[CodeGen] Centralize machine instruction erasure

10 files changed, 38 insertions, 127 deletions

diff --git a/backend/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp b/backend/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
index f87bb78..8361de2 100644
--- a/backend/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
+++ b/backend/lib/Target/RISCV/GISel/RISCVInstructionSelector.cpp
@@ -707,11 +707,7 @@ private:
       auto Constraint = constrainSelectedInstruction(**Result, Function, Target);
       if (!Constraint)
         return std::unexpected(Constraint.error());
-      MachineBasicBlock *Block = Instruction.parent();
-      if (Block == nullptr)
-        return makeUnexpected(ErrorCode::InternalError,
-                              "RISC-V global address is detached from its block");
-      return Block->removeInstruction(Instruction);
+      return Instruction.eraseFromParent();
     };
 
     if (UseGOT) {
@@ -781,11 +777,7 @@ private:
     auto LowConstraint = constrainSelectedInstruction(**Low, Function, Target);
     if (!LowConstraint)
       return std::unexpected(LowConstraint.error());
-    MachineBasicBlock *Block = Instruction.parent();
-    if (Block == nullptr)
-      return makeUnexpected(ErrorCode::InternalError,
-                            "RISC-V global address is detached from its block");
-    return Block->removeInstruction(Instruction);
+    return Instruction.eraseFromParent();
   }
 
   [[nodiscard]] Expected<void> selectCopy(MachineInstr &Instruction, MachineFunction &Function,
@@ -1107,11 +1099,7 @@ private:
       if (!Inverted)
         return std::unexpected(Inverted.error());
     }
-    MachineBasicBlock *Block = Instruction.parent();
-    if (Block == nullptr)
-      return makeUnexpected(ErrorCode::InternalError,
-                            "RISC-V floating comparison is detached from its block");
-    return Block->removeInstruction(Instruction);
+    return Instruction.eraseFromParent();
   }
 
   [[nodiscard]] Expected<void> selectFence(MachineInstr &Instruction) const {
diff --git a/backend/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp b/backend/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp
index 5d0be47..3c0ec35 100644
--- a/backend/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp
+++ b/backend/lib/Target/RISCV/GISel/RISCVLegalizerInfo.cpp
@@ -154,11 +154,7 @@ foldConstantExtension(MachineInstr &Instruction, MachineFunction &Function, Gene
     auto Added = Def->addOperand(MachineOperand::integerImmediate(std::move(*Extended)));
     if (!Added)
       return std::unexpected(Added.error());
-    MachineBasicBlock *Parent = Instruction.parent();
-    if (Parent == nullptr)
-      return makeUnexpected(ErrorCode::VerificationError,
-                            "RISC-V constant extension is detached during folding");
-    return Parent->removeInstruction(Instruction);
+    return Instruction.eraseFromParent();
   }
 
   auto SetOpcode = Instruction.setOpcode(opcode(GenericOpcode::G_CONSTANT));
@@ -175,11 +171,7 @@ foldConstantExtension(MachineInstr &Instruction, MachineFunction &Function, Gene
 
   if (Function.registerInfo().useEmpty(SourceRegister)) {
     MachineInstr *Def = const_cast<MachineInstr *>(SourceDef);
-    MachineBasicBlock *Parent = Def->parent();
-    if (Parent == nullptr)
-      return makeUnexpected(ErrorCode::VerificationError,
-                            "RISC-V constant extension source definition is detached");
-    auto Removed = Parent->removeInstruction(*Def);
+    auto Removed = Def->eraseFromParent();
     if (!Removed)
       return std::unexpected(Removed.error());
     // Keep the source register record as a tombstone-free historical vreg until
@@ -903,11 +895,7 @@ Expected<void> RISCVLegalizerInfo::legalizeBRJT(MachineInstr &Instruction,
   if (auto Built = BranchBuilder->build(); !Built)
     return std::unexpected(Built.error());
 
-  MachineBasicBlock *Block = Instruction.parent();
-  if (Block == nullptr)
-    return makeUnexpected(ErrorCode::InternalError,
-                          "RISC-V G_BRJT became detached during legalization");
-  return Block->removeInstruction(Instruction);
+  return Instruction.eraseFromParent();
 }
 
 Expected<void> RISCVLegalizerInfo::legalizeVAStart(MachineInstr &Instruction,
@@ -984,11 +972,7 @@ Expected<void> RISCVLegalizerInfo::legalizeVAStart(MachineInstr &Instruction,
   if (auto Built = StoreBuilder->build(); !Built)
     return std::unexpected(Built.error());
 
-  MachineBasicBlock *Block = Instruction.parent();
-  if (Block == nullptr)
-    return makeUnexpected(ErrorCode::InternalError,
-                          "RISC-V G_VASTART became detached during legalization");
-  return Block->removeInstruction(Instruction);
+  return Instruction.eraseFromParent();
 }
 
 Expected<void> RISCVLegalizerInfo::legalizeCustom(LegalizerHelper &Helper,
@@ -1243,11 +1227,7 @@ Expected<void> RISCVLegalizerInfo::legalizeCustom(LegalizerHelper &Helper,
         !Built) {
       return std::unexpected(Built.error());
     }
-    MachineBasicBlock *Block = Instruction.parent();
-    if (Block == nullptr)
-      return makeUnexpected(ErrorCode::InternalError,
-                            "RISC-V G_IS_FPCLASS became detached during lowering");
-    return Block->removeInstruction(Instruction);
+    return Instruction.eraseFromParent();
   }
   if (Instruction.opcode() == opcode(GenericOpcode::G_ANYEXT) ||
       Instruction.opcode() == opcode(GenericOpcode::G_SEXT) ||
@@ -1388,11 +1368,7 @@ Expected<bool> RISCVLegalizerInfo::legalizeIntrinsic(LegalizerHelper &Helper,
   if (auto Built = StoreBuilder->build(); !Built)
     return std::unexpected(Built.error());
 
-  MachineBasicBlock *Block = Instruction.parent();
-  if (Block == nullptr)
-    return makeUnexpected(ErrorCode::InternalError,
-                          "llvm.va_copy intrinsic became detached during lowering");
-  if (auto Removed = Block->removeInstruction(Instruction); !Removed)
+  if (auto Removed = Instruction.eraseFromParent(); !Removed)
     return std::unexpected(Removed.error());
   return true;
 }
diff --git a/backend/lib/Target/RISCV/RISCVFinalizeISel.cpp b/backend/lib/Target/RISCV/RISCVFinalizeISel.cpp
index 784490d..e2d99b3 100644
--- a/backend/lib/Target/RISCV/RISCVFinalizeISel.cpp
+++ b/backend/lib/Target/RISCV/RISCVFinalizeISel.cpp
@@ -254,10 +254,7 @@ buildPhi(MachineFunction &Function, const TargetDescription &Target, MachineBasi
 
 [[nodiscard]] Expected<void> moveInstructionToEnd(MachineInstr &Instruction,
                                                   MachineBasicBlock &Destination) {
-  MachineBasicBlock *Source = Instruction.parent();
-  if (Source == nullptr)
-    return makeUnexpected(ErrorCode::InternalError, "moved instruction is detached");
-  if (auto Removed = Source->removeInstruction(Instruction); !Removed)
+  if (auto Removed = Instruction.eraseFromParent(); !Removed)
     return std::unexpected(Removed.error());
   return Destination.appendInstruction(Instruction);
 }
@@ -326,11 +323,7 @@ buildPhi(MachineFunction &Function, const TargetDescription &Target, MachineBasi
       return std::unexpected(Phi.error());
   }
   for (MachineInstr *Select : Sequence->Selects) {
-    MachineBasicBlock *Parent = Select->parent();
-    if (Parent == nullptr)
-      return makeUnexpected(ErrorCode::InternalError,
-                            "RISC-V custom select became detached during expansion");
-    if (auto Removed = Parent->removeInstruction(*Select); !Removed)
+    if (auto Removed = Select->eraseFromParent(); !Removed)
       return std::unexpected(Removed.error());
   }
   Function.properties().clear(MachineFunctionProperty::NoPHIs);
@@ -468,12 +461,9 @@ emitCascadedSelect(MachineInstr &First, MachineInstr &Second, MachineBasicBlock
   if (!Phi)
     return std::unexpected(Phi.error());
 
-  if (auto Removed = Head.removeInstruction(First); !Removed)
+  if (auto Removed = First.eraseFromParent(); !Removed)
     return std::unexpected(Removed.error());
-  MachineBasicBlock *SecondParent = Second.parent();
-  if (SecondParent == nullptr)
-    return makeUnexpected(ErrorCode::InternalError, "cascaded select became detached");
-  if (auto Removed = SecondParent->removeInstruction(Second); !Removed)
+  if (auto Removed = Second.eraseFromParent(); !Removed)
     return std::unexpected(Removed.error());
   Function.properties().clear(MachineFunctionProperty::NoPHIs);
   return Sink;
diff --git a/backend/lib/Target/RISCV/RISCVFrameLowering.cpp b/backend/lib/Target/RISCV/RISCVFrameLowering.cpp
index 8a40bc1..1c9ec62 100644
--- a/backend/lib/Target/RISCV/RISCVFrameLowering.cpp
+++ b/backend/lib/Target/RISCV/RISCVFrameLowering.cpp
@@ -1714,7 +1714,7 @@ public:
       if (!Adjusted)
         return std::unexpected(Adjusted.error());
     }
-    return Block->removeInstruction(Instruction);
+    return Instruction.eraseFromParent();
   }
 
   [[nodiscard]] Expected<void> emitPrologue(MachineFunction &Function,
@@ -2291,7 +2291,7 @@ public:
       auto Built = Pending->build();
       if (!Built)
         return std::unexpected(Built.error());
-      auto Removed = Block.removeInstruction(Terminator);
+      auto Removed = Terminator.eraseFromParent();
       if (!Removed)
         return std::unexpected(Removed.error());
     }
diff --git a/backend/lib/Target/RISCV/RISCVInstrInfo.cpp b/backend/lib/Target/RISCV/RISCVInstrInfo.cpp
index 11387c1..6e356a6 100644
--- a/backend/lib/Target/RISCV/RISCVInstrInfo.cpp
+++ b/backend/lib/Target/RISCV/RISCVInstrInfo.cpp
@@ -218,15 +218,6 @@ constexpr std::uint32_t PCRelativeLowFlag = 4;
   return Operand->setBasicBlock(TargetBlock);
 }
 
-[[nodiscard]] Expected<void> removeInstruction(MachineInstr &Instruction) {
-  MachineBasicBlock *Block = Instruction.parent();
-  if (Block == nullptr) {
-    return makeUnexpected(ErrorCode::InvalidArgument,
-                          "RISC-V branch instruction is not linked to a block");
-  }
-  return Block->removeInstruction(Instruction);
-}
-
 [[nodiscard]] Expected<MachineInstr *>
 buildJAL(MachineFunction &Function, const TargetDescription &Target, MachineBasicBlock &Block,
          MachineInstr *Before, PhysicalRegister Destination, MachineBasicBlock &TargetBlock) {
@@ -380,7 +371,7 @@ selectLongBranchScratch(const MachineInstr &Instruction, const MachineBasicBlock
     auto Annotations = copySingleInstructionAnnotations(Instruction, **Replacement);
     if (!Annotations)
       return std::unexpected(Annotations.error());
-    auto Removed = removeInstruction(Instruction);
+    auto Removed = Instruction.eraseFromParent();
     if (!Removed)
       return std::unexpected(Removed.error());
     return true;
@@ -415,7 +406,7 @@ selectLongBranchScratch(const MachineInstr &Instruction, const MachineBasicBlock
   auto Annotations = copySingleInstructionAnnotations(Instruction, **Replacement);
   if (!Annotations)
     return std::unexpected(Annotations.error());
-  auto Removed = removeInstruction(Instruction);
+  auto Removed = Instruction.eraseFromParent();
   if (!Removed)
     return std::unexpected(Removed.error());
   return true;
@@ -436,7 +427,7 @@ selectLongBranchScratch(const MachineInstr &Instruction, const MachineBasicBlock
     if (!FalseTarget)
       return std::unexpected(FalseTarget.error());
     if (*FalseTarget == *TrueTarget) {
-      auto Removed = removeInstruction(Instruction);
+      auto Removed = Instruction.eraseFromParent();
       if (!Removed)
         return std::unexpected(Removed.error());
       return true;
@@ -589,7 +580,7 @@ selectLongBranchScratch(const MachineInstr &Instruction, const MachineBasicBlock
   LowFlags.clear(MachineInstrFlag::BundledWithPred);
   LowFlags.set(MachineInstrFlag::BundledWithPred);
   (*Low)->setFlags(LowFlags);
-  auto Removed = removeInstruction(Instruction);
+  auto Removed = Instruction.eraseFromParent();
   if (!Removed)
     return std::unexpected(Removed.error());
   return true;
@@ -798,7 +789,7 @@ public:
     if (&Branch.function() != &Function)
       return makeUnexpected(ErrorCode::InvalidArgument,
                             "RISC-V branch removal references another function");
-    return removeInstruction(Branch);
+    return Branch.eraseFromParent();
   }
 
   [[nodiscard]] Expected<bool> rewriteBranchTarget(MachineBasicBlock &Block,
diff --git a/backend/lib/Target/RISCV/RISCVMergeBaseOffset.cpp b/backend/lib/Target/RISCV/RISCVMergeBaseOffset.cpp
index d9b2f4b..8ef05aa 100644
--- a/backend/lib/Target/RISCV/RISCVMergeBaseOffset.cpp
+++ b/backend/lib/Target/RISCV/RISCVMergeBaseOffset.cpp
@@ -176,10 +176,7 @@ struct AddressPair final {
   auto ReplacedRegisters = Registers.replaceRegWith(*TailRegister, *LowRegister);
   if (!ReplacedRegisters)
     return std::unexpected(ReplacedRegisters.error());
-  MachineBasicBlock *Block = Tail.parent();
-  if (Block == nullptr)
-    return makeUnexpected(ErrorCode::InternalError, "RISC-V offset tail is not linked");
-  auto Removed = Block->removeInstruction(Tail);
+  auto Removed = Tail.eraseFromParent();
   if (!Removed)
     return std::unexpected(Removed.error());
   return true;
@@ -215,10 +212,7 @@ struct AddressPair final {
       auto Folded = foldOffset(Pair, Tail, *Low, Registers);
       if (!Folded || !*Folded)
         return Folded;
-      MachineBasicBlock *Block = OffsetTail->parent();
-      if (Block == nullptr)
-        return makeUnexpected(ErrorCode::InternalError, "RISC-V offset instruction is not linked");
-      auto Removed = Block->removeInstruction(*OffsetTail);
+      auto Removed = OffsetTail->eraseFromParent();
       if (!Removed)
         return std::unexpected(Removed.error());
       return true;
@@ -239,14 +233,10 @@ struct AddressPair final {
     auto Folded = foldOffset(Pair, Tail, Offset, Registers);
     if (!Folded || !*Folded)
       return Folded;
-    MachineBasicBlock *Block = OffsetTail->parent();
-    MachineBasicBlock *HighBlock = OffsetHigh->parent();
-    if (Block == nullptr || HighBlock == nullptr)
-      return makeUnexpected(ErrorCode::InternalError, "RISC-V offset instructions are not linked");
-    auto Removed = Block->removeInstruction(*OffsetTail);
+    auto Removed = OffsetTail->eraseFromParent();
     if (!Removed)
       return std::unexpected(Removed.error());
-    Removed = HighBlock->removeInstruction(*OffsetHigh);
+    Removed = OffsetHigh->eraseFromParent();
     if (!Removed)
       return std::unexpected(Removed.error());
     return true;
@@ -263,10 +253,7 @@ struct AddressPair final {
   auto Folded = foldOffset(Pair, Tail, Offset, Registers);
   if (!Folded || !*Folded)
     return Folded;
-  MachineBasicBlock *Block = OffsetTail->parent();
-  if (Block == nullptr)
-    return makeUnexpected(ErrorCode::InternalError, "RISC-V offset instruction is not linked");
-  auto Removed = Block->removeInstruction(*OffsetTail);
+  auto Removed = OffsetTail->eraseFromParent();
   if (!Removed)
     return std::unexpected(Removed.error());
   return true;
@@ -306,10 +293,7 @@ struct AddressPair final {
   auto Folded = foldOffset(Pair, Tail, Offset, Registers);
   if (!Folded || !*Folded)
     return Folded;
-  MachineBasicBlock *Block = OffsetTail->parent();
-  if (Block == nullptr)
-    return makeUnexpected(ErrorCode::InternalError, "RISC-V offset instruction is not linked");
-  auto Removed = Block->removeInstruction(*OffsetTail);
+  auto Removed = OffsetTail->eraseFromParent();
   if (!Removed)
     return std::unexpected(Removed.error());
   return true;
@@ -343,11 +327,7 @@ struct AddressPair final {
         auto Folded = foldOffset(Pair, *SecondTail, *Immediate + *SecondImmediate, Registers);
         if (!Folded || !*Folded)
           return Folded;
-        MachineBasicBlock *Block = Tail->parent();
-        if (Block == nullptr)
-          return makeUnexpected(ErrorCode::InternalError,
-                                "RISC-V offset instruction is not linked");
-        auto Removed = Block->removeInstruction(*Tail);
+        auto Removed = Tail->eraseFromParent();
         if (!Removed)
           return std::unexpected(Removed.error());
         return true;
@@ -444,10 +424,7 @@ struct AddressPair final {
     if (!ReplacedOffset)
       return std::unexpected(ReplacedOffset.error());
   }
-  MachineBasicBlock *Block = Pair.Low->parent();
-  if (Block == nullptr)
-    return makeUnexpected(ErrorCode::InternalError, "RISC-V low address instruction is not linked");
-  auto Removed = Block->removeInstruction(*Pair.Low);
+  auto Removed = Pair.Low->eraseFromParent();
   if (!Removed)
     return std::unexpected(Removed.error());
   return true;
diff --git a/backend/lib/Target/RISCV/RISCVMoveMerger.cpp b/backend/lib/Target/RISCV/RISCVMoveMerger.cpp
index fa1b1ee..1accb2e 100644
--- a/backend/lib/Target/RISCV/RISCVMoveMerger.cpp
+++ b/backend/lib/Target/RISCV/RISCVMoveMerger.cpp
@@ -241,10 +241,10 @@ struct CopyOperands final {
     auto Merged = mergeCopies(Function, *Instruction, *Paired, MoveFromSavedToArgument, Target);
     if (!Merged)
       return std::unexpected(Merged.error());
-    auto RemovedFirst = Block.removeInstruction(*Instruction);
+    auto RemovedFirst = Instruction->eraseFromParent();
     if (!RemovedFirst)
       return std::unexpected(RemovedFirst.error());
-    auto RemovedPaired = Block.removeInstruction(*Paired);
+    auto RemovedPaired = Paired->eraseFromParent();
     if (!RemovedPaired)
       return std::unexpected(RemovedPaired.error());
     Changed = true;
diff --git a/backend/lib/Target/RISCV/RISCVOptWInstrs.cpp b/backend/lib/Target/RISCV/RISCVOptWInstrs.cpp
index 124a4f0..5448ae1 100644
--- a/backend/lib/Target/RISCV/RISCVOptWInstrs.cpp
+++ b/backend/lib/Target/RISCV/RISCVOptWInstrs.cpp
@@ -475,7 +475,7 @@ void clearWordInvalidFlags(MachineInstr &Instruction) {
       auto Cleared = clearKillFlags(Function, *Source);
       if (!Cleared)
         return std::unexpected(Cleared.error());
-      auto Removed = Block->removeInstruction(*Instruction);
+      auto Removed = Instruction->eraseFromParent();
       if (!Removed)
         return std::unexpected(Removed.error());
       Changed = true;
diff --git a/backend/lib/Target/RISCV/RISCVPseudoExpansion.cpp b/backend/lib/Target/RISCV/RISCVPseudoExpansion.cpp
index 6945f68..3b3a205 100644
--- a/backend/lib/Target/RISCV/RISCVPseudoExpansion.cpp
+++ b/backend/lib/Target/RISCV/RISCVPseudoExpansion.cpp
@@ -121,13 +121,6 @@ registerBank(Register Reg, const MachineFunction &Function, const TargetDescript
   return {};
 }
 
-[[nodiscard]] Expected<void> removeOldInstruction(MachineInstr &Instruction) {
-  MachineBasicBlock *Block = Instruction.parent();
-  if (Block == nullptr)
-    return makeUnexpected(ErrorCode::InvalidArgument, "pseudo instruction is not linked");
-  return Block->removeInstruction(Instruction);
-}
-
 [[nodiscard]] Expected<std::pair<Register, Register>>
 copyRegisters(const MachineInstr &Instruction) {
   const MachineOperand *DestinationOperand = Instruction.operandAt(0);
@@ -190,7 +183,7 @@ copyRegisters(const MachineInstr &Instruction) {
                           "RISC-V post-RA COPY retains a virtual register");
   }
   if (Destination == Source) {
-    auto Removed = removeOldInstruction(Instruction);
+    auto Removed = Instruction.eraseFromParent();
     if (!Removed)
       return std::unexpected(Removed.error());
     return true;
@@ -270,7 +263,7 @@ copyRegisters(const MachineInstr &Instruction) {
   auto Decoration = copyCommonDecoration(Instruction, **Replacement, true, true, true);
   if (!Decoration)
     return std::unexpected(Decoration.error());
-  auto Removed = removeOldInstruction(Instruction);
+  auto Removed = Instruction.eraseFromParent();
   if (!Removed)
     return std::unexpected(Removed.error());
   return true;
@@ -418,7 +411,7 @@ copyRegisters(const MachineInstr &Instruction) {
       Function.records().replaceInstructionReference(Instruction.stableID(), (*Low)->stableID());
   if (!Records)
     return std::unexpected(Records.error());
-  auto Removed = removeOldInstruction(Instruction);
+  auto Removed = Instruction.eraseFromParent();
   if (!Removed)
     return std::unexpected(Removed.error());
   return true;
@@ -560,7 +553,7 @@ copyRegisters(const MachineInstr &Instruction) {
       Function.records().replaceInstructionReference(Instruction.stableID(), (*Low)->stableID());
   if (!Records)
     return std::unexpected(Records.error());
-  auto Removed = removeOldInstruction(Instruction);
+  auto Removed = Instruction.eraseFromParent();
   if (!Removed)
     return std::unexpected(Removed.error());
   return true;
diff --git a/backend/lib/Target/RISCV/RISCVPushPopOptimizer.cpp b/backend/lib/Target/RISCV/RISCVPushPopOptimizer.cpp
index 16928fb..dc33ad1 100644
--- a/backend/lib/Target/RISCV/RISCVPushPopOptimizer.cpp
+++ b/backend/lib/Target/RISCV/RISCVPushPopOptimizer.cpp
@@ -127,11 +127,7 @@ struct PushPopOpcodes final {
       const std::optional<Register> Source = Copy->Source->registerValue();
       if (Destination && Source && Destination->physicalRegister() == ReturnRegister &&
           Source->physicalRegister() == ZeroRegister) {
-        MachineBasicBlock *Parent = Instruction->parent();
-        if (Parent == nullptr)
-          return makeUnexpected(ErrorCode::InternalError,
-                                "RISC-V return-value assignment became detached");
-        if (auto Removed = Parent->removeInstruction(*Instruction); !Removed)
+        if (auto Removed = Instruction->eraseFromParent(); !Removed)
           return std::unexpected(Removed.error());
         return true;
       }
@@ -244,9 +240,9 @@ public:
           buildPopReturn(*PopInstruction, *Return, *ReturnZero, Opcodes, Function, Target);
       if (!NewReturn)
         return std::unexpected(NewReturn.error());
-      if (auto Removed = Block->removeInstruction(*PopInstruction); !Removed)
+      if (auto Removed = PopInstruction->eraseFromParent(); !Removed)
         return std::unexpected(Removed.error());
-      if (auto Removed = Block->removeInstruction(*Return); !Removed)
+      if (auto Removed = Return->eraseFromParent(); !Removed)
         return std::unexpected(Removed.error());
       Result.Changes.add(MachinePassChange::Instructions);
       Result.Changes.add(MachinePassChange::Operands);