[DebugInfo] Remove getPrevNonDebugInstruction (#148859)

With the advent of intrinsic-less debug-info, we no longer need to
scatter calls to getPrevNonDebugInstruction around the codebase. Remove
most of them -- there are one or two that have the "SkipPseudoOp" flag
turned on, however they don't seem to be in positions where skipping
anything would be reasonable.

Author: jmorse

llvm/include/llvm/IR/Instruction.h

@@ -898,17 +898,6 @@ class Instruction : public User,
   /// Return true if the instruction is a DbgInfoIntrinsic or PseudoProbeInst.
   LLVM_ABI bool isDebugOrPseudoInst() const LLVM_READONLY;
 
-  /// Return a pointer to the previous non-debug instruction in the same basic
-  /// block as 'this', or nullptr if no such instruction exists. Skip any pseudo
-  /// operations if \c SkipPseudoOp is true.
-  LLVM_ABI const Instruction *
-  getPrevNonDebugInstruction(bool SkipPseudoOp = false) const;
-  Instruction *getPrevNonDebugInstruction(bool SkipPseudoOp = false) {
-    return const_cast<Instruction *>(
-        static_cast<const Instruction *>(this)->getPrevNonDebugInstruction(
-            SkipPseudoOp));
-  }
-
   /// Create a copy of 'this' instruction that is identical in all ways except
   /// the following:
   ///   * The instruction has no parent

llvm/include/llvm/Transforms/Utils/LockstepReverseIterator.h

@@ -61,7 +61,7 @@ class LockstepReverseIterator
     }
     Insts.clear();
     for (BasicBlock *BB : Blocks) {
-      Instruction *Prev = BB->getTerminator()->getPrevNonDebugInstruction();
+      Instruction *Prev = BB->getTerminator()->getPrevNode();
       if (!Prev) {
         // Block wasn't big enough - only contained a terminator.
         if constexpr (EarlyFailure) {
@@ -108,7 +108,7 @@ class LockstepReverseIterator
       return *this;
     SmallVector<Instruction *, 4> NewInsts;
     for (Instruction *Inst : Insts) {
-      Instruction *Prev = Inst->getPrevNonDebugInstruction();
+      Instruction *Prev = Inst->getPrevNode();
       if (!Prev) {
         if constexpr (!EarlyFailure) {
           this->ActiveBlocks.remove(Inst->getParent());

llvm/lib/CodeGen/CodeGenPrepare.cpp

@@ -3015,7 +3015,7 @@ bool CodeGenPrepare::dupRetToEnableTailCallOpts(BasicBlock *BB,
         //   %phi = phi ptr [ %0, %bb0 ], [ %2, %entry ]
         if (PredBB && PredBB->getSingleSuccessor() == BB)
           CI = dyn_cast_or_null<CallInst>(
-              PredBB->getTerminator()->getPrevNonDebugInstruction(true));
+              PredBB->getTerminator()->getPrevNode());
 
         if (CI && CI->use_empty() &&
             isIntrinsicOrLFToBeTailCalled(TLInfo, CI) &&
@@ -3032,7 +3032,7 @@ bool CodeGenPrepare::dupRetToEnableTailCallOpts(BasicBlock *BB,
     for (BasicBlock *Pred : predecessors(BB)) {
       if (!VisitedBBs.insert(Pred).second)
         continue;
-      if (Instruction *I = Pred->rbegin()->getPrevNonDebugInstruction(true)) {
+      if (Instruction *I = Pred->rbegin()->getPrevNode()) {
         CallInst *CI = dyn_cast<CallInst>(I);
         if (CI && CI->use_empty() && TLI->mayBeEmittedAsTailCall(CI) &&
             attributesPermitTailCall(F, CI, RetI, *TLI)) {

llvm/lib/CodeGen/StackProtector.cpp

@@ -626,7 +626,7 @@ bool InsertStackProtectors(const TargetMachine *TM, Function *F,
 
     // If we're instrumenting a block with a tail call, the check has to be
     // inserted before the call rather than between it and the return.
-    Instruction *Prev = CheckLoc->getPrevNonDebugInstruction();
+    Instruction *Prev = CheckLoc->getPrevNode();
     if (auto *CI = dyn_cast_if_present<CallInst>(Prev))
       if (CI->isTailCall() && isInTailCallPosition(*CI, *TM))
         CheckLoc = Prev;

llvm/lib/IR/Instruction.cpp

@@ -1235,14 +1235,6 @@ bool Instruction::isDebugOrPseudoInst() const {
   return isa<DbgInfoIntrinsic>(this) || isa<PseudoProbeInst>(this);
 }
 
-const Instruction *
-Instruction::getPrevNonDebugInstruction(bool SkipPseudoOp) const {
-  for (const Instruction *I = getPrevNode(); I; I = I->getPrevNode())
-    if (!isa<DbgInfoIntrinsic>(I) && !(SkipPseudoOp && isa<PseudoProbeInst>(I)))
-      return I;
-  return nullptr;
-}
-
 const DebugLoc &Instruction::getStableDebugLoc() const {
   return getDebugLoc();
 }

llvm/lib/Transforms/IPO/OpenMPOpt.cpp

@@ -2875,7 +2875,7 @@ struct AAExecutionDomainFunction : public AAExecutionDomain {
       if (It->getSecond().IsReachedFromAlignedBarrierOnly)
         break;
       return false;
-    } while ((CurI = CurI->getPrevNonDebugInstruction()));
+    } while ((CurI = CurI->getPrevNode()));
 
     // Delayed decision on the forward pass to allow aligned barrier detection
     // in the backwards traversal.

llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

@@ -3933,7 +3933,7 @@ Instruction *InstCombinerImpl::visitFenceInst(FenceInst &FI) {
   if (NFI && isIdenticalOrStrongerFence(NFI, &FI))
     return eraseInstFromFunction(FI);
 
-  if (auto *PFI = dyn_cast_or_null<FenceInst>(FI.getPrevNonDebugInstruction()))
+  if (auto *PFI = dyn_cast_or_null<FenceInst>(FI.getPrevNode()))
     if (isIdenticalOrStrongerFence(PFI, &FI))
       return eraseInstFromFunction(FI);
   return nullptr;

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -3890,7 +3890,7 @@ bool InstCombinerImpl::removeInstructionsBeforeUnreachable(Instruction &I) {
   // This includes instructions like stores and "llvm.assume" that may not get
   // removed by simple dead code elimination.
   bool Changed = false;
-  while (Instruction *Prev = I.getPrevNonDebugInstruction()) {
+  while (Instruction *Prev = I.getPrevNode()) {
     // While we theoretically can erase EH, that would result in a block that
     // used to start with an EH no longer starting with EH, which is invalid.
     // To make it valid, we'd need to fixup predecessors to no longer refer to

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

@@ -3424,7 +3424,7 @@ static void findStoresToUninstrumentedArgAllocas(
           isa<Argument>(cast<CastInst>(Val)->getOperand(0)) &&
           // Check that the cast appears directly before the store. Otherwise
           // moving the cast before InsBefore may break the IR.
-          Val == It->getPrevNonDebugInstruction();
+          Val == It->getPrevNode();
       bool IsArgInit = IsDirectArgInit || IsArgInitViaCast;
       if (!IsArgInit)
         continue;

llvm/lib/Transforms/Scalar/GVN.cpp

@@ -1310,7 +1310,7 @@ static Value *findDominatingValue(const MemoryLocation &Loc, Type *LoadTy,
   BatchAAResults BatchAA(*AA);
   for (BasicBlock *BB = FromBB; BB; BB = BB->getSinglePredecessor())
     for (auto *Inst = BB == FromBB ? From : BB->getTerminator();
-         Inst != nullptr; Inst = Inst->getPrevNonDebugInstruction()) {
+         Inst != nullptr; Inst = Inst->getPrevNode()) {
       // Stop the search if limit is reached.
       if (++NumVisitedInsts > MaxNumVisitedInsts)
         return nullptr;