Use the target options specified on a function to reset the back-end.

During LTO, the target options on functions within the same Module may
change. This would necessitate resetting some of the back-end. Do this for X86,
because it's a Friday afternoon.

llvm-svn: 178917

llvm/include/llvm/Target/TargetLowering.h

@@ -135,6 +135,11 @@ public:
                               const TargetLoweringObjectFile *TLOF);
   virtual ~TargetLoweringBase();
 
+protected:
+  /// \brief Initialize all of the actions to default values.
+  void initActions();
+
+public:
   const TargetMachine &getTargetMachine() const { return TM; }
   const DataLayout *getDataLayout() const { return TD; }
   const TargetLoweringObjectFile &getObjFileLowering() const { return TLOF; }
@@ -851,6 +856,9 @@ public:
   // the derived class constructor to configure this object for the target.
   //
 
+  /// \brief Reset the operation actions based on target options.
+  virtual void resetOperationActions() {}
+
 protected:
   /// setBooleanContents - Specify how the target extends the result of a
   /// boolean value from i1 to a wider type.  See getBooleanContents.
@@ -951,13 +959,17 @@ protected:
     RegClassForVT[VT.SimpleTy] = RC;
   }
 
-  /// clearRegisterClasses - remove all register classes
+  /// clearRegisterClasses - Remove all register classes.
   void clearRegisterClasses() {
-    for (unsigned i = 0 ; i<array_lengthof(RegClassForVT); i++)
-      RegClassForVT[i] = 0;
+    memset(RegClassForVT, 0,MVT::LAST_VALUETYPE * sizeof(TargetRegisterClass*));
+
     AvailableRegClasses.clear();
   }
 
+  /// \brief Remove all operation actions.
+  void clearOperationActions() {
+  }
+
   /// findRepresentativeClass - Return the largest legal super-reg register class
   /// of the register class for the specified type and its associated "cost".
   virtual std::pair<const TargetRegisterClass*, uint8_t>

llvm/include/llvm/Target/TargetOptions.h

@@ -208,6 +208,7 @@ namespace llvm {
     /// the value of this option.
     FPOpFusion::FPOpFusionMode AllowFPOpFusion;
 
+    bool operator==(const TargetOptions &);
   };
 } // End llvm namespace
 

llvm/lib/CodeGen/TargetLoweringBase.cpp

@@ -620,12 +620,56 @@ static void InitCmpLibcallCCs(ISD::CondCode *CCs) {
 TargetLoweringBase::TargetLoweringBase(const TargetMachine &tm,
                                        const TargetLoweringObjectFile *tlof)
   : TM(tm), TD(TM.getDataLayout()), TLOF(*tlof) {
+  initActions();
+
+  // Perform these initializations only once.
+  IsLittleEndian = TD->isLittleEndian();
+  PointerTy = MVT::getIntegerVT(8*TD->getPointerSize(0));
+  MaxStoresPerMemset = MaxStoresPerMemcpy = MaxStoresPerMemmove = 8;
+  MaxStoresPerMemsetOptSize = MaxStoresPerMemcpyOptSize
+    = MaxStoresPerMemmoveOptSize = 4;
+  UseUnderscoreSetJmp = false;
+  UseUnderscoreLongJmp = false;
+  SelectIsExpensive = false;
+  IntDivIsCheap = false;
+  Pow2DivIsCheap = false;
+  JumpIsExpensive = false;
+  PredictableSelectIsExpensive = false;
+  StackPointerRegisterToSaveRestore = 0;
+  ExceptionPointerRegister = 0;
+  ExceptionSelectorRegister = 0;
+  BooleanContents = UndefinedBooleanContent;
+  BooleanVectorContents = UndefinedBooleanContent;
+  SchedPreferenceInfo = Sched::ILP;
+  JumpBufSize = 0;
+  JumpBufAlignment = 0;
+  MinFunctionAlignment = 0;
+  PrefFunctionAlignment = 0;
+  PrefLoopAlignment = 0;
+  MinStackArgumentAlignment = 1;
+  ShouldFoldAtomicFences = false;
+  InsertFencesForAtomic = false;
+  SupportJumpTables = true;
+  MinimumJumpTableEntries = 4;
+
+  InitLibcallNames(LibcallRoutineNames, TM);
+  InitCmpLibcallCCs(CmpLibcallCCs);
+  InitLibcallCallingConvs(LibcallCallingConvs);
+}
+
+TargetLoweringBase::~TargetLoweringBase() {
+  delete &TLOF;
+}
+
+void TargetLoweringBase::initActions() {
   // All operations default to being supported.
   memset(OpActions, 0, sizeof(OpActions));
   memset(LoadExtActions, 0, sizeof(LoadExtActions));
   memset(TruncStoreActions, 0, sizeof(TruncStoreActions));
   memset(IndexedModeActions, 0, sizeof(IndexedModeActions));
   memset(CondCodeActions, 0, sizeof(CondCodeActions));
+  memset(RegClassForVT, 0,MVT::LAST_VALUETYPE*sizeof(TargetRegisterClass*));
+  memset(TargetDAGCombineArray, 0, array_lengthof(TargetDAGCombineArray));
 
   // Set default actions for various operations.
   for (unsigned VT = 0; VT != (unsigned)MVT::LAST_VALUETYPE; ++VT) {
@@ -702,45 +746,6 @@ TargetLoweringBase::TargetLoweringBase(const TargetMachine &tm,
   // here is to inform DAG Legalizer to replace DEBUGTRAP with TRAP.
   //
   setOperationAction(ISD::DEBUGTRAP, MVT::Other, Expand);
-
-  IsLittleEndian = TD->isLittleEndian();
-  PointerTy = MVT::getIntegerVT(8*TD->getPointerSize(0));
-  memset(RegClassForVT, 0,MVT::LAST_VALUETYPE*sizeof(TargetRegisterClass*));
-  memset(TargetDAGCombineArray, 0, array_lengthof(TargetDAGCombineArray));
-  MaxStoresPerMemset = MaxStoresPerMemcpy = MaxStoresPerMemmove = 8;
-  MaxStoresPerMemsetOptSize = MaxStoresPerMemcpyOptSize
-    = MaxStoresPerMemmoveOptSize = 4;
-  UseUnderscoreSetJmp = false;
-  UseUnderscoreLongJmp = false;
-  SelectIsExpensive = false;
-  IntDivIsCheap = false;
-  Pow2DivIsCheap = false;
-  JumpIsExpensive = false;
-  PredictableSelectIsExpensive = false;
-  StackPointerRegisterToSaveRestore = 0;
-  ExceptionPointerRegister = 0;
-  ExceptionSelectorRegister = 0;
-  BooleanContents = UndefinedBooleanContent;
-  BooleanVectorContents = UndefinedBooleanContent;
-  SchedPreferenceInfo = Sched::ILP;
-  JumpBufSize = 0;
-  JumpBufAlignment = 0;
-  MinFunctionAlignment = 0;
-  PrefFunctionAlignment = 0;
-  PrefLoopAlignment = 0;
-  MinStackArgumentAlignment = 1;
-  ShouldFoldAtomicFences = false;
-  InsertFencesForAtomic = false;
-  SupportJumpTables = true;
-  MinimumJumpTableEntries = 4;
-
-  InitLibcallNames(LibcallRoutineNames, TM);
-  InitCmpLibcallCCs(CmpLibcallCCs);
-  InitLibcallCallingConvs(LibcallCallingConvs);
-}
-
-TargetLoweringBase::~TargetLoweringBase() {
-  delete &TLOF;
 }
 
 MVT TargetLoweringBase::getScalarShiftAmountTy(EVT LHSTy) const {

llvm/lib/CodeGen/TargetOptionsImpl.cpp

@@ -50,3 +50,29 @@ StringRef TargetOptions::getTrapFunctionName() const {
   return TrapFuncName;
 }
 
+bool TargetOptions::operator==(const TargetOptions &TO) {
+#define ARE_EQUAL(X) X == TO.X
+  return
+    ARE_EQUAL(UnsafeFPMath) &&
+    ARE_EQUAL(NoInfsFPMath) &&
+    ARE_EQUAL(NoNaNsFPMath) &&
+    ARE_EQUAL(HonorSignDependentRoundingFPMathOption) &&
+    ARE_EQUAL(UseSoftFloat) &&
+    ARE_EQUAL(NoZerosInBSS) &&
+    ARE_EQUAL(JITExceptionHandling) &&
+    ARE_EQUAL(JITEmitDebugInfo) &&
+    ARE_EQUAL(JITEmitDebugInfoToDisk) &&
+    ARE_EQUAL(GuaranteedTailCallOpt) &&
+    ARE_EQUAL(DisableTailCalls) &&
+    ARE_EQUAL(StackAlignmentOverride) &&
+    ARE_EQUAL(RealignStack) &&
+    ARE_EQUAL(SSPBufferSize) &&
+    ARE_EQUAL(EnableFastISel) &&
+    ARE_EQUAL(PositionIndependentExecutable) &&
+    ARE_EQUAL(EnableSegmentedStacks) &&
+    ARE_EQUAL(UseInitArray) &&
+    ARE_EQUAL(TrapFuncName) &&
+    ARE_EQUAL(FloatABIType) &&
+    ARE_EQUAL(AllowFPOpFusion);
+#undef ARE_EQUAL
+}

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -163,10 +163,28 @@ X86TargetLowering::X86TargetLowering(X86TargetMachine &TM)
   Subtarget = &TM.getSubtarget<X86Subtarget>();
   X86ScalarSSEf64 = Subtarget->hasSSE2();
   X86ScalarSSEf32 = Subtarget->hasSSE1();
-
   RegInfo = TM.getRegisterInfo();
   TD = getDataLayout();
 
+  resetOperationActions();
+}
+
+void X86TargetLowering::resetOperationActions() {
+  const TargetMachine &TM = getTargetMachine();
+  static bool FirstTimeThrough = true;
+
+  // If none of the target options have changed, then we don't need to reset the
+  // operation actions.
+  if (!FirstTimeThrough && TO == TM.Options) return;
+
+  if (!FirstTimeThrough) {
+    // Reinitialize the actions.
+    initActions();
+    FirstTimeThrough = false;
+  }
+
+  TO = TM.Options;
+
   // Set up the TargetLowering object.
   static const MVT IntVTs[] = { MVT::i8, MVT::i16, MVT::i32, MVT::i64 };
 

llvm/lib/Target/X86/X86ISelLowering.h

@@ -723,6 +723,9 @@ namespace llvm {
     SDValue BuildFILD(SDValue Op, EVT SrcVT, SDValue Chain, SDValue StackSlot,
                       SelectionDAG &DAG) const;
 
+    /// \brief Reset the operation actions based on target options.
+    virtual void resetOperationActions();
+
   protected:
     std::pair<const TargetRegisterClass*, uint8_t>
     findRepresentativeClass(MVT VT) const;
@@ -734,6 +737,10 @@ namespace llvm {
     const X86RegisterInfo *RegInfo;
     const DataLayout *TD;
 
+    /// Used to store the TargetOptions so that we don't waste time resetting
+    /// the operation actions unless we have to.
+    TargetOptions TO;
+
     /// X86ScalarSSEf32, X86ScalarSSEf64 - Select between SSE or x87
     /// floating point ops.
     /// When SSE is available, use it for f32 operations.