[GlobalISel] Add support for *_fpmode intrinsics

[sepavloff]

Summary

The change implements support of the intrinsics get_fpmode,
set_fpmode and reset_fpmode in Global Instruction Selector. Now they
are lowered into library function calls.

[arsenm]

llvm/include/llvm/Target/GenericOpcodes.td

1017

"use this way" doesn't read right

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

837

TLI is already available as a member of LegalizerHelper

845

StateTy.getStoreSize

863

Need to erase the original instruction

877

TLI already a member

897

Didn't erase original instruction?

917–918

This is a roundabout way of doing DL.getPointerSizeInBits()

921–922

can fold these together with auto Dest = buildIntToPtr(MemTy)

925

Didn't erase original instruction?

970–971

Unrelated?

llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp

123

Were there really no other typeless G_* instructions before?

[tschuett]

llvm/include/llvm/Target/GenericOpcodes.td

1016

side effects and access.

[sepavloff]

Address review comments, rebase

[sepavloff]

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

863

This function is called from LegalizerHelper::libcall, which erases the original instruction.

897

LegalizerHelper::libcall will remove it.

925

LegalizerHelper::libcall will remove it.

970–971

As LLTy is not calculated at the beginning of the function anymore, it should be introduced when needed.

llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp

123

G_RESET_FPMODE does not have nor input operands, nor output value, this is the first such instruction.

[arsenm]

llvm/test/CodeGen/AArch64/GlobalISel/legalize-fpmode.mir

5

Probably don't need the IR section

[sepavloff]

Thanks!

llvm/include/llvm/CodeGen/GlobalISel/Legalizer.h

public:
   }
 
   MachineFunctionProperties getSetProperties() const override {
     return MachineFunctionProperties().set(
         MachineFunctionProperties::Property::Legalized);
   }
 
   MachineFunctionProperties getClearedProperties() const override {
-    return MachineFunctionProperties().set(
-        MachineFunctionProperties::Property::NoPHIs);
+    return MachineFunctionProperties()
+        .set(MachineFunctionProperties::Property::NoPHIs)
+        .set(MachineFunctionProperties::Property::NoVRegs);
   }
 
   bool runOnMachineFunction(MachineFunction &MF) override;
 
   static MFResult
   legalizeMachineFunction(MachineFunction &MF, const LegalizerInfo &LI,
                           ArrayRef<GISelChangeObserver *> AuxObservers,
                           LostDebugLocObserver &LocObserver,
                           MachineIRBuilder &MIRBuilder, GISelKnownBits *KB);
 };
 } // End namespace llvm.
 
 #endif

llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h

LegalizeResult lowerMemcpyInline(MachineInstr &MI, Register Dst, Register Src,
                                    Align SrcAlign, bool IsVolatile);
   LegalizeResult lowerMemcpy(MachineInstr &MI, Register Dst, Register Src,
                              uint64_t KnownLen, uint64_t Limit, Align DstAlign,
                              Align SrcAlign, bool IsVolatile);
   LegalizeResult lowerMemmove(MachineInstr &MI, Register Dst, Register Src,
                               uint64_t KnownLen, Align DstAlign, Align SrcAlign,
                               bool IsVolatile);
 
+  // Implements floating-point environment read/write via library function call.
+  LegalizeResult createGetStateLibcall(MachineIRBuilder &MIRBuilder,
+                                       MachineInstr &MI);
+  LegalizeResult createSetStateLibcall(MachineIRBuilder &MIRBuilder,
+                                       MachineInstr &MI);
+  LegalizeResult createResetStateLibcall(MachineIRBuilder &MIRBuilder,
+                                         MachineInstr &MI);
+
 public:
   /// Return the alignment to use for a stack temporary object with the given
   /// type.
   Align getStackTemporaryAlignment(LLT Type, Align MinAlign = Align()) const;
 
   /// Create a stack temporary based on the size in bytes and the alignment
   MachineInstrBuilder createStackTemporary(TypeSize Bytes, Align Alignment,
                                            MachinePointerInfo &PtrInfo);
createLibcall(MachineIRBuilder &MIRBuilder, RTLIB::Libcall Libcall,
               const CallLowering::ArgInfo &Result,
               ArrayRef<CallLowering::ArgInfo> Args);
 
 /// Create a libcall to memcpy et al.
 LegalizerHelper::LegalizeResult
 createMemLibcall(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI,
                  MachineInstr &MI, LostDebugLocObserver &LocObserver);
 
+
 } // End namespace llvm.
 
 #endif

llvm/include/llvm/Support/TargetOpcodes.def

 /// FP min/max matching IEEE-754 2008's minnum/maxnum semantics.
 HANDLE_TARGET_OPCODE(G_FMINNUM_IEEE)
 HANDLE_TARGET_OPCODE(G_FMAXNUM_IEEE)
 
 /// FP min/max matching IEEE-754 2018 draft semantics.
 HANDLE_TARGET_OPCODE(G_FMINIMUM)
 HANDLE_TARGET_OPCODE(G_FMAXIMUM)
 
+/// Access to FP environment.
+HANDLE_TARGET_OPCODE(G_GET_FPMODE)
+HANDLE_TARGET_OPCODE(G_SET_FPMODE)
+HANDLE_TARGET_OPCODE(G_RESET_FPMODE)
+
 /// Generic pointer offset
 HANDLE_TARGET_OPCODE(G_PTR_ADD)
 
 /// Clear the specified bits in a pointer.
 HANDLE_TARGET_OPCODE(G_PTRMASK)
 
 /// Generic signed integer minimum.
 HANDLE_TARGET_OPCODE(G_SMIN)

llvm/include/llvm/Target/GenericOpcodes.td

 // Floating point round to the nearest integer.
 def G_FNEARBYINT : GenericInstruction {
   let OutOperandList = (outs type0:$dst);
   let InOperandList = (ins type0:$src1);
   let hasSideEffects = false;
 }
 
 //------------------------------------------------------------------------------
+// Access to floating-point environment.
+//------------------------------------------------------------------------------
+
+// These operations read/write floating-point environment. The interaction with
+// it is modeled as a side effect, because constrained intrinsics use the same
+// method.
+
+// Reading floating-point control modes.
+def G_GET_FPMODE : GenericInstruction {
+  let OutOperandList = (outs type0:$dst);
+  let InOperandList = (ins);
+  let hasSideEffects = true;
+}
+
+// Setting floating-point control modes.
+def G_SET_FPMODE : GenericInstruction {
+  let OutOperandList = (outs);
+  let InOperandList = (ins type0:$src);
+  let hasSideEffects = true;
+}
+
+// Setting floating-point control modes to default state.
+def G_RESET_FPMODE : GenericInstruction {
+  let OutOperandList = (outs);
+  let InOperandList = (ins);
+  let hasSideEffects = true;
+}
+
+//------------------------------------------------------------------------------
 // Opcodes for LLVM Intrinsics
 //------------------------------------------------------------------------------
 def G_INTRINSIC_FPTRUNC_ROUND : GenericInstruction {
   let OutOperandList = (outs type0:$dst);
   let InOperandList = (ins type1:$src1, i32imm:$round_mode);
   let hasSideEffects = false;
 }
 

llvm/include/llvm/Target/GlobalISel/SelectionDAGCompat.td

 def : GINodeEquiv<G_FLDEXP, fldexp>;
 def : GINodeEquiv<G_FCANONICALIZE, fcanonicalize>;
 def : GINodeEquiv<G_IS_FPCLASS, is_fpclass>;
 
 def : GINodeEquiv<G_INTRINSIC, intrinsic_wo_chain> {
   let IfConvergent = G_INTRINSIC_CONVERGENT;
 }
 
+def : GINodeEquiv<G_GET_FPMODE, get_fpmode>;
+def : GINodeEquiv<G_SET_FPMODE, set_fpmode>;
+def : GINodeEquiv<G_RESET_FPMODE, reset_fpmode>;
+
 // ISD::INTRINSIC_VOID can also be handled with G_INTRINSIC_W_SIDE_EFFECTS.
 let IfConvergent = G_INTRINSIC_CONVERGENT_W_SIDE_EFFECTS in {
   def : GINodeEquiv<G_INTRINSIC_W_SIDE_EFFECTS, intrinsic_void>;
   def : GINodeEquiv<G_INTRINSIC_W_SIDE_EFFECTS, intrinsic_w_chain>;
 }
 
 def : GINodeEquiv<G_BR, br>;
 def : GINodeEquiv<G_BSWAP, bswap>;

llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp

switch (ID) {
     case Intrinsic::vector_reduce_umax:
       return TargetOpcode::G_VECREDUCE_UMAX;
     case Intrinsic::vector_reduce_umin:
       return TargetOpcode::G_VECREDUCE_UMIN;
     case Intrinsic::lround:
       return TargetOpcode::G_LROUND;
     case Intrinsic::llround:
       return TargetOpcode::G_LLROUND;
+    case Intrinsic::get_fpmode:
+      return TargetOpcode::G_GET_FPMODE;
   }
   return Intrinsic::not_intrinsic;
 }
 
 bool IRTranslator::translateSimpleIntrinsic(const CallInst &CI,
                                             Intrinsic::ID ID,
                                             MachineIRBuilder &MIRBuilder) {
 
case Intrinsic::is_fpclass: {
 
     MIRBuilder
         .buildInstr(TargetOpcode::G_IS_FPCLASS, {getOrCreateVReg(CI)},
                     {getOrCreateVReg(*FpValue)})
         .addImm(TestMaskValue->getZExtValue());
 
     return true;
   }
+  case Intrinsic::set_fpmode: {
+    Value *FPState = CI.getOperand(0);
+    MIRBuilder.buildInstr(TargetOpcode::G_SET_FPMODE, {},
+                          { getOrCreateVReg(*FPState) });
+    return true;
+  }
+  case Intrinsic::reset_fpmode: {
+    MIRBuilder.buildInstr(TargetOpcode::G_RESET_FPMODE, {}, {});
+    return true;
+  }
 #define INSTRUCTION(NAME, NARG, ROUND_MODE, INTRINSIC)  \
   case Intrinsic::INTRINSIC:
 #include "llvm/IR/ConstrainedOps.def"
     return translateConstrainedFPIntrinsic(cast<ConstrainedFPIntrinsic>(CI),
                                            MIRBuilder);
 
   }
   return false;

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

 conversionLibcall(MachineInstr &MI, MachineIRBuilder &MIRBuilder, Type *ToType,
                   Type *FromType) {
   RTLIB::Libcall Libcall = getConvRTLibDesc(MI.getOpcode(), ToType, FromType);
   return createLibcall(MIRBuilder, Libcall,
                        {MI.getOperand(0).getReg(), ToType, 0},
                        {{MI.getOperand(1).getReg(), FromType, 0}});
 }
 
+static RTLIB::Libcall
+getStateLibraryFunctionFor(MachineInstr &MI, const TargetLowering &TLI) {
+  RTLIB::Libcall RTLibcall;
+  switch (MI.getOpcode()) {
+  case TargetOpcode::G_GET_FPMODE:
+    RTLibcall = RTLIB::FEGETMODE;
+    break;
+  case TargetOpcode::G_SET_FPMODE:
+  case TargetOpcode::G_RESET_FPMODE:
+    RTLibcall = RTLIB::FESETMODE;
+    break;
+  default:
+    llvm_unreachable("Unexpected opcode");
+  }
+  return RTLibcall;
+}
+
+// Some library functions that read FP state (fegetmode, fegetenv) write the
+// state into a region in memory. IR intrinsics that do the same operations
+// (get_fpmode, get_fpenv) return the state as integer value. To implement these
+// intrinsics via the library functions, we need to use temporary variable,
+// for example:
+//
+//     %0:_(s32) = G_GET_FPMODE
+//
+// is transformed to:
+//
+//     %1:_(p0) = G_FRAME_INDEX %stack.0
+//     BL &fegetmode
+//     %0:_(s32) = G_LOAD % 1
+//
+LegalizerHelper::LegalizeResult
+LegalizerHelper::createGetStateLibcall(MachineIRBuilder &MIRBuilder,
+                                       MachineInstr &MI) {
+  const DataLayout &DL = MIRBuilder.getDataLayout();
+  auto &MF = MIRBuilder.getMF();
+  auto &MRI = *MIRBuilder.getMRI();
+  auto &Ctx = MF.getFunction().getContext();
+
+  // Create temporary, where library function will put the read state.
+  Register Dst = MI.getOperand(0).getReg();
+  LLT StateTy = MRI.getType(Dst);
+  TypeSize StateSize = StateTy.getSizeInBytes();
+  Align TempAlign = getStackTemporaryAlignment(StateTy);
+  MachinePointerInfo TempPtrInfo;
+  auto Temp = createStackTemporary(StateSize, TempAlign, TempPtrInfo);
+
+  // Create a call to library function, with the temporary as an argument.
+  unsigned TempAddrSpace = DL.getAllocaAddrSpace();
+  Type *StatePtrTy = PointerType::get(Ctx, TempAddrSpace);
+  RTLIB::Libcall RTLibcall = getStateLibraryFunctionFor(MI, TLI);
+  auto Res =
+      createLibcall(MIRBuilder, RTLibcall,
+                    CallLowering::ArgInfo({0}, Type::getVoidTy(Ctx), 0),
+                    CallLowering::ArgInfo({Temp.getReg(0), StatePtrTy, 0}));
+  if (Res != LegalizerHelper::Legalized)
+    return Res;
+
+  // Create a load from the temporary.
+  MachineMemOperand *MMO = MF.getMachineMemOperand(
+      TempPtrInfo, MachineMemOperand::MOLoad, StateTy, TempAlign);
+  MIRBuilder.buildLoadInstr(TargetOpcode::G_LOAD, Dst, Temp, *MMO);
+
+  return LegalizerHelper::Legalized;
+}
+
+// Similar to `createGetStateLibcall` the function calls a library function
+// using transient space in stack. In this case the library function reads
+// content of memory region.
+LegalizerHelper::LegalizeResult
+LegalizerHelper::createSetStateLibcall(MachineIRBuilder &MIRBuilder,
+                                       MachineInstr &MI) {
+  const DataLayout &DL = MIRBuilder.getDataLayout();
+  auto &MF = MIRBuilder.getMF();
+  auto &MRI = *MIRBuilder.getMRI();
+  auto &Ctx = MF.getFunction().getContext();
+
+  // Create temporary, where library function will get the new state.
+  Register Src = MI.getOperand(0).getReg();
+  LLT StateTy = MRI.getType(Src);
+  TypeSize StateSize = StateTy.getSizeInBytes();
+  Align TempAlign = getStackTemporaryAlignment(StateTy);
+  MachinePointerInfo TempPtrInfo;
+  auto Temp = createStackTemporary(StateSize, TempAlign, TempPtrInfo);
+
+  // Put the new state into the temporary.
+  MachineMemOperand *MMO = MF.getMachineMemOperand(
+      TempPtrInfo, MachineMemOperand::MOStore, StateTy, TempAlign);
+  MIRBuilder.buildStore(Src, Temp, *MMO);
+
+  // Create a call to library function, with the temporary as an argument.
+  unsigned TempAddrSpace = DL.getAllocaAddrSpace();
+  Type *StatePtrTy = PointerType::get(Ctx, TempAddrSpace);
+  RTLIB::Libcall RTLibcall = getStateLibraryFunctionFor(MI, TLI);
+  return createLibcall(MIRBuilder, RTLibcall,
+                       CallLowering::ArgInfo({0}, Type::getVoidTy(Ctx), 0),
+                       CallLowering::ArgInfo({Temp.getReg(0), StatePtrTy, 0}));
+}
+
+// The function is used to legalize operations that set default environment
+// state. In C library a call like `fesetmode(FE_DFL_MODE)` is used for that.
+// On most targets supported in glibc FE_DFL_MODE is defined as
+// `((const femode_t *) -1)`. Such assumption is used here. If for some target
+// it is not true, the target must provide custom lowering.
+LegalizerHelper::LegalizeResult
+LegalizerHelper::createResetStateLibcall(MachineIRBuilder &MIRBuilder,
+                                         MachineInstr &MI) {
+  const DataLayout &DL = MIRBuilder.getDataLayout();
+  auto &MF = MIRBuilder.getMF();
+  auto &Ctx = MF.getFunction().getContext();
+
+  // Create an argument for the library function.
+  unsigned AddrSpace = DL.getDefaultGlobalsAddressSpace();
+  Type *StatePtrTy = PointerType::get(Ctx, AddrSpace);
+  unsigned PtrSize = DL.getPointerSizeInBits(AddrSpace);
+  LLT MemTy = LLT::pointer(AddrSpace, PtrSize);
+  auto DefValue = MIRBuilder.buildConstant(LLT::scalar(PtrSize), -1LL);
+  DstOp Dest(MRI.createGenericVirtualRegister(MemTy));
+  MIRBuilder.buildIntToPtr(Dest, DefValue);
+
+  RTLIB::Libcall RTLibcall = getStateLibraryFunctionFor(MI, TLI);
+  return createLibcall(MIRBuilder, RTLibcall,
+                       CallLowering::ArgInfo({0}, Type::getVoidTy(Ctx), 0),
+                       CallLowering::ArgInfo({ Dest.getReg(), StatePtrTy, 0}));
+}
+
 LegalizerHelper::LegalizeResult
 LegalizerHelper::libcall(MachineInstr &MI, LostDebugLocObserver &LocObserver) {
-  LLT LLTy = MRI.getType(MI.getOperand(0).getReg());
-  unsigned Size = LLTy.getSizeInBits();
   auto &Ctx = MIRBuilder.getMF().getFunction().getContext();
 
   switch (MI.getOpcode()) {
   default:
     return UnableToLegalize;
   case TargetOpcode::G_MUL:
   case TargetOpcode::G_SDIV:
   case TargetOpcode::G_UDIV:
   case TargetOpcode::G_SREM:
   case TargetOpcode::G_UREM:
   case TargetOpcode::G_CTLZ_ZERO_UNDEF: {
+    LLT LLTy = MRI.getType(MI.getOperand(0).getReg());
+    unsigned Size = LLTy.getSizeInBits();
     Type *HLTy = IntegerType::get(Ctx, Size);
     auto Status = simpleLibcall(MI, MIRBuilder, Size, HLTy);
     if (Status != Legalized)
       return Status;
     break;
   }
   case TargetOpcode::G_FADD:
   case TargetOpcode::G_FSUB:
LegalizerHelper::libcall(MachineInstr &MI, LostDebugLocObserver &LocObserver) {
   case TargetOpcode::G_FCEIL:
   case TargetOpcode::G_FFLOOR:
   case TargetOpcode::G_FMINNUM:
   case TargetOpcode::G_FMAXNUM:
   case TargetOpcode::G_FSQRT:
   case TargetOpcode::G_FRINT:
   case TargetOpcode::G_FNEARBYINT:
   case TargetOpcode::G_INTRINSIC_ROUNDEVEN: {
+    LLT LLTy = MRI.getType(MI.getOperand(0).getReg());
+    unsigned Size = LLTy.getSizeInBits();
     Type *HLTy = getFloatTypeForLLT(Ctx, LLTy);
     if (!HLTy || (Size != 32 && Size != 64 && Size != 80 && Size != 128)) {
       LLVM_DEBUG(dbgs() << "No libcall available for type " << LLTy << ".\n");
       return UnableToLegalize;
     }
     auto Status = simpleLibcall(MI, MIRBuilder, Size, HLTy);
     if (Status != Legalized)
       return Status;
LegalizerHelper::libcall(MachineInstr &MI, LostDebugLocObserver &LocObserver) {
   case TargetOpcode::G_MEMSET: {
     LegalizeResult Result =
         createMemLibcall(MIRBuilder, *MIRBuilder.getMRI(), MI, LocObserver);
     if (Result != Legalized)
       return Result;
     MI.eraseFromParent();
     return Result;
   }
+  case TargetOpcode::G_GET_FPMODE: {
+    LegalizeResult Result = createGetStateLibcall(MIRBuilder, MI);
+    if (Result != Legalized)
+      return Result;
+    break;
+  }
+  case TargetOpcode::G_SET_FPMODE: {
+    LegalizeResult Result = createSetStateLibcall(MIRBuilder, MI);
+    if (Result != Legalized)
+      return Result;
+    break;
+  }
+  case TargetOpcode::G_RESET_FPMODE: {
+    LegalizeResult Result = createResetStateLibcall(MIRBuilder, MI);
+    if (Result != Legalized)
+      return Result;
+    break;
+  }
   }
 
   MI.eraseFromParent();
   return Legalized;
 }
 
 LegalizerHelper::LegalizeResult LegalizerHelper::narrowScalar(MachineInstr &MI,
                                                               unsigned TypeIdx,

llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp

 static bool hasNoSimpleLoops(const LegalizeRule &Rule, const LegalityQuery &Q,
                              const std::pair<unsigned, LLT> &Mutation) {
   switch (Rule.getAction()) {
   case Legal:
   case Custom:
   case Lower:
   case MoreElements:
   case FewerElements:
+  case Libcall:
     break;
   default:
     return Q.Types[Mutation.first] != Mutation.second;
   }
   return true;
 }
 
 // Make sure the returned mutation makes sense for the match type.
 static bool mutationIsSane(const LegalizeRule &Rule,
                            const LegalityQuery &Q,
                            std::pair<unsigned, LLT> Mutation) {
   // If the user wants a custom mutation, then we can't really say much about
   // it. Return true, and trust that they're doing the right thing.
   if (Rule.getAction() == Custom || Rule.getAction() == Legal)
     return true;
 
+  // Skip null mutation.
+  if (!Mutation.second.isValid())
+    return true;
+
   const unsigned TypeIdx = Mutation.first;
   const LLT OldTy = Q.Types[TypeIdx];
   const LLT NewTy = Mutation.second;
 
   switch (Rule.getAction()) {
   case FewerElements:
     if (!OldTy.isVector())
       return false;

llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp

AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST)
 
   // TODO: Custom legalization for vector types.
   // TODO: Custom legalization for mismatched types.
   // TODO: s16 support.
   getActionDefinitionsBuilder(G_FCOPYSIGN).customFor({{s32, s32}, {s64, s64}});
 
   getActionDefinitionsBuilder(G_FMAD).lower();
 
+  // Access to floating-point environment.
+  getActionDefinitionsBuilder({G_GET_FPMODE, G_SET_FPMODE, G_RESET_FPMODE})
+      .libcall();
+
   getLegacyLegalizerInfo().computeTables();
   verify(*ST.getInstrInfo());
 }
 
 bool AArch64LegalizerInfo::legalizeCustom(LegalizerHelper &Helper,
                                           MachineInstr &MI) const {
   MachineIRBuilder &MIRBuilder = Helper.MIRBuilder;
   MachineRegisterInfo &MRI = *MIRBuilder.getMRI();

llvm/test/CodeGen/AArch64/GlobalISel/irtranslator-fpenv.ll

+; NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+; RUN: llc -O0 -mtriple=aarch64-linux-gnu -global-isel -stop-after=irtranslator %s -o - | FileCheck %s
+
+declare i32 @llvm.get.fpmode.i32()
+declare void @llvm.set.fpmode.i32(i32 %fpmode)
+declare void @llvm.reset.fpmode()
+
+define i32 @func_get_fpmode() #0 {
+  ; CHECK-LABEL: name: func_get_fpmode
+  ; CHECK: bb.1.entry:
+  ; CHECK-NEXT:   [[GET_FPMODE:%[0-9]+]]:_(s32) = G_GET_FPMODE
+  ; CHECK-NEXT:   $w0 = COPY [[GET_FPMODE]](s32)
+  ; CHECK-NEXT:   RET_ReallyLR implicit $w0
+entry:
+  %fpmode = call i32 @llvm.get.fpmode.i32()
+  ret i32 %fpmode
+}
+
+define void @func_set_fpmode(i32 %fpmode) #0 {
+  ; CHECK-LABEL: name: func_set_fpmode
+  ; CHECK: bb.1.entry:
+  ; CHECK-NEXT:   liveins: $w0
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:_(s32) = COPY $w0
+  ; CHECK-NEXT:   G_SET_FPMODE [[COPY]](s32)
+  ; CHECK-NEXT:   RET_ReallyLR
+entry:
+  call void @llvm.set.fpmode.i32(i32 %fpmode)
+  ret void
+}
+
+
+define void @func_reset() #0 {
+  ; CHECK-LABEL: name: func_reset
+  ; CHECK: bb.1.entry:
+  ; CHECK-NEXT:   G_RESET_FPMODE
+  ; CHECK-NEXT:   RET_ReallyLR
+entry:
+  call void @llvm.reset.fpmode()
+  ret void
+}
+
+attributes #0 = { nounwind "use-soft-float"="true" }

llvm/test/CodeGen/AArch64/GlobalISel/legalize-fpmode.mir

+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 2
+# RUN: llc -mtriple=aarch64-linux-gnu -run-pass=legalizer %s -o - | FileCheck %s
+
+--- |
+  target triple = "aarch64-unknown-linux-gnu"
+
+  declare i32 @llvm.get.fpmode.i32()
+  declare void @llvm.set.fpmode.i32(i32)
+  declare void @llvm.reset.fpmode()
+
+  define i32 @func_get_fpmode() #0 {
+  entry:
+    %fpmode = call i32 @llvm.get.fpmode.i32()
+    ret i32 %fpmode
+  }
+
+  define void @func_set_fpmode(i32 %fpmode) #0 {
+  entry:
+    call void @llvm.set.fpmode.i32(i32 %fpmode)
+    ret void
+  }
+
+  define void @func_reset() #0 {
+  entry:
+    call void @llvm.reset.fpmode()
+    ret void
+  }
+
+  attributes #0 = { nounwind "use-soft-float"="true" }
+
+...
+---
+name:            func_get_fpmode
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    ; CHECK-LABEL: name: func_get_fpmode
+    ; CHECK: [[FRAME_INDEX:%[0-9]+]]:_(p0) = G_FRAME_INDEX %stack.0
+    ; CHECK-NEXT: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK-NEXT: $x0 = COPY [[FRAME_INDEX]](p0)
+    ; CHECK-NEXT: BL &fegetmode, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $x0
+    ; CHECK-NEXT: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK-NEXT: [[LOAD:%[0-9]+]]:_(s32) = G_LOAD [[FRAME_INDEX]](p0) :: (load (s32) from %stack.0)
+    ; CHECK-NEXT: $w0 = COPY [[LOAD]](s32)
+    ; CHECK-NEXT: RET_ReallyLR implicit $w0
+    %0:_(s32) = G_GET_FPMODE
+    $w0 = COPY %0(s32)
+    RET_ReallyLR implicit $w0
+
+...
+---
+name:            func_set_fpmode
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    liveins: $w0
+
+    ; CHECK-LABEL: name: func_set_fpmode
+    ; CHECK: liveins: $w0
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s32) = COPY $w0
+    ; CHECK-NEXT: [[FRAME_INDEX:%[0-9]+]]:_(p0) = G_FRAME_INDEX %stack.0
+    ; CHECK-NEXT: G_STORE [[COPY]](s32), [[FRAME_INDEX]](p0) :: (store (s32) into %stack.0)
+    ; CHECK-NEXT: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK-NEXT: $x0 = COPY [[FRAME_INDEX]](p0)
+    ; CHECK-NEXT: BL &fesetmode, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $x0
+    ; CHECK-NEXT: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK-NEXT: RET_ReallyLR
+    %0:_(s32) = COPY $w0
+    G_SET_FPMODE %0(s32)
+    RET_ReallyLR
+
+...
+---
+name:            func_reset
+tracksRegLiveness: true
+body:             |
+  bb.1.entry:
+    ; CHECK-LABEL: name: func_reset
+    ; CHECK: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 -1
+    ; CHECK-NEXT: [[INTTOPTR:%[0-9]+]]:_(p0) = G_INTTOPTR [[C]](s64)
+    ; CHECK-NEXT: ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK-NEXT: $x0 = COPY [[INTTOPTR]](p0)
+    ; CHECK-NEXT: BL &fesetmode, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit $x0
+    ; CHECK-NEXT: ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+    ; CHECK-NEXT: RET_ReallyLR
+    G_RESET_FPMODE
+    RET_ReallyLR
+
+...

llvm/test/CodeGen/AArch64/GlobalISel/legalizer-info-validation.mir

 # DEBUG-NEXT: G_FMINIMUM (opcode {{[0-9]+}}): 1 type index
 # DEBUG-NEXT: .. opcode {{[0-9]+}} is aliased to {{[0-9]+}}
 # DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: G_FMAXIMUM (opcode {{[0-9]+}}): 1 type index
 # DEBUG-NEXT: .. opcode {{[0-9]+}} is aliased to {{[0-9]+}}
 # DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
+# DEBUG-NEXT: G_GET_FPMODE (opcode 196): 1 type index, 0 imm indices
+# DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
+# DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
+# DEBUG-NEXT: G_SET_FPMODE (opcode 197): 1 type index, 0 imm indices
+# DEBUG-NEXT: .. opcode 197 is aliased to 196
+# DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
+# DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
+# DEBUG-NEXT: G_RESET_FPMODE (opcode 198): 0 type indices, 0 imm indices
+# DEBUG-NEXT: .. opcode 198 is aliased to 196
+# DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected
+# DEBUG-NEXT: .. imm index coverage check SKIPPED: user-defined predicate detected
 # DEBUG-NEXT: G_PTR_ADD (opcode {{[0-9]+}}): 2 type indices, 0 imm indices
 # DEBUG-NEXT: .. the first uncovered type index: 2, OK
 # DEBUG-NEXT: .. the first uncovered imm index: 0, OK
 # DEBUG-NEXT: G_PTRMASK (opcode {{[0-9]+}}): 2 type indices, 0 imm indices
 # DEBUG-NEXT: .. the first uncovered type index: 2, OK
 # DEBUG-NEXT: .. the first uncovered imm index: 0, OK
 # DEBUG: G_SMIN (opcode {{[0-9]+}}): 1 type index
 # DEBUG-NEXT: .. type index coverage check SKIPPED: user-defined predicate detected

llvm/test/CodeGen/AArch64/fpmode.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 2
+; RUN: llc -mtriple=aarch64-none-linux-gnu %s -o - | FileCheck --check-prefix=DAG %s
+; RUN: llc -mtriple=aarch64-none-linux-gnu -global-isel %s -o - | FileCheck --check-prefix=GIS %s
+
+declare i32 @llvm.get.fpmode.i32()
+declare void @llvm.set.fpmode.i32(i32 %fpmode)
+declare void @llvm.reset.fpmode()
+
+define i32 @func_get_fpmode_soft() #0 {
+; DAG-LABEL: func_get_fpmode_soft:
+; DAG:       // %bb.0: // %entry
+; DAG-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; DAG-NEXT:    add x0, sp, #12
+; DAG-NEXT:    bl fegetmode
+; DAG-NEXT:    ldr w0, [sp, #12]
+; DAG-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; DAG-NEXT:    ret
+;
+; GIS-LABEL: func_get_fpmode_soft:
+; GIS:       // %bb.0: // %entry
+; GIS-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; GIS-NEXT:    add x0, sp, #12
+; GIS-NEXT:    bl fegetmode
+; GIS-NEXT:    ldr w0, [sp, #12]
+; GIS-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; GIS-NEXT:    ret
+entry:
+  %fpmode = call i32 @llvm.get.fpmode.i32()
+  ret i32 %fpmode
+}
+
+define void @func_set_fpmode_soft(i32 %fpmode) #0 {
+; DAG-LABEL: func_set_fpmode_soft:
+; DAG:       // %bb.0: // %entry
+; DAG-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; DAG-NEXT:    str w0, [sp, #12]
+; DAG-NEXT:    add x0, sp, #12
+; DAG-NEXT:    bl fesetmode
+; DAG-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; DAG-NEXT:    ret
+;
+; GIS-LABEL: func_set_fpmode_soft:
+; GIS:       // %bb.0: // %entry
+; GIS-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; GIS-NEXT:    str w0, [sp, #12]
+; GIS-NEXT:    add x0, sp, #12
+; GIS-NEXT:    bl fesetmode
+; GIS-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; GIS-NEXT:    ret
+entry:
+  call void @llvm.set.fpmode.i32(i32 %fpmode)
+  ret void
+}
+
+define void @func_reset_fpmode_soft() #0 {
+; DAG-LABEL: func_reset_fpmode_soft:
+; DAG:       // %bb.0: // %entry
+; DAG-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; DAG-NEXT:    mov x0, #-1 // =0xffffffffffffffff
+; DAG-NEXT:    bl fesetmode
+; DAG-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; DAG-NEXT:    ret
+;
+; GIS-LABEL: func_reset_fpmode_soft:
+; GIS:       // %bb.0: // %entry
+; GIS-NEXT:    str x30, [sp, #-16]! // 8-byte Folded Spill
+; GIS-NEXT:    mov x0, #-1 // =0xffffffffffffffff
+; GIS-NEXT:    bl fesetmode
+; GIS-NEXT:    ldr x30, [sp], #16 // 8-byte Folded Reload
+; GIS-NEXT:    ret
+entry:
+  call void @llvm.reset.fpmode()
+  ret void
+}
+
+attributes #0 = { nounwind "use-soft-float"="true" }