NeedPlus = false;
+ OS << "[";
+ if (AM.BaseGV)
+ OS << (NeedPlus ? " + " : "")
+ << "GV:%" << AM.BaseGV->getName(), NeedPlus = true;
+
+ if (AM.BaseOffs)
+ OS << (NeedPlus ? " + " : "") << AM.BaseOffs, NeedPlus = true;
+
+ if (AM.BaseReg)
+ OS << (NeedPlus ? " + " : "")
+ << "Base:%" << AM.BaseReg->getName(), NeedPlus = true;
+ if (AM.Scale)
+ OS << (NeedPlus ? " + " : "")
+ << AM.Scale << "*%" << AM.ScaledReg->getName(), NeedPlus = true;
+
+ return OS << "]";
+}
+
+void ExtAddrMode::dump() const {
+ cerr << *this << "\n";
+}
+
+static bool TryMatchingScaledValue(Value *ScaleReg, int64_t Scale,
+ const Type *AccessTy, ExtAddrMode &AddrMode,
+ SmallVector<Instruction*, 16> &AddrModeInsts,
+ const TargetLowering &TLI, unsigned Depth);
+
+/// FindMaximalLegalAddressingMode - If we can, try to merge the computation of
+/// Addr into the specified addressing mode. If Addr can't be added to AddrMode
+/// this returns false. This assumes that Addr is either a pointer type or
+/// intptr_t for the target.
+static bool FindMaximalLegalAddressingMode(Value *Addr, const Type *AccessTy,
+ ExtAddrMode &AddrMode,
+ SmallVector<Instruction*, 16> &AddrModeInsts,
+ const TargetLowering &TLI,
+ unsigned Depth) {
+
+ // If this is a global variable, fold it into the addressing mode if possible.
+ if (GlobalValue *GV = dyn_cast<GlobalValue>(Addr)) {
+ if (AddrMode.BaseGV == 0) {
+ AddrMode.BaseGV = GV;
+ if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
+ return true;
+ AddrMode.BaseGV = 0;
}
+ } else if (ConstantInt *CI = dyn_cast<ConstantInt>(Addr)) {
+ AddrMode.BaseOffs += CI->getSExtValue();
+ if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
+ return true;
+ AddrMode.BaseOffs -= CI->getSExtValue();
+ } else if (isa<ConstantPointerNull>(Addr)) {
+ return true;
}
- if (!isUsedOutsideDefBB) return false;
-
- // If this GEP has no non-zero constant indices, there is nothing we can do,
- // ignore it.
- bool hasConstantIndex = false;
- bool hasVariableIndex = false;
- for (GetElementPtrInst::op_iterator OI = GEPI->op_begin()+1,
- E = GEPI->op_end(); OI != E; ++OI) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(*OI)) {
- if (!CI->isZero()) {
- hasConstantIndex = true;
- break;
+
+ // Look through constant exprs and instructions.
+ unsigned Opcode = ~0U;
+ User *AddrInst = 0;
+ if (Instruction *I = dyn_cast<Instruction>(Addr)) {
+ Opcode = I->getOpcode();
+ AddrInst = I;
+ } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr)) {
+ Opcode = CE->getOpcode();
+ AddrInst = CE;
+ }
+
+ // Limit recursion to avoid exponential behavior.
+ if (Depth == 5) { AddrInst = 0; Opcode = ~0U; }
+
+ // If this is really an instruction, add it to our list of related
+ // instructions.
+ if (Instruction *I = dyn_cast_or_null<Instruction>(AddrInst))
+ AddrModeInsts.push_back(I);
+
+ switch (Opcode) {
+ case Instruction::PtrToInt:
+ // PtrToInt is always a noop, as we know that the int type is pointer sized.
+ if (FindMaximalLegalAddressingMode(AddrInst->getOperand(0), AccessTy,
+ AddrMode, AddrModeInsts, TLI, Depth))
+ return true;
+ break;
+ case Instruction::IntToPtr:
+ // This inttoptr is a no-op if the integer type is pointer sized.
+ if (TLI.getValueType(AddrInst->getOperand(0)->getType()) ==
+ TLI.getPointerTy()) {
+ if (FindMaximalLegalAddressingMode(AddrInst->getOperand(0), AccessTy,
+ AddrMode, AddrModeInsts, TLI, Depth))
+ return true;
+ }
+ break;
+ case Instruction::Add: {
+ // Check to see if we can merge in the RHS then the LHS. If so, we win.
+ ExtAddrMode BackupAddrMode = AddrMode;
+ unsigned OldSize = AddrModeInsts.size();
+ if (FindMaximalLegalAddressingMode(AddrInst->getOperand(1), AccessTy,
+ AddrMode, AddrModeInsts, TLI, Depth+1) &&
+ FindMaximalLegalAddressingMode(AddrInst->getOperand(0), AccessTy,
+ AddrMode, AddrModeInsts, TLI, Depth+1))
+ return true;
+
+ // Restore the old addr mode info.
+ AddrMode = BackupAddrMode;
+ AddrModeInsts.resize(OldSize);
+
+ // Otherwise this was over-aggressive. Try merging in the LHS then the RHS.
+ if (FindMaximalLegalAddressingMode(AddrInst->getOperand(0), AccessTy,
+ AddrMode, AddrModeInsts, TLI, Depth+1) &&
+ FindMaximalLegalAddressingMode(AddrInst->getOperand(1), AccessTy,
+ AddrMode, AddrModeInsts, TLI, Depth+1))
+ return true;
+
+ // Otherwise we definitely can't merge the ADD in.
+ AddrMode = BackupAddrMode;
+ AddrModeInsts.resize(OldSize);
+ break;
+ }
+ case Instruction::Or: {
+ ConstantInt *RHS = dyn_cast<ConstantInt>(AddrInst->getOperand(1));
+ if (!RHS) break;
+ // TODO: We can handle "Or Val, Imm" iff this OR is equivalent to an ADD.
+ break;
+ }
+ case Instruction::Mul:
+ case Instruction::Shl: {
+ // Can only handle X*C and X << C, and can only handle this when the scale
+ // field is available.
+ ConstantInt *RHS = dyn_cast<ConstantInt>(AddrInst->getOperand(1));
+ if (!RHS) break;
+ int64_t Scale = RHS->getSExtValue();
+ if (Opcode == Instruction::Shl)
+ Scale = 1 << Scale;
+
+ if (TryMatchingScaledValue(AddrInst->getOperand(0), Scale, AccessTy,
+ AddrMode, AddrModeInsts, TLI, Depth))
+ return true;
+ break;
+ }
+ case Instruction::GetElementPtr: {
+ // Scan the GEP. We check it if it contains constant offsets and at most
+ // one variable offset.
+ int VariableOperand = -1;
+ unsigned VariableScale = 0;
+
+ int64_t ConstantOffset = 0;
+ const TargetData *TD = TLI.getTargetData();
+ gep_type_iterator GTI = gep_type_begin(AddrInst);
+ for (unsigned i = 1, e = AddrInst->getNumOperands(); i != e; ++i, ++GTI) {
+ if (const StructType *STy = dyn_cast<StructType>(*GTI)) {
+ const StructLayout *SL = TD->getStructLayout(STy);
+ unsigned Idx =
+ cast<ConstantInt>(AddrInst->getOperand(i))->getZExtValue();
+ ConstantOffset += SL->getElementOffset(Idx);
+ } else {
+ uint64_t TypeSize = TD->getABITypeSize(GTI.getIndexedType());
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(AddrInst->getOperand(i))) {
+ ConstantOffset += CI->getSExtValue()*TypeSize;
+ } else if (TypeSize) { // Scales of zero don't do anything.
+ // We only allow one variable index at the moment.
+ if (VariableOperand != -1) {
+ VariableOperand = -2;
+ break;
+ }
+
+ // Remember the variable index.
+ VariableOperand = i;
+ VariableScale = TypeSize;
+ }
+ }
+ }
+
+ // If the GEP had multiple variable indices, punt.
+ if (VariableOperand == -2)
+ break;
+
+ // A common case is for the GEP to only do a constant offset. In this case,
+ // just add it to the disp field and check validity.
+ if (VariableOperand == -1) {
+ AddrMode.BaseOffs += ConstantOffset;
+ if (ConstantOffset == 0 || TLI.isLegalAddressingMode(AddrMode, AccessTy)){
+ // Check to see if we can fold the base pointer in too.
+ if (FindMaximalLegalAddressingMode(AddrInst->getOperand(0), AccessTy,
+ AddrMode, AddrModeInsts, TLI,
+ Depth+1))
+ return true;
}
+ AddrMode.BaseOffs -= ConstantOffset;
} else {
- hasVariableIndex = true;
+ // Check that this has no base reg yet. If so, we won't have a place to
+ // put the base of the GEP (assuming it is not a null ptr).
+ bool SetBaseReg = false;
+ if (AddrMode.HasBaseReg) {
+ if (!isa<ConstantPointerNull>(AddrInst->getOperand(0)))
+ break;
+ } else {
+ AddrMode.HasBaseReg = true;
+ AddrMode.BaseReg = AddrInst->getOperand(0);
+ SetBaseReg = true;
+ }
+
+ // See if the scale amount is valid for this target.
+ AddrMode.BaseOffs += ConstantOffset;
+ if (TryMatchingScaledValue(AddrInst->getOperand(VariableOperand),
+ VariableScale, AccessTy, AddrMode,
+ AddrModeInsts, TLI, Depth)) {
+ if (!SetBaseReg) return true;
+
+ // If this match succeeded, we know that we can form an address with the
+ // GepBase as the basereg. See if we can match *more*.
+ AddrMode.HasBaseReg = false;
+ AddrMode.BaseReg = 0;
+ if (FindMaximalLegalAddressingMode(AddrInst->getOperand(0), AccessTy,
+ AddrMode, AddrModeInsts, TLI,
+ Depth+1))
+ return true;
+ // Strange, shouldn't happen. Restore the base reg and succeed the easy
+ // way.
+ AddrMode.HasBaseReg = true;
+ AddrMode.BaseReg = AddrInst->getOperand(0);
+ return true;
+ }
+
+ AddrMode.BaseOffs -= ConstantOffset;
+ if (SetBaseReg) {
+ AddrMode.HasBaseReg = false;
+ AddrMode.BaseReg = 0;
+ }
}
+ break;
+ }
}
- // If this is a "GEP X, 0, 0, 0", turn this into a cast.
- if (!hasConstantIndex && !hasVariableIndex) {
- /// The GEP operand must be a pointer, so must its result -> BitCast
- Value *NC = new BitCastInst(GEPI->getOperand(0), GEPI->getType(),
- GEPI->getName(), GEPI);
- GEPI->replaceAllUsesWith(NC);
- GEPI->eraseFromParent();
- return true;
+ if (Instruction *I = dyn_cast_or_null<Instruction>(AddrInst)) {
+ assert(AddrModeInsts.back() == I && "Stack imbalance");
+ AddrModeInsts.pop_back();
}
- // If this is a GEP &Alloca, 0, 0, forward subst the frame index into uses.
- if (!hasConstantIndex && !isa<AllocaInst>(GEPI->getOperand(0)))
+ // Worse case, the target should support [reg] addressing modes. :)
+ if (!AddrMode.HasBaseReg) {
+ AddrMode.HasBaseReg = true;
+ // Still check for legality in case the target supports [imm] but not [i+r].
+ if (TLI.isLegalAddressingMode(AddrMode, AccessTy)) {
+ AddrMode.BaseReg = Addr;
+ return true;
+ }
+ AddrMode.HasBaseReg = false;
+ }
+
+ // If the base register is already taken, see if we can do [r+r].
+ if (AddrMode.Scale == 0) {
+ AddrMode.Scale = 1;
+ if (TLI.isLegalAddressingMode(AddrMode, AccessTy)) {
+ AddrMode.ScaledReg = Addr;
+ return true;
+ }
+ AddrMode.Scale = 0;
+ }
+ // Couldn't match.
+ return false;
+}
+
+/// TryMatchingScaledValue - Try adding ScaleReg*Scale to the specified
+/// addressing mode. Return true if this addr mode is legal for the target,
+/// false if not.
+static bool TryMatchingScaledValue(Value *ScaleReg, int64_t Scale,
+ const Type *AccessTy, ExtAddrMode &AddrMode,
+ SmallVector<Instruction*, 16> &AddrModeInsts,
+ const TargetLowering &TLI, unsigned Depth) {
+ // If we already have a scale of this value, we can add to it, otherwise, we
+ // need an available scale field.
+ if (AddrMode.Scale != 0 && AddrMode.ScaledReg != ScaleReg)
return false;
+
+ ExtAddrMode InputAddrMode = AddrMode;
+
+ // Add scale to turn X*4+X*3 -> X*7. This could also do things like
+ // [A+B + A*7] -> [B+A*8].
+ AddrMode.Scale += Scale;
+ AddrMode.ScaledReg = ScaleReg;
+
+ if (TLI.isLegalAddressingMode(AddrMode, AccessTy)) {
+ // Okay, we decided that we can add ScaleReg+Scale to AddrMode. Check now
+ // to see if ScaleReg is actually X+C. If so, we can turn this into adding
+ // X*Scale + C*Scale to addr mode.
+ BinaryOperator *BinOp = dyn_cast<BinaryOperator>(ScaleReg);
+ if (BinOp && BinOp->getOpcode() == Instruction::Add &&
+ isa<ConstantInt>(BinOp->getOperand(1)) && InputAddrMode.ScaledReg ==0) {
+
+ InputAddrMode.Scale = Scale;
+ InputAddrMode.ScaledReg = BinOp->getOperand(0);
+ InputAddrMode.BaseOffs +=
+ cast<ConstantInt>(BinOp->getOperand(1))->getSExtValue()*Scale;
+ if (TLI.isLegalAddressingMode(InputAddrMode, AccessTy)) {
+ AddrModeInsts.push_back(BinOp);
+ AddrMode = InputAddrMode;
+ return true;
+ }
+ }
- // If we don't have target lowering info, we can't lower the GEP.
- if (!TLI) return false;
- const TargetData *TD = TLI->getTargetData();
-
- // Otherwise, decompose the GEP instruction into multiplies and adds. Sum the
- // constant offset (which we now know is non-zero) and deal with it later.
- uint64_t ConstantOffset = 0;
- const Type *UIntPtrTy = TD->getIntPtrType();
- Value *Ptr = new PtrToIntInst(GEPI->getOperand(0), UIntPtrTy, "", GEPI);
- const Type *Ty = GEPI->getOperand(0)->getType();
-
- for (GetElementPtrInst::op_iterator OI = GEPI->op_begin()+1,
- E = GEPI->op_end(); OI != E; ++OI) {
- Value *Idx = *OI;
- if (const StructType *StTy = dyn_cast<StructType>(Ty)) {
- unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
- if (Field)
- ConstantOffset += TD->getStructLayout(StTy)->getElementOffset(Field);
- Ty = StTy->getElementType(Field);
- } else {
- Ty = cast<SequentialType>(Ty)->getElementType();
+ // Otherwise, not (x+c)*scale, just return what we have.
+ return true;
+ }
+
+ // Otherwise, back this attempt out.
+ AddrMode.Scale -= Scale;
+ if (AddrMode.Scale == 0) AddrMode.ScaledReg = 0;
+
+ return false;
+}
- // Handle constant subscripts.
- if (ConstantInt *CI = dyn_cast<ConstantInt>(Idx)) {
- if (CI->getZExtValue() == 0) continue;
- ConstantOffset += (int64_t)TD->getTypeSize(Ty)*CI->getSExtValue();
- continue;
- }
-
- // Ptr = Ptr + Idx * ElementSize;
-
- // Cast Idx to UIntPtrTy if needed.
- Idx = CastInst::createIntegerCast(Idx, UIntPtrTy, true/*SExt*/, "", GEPI);
-
- uint64_t ElementSize = TD->getTypeSize(Ty);
- // Mask off bits that should not be set.
- ElementSize &= ~0ULL >> (64-UIntPtrTy->getPrimitiveSizeInBits());
- Constant *SizeCst = ConstantInt::get(UIntPtrTy, ElementSize);
-
- // Multiply by the element size and add to the base.
- Idx = BinaryOperator::createMul(Idx, SizeCst, "", GEPI);
- Ptr = BinaryOperator::createAdd(Ptr, Idx, "", GEPI);
+
+/// IsNonLocalValue - Return true if the specified values are defined in a
+/// different basic block than BB.
+static bool IsNonLocalValue(Value *V, BasicBlock *BB) {
+ if (Instruction *I = dyn_cast<Instruction>(V))
+ return I->getParent() != BB;
+ return false;
+}
+
+/// OptimizeLoadStoreInst - Load and Store Instructions have often have
+/// addressing modes that can do significant amounts of computation. As such,
+/// instruction selection will try to get the load or store to do as much
+/// computation as possible for the program. The problem is that isel can only
+/// see within a single block. As such, we sink as much legal addressing mode
+/// stuff into the block as possible.
+bool CodeGenPrepare::OptimizeLoadStoreInst(Instruction *LdStInst, Value *Addr,
+ const Type *AccessTy,
+ DenseMap<Value*,Value*> &SunkAddrs) {
+ // Figure out what addressing mode will be built up for this operation.
+ SmallVector<Instruction*, 16> AddrModeInsts;
+ ExtAddrMode AddrMode;
+ bool Success = FindMaximalLegalAddressingMode(Addr, AccessTy, AddrMode,
+ AddrModeInsts, *TLI, 0);
+ Success = Success; assert(Success && "Couldn't select *anything*?");
+
+ // Check to see if any of the instructions supersumed by this addr mode are
+ // non-local to I's BB.
+ bool AnyNonLocal = false;
+ for (unsigned i = 0, e = AddrModeInsts.size(); i != e; ++i) {
+ if (IsNonLocalValue(AddrModeInsts[i], LdStInst->getParent())) {
+ AnyNonLocal = true;
+ break;
}
}
- // Make sure that the offset fits in uintptr_t.
- ConstantOffset &= ~0ULL >> (64-UIntPtrTy->getPrimitiveSizeInBits());
- Constant *PtrOffset = ConstantInt::get(UIntPtrTy, ConstantOffset);
+ // If all the instructions matched are already in this BB, don't do anything.
+ if (!AnyNonLocal) {
+ DEBUG(cerr << "CGP: Found local addrmode: " << AddrMode << "\n");
+ return false;
+ }
- // Okay, we have now emitted all of the variable index parts to the BB that
- // the GEP is defined in. Loop over all of the using instructions, inserting
- // an "add Ptr, ConstantOffset" into each block that uses it and update the
- // instruction to use the newly computed value, making GEPI dead. When the
- // user is a load or store instruction address, we emit the add into the user
- // block, otherwise we use a canonical version right next to the gep (these
- // won't be foldable as addresses, so we might as well share the computation).
+ // Insert this computation right after this user. Since our caller is
+ // scanning from the top of the BB to the bottom, reuse of the expr are
+ // guaranteed to happen later.
+ BasicBlock::iterator InsertPt = LdStInst;
- std::map<BasicBlock*,Instruction*> InsertedExprs;
- ReplaceUsesOfGEPInst(GEPI, Ptr, PtrOffset, DefBB, GEPI, InsertedExprs);
+ // Now that we determined the addressing expression we want to use and know
+ // that we have to sink it into this block. Check to see if we have already
+ // done this for some other load/store instr in this block. If so, reuse the
+ // computation.
+ Value *&SunkAddr = SunkAddrs[Addr];
+ if (SunkAddr) {
+ DEBUG(cerr << "CGP: Reusing nonlocal addrmode: " << AddrMode << "\n");
+ if (SunkAddr->getType() != Addr->getType())
+ SunkAddr = new BitCastInst(SunkAddr, Addr->getType(), "tmp", InsertPt);
+ } else {
+ DEBUG(cerr << "CGP: SINKING nonlocal addrmode: " << AddrMode << "\n");
+ const Type *IntPtrTy = TLI->getTargetData()->getIntPtrType();
+
+ Value *Result = 0;
+ // Start with the scale value.
+ if (AddrMode.Scale) {
+ Value *V = AddrMode.ScaledReg;
+ if (V->getType() == IntPtrTy) {
+ // done.
+ } else if (isa<PointerType>(V->getType())) {
+ V = new PtrToIntInst(V, IntPtrTy, "sunkaddr", InsertPt);
+ } else if (cast<IntegerType>(IntPtrTy)->getBitWidth() <
+ cast<IntegerType>(V->getType())->getBitWidth()) {
+ V = new TruncInst(V, IntPtrTy, "sunkaddr", InsertPt);
+ } else {
+ V = new SExtInst(V, IntPtrTy, "sunkaddr", InsertPt);
+ }
+ if (AddrMode.Scale != 1)
+ V = BinaryOperator::createMul(V, ConstantInt::get(IntPtrTy,
+ AddrMode.Scale),
+ "sunkaddr", InsertPt);
+ Result = V;
+ }
+
+ // Add in the base register.
+ if (AddrMode.BaseReg) {
+ Value *V = AddrMode.BaseReg;
+ if (V->getType() != IntPtrTy)
+ V = new PtrToIntInst(V, IntPtrTy, "sunkaddr", InsertPt);
+ if (Result)
+ Result = BinaryOperator::createAdd(Result, V, "sunkaddr", InsertPt);
+ else
+ Result = V;
+ }
+
+ // Add in the BaseGV if present.
+ if (AddrMode.BaseGV) {
+ Value *V = new PtrToIntInst(AddrMode.BaseGV, IntPtrTy, "sunkaddr",
+ InsertPt);
+ if (Result)
+ Result = BinaryOperator::createAdd(Result, V, "sunkaddr", InsertPt);
+ else
+ Result = V;
+ }
+
+ // Add in the Base Offset if present.
+ if (AddrMode.BaseOffs) {
+ Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
+ if (Result)
+ Result = BinaryOperator::createAdd(Result, V, "sunkaddr", InsertPt);
+ else
+ Result = V;
+ }
+
+ if (Result == 0)
+ SunkAddr = Constant::getNullValue(Addr->getType());
+ else
+ SunkAddr = new IntToPtrInst(Result, Addr->getType(), "sunkaddr",InsertPt);
+ }
- // Finally, the GEP is dead, remove it.
- GEPI->eraseFromParent();
+ LdStInst->replaceUsesOfWith(Addr, SunkAddr);
+ if (Addr->use_empty())
+ EraseDeadInstructions(Addr);
return true;
}
-/// SinkInvariantGEPIndex - If a GEP instruction has a variable index that has
-/// been hoisted out of the loop by LICM pass, sink it back into the use BB
-/// if it can be determined that the index computation can be folded into the
-/// addressing mode of the load / store uses.
-static bool SinkInvariantGEPIndex(BinaryOperator *BinOp,
- const TargetLowering &TLI) {
- // Only look at Add.
- if (BinOp->getOpcode() != Instruction::Add)
- return false;
-
- // DestBBs - These are the blocks where a copy of BinOp will be inserted.
- SmallSet<BasicBlock*, 8> DestBBs;
- BasicBlock *DefBB = BinOp->getParent();
+/// OptimizeInlineAsmInst - If there are any memory operands, use
+/// OptimizeLoadStoreInt to sink their address computing into the block when
+/// possible / profitable.
+bool CodeGenPrepare::OptimizeInlineAsmInst(Instruction *I, CallSite CS,
+ DenseMap<Value*,Value*> &SunkAddrs) {
bool MadeChange = false;
- for (Value::use_iterator UI = BinOp->use_begin(), E = BinOp->use_end();
- UI != E; ++UI) {
- Instruction *GEPI = cast<Instruction>(*UI);
- // Only look for GEP use in another block.
- if (GEPI->getParent() == DefBB) continue;
-
- if (isa<GetElementPtrInst>(GEPI)) {
- // If the GEP has another variable index, abondon.
- bool hasVariableIndex = false;
- for (GetElementPtrInst::op_iterator OI = GEPI->op_begin()+1,
- OE = GEPI->op_end(); OI != OE; ++OI)
- if (*OI != BinOp && !isa<ConstantInt>(*OI)) {
- hasVariableIndex = true;
- break;
- }
- if (hasVariableIndex)
- break;
+ InlineAsm *IA = cast<InlineAsm>(CS.getCalledValue());
- BasicBlock *GEPIBB = GEPI->getParent();
- for (Value::use_iterator UUI = GEPI->use_begin(), UE = GEPI->use_end();
- UUI != UE; ++UUI) {
- Instruction *GEPIUser = cast<Instruction>(*UUI);
- const Type *UseTy = NULL;
- if (LoadInst *Load = dyn_cast<LoadInst>(GEPIUser))
- UseTy = Load->getType();
- else if (StoreInst *Store = dyn_cast<StoreInst>(GEPIUser))
- UseTy = Store->getOperand(0)->getType();
-
- // Check if it is possible to fold the expression to address mode.
- if (UseTy && isa<ConstantInt>(BinOp->getOperand(1))) {
- uint64_t Scale = TLI.getTargetData()->getTypeSize(UseTy);
- int64_t Cst = cast<ConstantInt>(BinOp->getOperand(1))->getSExtValue();
- // e.g. load (gep i32 * %P, (X+42)) => load (%P + X*4 + 168).
- if (TLI.isLegalAddressImmediate(Cst*Scale, UseTy) &&
- (Scale == 1 || TLI.isLegalAddressScale(Scale, UseTy))) {
- DestBBs.insert(GEPIBB);
- MadeChange = true;
- break;
- }
- }
- }
+ // Do a prepass over the constraints, canonicalizing them, and building up the
+ // ConstraintOperands list.
+ std::vector<InlineAsm::ConstraintInfo>
+ ConstraintInfos = IA->ParseConstraints();
+
+ /// ConstraintOperands - Information about all of the constraints.
+ std::vector<TargetLowering::AsmOperandInfo> ConstraintOperands;
+ unsigned ArgNo = 0; // ArgNo - The argument of the CallInst.
+ for (unsigned i = 0, e = ConstraintInfos.size(); i != e; ++i) {
+ ConstraintOperands.
+ push_back(TargetLowering::AsmOperandInfo(ConstraintInfos[i]));
+ TargetLowering::AsmOperandInfo &OpInfo = ConstraintOperands.back();
+
+ // Compute the value type for each operand.
+ switch (OpInfo.Type) {
+ case InlineAsm::isOutput:
+ if (OpInfo.isIndirect)
+ OpInfo.CallOperandVal = CS.getArgument(ArgNo++);
+ break;
+ case InlineAsm::isInput:
+ OpInfo.CallOperandVal = CS.getArgument(ArgNo++);
+ break;
+ case InlineAsm::isClobber:
+ // Nothing to do.
+ break;
+ }
+
+ // Compute the constraint code and ConstraintType to use.
+ OpInfo.ComputeConstraintToUse(*TLI);
+
+ if (OpInfo.ConstraintType == TargetLowering::C_Memory &&
+ OpInfo.isIndirect) {
+ Value *OpVal = OpInfo.CallOperandVal;
+ MadeChange |= OptimizeLoadStoreInst(I, OpVal, OpVal->getType(),
+ SunkAddrs);
}
}
- // Nothing to do.
- if (!MadeChange)
+ return MadeChange;
+}
+
+bool CodeGenPrepare::OptimizeExtUses(Instruction *I) {
+ BasicBlock *DefBB = I->getParent();
+
+ // If both result of the {s|z}xt and its source are live out, rewrite all
+ // other uses of the source with result of extension.
+ Value *Src = I->getOperand(0);
+ if (Src->hasOneUse())
return false;
- /// InsertedOps - Only insert a duplicate in each block once.
- std::map<BasicBlock*, BinaryOperator*> InsertedOps;
- for (Value::use_iterator UI = BinOp->use_begin(), E = BinOp->use_end();
- UI != E; ) {
- Instruction *User = cast<Instruction>(*UI);
- BasicBlock *UserBB = User->getParent();
+ // Only do this xform if truncating is free.
+ if (TLI && !TLI->isTruncateFree(I->getType(), Src->getType()))
+ return false;
- // Preincrement use iterator so we don't invalidate it.
- ++UI;
+ // Only safe to perform the optimization if the source is also defined in
+ // this block.
+ if (!isa<Instruction>(Src) || DefBB != cast<Instruction>(Src)->getParent())
+ return false;
- // If any user in this BB wants it, replace all the uses in the BB.
- if (DestBBs.count(UserBB)) {
- // Sink it into user block.
- BinaryOperator *&InsertedOp = InsertedOps[UserBB];
- if (!InsertedOp) {
- BasicBlock::iterator InsertPt = UserBB->begin();
- while (isa<PHINode>(InsertPt)) ++InsertPt;
-
- InsertedOp =
- BinaryOperator::create(BinOp->getOpcode(), BinOp->getOperand(0),
- BinOp->getOperand(1), "", InsertPt);
- }
+ bool DefIsLiveOut = false;
+ for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
+ UI != E; ++UI) {
+ Instruction *User = cast<Instruction>(*UI);
- User->replaceUsesOfWith(BinOp, InsertedOp);
- }
+ // Figure out which BB this ext is used in.
+ BasicBlock *UserBB = User->getParent();
+ if (UserBB == DefBB) continue;
+ DefIsLiveOut = true;
+ break;
}
+ if (!DefIsLiveOut)
+ return false;
- if (BinOp->use_empty())
- BinOp->eraseFromParent();
+ // Make sure non of the uses are PHI nodes.
+ for (Value::use_iterator UI = Src->use_begin(), E = Src->use_end();
+ UI != E; ++UI) {
+ Instruction *User = cast<Instruction>(*UI);
+ BasicBlock *UserBB = User->getParent();
+ if (UserBB == DefBB) continue;
+ // Be conservative. We don't want this xform to end up introducing
+ // reloads just before load / store instructions.
+ if (isa<PHINode>(User) || isa<LoadInst>(User) || isa<StoreInst>(User))
+ return false;
+ }
- return true;
-}
+ // InsertedTruncs - Only insert one trunc in each block once.
+ DenseMap<BasicBlock*, Instruction*> InsertedTruncs;
-/// OptimizeNoopCopyExpression - We have determined that the specified cast
-/// instruction is a noop copy (e.g. it's casting from one pointer type to
-/// another, int->uint, or int->sbyte on PPC.
-///
-/// Return true if any changes are made.
-static bool OptimizeNoopCopyExpression(CastInst *CI) {
- BasicBlock *DefBB = CI->getParent();
-
- /// InsertedCasts - Only insert a cast in each block once.
- std::map<BasicBlock*, CastInst*> InsertedCasts;
-
bool MadeChange = false;
- for (Value::use_iterator UI = CI->use_begin(), E = CI->use_end();
- UI != E; ) {
+ for (Value::use_iterator UI = Src->use_begin(), E = Src->use_end();
+ UI != E; ++UI) {
Use &TheUse = UI.getUse();
Instruction *User = cast<Instruction>(*UI);
-
- // Figure out which BB this cast is used in. For PHI's this is the
- // appropriate predecessor block.
+
+ // Figure out which BB this ext is used in.
BasicBlock *UserBB = User->getParent();
- if (PHINode *PN = dyn_cast<PHINode>(User)) {
- unsigned OpVal = UI.getOperandNo()/2;
- UserBB = PN->getIncomingBlock(OpVal);
- }
-
- // Preincrement use iterator so we don't invalidate it.
- ++UI;
-
- // If this user is in the same block as the cast, don't change the cast.
if (UserBB == DefBB) continue;
-
- // If we have already inserted a cast into this block, use it.
- CastInst *&InsertedCast = InsertedCasts[UserBB];
- if (!InsertedCast) {
+ // Both src and def are live in this block. Rewrite the use.
+ Instruction *&InsertedTrunc = InsertedTruncs[UserBB];
+
+ if (!InsertedTrunc) {
BasicBlock::iterator InsertPt = UserBB->begin();
while (isa<PHINode>(InsertPt)) ++InsertPt;
- InsertedCast =
- CastInst::create(CI->getOpcode(), CI->getOperand(0), CI->getType(), "",
- InsertPt);
- MadeChange = true;
+ InsertedTrunc = new TruncInst(I, Src->getType(), "", InsertPt);
}
-
- // Replace a use of the cast with a use of the new casat.
- TheUse = InsertedCast;
+
+ // Replace a use of the {s|z}ext source with a use of the result.
+ TheUse = InsertedTrunc;
+
+ MadeChange = true;
}
-
- // If we removed all uses, nuke the cast.
- if (CI->use_empty())
- CI->eraseFromParent();
-
+
return MadeChange;
}
-
-
// In this pass we look for GEP and cast instructions that are used
// across basic blocks and rewrite them to improve basic-block-at-a-time
// selection.
}
+ // Keep track of non-local addresses that have been sunk into this block.
+ // This allows us to avoid inserting duplicate code for blocks with multiple
+ // load/stores of the same address.
+ DenseMap<Value*, Value*> SunkAddrs;
+
for (BasicBlock::iterator BBI = BB.begin(), E = BB.end(); BBI != E; ) {
Instruction *I = BBI++;
- if (CallInst *CI = dyn_cast<CallInst>(I)) {
- // If we found an inline asm expession, and if the target knows how to
- // lower it to normal LLVM code, do so now.
- if (TLI && isa<InlineAsm>(CI->getCalledValue()))
- if (const TargetAsmInfo *TAI =
- TLI->getTargetMachine().getTargetAsmInfo()) {
- if (TAI->ExpandInlineAsm(CI))
- BBI = BB.begin();
- }
- } else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) {
- MadeChange |= OptimizeGEPExpression(GEPI);
- } else if (CastInst *CI = dyn_cast<CastInst>(I)) {
+ if (CastInst *CI = dyn_cast<CastInst>(I)) {
// If the source of the cast is a constant, then this should have
// already been constant folded. The only reason NOT to constant fold
// it is if something (e.g. LSR) was careful to place the constant
if (isa<Constant>(CI->getOperand(0)))
continue;
- if (!TLI) continue;
-
- // If this is a noop copy, sink it into user blocks to reduce the number
- // of virtual registers that must be created and coallesced.
- MVT::ValueType SrcVT = TLI->getValueType(CI->getOperand(0)->getType());
- MVT::ValueType DstVT = TLI->getValueType(CI->getType());
-
- // This is an fp<->int conversion?
- if (MVT::isInteger(SrcVT) != MVT::isInteger(DstVT))
- continue;
-
- // If this is an extension, it will be a zero or sign extension, which
- // isn't a noop.
- if (SrcVT < DstVT) continue;
-
- // If these values will be promoted, find out what they will be promoted
- // to. This helps us consider truncates on PPC as noop copies when they
- // are.
- if (TLI->getTypeAction(SrcVT) == TargetLowering::Promote)
- SrcVT = TLI->getTypeToTransformTo(SrcVT);
- if (TLI->getTypeAction(DstVT) == TargetLowering::Promote)
- DstVT = TLI->getTypeToTransformTo(DstVT);
-
- // If, after promotion, these are the same types, this is a noop copy.
- if (SrcVT == DstVT)
- MadeChange |= OptimizeNoopCopyExpression(CI);
- } else if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(I)) {
+ bool Change = false;
+ if (TLI) {
+ Change = OptimizeNoopCopyExpression(CI, *TLI);
+ MadeChange |= Change;
+ }
+
+ if (OptExtUses && !Change && (isa<ZExtInst>(I) || isa<SExtInst>(I)))
+ MadeChange |= OptimizeExtUses(I);
+ } else if (CmpInst *CI = dyn_cast<CmpInst>(I)) {
+ MadeChange |= OptimizeCmpExpression(CI);
+ } else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
+ if (TLI)
+ MadeChange |= OptimizeLoadStoreInst(I, I->getOperand(0), LI->getType(),
+ SunkAddrs);
+ } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
if (TLI)
- MadeChange |= SinkInvariantGEPIndex(BinOp, *TLI);
+ MadeChange |= OptimizeLoadStoreInst(I, SI->getOperand(1),
+ SI->getOperand(0)->getType(),
+ SunkAddrs);
+ } else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) {
+ if (GEPI->hasAllZeroIndices()) {
+ /// The GEP operand must be a pointer, so must its result -> BitCast
+ Instruction *NC = new BitCastInst(GEPI->getOperand(0), GEPI->getType(),
+ GEPI->getName(), GEPI);
+ GEPI->replaceAllUsesWith(NC);
+ GEPI->eraseFromParent();
+ MadeChange = true;
+ BBI = NC;
+ }
+ } else if (CallInst *CI = dyn_cast<CallInst>(I)) {
+ // If we found an inline asm expession, and if the target knows how to
+ // lower it to normal LLVM code, do so now.
+ if (TLI && isa<InlineAsm>(CI->getCalledValue()))
+ if (const TargetAsmInfo *TAI =
+ TLI->getTargetMachine().getTargetAsmInfo()) {
+ if (TAI->ExpandInlineAsm(CI))
+ BBI = BB.begin();
+ else
+ // Sink address computing for memory operands into the block.
+ MadeChange |= OptimizeInlineAsmInst(I, &(*CI), SunkAddrs);
+ }
}
}
+
return MadeChange;
}
projects / oota-llvm.git / blobdiff