diff options
| -rw-r--r-- | llvm/include/llvm/CodeGen/FastISel.h | 1 | ||||
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/FastISel.cpp | 27 |
2 files changed, 16 insertions, 12 deletions
diff --git a/llvm/include/llvm/CodeGen/FastISel.h b/llvm/include/llvm/CodeGen/FastISel.h index 15cbe65aeb5..71c80d53538 100644 --- a/llvm/include/llvm/CodeGen/FastISel.h +++ b/llvm/include/llvm/CodeGen/FastISel.h @@ -36,6 +36,7 @@ class TargetRegisterClass; class FastISel { protected: MachineBasicBlock *MBB; + DenseMap<const Value *, unsigned> LocalValueMap; DenseMap<const Value *, unsigned> &ValueMap; DenseMap<const BasicBlock *, MachineBasicBlock *> &MBBMap; MachineFunction &MF; diff --git a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp index c057be5f769..d118eefd221 100644 --- a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp @@ -21,13 +21,16 @@ #include "llvm/Target/TargetMachine.h" using namespace llvm; -// Don't cache constant materializations. To do so would require -// tracking what uses they dominate. Non-constants, however, already -// have the SSA def-doms-use requirement enforced, so we can cache their -// computations. unsigned FastISel::getRegForValue(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. if (ValueMap.count(V)) return ValueMap[V]; + unsigned Reg = LocalValueMap[V]; + if (Reg != 0) + return Reg; MVT::SimpleValueType VT = TLI.getValueType(V->getType()).getSimpleVT(); if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) { @@ -35,11 +38,11 @@ unsigned FastISel::getRegForValue(Value *V) { return 0; // Don't cache constant materializations. To do so would require // tracking what uses they dominate. - return FastEmit_i(VT, VT, ISD::Constant, CI->getZExtValue()); + Reg = FastEmit_i(VT, VT, ISD::Constant, CI->getZExtValue()); } else if (isa<ConstantPointerNull>(V)) { - return FastEmit_i(VT, VT, ISD::Constant, 0); + Reg = FastEmit_i(VT, VT, ISD::Constant, 0); } else if (ConstantFP *CF = dyn_cast<ConstantFP>(V)) { - unsigned Reg = FastEmit_f(VT, VT, ISD::ConstantFP, CF); + Reg = FastEmit_f(VT, VT, ISD::ConstantFP, CF); if (!Reg) { const APFloat &Flt = CF->getValueAPF(); @@ -60,15 +63,15 @@ unsigned FastISel::getRegForValue(Value *V) { if (Reg == 0) return 0; } - - return Reg; } else if (isa<UndefValue>(V)) { - unsigned Reg = createResultReg(TLI.getRegClassFor(VT)); + Reg = createResultReg(TLI.getRegClassFor(VT)); BuildMI(MBB, TII.get(TargetInstrInfo::IMPLICIT_DEF), Reg); - return Reg; + } else { + return 0; } - return 0; + LocalValueMap[V] = Reg; + return Reg; } /// UpdateValueMap - Update the value map to include the new mapping for this |
