#define DEBUG_TYPE "isel"
#include "llvm/CodeGen/FastISel.h"
+#include "llvm/ADT/Optional.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/Loads.h"
#include "llvm/CodeGen/Analysis.h"
void FastISel::startNewBlock() {
LocalValueMap.clear();
+ // Instructions are appended to FuncInfo.MBB. If the basic block already
+ // contains labels or copies, use the last instruction as the last local
+ // value.
EmitStartPt = 0;
-
- // Advance the emit start point past any EH_LABEL instructions.
- MachineBasicBlock::iterator
- I = FuncInfo.MBB->begin(), E = FuncInfo.MBB->end();
- while (I != E && I->getOpcode() == TargetOpcode::EH_LABEL) {
- EmitStartPt = I;
- ++I;
- }
+ if (!FuncInfo.MBB->empty())
+ EmitStartPt = &FuncInfo.MBB->back();
LastLocalValue = EmitStartPt;
}
// Fallback to SDISel argument lowering code to deal with sret pointer
// parameter.
return false;
-
+
if (!FastLowerArguments())
return false;
- // Enter non-dead arguments into ValueMap for uses in non-entry BBs.
+ // Enter arguments into ValueMap for uses in non-entry BBs.
for (Function::const_arg_iterator I = FuncInfo.Fn->arg_begin(),
E = FuncInfo.Fn->arg_end(); I != E; ++I) {
- if (!I->use_empty()) {
- DenseMap<const Value *, unsigned>::iterator VI = LocalValueMap.find(I);
- assert(VI != LocalValueMap.end() && "Missed an argument?");
- FuncInfo.ValueMap[I] = VI->second;
- }
+ DenseMap<const Value *, unsigned>::iterator VI = LocalValueMap.find(I);
+ assert(VI != LocalValueMap.end() && "Missed an argument?");
+ FuncInfo.ValueMap[I] = VI->second;
}
return true;
}
case Intrinsic::dbg_declare: {
const DbgDeclareInst *DI = cast<DbgDeclareInst>(Call);
- if (!DIVariable(DI->getVariable()).Verify() ||
+ DIVariable DIVar(DI->getVariable());
+ assert((!DIVar || DIVar.isVariable()) &&
+ "Variable in DbgDeclareInst should be either null or a DIVariable.");
+ if (!DIVar ||
!FuncInfo.MF->getMMI().hasDebugInfo()) {
DEBUG(dbgs() << "Dropping debug info for " << *DI << "\n");
return true;
return true;
}
- unsigned Reg = 0;
unsigned Offset = 0;
- if (const Argument *Arg = dyn_cast<Argument>(Address)) {
+ Optional<MachineOperand> Op;
+ if (const Argument *Arg = dyn_cast<Argument>(Address))
// Some arguments' frame index is recorded during argument lowering.
Offset = FuncInfo.getArgumentFrameIndex(Arg);
- if (Offset)
- Reg = TRI.getFrameRegister(*FuncInfo.MF);
- }
- if (!Reg)
- Reg = lookUpRegForValue(Address);
+ if (Offset)
+ Op = MachineOperand::CreateFI(Offset);
+ if (!Op)
+ if (unsigned Reg = lookUpRegForValue(Address))
+ Op = MachineOperand::CreateReg(Reg, false);
// If we have a VLA that has a "use" in a metadata node that's then used
// here but it has no other uses, then we have a problem. E.g.,
// If we assign 'a' a vreg and fast isel later on has to use the selection
// DAG isel, it will want to copy the value to the vreg. However, there are
// no uses, which goes counter to what selection DAG isel expects.
- if (!Reg && !Address->use_empty() && isa<Instruction>(Address) &&
+ if (!Op && !Address->use_empty() && isa<Instruction>(Address) &&
(!isa<AllocaInst>(Address) ||
!FuncInfo.StaticAllocaMap.count(cast<AllocaInst>(Address))))
- Reg = FuncInfo.InitializeRegForValue(Address);
-
- if (Reg)
+ Op = MachineOperand::CreateReg(FuncInfo.InitializeRegForValue(Address),
+ false);
+
+ if (Op) {
+ if (Op->isReg()) {
+ Op->setIsDebug(true);
+ BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
+ TII.get(TargetOpcode::DBG_VALUE),
+ false, Op->getReg(), 0, DI->getVariable());
+ } else
BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
TII.get(TargetOpcode::DBG_VALUE))
- .addReg(Reg, RegState::Debug).addImm(Offset)
+ .addOperand(*Op).addImm(0)
.addMetadata(DI->getVariable());
- else
+ } else {
// We can't yet handle anything else here because it would require
// generating code, thus altering codegen because of debug info.
- DEBUG(dbgs() << "Dropping debug info for " << DI);
+ DEBUG(dbgs() << "Dropping debug info for " << *DI << "\n");
+ }
return true;
}
case Intrinsic::dbg_value: {
.addFPImm(CF).addImm(DI->getOffset())
.addMetadata(DI->getVariable());
} else if (unsigned Reg = lookUpRegForValue(V)) {
- BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
- .addReg(Reg, RegState::Debug).addImm(DI->getOffset())
- .addMetadata(DI->getVariable());
+ // FIXME: This does not handle register-indirect values at offset 0.
+ bool IsIndirect = DI->getOffset() != 0;
+ BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, IsIndirect,
+ Reg, DI->getOffset(), DI->getVariable());
} else {
// We can't yet handle anything else here because it would require
// generating code, thus altering codegen because of debug info.
- DEBUG(dbgs() << "Dropping debug info for " << DI);
+ DEBUG(dbgs() << "Dropping debug info for " << *DI << "\n");
}
return true;
}
UpdateValueMap(Call, ResultReg);
return true;
}
+ case Intrinsic::expect: {
+ unsigned ResultReg = getRegForValue(Call->getArgOperand(0));
+ if (ResultReg == 0)
+ return false;
+ UpdateValueMap(Call, ResultReg);
+ return true;
+ }
}
// Usually, it does not make sense to initialize a value,
// all the values which have already been materialized,
// appear after the call. It also makes sense to skip intrinsics
// since they tend to be inlined.
- if (!isa<IntrinsicInst>(F))
+ if (!isa<IntrinsicInst>(Call))
flushLocalValueMap();
// An arbitrary call. Bail.
IntegerType *ITy = IntegerType::get(FuncInfo.Fn->getContext(),
VT.getSizeInBits());
MaterialReg = getRegForValue(ConstantInt::get(ITy, Imm));
+ assert (MaterialReg != 0 && "Unable to materialize imm.");
+ if (MaterialReg == 0) return 0;
}
return FastEmit_rr(VT, VT, Opcode,
Op0, Op0IsKill,
return true;
}
+
+bool FastISel::tryToFoldLoad(const LoadInst *LI, const Instruction *FoldInst) {
+ assert(LI->hasOneUse() &&
+ "tryToFoldLoad expected a LoadInst with a single use");
+ // We know that the load has a single use, but don't know what it is. If it
+ // isn't one of the folded instructions, then we can't succeed here. Handle
+ // this by scanning the single-use users of the load until we get to FoldInst.
+ unsigned MaxUsers = 6; // Don't scan down huge single-use chains of instrs.
+
+ const Instruction *TheUser = LI->use_back();
+ while (TheUser != FoldInst && // Scan up until we find FoldInst.
+ // Stay in the right block.
+ TheUser->getParent() == FoldInst->getParent() &&
+ --MaxUsers) { // Don't scan too far.
+ // If there are multiple or no uses of this instruction, then bail out.
+ if (!TheUser->hasOneUse())
+ return false;
+
+ TheUser = TheUser->use_back();
+ }
+
+ // If we didn't find the fold instruction, then we failed to collapse the
+ // sequence.
+ if (TheUser != FoldInst)
+ return false;
+
+ // Don't try to fold volatile loads. Target has to deal with alignment
+ // constraints.
+ if (LI->isVolatile())
+ return false;
+
+ // Figure out which vreg this is going into. If there is no assigned vreg yet
+ // then there actually was no reference to it. Perhaps the load is referenced
+ // by a dead instruction.
+ unsigned LoadReg = getRegForValue(LI);
+ if (LoadReg == 0)
+ return false;
+
+ // We can't fold if this vreg has no uses or more than one use. Multiple uses
+ // may mean that the instruction got lowered to multiple MIs, or the use of
+ // the loaded value ended up being multiple operands of the result.
+ if (!MRI.hasOneUse(LoadReg))
+ return false;
+
+ MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(LoadReg);
+ MachineInstr *User = &*RI;
+
+ // Set the insertion point properly. Folding the load can cause generation of
+ // other random instructions (like sign extends) for addressing modes; make
+ // sure they get inserted in a logical place before the new instruction.
+ FuncInfo.InsertPt = User;
+ FuncInfo.MBB = User->getParent();
+
+ // Ask the target to try folding the load.
+ return tryToFoldLoadIntoMI(User, RI.getOperandNo(), LI);
+}
+
+
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