#include "MCTargetDesc/PPCPredicates.h"
#include "PPCMachineFunctionInfo.h"
#include "PPCTargetMachine.h"
+#include "llvm/Analysis/BranchProbabilityInfo.h"
+#include "llvm/CodeGen/FunctionLoweringInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
"bit permutations"),
cl::Hidden);
+static cl::opt<bool> EnableBranchHint(
+ "ppc-use-branch-hint", cl::init(true),
+ cl::desc("Enable static hinting of branches on ppc"),
+ cl::Hidden);
+
namespace llvm {
void initializePPCDAGToDAGISelPass(PassRegistry&);
}
return isInt32Immediate(N.getNode(), Imm);
}
+static unsigned getBranchHint(unsigned PCC, FunctionLoweringInfo *FuncInfo,
+ const SDValue &DestMBB) {
+ assert(isa<BasicBlockSDNode>(DestMBB));
+
+ if (!FuncInfo->BPI) return PPC::BR_NO_HINT;
+
+ const BasicBlock *BB = FuncInfo->MBB->getBasicBlock();
+ const TerminatorInst *BBTerm = BB->getTerminator();
+
+ if (BBTerm->getNumSuccessors() != 2) return PPC::BR_NO_HINT;
+
+ const BasicBlock *TBB = BBTerm->getSuccessor(0);
+ const BasicBlock *FBB = BBTerm->getSuccessor(1);
+
+ auto TProb = FuncInfo->BPI->getEdgeProbability(BB, TBB);
+ auto FProb = FuncInfo->BPI->getEdgeProbability(BB, FBB);
+
+ // We only want to handle cases which are easy to predict at static time, e.g.
+ // C++ throw statement, that is very likely not taken, or calling never
+ // returned function, e.g. stdlib exit(). So we set Threshold to filter
+ // unwanted cases.
+ //
+ // Below is LLVM branch weight table, we only want to handle case 1, 2
+ //
+ // Case Taken:Nontaken Example
+ // 1. Unreachable 1048575:1 C++ throw, stdlib exit(),
+ // 2. Invoke-terminating 1:1048575
+ // 3. Coldblock 4:64 __builtin_expect
+ // 4. Loop Branch 124:4 For loop
+ // 5. PH/ZH/FPH 20:12
+ const uint32_t Threshold = 10000;
+
+ if (std::max(TProb, FProb) / Threshold < std::min(TProb, FProb))
+ return PPC::BR_NO_HINT;
+
+ DEBUG(dbgs() << "Use branch hint for '" << FuncInfo->Fn->getName() << "::"
+ << BB->getName() << "'\n"
+ << " -> " << TBB->getName() << ": " << TProb << "\n"
+ << " -> " << FBB->getName() << ": " << FProb << "\n");
+
+ const BasicBlockSDNode *BBDN = cast<BasicBlockSDNode>(DestMBB);
+
+ // If Dest BasicBlock is False-BasicBlock (FBB), swap branch probabilities,
+ // because we want 'TProb' stands for 'branch probability' to Dest BasicBlock
+ if (BBDN->getBasicBlock()->getBasicBlock() != TBB)
+ std::swap(TProb, FProb);
+
+ return (TProb > FProb) ? PPC::BR_TAKEN_HINT : PPC::BR_NONTAKEN_HINT;
+}
// isOpcWithIntImmediate - This method tests to see if the node is a specific
// opcode and that it has a immediate integer right operand.
return false;
}
- if (VRI.RLAmt != EffRLAmt)
- return false;
-
- return true;
+ return VRI.RLAmt == EffRLAmt;
};
for (auto &BG : BitGroups) {
if (PPCSubTarget->hasVSX() && (N->getValueType(0) == MVT::v2f64 ||
N->getValueType(0) == MVT::v2i64)) {
ShuffleVectorSDNode *SVN = cast<ShuffleVectorSDNode>(N);
-
+
SDValue Op1 = N->getOperand(SVN->getMaskElt(0) < 2 ? 0 : 1),
Op2 = N->getOperand(SVN->getMaskElt(1) < 2 ? 0 : 1);
unsigned DM[2];
// Op #3 is the Dest MBB
// Op #4 is the Flag.
// Prevent PPC::PRED_* from being selected into LI.
- SDValue Pred =
- getI32Imm(cast<ConstantSDNode>(N->getOperand(1))->getZExtValue(), dl);
+ unsigned PCC = cast<ConstantSDNode>(N->getOperand(1))->getZExtValue();
+ if (EnableBranchHint)
+ PCC |= getBranchHint(PCC, FuncInfo, N->getOperand(3));
+
+ SDValue Pred = getI32Imm(PCC, dl);
SDValue Ops[] = { Pred, N->getOperand(2), N->getOperand(3),
N->getOperand(0), N->getOperand(4) };
return CurDAG->SelectNodeTo(N, PPC::BCC, MVT::Other, Ops);
BitComp, N->getOperand(4), N->getOperand(0));
}
+ if (EnableBranchHint)
+ PCC |= getBranchHint(PCC, FuncInfo, N->getOperand(4));
+
SDValue CondCode = SelectCC(N->getOperand(2), N->getOperand(3), CC, dl);
SDValue Ops[] = { getI32Imm(PCC, dl), CondCode,
N->getOperand(4), N->getOperand(0) };
break;
// The first source operand is a TargetGlobalAddress or a TargetJumpTable.
- // If it is an externally defined symbol, a symbol with common linkage,
- // a non-local function address, or a jump table address, or if we are
- // generating code for large code model, we generate:
+ // If it must be toc-referenced according to PPCSubTarget, we generate:
// LDtocL(<ga:@sym>, ADDIStocHA(%X2, <ga:@sym>))
// Otherwise we generate:
// ADDItocL(ADDIStocHA(%X2, <ga:@sym>), <ga:@sym>)
MVT::i64, GA, SDValue(Tmp, 0)));
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(GA)) {
- const GlobalValue *GValue = G->getGlobal();
- if ((GValue->getType()->getElementType()->isFunctionTy() &&
- !GValue->isStrongDefinitionForLinker()) ||
- GValue->isDeclaration() || GValue->hasCommonLinkage() ||
- GValue->hasAvailableExternallyLinkage())
+ const GlobalValue *GV = G->getGlobal();
+ unsigned char GVFlags = PPCSubTarget->classifyGlobalReference(GV);
+ if (GVFlags & PPCII::MO_NLP_FLAG) {
return transferMemOperands(N, CurDAG->getMachineNode(PPC::LDtocL, dl,
MVT::i64, GA, SDValue(Tmp, 0)));
+ }
}
return CurDAG->getMachineNode(PPC::ADDItocL, dl, MVT::i64,
if (!CurDAG->MaskedValueIsZero(Op0,
APInt::getHighBitsSet(Bits, Bits - (b+1)*8)))
return false;
-
+
LHS = Op0.getOperand(0);
RHS = Op0.getOperand(1);
return true;
break;
}
- // If this is a load or store with a zero offset, we may be able to
- // fold an add-immediate into the memory operation.
- if (!isa<ConstantSDNode>(N->getOperand(FirstOp)) ||
- N->getConstantOperandVal(FirstOp) != 0)
+ // If this is a load or store with a zero offset, or within the alignment,
+ // we may be able to fold an add-immediate into the memory operation.
+ // The check against alignment is below, as it can't occur until we check
+ // the arguments to N
+ if (!isa<ConstantSDNode>(N->getOperand(FirstOp)))
continue;
SDValue Base = N->getOperand(FirstOp + 1);
if (!Base.isMachineOpcode())
continue;
+ // On targets with fusion, we don't want this to fire and remove a fusion
+ // opportunity, unless a) it results in another fusion opportunity or
+ // b) optimizing for size.
+ if (PPCSubTarget->hasFusion() &&
+ (!MF->getFunction()->optForSize() && !Base.hasOneUse()))
+ continue;
+
unsigned Flags = 0;
bool ReplaceFlags = true;
break;
}
+ SDValue ImmOpnd = Base.getOperand(1);
+ int MaxDisplacement = 0;
+ if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(ImmOpnd)) {
+ const GlobalValue *GV = GA->getGlobal();
+ MaxDisplacement = GV->getAlignment() - 1;
+ }
+
+ int Offset = N->getConstantOperandVal(FirstOp);
+ if (Offset < 0 || Offset > MaxDisplacement)
+ continue;
+
// We found an opportunity. Reverse the operands from the add
// immediate and substitute them into the load or store. If
// needed, update the target flags for the immediate operand to
DEBUG(N->dump(CurDAG));
DEBUG(dbgs() << "\n");
- SDValue ImmOpnd = Base.getOperand(1);
-
// If the relocation information isn't already present on the
// immediate operand, add it now.
if (ReplaceFlags) {
// is insufficient for the instruction encoding.
if (GV->getAlignment() < 4 &&
(StorageOpcode == PPC::LD || StorageOpcode == PPC::STD ||
- StorageOpcode == PPC::LWA)) {
+ StorageOpcode == PPC::LWA || (Offset % 4) != 0)) {
DEBUG(dbgs() << "Rejected this candidate for alignment.\n\n");
continue;
}
- ImmOpnd = CurDAG->getTargetGlobalAddress(GV, dl, MVT::i64, 0, Flags);
+ ImmOpnd = CurDAG->getTargetGlobalAddress(GV, dl, MVT::i64, Offset, Flags);
} else if (ConstantPoolSDNode *CP =
dyn_cast<ConstantPoolSDNode>(ImmOpnd)) {
const Constant *C = CP->getConstVal();
ImmOpnd = CurDAG->getTargetConstantPool(C, MVT::i64,
CP->getAlignment(),
- 0, Flags);
+ Offset, Flags);
}
}
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