[AArch64 GlobalISel] Cleanup CallLowering. NFCI

[rovka]

Summary

Now that lowerCall and lowerFormalArgs have been refactored, we can
simplify splitToValueTypes.

[rovka]

More context.

[aemerson]

Thanks so much for working on these patches Diana! It's tricky business, can you be sure to run test suites thoroughly before committing if you haven't already.

[rovka]

In D63552#1552762, @aemerson wrote:

Thanks so much for working on these patches Diana! It's tricky business, can you be sure to run test suites thoroughly before committing if you haven't already.

Will do, thanks :) I'll work on removing packArgs from the IRTranslator before committing these.

llvm/lib/Target/AArch64/AArch64CallLowering.h

 
 private:
   using RegHandler = std::function<void(MachineIRBuilder &, Type *, unsigned,
                                         CCValAssign &)>;
 
   using MemHandler =
       std::function<void(MachineIRBuilder &, int, CCValAssign &)>;
 
-  using SplitArgTy = std::function<void(unsigned, uint64_t)>;
-
   void splitToValueTypes(const ArgInfo &OrigArgInfo,
                          SmallVectorImpl<ArgInfo> &SplitArgs,
                          const DataLayout &DL, MachineRegisterInfo &MRI,
-                         CallingConv::ID CallConv,
-                         const SplitArgTy &SplitArg) const;
+                         CallingConv::ID CallConv) const;
 };
 
 } // end namespace llvm
 
 #endif // LLVM_LIB_TARGET_AARCH64_AARCH64CALLLOWERING_H

llvm/lib/Target/AArch64/AArch64CallLowering.cpp

struct OutgoingArgHandler : public CallLowering::ValueHandler {
   MachineInstrBuilder MIB;
   CCAssignFn *AssignFnVarArg;
   uint64_t StackSize;
 };
 } // namespace
 
 void AArch64CallLowering::splitToValueTypes(
     const ArgInfo &OrigArg, SmallVectorImpl<ArgInfo> &SplitArgs,
-    const DataLayout &DL, MachineRegisterInfo &MRI, CallingConv::ID CallConv,
-    const SplitArgTy &PerformArgSplit) const {
+    const DataLayout &DL, MachineRegisterInfo &MRI, CallingConv::ID CallConv) const {
   const AArch64TargetLowering &TLI = *getTLI<AArch64TargetLowering>();
   LLVMContext &Ctx = OrigArg.Ty->getContext();
 
   if (OrigArg.Ty->isVoidTy())
     return;
 
   SmallVector<EVT, 4> SplitVTs;
   SmallVector<uint64_t, 4> Offsets;
   ComputeValueVTs(TLI, DL, OrigArg.Ty, SplitVTs, &Offsets, 0);
 
   if (SplitVTs.size() == 1) {
     // No splitting to do, but we want to replace the original type (e.g. [1 x
     // double] -> double).
     SplitArgs.emplace_back(OrigArg.Regs[0], SplitVTs[0].getTypeForEVT(Ctx),
                            OrigArg.Flags, OrigArg.IsFixed);
     return;
   }
 
-  if (OrigArg.Regs.size() > 1) {
-    // Create one ArgInfo for each virtual register in the original ArgInfo.
-    assert(OrigArg.Regs.size() == SplitVTs.size() && "Regs / types mismatch");
 
-    bool NeedsRegBlock = TLI.functionArgumentNeedsConsecutiveRegisters(
-        OrigArg.Ty, CallConv, false);
-    for (unsigned i = 0, e = SplitVTs.size(); i < e; ++i) {
-      Type *SplitTy = SplitVTs[i].getTypeForEVT(Ctx);
-      SplitArgs.emplace_back(OrigArg.Regs[i], SplitTy, OrigArg.Flags,
-                             OrigArg.IsFixed);
-      if (NeedsRegBlock)
-        SplitArgs.back().Flags.setInConsecutiveRegs();
-    }
 
-    SplitArgs.back().Flags.setInConsecutiveRegsLast();
-    return;
-  }
-
-  unsigned FirstRegIdx = SplitArgs.size();
-  bool NeedsRegBlock = TLI.functionArgumentNeedsConsecutiveRegisters(
-      OrigArg.Ty, CallConv, false);
-  for (auto SplitVT : SplitVTs) {
-    Type *SplitTy = SplitVT.getTypeForEVT(Ctx);
-    SplitArgs.push_back(
-        ArgInfo{MRI.createGenericVirtualRegister(getLLTForType(*SplitTy, DL)),
-                SplitTy, OrigArg.Flags, OrigArg.IsFixed});
-    if (NeedsRegBlock)
-      SplitArgs.back().Flags.setInConsecutiveRegs();
-  }
-
-  SplitArgs.back().Flags.setInConsecutiveRegsLast();
-
-  for (unsigned i = 0; i < Offsets.size(); ++i)
-    PerformArgSplit(SplitArgs[FirstRegIdx + i].Regs[0], Offsets[i] * 8);
 }
 
 bool AArch64CallLowering::lowerReturn(MachineIRBuilder &MIRBuilder,
                                       const Value *Val,
                                       ArrayRef<unsigned> VRegs,
                                       unsigned SwiftErrorVReg) const {
   auto MIB = MIRBuilder.buildInstrNoInsert(AArch64::RET_ReallyLR);
   assert(((Val && !VRegs.empty()) || (!Val && VRegs.empty())) &&
for (unsigned i = 0; i < SplitEVTs.size(); ++i) {
           }
         }
       }
       if (CurVReg != CurArgInfo.Regs[0]) {
         CurArgInfo.Regs[0] = CurVReg;
         // Reset the arg flags after modifying CurVReg.
         setArgFlags(CurArgInfo, AttributeList::ReturnIndex, DL, F);
       }
-     splitToValueTypes(CurArgInfo, SplitArgs, DL, MRI, CC,
-                        [&](unsigned Reg, uint64_t Offset) {
-                          MIRBuilder.buildExtract(Reg, CurVReg, Offset);
-                        });
+     splitToValueTypes(CurArgInfo, SplitArgs, DL, MRI, CC);
     }
 
     OutgoingArgHandler Handler(MIRBuilder, MRI, MIB, AssignFn, AssignFn);
     Success = handleAssignments(MIRBuilder, SplitArgs, Handler);
   }
 
   if (SwiftErrorVReg) {
     MIB.addUse(AArch64::X21, RegState::Implicit);
bool AArch64CallLowering::lowerFormalArguments(
   unsigned i = 0;
   for (auto &Arg : F.args()) {
     if (DL.getTypeStoreSize(Arg.getType()) == 0)
       continue;
 
     ArgInfo OrigArg{VRegs[i], Arg.getType()};
     setArgFlags(OrigArg, i + AttributeList::FirstArgIndex, DL, F);
 
-    splitToValueTypes(OrigArg, SplitArgs, DL, MRI, F.getCallingConv(),
-                      [&](unsigned Reg, uint64_t Offset) {
-                        llvm_unreachable("Args should already be split");
-                      });
+    splitToValueTypes(OrigArg, SplitArgs, DL, MRI, F.getCallingConv());
     ++i;
   }
 
   if (!MBB.empty())
     MIRBuilder.setInstr(*MBB.begin());
 
   const AArch64TargetLowering &TLI = *getTLI<AArch64TargetLowering>();
   CCAssignFn *AssignFn =
bool AArch64CallLowering::lowerCall(MachineIRBuilder &MIRBuilder,
                                     unsigned SwiftErrorVReg) const {
   MachineFunction &MF = MIRBuilder.getMF();
   const Function &F = MF.getFunction();
   MachineRegisterInfo &MRI = MF.getRegInfo();
   auto &DL = F.getParent()->getDataLayout();
 
   SmallVector<ArgInfo, 8> SplitArgs;
   for (auto &OrigArg : OrigArgs) {
-    splitToValueTypes(OrigArg, SplitArgs, DL, MRI, CallConv,
-                      [&](unsigned Reg, uint64_t Offset) {
-                        llvm_unreachable("Call params should already be split");
-                      });
+    splitToValueTypes(OrigArg, SplitArgs, DL, MRI, CallConv);
     // AAPCS requires that we zero-extend i1 to 8 bits by the caller.
     if (OrigArg.Ty->isIntegerTy(1))
       SplitArgs.back().Flags.setZExt();
   }
 
   // Find out which ABI gets to decide where things go.
   const AArch64TargetLowering &TLI = *getTLI<AArch64TargetLowering>();
   CCAssignFn *AssignFnFixed =
bool AArch64CallLowering::lowerCall(MachineIRBuilder &MIRBuilder,
 
   // Finally we can copy the returned value back into its virtual-register. In
   // symmetry with the arugments, the physical register must be an
   // implicit-define of the call instruction.
   CCAssignFn *RetAssignFn = TLI.CCAssignFnForReturn(F.getCallingConv());
   if (!OrigRet.Ty->isVoidTy()) {
     SplitArgs.clear();
 
-    splitToValueTypes(OrigRet, SplitArgs, DL, MRI, F.getCallingConv(),
-                      [&](unsigned Reg, uint64_t Offset) {
-                        llvm_unreachable(
-                            "Call results should already be split");
-                      });
+    splitToValueTypes(OrigRet, SplitArgs, DL, MRI, F.getCallingConv());
 
     CallReturnHandler Handler(MIRBuilder, MRI, MIB, RetAssignFn);
     if (!handleAssignments(MIRBuilder, SplitArgs, Handler))
       return false;
   }
 
   if (SwiftErrorVReg) {
     MIB.addDef(AArch64::X21, RegState::Implicit);