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Diffstat (limited to 'lib/CodeGen/SelectionDAG/FastISel.cpp')
-rw-r--r--lib/CodeGen/SelectionDAG/FastISel.cpp211
1 files changed, 154 insertions, 57 deletions
diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp
index 4bf41f28c250..b4c38332691c 100644
--- a/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -1,4 +1,4 @@
-///===-- FastISel.cpp - Implementation of the FastISel class --------------===//
+//===-- FastISel.cpp - Implementation of the FastISel class ---------------===//
//
// The LLVM Compiler Infrastructure
//
@@ -52,10 +52,11 @@
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
+#include "llvm/Support/ErrorHandling.h"
#include "FunctionLoweringInfo.h"
using namespace llvm;
-unsigned FastISel::getRegForValue(Value *V) {
+unsigned FastISel::getRegForValue(const Value *V) {
EVT RealVT = TLI.getValueType(V->getType(), /*AllowUnknown=*/true);
// Don't handle non-simple values in FastISel.
if (!RealVT.isSimple())
@@ -83,7 +84,16 @@ unsigned FastISel::getRegForValue(Value *V) {
if (Reg != 0)
return Reg;
- if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
+ return materializeRegForValue(V, VT);
+}
+
+/// materializeRegForValue - Helper for getRegForVale. This function is
+/// called when the value isn't already available in a register and must
+/// be materialized with new instructions.
+unsigned FastISel::materializeRegForValue(const Value *V, MVT VT) {
+ unsigned Reg = 0;
+
+ if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
if (CI->getValue().getActiveBits() <= 64)
Reg = FastEmit_i(VT, VT, ISD::Constant, CI->getZExtValue());
} else if (isa<AllocaInst>(V)) {
@@ -93,10 +103,12 @@ unsigned FastISel::getRegForValue(Value *V) {
// local-CSE'd with actual integer zeros.
Reg =
getRegForValue(Constant::getNullValue(TD.getIntPtrType(V->getContext())));
- } else if (ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
+ } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
+ // Try to emit the constant directly.
Reg = FastEmit_f(VT, VT, ISD::ConstantFP, CF);
if (!Reg) {
+ // Try to emit the constant by using an integer constant with a cast.
const APFloat &Flt = CF->getValueAPF();
EVT IntVT = TLI.getPointerTy();
@@ -114,9 +126,9 @@ unsigned FastISel::getRegForValue(Value *V) {
Reg = FastEmit_r(IntVT.getSimpleVT(), VT, ISD::SINT_TO_FP, IntegerReg);
}
}
- } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
- if (!SelectOperator(CE, CE->getOpcode())) return 0;
- Reg = LocalValueMap[CE];
+ } else if (const Operator *Op = dyn_cast<Operator>(V)) {
+ if (!SelectOperator(Op, Op->getOpcode())) return 0;
+ Reg = LocalValueMap[Op];
} else if (isa<UndefValue>(V)) {
Reg = createResultReg(TLI.getRegClassFor(VT));
BuildMI(MBB, DL, TII.get(TargetOpcode::IMPLICIT_DEF), Reg);
@@ -134,11 +146,11 @@ unsigned FastISel::getRegForValue(Value *V) {
return Reg;
}
-unsigned FastISel::lookUpRegForValue(Value *V) {
+unsigned FastISel::lookUpRegForValue(const Value *V) {
// Look up the value to see if we already have a register for it. We
// cache values defined by Instructions across blocks, and other values
// only locally. This is because Instructions already have the SSA
- // def-dominatess-use requirement enforced.
+ // def-dominates-use requirement enforced.
if (ValueMap.count(V))
return ValueMap[V];
return LocalValueMap[V];
@@ -150,7 +162,7 @@ unsigned FastISel::lookUpRegForValue(Value *V) {
/// NOTE: This is only necessary because we might select a block that uses
/// a value before we select the block that defines the value. It might be
/// possible to fix this by selecting blocks in reverse postorder.
-unsigned FastISel::UpdateValueMap(Value* I, unsigned Reg) {
+unsigned FastISel::UpdateValueMap(const Value *I, unsigned Reg) {
if (!isa<Instruction>(I)) {
LocalValueMap[I] = Reg;
return Reg;
@@ -167,7 +179,7 @@ unsigned FastISel::UpdateValueMap(Value* I, unsigned Reg) {
return AssignedReg;
}
-unsigned FastISel::getRegForGEPIndex(Value *Idx) {
+unsigned FastISel::getRegForGEPIndex(const Value *Idx) {
unsigned IdxN = getRegForValue(Idx);
if (IdxN == 0)
// Unhandled operand. Halt "fast" selection and bail.
@@ -186,7 +198,7 @@ unsigned FastISel::getRegForGEPIndex(Value *Idx) {
/// SelectBinaryOp - Select and emit code for a binary operator instruction,
/// which has an opcode which directly corresponds to the given ISD opcode.
///
-bool FastISel::SelectBinaryOp(User *I, unsigned ISDOpcode) {
+bool FastISel::SelectBinaryOp(const User *I, unsigned ISDOpcode) {
EVT VT = EVT::getEVT(I->getType(), /*HandleUnknown=*/true);
if (VT == MVT::Other || !VT.isSimple())
// Unhandled type. Halt "fast" selection and bail.
@@ -252,7 +264,7 @@ bool FastISel::SelectBinaryOp(User *I, unsigned ISDOpcode) {
return true;
}
-bool FastISel::SelectGetElementPtr(User *I) {
+bool FastISel::SelectGetElementPtr(const User *I) {
unsigned N = getRegForValue(I->getOperand(0));
if (N == 0)
// Unhandled operand. Halt "fast" selection and bail.
@@ -260,9 +272,9 @@ bool FastISel::SelectGetElementPtr(User *I) {
const Type *Ty = I->getOperand(0)->getType();
MVT VT = TLI.getPointerTy();
- for (GetElementPtrInst::op_iterator OI = I->op_begin()+1, E = I->op_end();
- OI != E; ++OI) {
- Value *Idx = *OI;
+ for (GetElementPtrInst::const_op_iterator OI = I->op_begin()+1,
+ E = I->op_end(); OI != E; ++OI) {
+ const Value *Idx = *OI;
if (const StructType *StTy = dyn_cast<StructType>(Ty)) {
unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
if (Field) {
@@ -280,7 +292,7 @@ bool FastISel::SelectGetElementPtr(User *I) {
Ty = cast<SequentialType>(Ty)->getElementType();
// If this is a constant subscript, handle it quickly.
- if (ConstantInt *CI = dyn_cast<ConstantInt>(Idx)) {
+ if (const ConstantInt *CI = dyn_cast<ConstantInt>(Idx)) {
if (CI->getZExtValue() == 0) continue;
uint64_t Offs =
TD.getTypeAllocSize(Ty)*cast<ConstantInt>(CI)->getSExtValue();
@@ -316,51 +328,56 @@ bool FastISel::SelectGetElementPtr(User *I) {
return true;
}
-bool FastISel::SelectCall(User *I) {
- Function *F = cast<CallInst>(I)->getCalledFunction();
+bool FastISel::SelectCall(const User *I) {
+ const Function *F = cast<CallInst>(I)->getCalledFunction();
if (!F) return false;
+ // Handle selected intrinsic function calls.
unsigned IID = F->getIntrinsicID();
switch (IID) {
default: break;
case Intrinsic::dbg_declare: {
- DbgDeclareInst *DI = cast<DbgDeclareInst>(I);
+ const DbgDeclareInst *DI = cast<DbgDeclareInst>(I);
if (!DIDescriptor::ValidDebugInfo(DI->getVariable(), CodeGenOpt::None) ||
!MF.getMMI().hasDebugInfo())
return true;
- Value *Address = DI->getAddress();
+ const Value *Address = DI->getAddress();
if (!Address)
return true;
- AllocaInst *AI = dyn_cast<AllocaInst>(Address);
+ if (isa<UndefValue>(Address))
+ return true;
+ const AllocaInst *AI = dyn_cast<AllocaInst>(Address);
// Don't handle byval struct arguments or VLAs, for example.
- if (!AI) break;
- DenseMap<const AllocaInst*, int>::iterator SI =
- StaticAllocaMap.find(AI);
- if (SI == StaticAllocaMap.end()) break; // VLAs.
- int FI = SI->second;
- if (!DI->getDebugLoc().isUnknown())
- MF.getMMI().setVariableDbgInfo(DI->getVariable(), FI, DI->getDebugLoc());
-
- // Building the map above is target independent. Generating DBG_VALUE
- // inline is target dependent; do this now.
- (void)TargetSelectInstruction(cast<Instruction>(I));
+ // Note that if we have a byval struct argument, fast ISel is turned off;
+ // those are handled in SelectionDAGBuilder.
+ if (AI) {
+ DenseMap<const AllocaInst*, int>::iterator SI =
+ StaticAllocaMap.find(AI);
+ if (SI == StaticAllocaMap.end()) break; // VLAs.
+ int FI = SI->second;
+ if (!DI->getDebugLoc().isUnknown())
+ MF.getMMI().setVariableDbgInfo(DI->getVariable(), FI, DI->getDebugLoc());
+ } else
+ // Building the map above is target independent. Generating DBG_VALUE
+ // inline is target dependent; do this now.
+ (void)TargetSelectInstruction(cast<Instruction>(I));
return true;
}
case Intrinsic::dbg_value: {
- // This requires target support, but right now X86 is the only Fast target.
- DbgValueInst *DI = cast<DbgValueInst>(I);
+ // This form of DBG_VALUE is target-independent.
+ const DbgValueInst *DI = cast<DbgValueInst>(I);
const TargetInstrDesc &II = TII.get(TargetOpcode::DBG_VALUE);
- Value *V = DI->getValue();
+ const Value *V = DI->getValue();
if (!V) {
// Currently the optimizer can produce this; insert an undef to
// help debugging. Probably the optimizer should not do this.
BuildMI(MBB, DL, II).addReg(0U).addImm(DI->getOffset()).
addMetadata(DI->getVariable());
- } else if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
+ } else if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
BuildMI(MBB, DL, II).addImm(CI->getZExtValue()).addImm(DI->getOffset()).
addMetadata(DI->getVariable());
- } else if (ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
+ } else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
BuildMI(MBB, DL, II).addFPImm(CF).addImm(DI->getOffset()).
addMetadata(DI->getVariable());
} else if (unsigned Reg = lookUpRegForValue(V)) {
@@ -438,10 +455,12 @@ bool FastISel::SelectCall(User *I) {
break;
}
}
+
+ // An arbitrary call. Bail.
return false;
}
-bool FastISel::SelectCast(User *I, unsigned Opcode) {
+bool FastISel::SelectCast(const User *I, unsigned Opcode) {
EVT SrcVT = TLI.getValueType(I->getOperand(0)->getType());
EVT DstVT = TLI.getValueType(I->getType());
@@ -493,7 +512,7 @@ bool FastISel::SelectCast(User *I, unsigned Opcode) {
return true;
}
-bool FastISel::SelectBitCast(User *I) {
+bool FastISel::SelectBitCast(const User *I) {
// If the bitcast doesn't change the type, just use the operand value.
if (I->getType() == I->getOperand(0)->getType()) {
unsigned Reg = getRegForValue(I->getOperand(0));
@@ -544,15 +563,28 @@ bool FastISel::SelectBitCast(User *I) {
}
bool
-FastISel::SelectInstruction(Instruction *I) {
+FastISel::SelectInstruction(const Instruction *I) {
+ // Just before the terminator instruction, insert instructions to
+ // feed PHI nodes in successor blocks.
+ if (isa<TerminatorInst>(I))
+ if (!HandlePHINodesInSuccessorBlocks(I->getParent()))
+ return false;
+
+ DL = I->getDebugLoc();
+
// First, try doing target-independent selection.
- if (SelectOperator(I, I->getOpcode()))
+ if (SelectOperator(I, I->getOpcode())) {
+ DL = DebugLoc();
return true;
+ }
// Next, try calling the target to attempt to handle the instruction.
- if (TargetSelectInstruction(I))
+ if (TargetSelectInstruction(I)) {
+ DL = DebugLoc();
return true;
+ }
+ DL = DebugLoc();
return false;
}
@@ -573,7 +605,7 @@ FastISel::FastEmitBranch(MachineBasicBlock *MSucc) {
/// SelectFNeg - Emit an FNeg operation.
///
bool
-FastISel::SelectFNeg(User *I) {
+FastISel::SelectFNeg(const User *I) {
unsigned OpReg = getRegForValue(BinaryOperator::getFNegArgument(I));
if (OpReg == 0) return false;
@@ -614,7 +646,7 @@ FastISel::SelectFNeg(User *I) {
}
bool
-FastISel::SelectOperator(User *I, unsigned Opcode) {
+FastISel::SelectOperator(const User *I, unsigned Opcode) {
switch (Opcode) {
case Instruction::Add:
return SelectBinaryOp(I, ISD::ADD);
@@ -660,10 +692,10 @@ FastISel::SelectOperator(User *I, unsigned Opcode) {
return SelectGetElementPtr(I);
case Instruction::Br: {
- BranchInst *BI = cast<BranchInst>(I);
+ const BranchInst *BI = cast<BranchInst>(I);
if (BI->isUnconditional()) {
- BasicBlock *LLVMSucc = BI->getSuccessor(0);
+ const BasicBlock *LLVMSucc = BI->getSuccessor(0);
MachineBasicBlock *MSucc = MBBMap[LLVMSucc];
FastEmitBranch(MSucc);
return true;
@@ -678,10 +710,6 @@ FastISel::SelectOperator(User *I, unsigned Opcode) {
// Nothing to emit.
return true;
- case Instruction::PHI:
- // PHI nodes are already emitted.
- return true;
-
case Instruction::Alloca:
// FunctionLowering has the static-sized case covered.
if (StaticAllocaMap.count(cast<AllocaInst>(I)))
@@ -721,6 +749,9 @@ FastISel::SelectOperator(User *I, unsigned Opcode) {
return true;
}
+ case Instruction::PHI:
+ llvm_unreachable("FastISel shouldn't visit PHI nodes!");
+
default:
// Unhandled instruction. Halt "fast" selection and bail.
return false;
@@ -730,15 +761,17 @@ FastISel::SelectOperator(User *I, unsigned Opcode) {
FastISel::FastISel(MachineFunction &mf,
DenseMap<const Value *, unsigned> &vm,
DenseMap<const BasicBlock *, MachineBasicBlock *> &bm,
- DenseMap<const AllocaInst *, int> &am
+ DenseMap<const AllocaInst *, int> &am,
+ std::vector<std::pair<MachineInstr*, unsigned> > &pn
#ifndef NDEBUG
- , SmallSet<Instruction*, 8> &cil
+ , SmallSet<const Instruction *, 8> &cil
#endif
)
: MBB(0),
ValueMap(vm),
MBBMap(bm),
StaticAllocaMap(am),
+ PHINodesToUpdate(pn),
#ifndef NDEBUG
CatchInfoLost(cil),
#endif
@@ -775,7 +808,7 @@ unsigned FastISel::FastEmit_i(MVT, MVT, unsigned, uint64_t /*Imm*/) {
}
unsigned FastISel::FastEmit_f(MVT, MVT,
- unsigned, ConstantFP * /*FPImm*/) {
+ unsigned, const ConstantFP * /*FPImm*/) {
return 0;
}
@@ -787,7 +820,7 @@ unsigned FastISel::FastEmit_ri(MVT, MVT,
unsigned FastISel::FastEmit_rf(MVT, MVT,
unsigned, unsigned /*Op0*/,
- ConstantFP * /*FPImm*/) {
+ const ConstantFP * /*FPImm*/) {
return 0;
}
@@ -820,7 +853,7 @@ unsigned FastISel::FastEmit_ri_(MVT VT, unsigned Opcode,
/// FastEmit_rf. If that fails, it materializes the immediate into a register
/// and try FastEmit_rr instead.
unsigned FastISel::FastEmit_rf_(MVT VT, unsigned Opcode,
- unsigned Op0, ConstantFP *FPImm,
+ unsigned Op0, const ConstantFP *FPImm,
MVT ImmType) {
// First check if immediate type is legal. If not, we can't use the rf form.
unsigned ResultReg = FastEmit_rf(VT, VT, Opcode, Op0, FPImm);
@@ -930,7 +963,7 @@ unsigned FastISel::FastEmitInst_ri(unsigned MachineInstOpcode,
unsigned FastISel::FastEmitInst_rf(unsigned MachineInstOpcode,
const TargetRegisterClass *RC,
- unsigned Op0, ConstantFP *FPImm) {
+ unsigned Op0, const ConstantFP *FPImm) {
unsigned ResultReg = createResultReg(RC);
const TargetInstrDesc &II = TII.get(MachineInstOpcode);
@@ -1006,3 +1039,67 @@ unsigned FastISel::FastEmitInst_extractsubreg(MVT RetVT,
unsigned FastISel::FastEmitZExtFromI1(MVT VT, unsigned Op) {
return FastEmit_ri(VT, VT, ISD::AND, Op, 1);
}
+
+/// HandlePHINodesInSuccessorBlocks - Handle PHI nodes in successor blocks.
+/// Emit code to ensure constants are copied into registers when needed.
+/// Remember the virtual registers that need to be added to the Machine PHI
+/// nodes as input. We cannot just directly add them, because expansion
+/// might result in multiple MBB's for one BB. As such, the start of the
+/// BB might correspond to a different MBB than the end.
+bool FastISel::HandlePHINodesInSuccessorBlocks(const BasicBlock *LLVMBB) {
+ const TerminatorInst *TI = LLVMBB->getTerminator();
+
+ SmallPtrSet<MachineBasicBlock *, 4> SuccsHandled;
+ unsigned OrigNumPHINodesToUpdate = PHINodesToUpdate.size();
+
+ // Check successor nodes' PHI nodes that expect a constant to be available
+ // from this block.
+ for (unsigned succ = 0, e = TI->getNumSuccessors(); succ != e; ++succ) {
+ const BasicBlock *SuccBB = TI->getSuccessor(succ);
+ if (!isa<PHINode>(SuccBB->begin())) continue;
+ MachineBasicBlock *SuccMBB = MBBMap[SuccBB];
+
+ // If this terminator has multiple identical successors (common for
+ // switches), only handle each succ once.
+ if (!SuccsHandled.insert(SuccMBB)) continue;
+
+ MachineBasicBlock::iterator MBBI = SuccMBB->begin();
+
+ // At this point we know that there is a 1-1 correspondence between LLVM PHI
+ // nodes and Machine PHI nodes, but the incoming operands have not been
+ // emitted yet.
+ for (BasicBlock::const_iterator I = SuccBB->begin();
+ const PHINode *PN = dyn_cast<PHINode>(I); ++I) {
+ // Ignore dead phi's.
+ if (PN->use_empty()) continue;
+
+ // Only handle legal types. Two interesting things to note here. First,
+ // by bailing out early, we may leave behind some dead instructions,
+ // since SelectionDAG's HandlePHINodesInSuccessorBlocks will insert its
+ // own moves. Second, this check is necessary becuase FastISel doesn't
+ // use CreateRegForValue to create registers, so it always creates
+ // exactly one register for each non-void instruction.
+ EVT VT = TLI.getValueType(PN->getType(), /*AllowUnknown=*/true);
+ if (VT == MVT::Other || !TLI.isTypeLegal(VT)) {
+ // Promote MVT::i1.
+ if (VT == MVT::i1)
+ VT = TLI.getTypeToTransformTo(LLVMBB->getContext(), VT);
+ else {
+ PHINodesToUpdate.resize(OrigNumPHINodesToUpdate);
+ return false;
+ }
+ }
+
+ const Value *PHIOp = PN->getIncomingValueForBlock(LLVMBB);
+
+ unsigned Reg = getRegForValue(PHIOp);
+ if (Reg == 0) {
+ PHINodesToUpdate.resize(OrigNumPHINodesToUpdate);
+ return false;
+ }
+ PHINodesToUpdate.push_back(std::make_pair(MBBI++, Reg));
+ }
+ }
+
+ return true;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-02-24 23:45:42 +0000