[Atomic] Remove IsStore/IsLoad in the interface, and pass the instruction instead. NFC.

Now both emitLeadingFence and emitTrailingFence take the instruction
itself, instead of taking IsLoad/IsStore pairs.
Instruction::mayReadFromMemory and Instrucion::mayWriteToMemory are used
for determining those two booleans.

The instruction argument is also useful for later D32763, in
emitTrailingFence. For emitLeadingFence, it seems to have cleaner
interface with the proposed change.

Differential Revision: https://reviews.llvm.org/D32762

llvm-svn: 302539

8 files changed, 70 insertions, 51 deletions

diff --git a/llvm/include/llvm/IR/Instruction.h b/llvm/include/llvm/IR/Instruction.h
index 90c3175122f..fca29900f4c 100644
--- a/llvm/include/llvm/IR/Instruction.h
+++ b/llvm/include/llvm/IR/Instruction.h
@@ -456,6 +456,12 @@ public:
   /// higher.
   bool isAtomic() const;
 
+  /// Return true if this atomic instruction loads from memory.
+  bool hasAtomicLoad() const;
+
+  /// Return true if this atomic instruction stores to memory.
+  bool hasAtomicStore() const;
+
   /// Return true if this instruction may throw an exception.
   bool mayThrow() const;
 
diff --git a/llvm/include/llvm/Target/TargetLowering.h b/llvm/include/llvm/Target/TargetLowering.h
index ced18385214..e282ca15770 100644
--- a/llvm/include/llvm/Target/TargetLowering.h
+++ b/llvm/include/llvm/Target/TargetLowering.h
@@ -1396,7 +1396,10 @@ public:
   /// It is called by AtomicExpandPass before expanding an
   ///   AtomicRMW/AtomicCmpXchg/AtomicStore/AtomicLoad
   ///   if shouldInsertFencesForAtomic returns true.
-  /// RMW and CmpXchg set both IsStore and IsLoad to true.
+  ///
+  /// Inst is the original atomic instruction, prior to other expansions that
+  /// may be performed.
+  ///
   /// This function should either return a nullptr, or a pointer to an IR-level
   ///   Instruction*. Even complex fence sequences can be represented by a
   ///   single Instruction* through an intrinsic to be lowered later.
@@ -1422,18 +1425,17 @@ public:
   ///  seq_cst. But if they are lowered to monotonic accesses, no amount of
   ///  IR-level fences can prevent it.
   /// @{
-  virtual Instruction *emitLeadingFence(IRBuilder<> &Builder,
-                                        AtomicOrdering Ord, bool IsStore,
-                                        bool IsLoad) const {
-    if (isReleaseOrStronger(Ord) && IsStore)
+  virtual Instruction *emitLeadingFence(IRBuilder<> &Builder, Instruction *Inst,
+                                        AtomicOrdering Ord) const {
+    if (isReleaseOrStronger(Ord) && Inst->hasAtomicStore())
       return Builder.CreateFence(Ord);
     else
       return nullptr;
   }
 
   virtual Instruction *emitTrailingFence(IRBuilder<> &Builder,
-                                         AtomicOrdering Ord, bool IsStore,
-                                         bool IsLoad) const {
+                                         Instruction *Inst,
+                                         AtomicOrdering Ord) const {
     if (isAcquireOrStronger(Ord))
       return Builder.CreateFence(Ord);
     else
diff --git a/llvm/lib/CodeGen/AtomicExpandPass.cpp b/llvm/lib/CodeGen/AtomicExpandPass.cpp
index 9c19a4fd3c3..17e6be05eb4 100644
--- a/llvm/lib/CodeGen/AtomicExpandPass.cpp
+++ b/llvm/lib/CodeGen/AtomicExpandPass.cpp
@@ -47,8 +47,7 @@ namespace {
     bool runOnFunction(Function &F) override;
 
   private:
-    bool bracketInstWithFences(Instruction *I, AtomicOrdering Order,
-                               bool IsStore, bool IsLoad);
+    bool bracketInstWithFences(Instruction *I, AtomicOrdering Order);
     IntegerType *getCorrespondingIntegerType(Type *T, const DataLayout &DL);
     LoadInst *convertAtomicLoadToIntegerType(LoadInst *LI);
     bool tryExpandAtomicLoad(LoadInst *LI);
@@ -224,22 +223,16 @@ bool AtomicExpand::runOnFunction(Function &F) {
 
     if (TLI->shouldInsertFencesForAtomic(I)) {
       auto FenceOrdering = AtomicOrdering::Monotonic;
-      bool IsStore, IsLoad;
       if (LI && isAcquireOrStronger(LI->getOrdering())) {
         FenceOrdering = LI->getOrdering();
         LI->setOrdering(AtomicOrdering::Monotonic);
-        IsStore = false;
-        IsLoad = true;
       } else if (SI && isReleaseOrStronger(SI->getOrdering())) {
         FenceOrdering = SI->getOrdering();
         SI->setOrdering(AtomicOrdering::Monotonic);
-        IsStore = true;
-        IsLoad = false;
       } else if (RMWI && (isReleaseOrStronger(RMWI->getOrdering()) ||
                           isAcquireOrStronger(RMWI->getOrdering()))) {
         FenceOrdering = RMWI->getOrdering();
         RMWI->setOrdering(AtomicOrdering::Monotonic);
-        IsStore = IsLoad = true;
       } else if (CASI && !TLI->shouldExpandAtomicCmpXchgInIR(CASI) &&
                  (isReleaseOrStronger(CASI->getSuccessOrdering()) ||
                   isAcquireOrStronger(CASI->getSuccessOrdering()))) {
@@ -250,11 +243,10 @@ bool AtomicExpand::runOnFunction(Function &F) {
         FenceOrdering = CASI->getSuccessOrdering();
         CASI->setSuccessOrdering(AtomicOrdering::Monotonic);
         CASI->setFailureOrdering(AtomicOrdering::Monotonic);
-        IsStore = IsLoad = true;
       }
 
       if (FenceOrdering != AtomicOrdering::Monotonic) {
-        MadeChange |= bracketInstWithFences(I, FenceOrdering, IsStore, IsLoad);
+        MadeChange |= bracketInstWithFences(I, FenceOrdering);
       }
     }
 
@@ -320,13 +312,12 @@ bool AtomicExpand::runOnFunction(Function &F) {
   return MadeChange;
 }
 
-bool AtomicExpand::bracketInstWithFences(Instruction *I, AtomicOrdering Order,
-                                         bool IsStore, bool IsLoad) {
+bool AtomicExpand::bracketInstWithFences(Instruction *I, AtomicOrdering Order) {
   IRBuilder<> Builder(I);
 
-  auto LeadingFence = TLI->emitLeadingFence(Builder, Order, IsStore, IsLoad);
+  auto LeadingFence = TLI->emitLeadingFence(Builder, I, Order);
 
-  auto TrailingFence = TLI->emitTrailingFence(Builder, Order, IsStore, IsLoad);
+  auto TrailingFence = TLI->emitTrailingFence(Builder, I, Order);
   // The trailing fence is emitted before the instruction instead of after
   // because there is no easy way of setting Builder insertion point after
   // an instruction. So we must erase it from the BB, and insert it back
@@ -1048,8 +1039,7 @@ bool AtomicExpand::expandAtomicCmpXchg(AtomicCmpXchgInst *CI) {
   std::prev(BB->end())->eraseFromParent();
   Builder.SetInsertPoint(BB);
   if (ShouldInsertFencesForAtomic && UseUnconditionalReleaseBarrier)
-    TLI->emitLeadingFence(Builder, SuccessOrder, /*IsStore=*/true,
-                          /*IsLoad=*/true);
+    TLI->emitLeadingFence(Builder, CI, SuccessOrder);
   Builder.CreateBr(StartBB);
 
   // Start the main loop block now that we've taken care of the preliminaries.
@@ -1064,8 +1054,7 @@ bool AtomicExpand::expandAtomicCmpXchg(AtomicCmpXchgInst *CI) {
 
   Builder.SetInsertPoint(ReleasingStoreBB);
   if (ShouldInsertFencesForAtomic && !UseUnconditionalReleaseBarrier)
-    TLI->emitLeadingFence(Builder, SuccessOrder, /*IsStore=*/true,
-                          /*IsLoad=*/true);
+    TLI->emitLeadingFence(Builder, CI, SuccessOrder);
   Builder.CreateBr(TryStoreBB);
 
   Builder.SetInsertPoint(TryStoreBB);
@@ -1094,8 +1083,7 @@ bool AtomicExpand::expandAtomicCmpXchg(AtomicCmpXchgInst *CI) {
   // necessary.
   Builder.SetInsertPoint(SuccessBB);
   if (ShouldInsertFencesForAtomic)
-    TLI->emitTrailingFence(Builder, SuccessOrder, /*IsStore=*/true,
-                           /*IsLoad=*/true);
+    TLI->emitTrailingFence(Builder, CI, SuccessOrder);
   Builder.CreateBr(ExitBB);
 
   Builder.SetInsertPoint(NoStoreBB);
@@ -1107,8 +1095,7 @@ bool AtomicExpand::expandAtomicCmpXchg(AtomicCmpXchgInst *CI) {
 
   Builder.SetInsertPoint(FailureBB);
   if (ShouldInsertFencesForAtomic)
-    TLI->emitTrailingFence(Builder, FailureOrder, /*IsStore=*/true,
-                           /*IsLoad=*/true);
+    TLI->emitTrailingFence(Builder, CI, FailureOrder);
   Builder.CreateBr(ExitBB);
 
   // Finally, we have control-flow based knowledge of whether the cmpxchg
diff --git a/llvm/lib/IR/Instruction.cpp b/llvm/lib/IR/Instruction.cpp
index 906a28a5c88..91b9d9232b5 100644
--- a/llvm/lib/IR/Instruction.cpp
+++ b/llvm/lib/IR/Instruction.cpp
@@ -534,6 +534,30 @@ bool Instruction::isAtomic() const {
   }
 }
 
+bool Instruction::hasAtomicLoad() const {
+  assert(isAtomic());
+  switch (getOpcode()) {
+  default:
+    return false;
+  case Instruction::AtomicCmpXchg:
+  case Instruction::AtomicRMW:
+  case Instruction::Load:
+    return true;
+  }
+}
+
+bool Instruction::hasAtomicStore() const {
+  assert(isAtomic());
+  switch (getOpcode()) {
+  default:
+    return false;
+  case Instruction::AtomicCmpXchg:
+  case Instruction::AtomicRMW:
+  case Instruction::Store:
+    return true;
+  }
+}
+
 bool Instruction::mayThrow() const {
   if (const CallInst *CI = dyn_cast<CallInst>(this))
     return !CI->doesNotThrow();
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 69b511d5add..6fbb61c770d 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -13416,9 +13416,9 @@ Instruction* ARMTargetLowering::makeDMB(IRBuilder<> &Builder,
 }
 
 // Based on http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html
-Instruction* ARMTargetLowering::emitLeadingFence(IRBuilder<> &Builder,
-                                         AtomicOrdering Ord, bool IsStore,
-                                         bool IsLoad) const {
+Instruction *ARMTargetLowering::emitLeadingFence(IRBuilder<> &Builder,
+                                                 Instruction *Inst,
+                                                 AtomicOrdering Ord) const {
   switch (Ord) {
   case AtomicOrdering::NotAtomic:
   case AtomicOrdering::Unordered:
@@ -13427,7 +13427,7 @@ Instruction* ARMTargetLowering::emitLeadingFence(IRBuilder<> &Builder,
   case AtomicOrdering::Acquire:
     return nullptr; // Nothing to do
   case AtomicOrdering::SequentiallyConsistent:
-    if (!IsStore)
+    if (!Inst->hasAtomicStore())
       return nullptr; // Nothing to do
     /*FALLTHROUGH*/
   case AtomicOrdering::Release:
@@ -13441,9 +13441,9 @@ Instruction* ARMTargetLowering::emitLeadingFence(IRBuilder<> &Builder,
   llvm_unreachable("Unknown fence ordering in emitLeadingFence");
 }
 
-Instruction* ARMTargetLowering::emitTrailingFence(IRBuilder<> &Builder,
-                                          AtomicOrdering Ord, bool IsStore,
-                                          bool IsLoad) const {
+Instruction *ARMTargetLowering::emitTrailingFence(IRBuilder<> &Builder,
+                                                  Instruction *Inst,
+                                                  AtomicOrdering Ord) const {
   switch (Ord) {
   case AtomicOrdering::NotAtomic:
   case AtomicOrdering::Unordered:
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.h b/llvm/lib/Target/ARM/ARMISelLowering.h
index 08c51b66dfe..875c06210ae 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.h
+++ b/llvm/lib/Target/ARM/ARMISelLowering.h
@@ -483,10 +483,10 @@ class InstrItineraryData;
 
     void emitAtomicCmpXchgNoStoreLLBalance(IRBuilder<> &Builder) const override;
 
-    Instruction* emitLeadingFence(IRBuilder<> &Builder, AtomicOrdering Ord,
-                          bool IsStore, bool IsLoad) const override;
-    Instruction* emitTrailingFence(IRBuilder<> &Builder, AtomicOrdering Ord,
-                           bool IsStore, bool IsLoad) const override;
+    Instruction *emitLeadingFence(IRBuilder<> &Builder, Instruction *Inst,
+                                  AtomicOrdering Ord) const override;
+    Instruction *emitTrailingFence(IRBuilder<> &Builder, Instruction *Inst,
+                                   AtomicOrdering Ord) const override;
 
     unsigned getMaxSupportedInterleaveFactor() const override { return 4; }
 
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 46cd75bc9b2..5de774ea372 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -8737,9 +8737,9 @@ static Instruction* callIntrinsic(IRBuilder<> &Builder, Intrinsic::ID Id) {
 
 // The mappings for emitLeading/TrailingFence is taken from
 // http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html
-Instruction* PPCTargetLowering::emitLeadingFence(IRBuilder<> &Builder,
-                                         AtomicOrdering Ord, bool IsStore,
-                                         bool IsLoad) const {
+Instruction *PPCTargetLowering::emitLeadingFence(IRBuilder<> &Builder,
+                                                 Instruction *Inst,
+                                                 AtomicOrdering Ord) const {
   if (Ord == AtomicOrdering::SequentiallyConsistent)
     return callIntrinsic(Builder, Intrinsic::ppc_sync);
   if (isReleaseOrStronger(Ord))
@@ -8747,10 +8747,10 @@ Instruction* PPCTargetLowering::emitLeadingFence(IRBuilder<> &Builder,
   return nullptr;
 }
 
-Instruction* PPCTargetLowering::emitTrailingFence(IRBuilder<> &Builder,
-                                          AtomicOrdering Ord, bool IsStore,
-                                          bool IsLoad) const {
-  if (IsLoad && isAcquireOrStronger(Ord))
+Instruction *PPCTargetLowering::emitTrailingFence(IRBuilder<> &Builder,
+                                                  Instruction *Inst,
+                                                  AtomicOrdering Ord) const {
+  if (Inst->hasAtomicLoad() && isAcquireOrStronger(Ord))
     return callIntrinsic(Builder, Intrinsic::ppc_lwsync);
   // FIXME: this is too conservative, a dependent branch + isync is enough.
   // See http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html and
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.h b/llvm/lib/Target/PowerPC/PPCISelLowering.h
index 32661099b79..d0793c7a3ae 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.h
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.h
@@ -617,10 +617,10 @@ namespace llvm {
       return true;
     }
 
-    Instruction* emitLeadingFence(IRBuilder<> &Builder, AtomicOrdering Ord,
-                                  bool IsStore, bool IsLoad) const override;
-    Instruction* emitTrailingFence(IRBuilder<> &Builder, AtomicOrdering Ord,
-                                   bool IsStore, bool IsLoad) const override;
+    Instruction *emitLeadingFence(IRBuilder<> &Builder, Instruction *Inst,
+                                  AtomicOrdering Ord) const override;
+    Instruction *emitTrailingFence(IRBuilder<> &Builder, Instruction *Inst,
+                                   AtomicOrdering Ord) const override;
 
     MachineBasicBlock *
     EmitInstrWithCustomInserter(MachineInstr &MI,