1 files changed, 191 insertions, 196 deletions
diff --git a/contrib/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/contrib/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index e9c25d3..af1694d 100644
--- a/contrib/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/contrib/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -15,6 +15,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/Loads.h"
 #include "llvm/IR/DataLayout.h"
+#include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include "llvm/Transforms/Utils/Local.h"
@@ -267,8 +268,8 @@ Instruction *InstCombiner::visitAllocaInst(AllocaInst &AI) {
     // is only subsequently read.
     SmallVector<Instruction *, 4> ToDelete;
     if (MemTransferInst *Copy = isOnlyCopiedFromConstantGlobal(&AI, ToDelete)) {
-      unsigned SourceAlign = getOrEnforceKnownAlignment(Copy->getSource(),
-                                                        AI.getAlignment(), DL);
+      unsigned SourceAlign = getOrEnforceKnownAlignment(
+          Copy->getSource(), AI.getAlignment(), DL, AC, &AI, DT);
       if (AI.getAlignment() <= SourceAlign) {
         DEBUG(dbgs() << "Found alloca equal to global: " << AI << '\n');
         DEBUG(dbgs() << "  memcpy = " << *Copy << '\n');
@@ -290,80 +291,111 @@ Instruction *InstCombiner::visitAllocaInst(AllocaInst &AI) {
   return visitAllocSite(AI);
 }
 
+/// \brief Helper to combine a load to a new type.
+///
+/// This just does the work of combining a load to a new type. It handles
+/// metadata, etc., and returns the new instruction. The \c NewTy should be the
+/// loaded *value* type. This will convert it to a pointer, cast the operand to
+/// that pointer type, load it, etc.
+///
+/// Note that this will create all of the instructions with whatever insert
+/// point the \c InstCombiner currently is using.
+static LoadInst *combineLoadToNewType(InstCombiner &IC, LoadInst &LI, Type *NewTy) {
+  Value *Ptr = LI.getPointerOperand();
+  unsigned AS = LI.getPointerAddressSpace();
+  SmallVector<std::pair<unsigned, MDNode *>, 8> MD;
+  LI.getAllMetadata(MD);
+
+  LoadInst *NewLoad = IC.Builder->CreateAlignedLoad(
+      IC.Builder->CreateBitCast(Ptr, NewTy->getPointerTo(AS)),
+      LI.getAlignment(), LI.getName());
+  for (const auto &MDPair : MD) {
+    unsigned ID = MDPair.first;
+    MDNode *N = MDPair.second;
+    // Note, essentially every kind of metadata should be preserved here! This
+    // routine is supposed to clone a load instruction changing *only its type*.
+    // The only metadata it makes sense to drop is metadata which is invalidated
+    // when the pointer type changes. This should essentially never be the case
+    // in LLVM, but we explicitly switch over only known metadata to be
+    // conservatively correct. If you are adding metadata to LLVM which pertains
+    // to loads, you almost certainly want to add it here.
+    switch (ID) {
+    case LLVMContext::MD_dbg:
+    case LLVMContext::MD_tbaa:
+    case LLVMContext::MD_prof:
+    case LLVMContext::MD_fpmath:
+    case LLVMContext::MD_tbaa_struct:
+    case LLVMContext::MD_invariant_load:
+    case LLVMContext::MD_alias_scope:
+    case LLVMContext::MD_noalias:
+    case LLVMContext::MD_nontemporal:
+    case LLVMContext::MD_mem_parallel_loop_access:
+    case LLVMContext::MD_nonnull:
+      // All of these directly apply.
+      NewLoad->setMetadata(ID, N);
+      break;
 
-/// InstCombineLoadCast - Fold 'load (cast P)' -> cast (load P)' when possible.
-static Instruction *InstCombineLoadCast(InstCombiner &IC, LoadInst &LI,
-                                        const DataLayout *DL) {
-  User *CI = cast<User>(LI.getOperand(0));
-  Value *CastOp = CI->getOperand(0);
-
-  PointerType *DestTy = cast<PointerType>(CI->getType());
-  Type *DestPTy = DestTy->getElementType();
-  if (PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType())) {
-
-    // If the address spaces don't match, don't eliminate the cast.
-    if (DestTy->getAddressSpace() != SrcTy->getAddressSpace())
-      return nullptr;
-
-    Type *SrcPTy = SrcTy->getElementType();
-
-    if (DestPTy->isIntegerTy() || DestPTy->isPointerTy() ||
-         DestPTy->isVectorTy()) {
-      // If the source is an array, the code below will not succeed.  Check to
-      // see if a trivial 'gep P, 0, 0' will help matters.  Only do this for
-      // constants.
-      if (ArrayType *ASrcTy = dyn_cast<ArrayType>(SrcPTy))
-        if (Constant *CSrc = dyn_cast<Constant>(CastOp))
-          if (ASrcTy->getNumElements() != 0) {
-            Type *IdxTy = DL
-                        ? DL->getIntPtrType(SrcTy)
-                        : Type::getInt64Ty(SrcTy->getContext());
-            Value *Idx = Constant::getNullValue(IdxTy);
-            Value *Idxs[2] = { Idx, Idx };
-            CastOp = ConstantExpr::getGetElementPtr(CSrc, Idxs);
-            SrcTy = cast<PointerType>(CastOp->getType());
-            SrcPTy = SrcTy->getElementType();
-          }
-
-      if (IC.getDataLayout() &&
-          (SrcPTy->isIntegerTy() || SrcPTy->isPointerTy() ||
-            SrcPTy->isVectorTy()) &&
-          // Do not allow turning this into a load of an integer, which is then
-          // casted to a pointer, this pessimizes pointer analysis a lot.
-          (SrcPTy->isPtrOrPtrVectorTy() ==
-           LI.getType()->isPtrOrPtrVectorTy()) &&
-          IC.getDataLayout()->getTypeSizeInBits(SrcPTy) ==
-               IC.getDataLayout()->getTypeSizeInBits(DestPTy)) {
-
-        // Okay, we are casting from one integer or pointer type to another of
-        // the same size.  Instead of casting the pointer before the load, cast
-        // the result of the loaded value.
-        LoadInst *NewLoad =
-          IC.Builder->CreateLoad(CastOp, LI.isVolatile(), CI->getName());
-        NewLoad->setAlignment(LI.getAlignment());
-        NewLoad->setAtomic(LI.getOrdering(), LI.getSynchScope());
-        // Now cast the result of the load.
-        PointerType *OldTy = dyn_cast<PointerType>(NewLoad->getType());
-        PointerType *NewTy = dyn_cast<PointerType>(LI.getType());
-        if (OldTy && NewTy &&
-            OldTy->getAddressSpace() != NewTy->getAddressSpace()) {
-          return new AddrSpaceCastInst(NewLoad, LI.getType());
-        }
-
-        return new BitCastInst(NewLoad, LI.getType());
-      }
+    case LLVMContext::MD_range:
+      // FIXME: It would be nice to propagate this in some way, but the type
+      // conversions make it hard.
+      break;
     }
   }
+  return NewLoad;
+}
+
+/// \brief Combine loads to match the type of value their uses after looking
+/// through intervening bitcasts.
+///
+/// The core idea here is that if the result of a load is used in an operation,
+/// we should load the type most conducive to that operation. For example, when
+/// loading an integer and converting that immediately to a pointer, we should
+/// instead directly load a pointer.
+///
+/// However, this routine must never change the width of a load or the number of
+/// loads as that would introduce a semantic change. This combine is expected to
+/// be a semantic no-op which just allows loads to more closely model the types
+/// of their consuming operations.
+///
+/// Currently, we also refuse to change the precise type used for an atomic load
+/// or a volatile load. This is debatable, and might be reasonable to change
+/// later. However, it is risky in case some backend or other part of LLVM is
+/// relying on the exact type loaded to select appropriate atomic operations.
+static Instruction *combineLoadToOperationType(InstCombiner &IC, LoadInst &LI) {
+  // FIXME: We could probably with some care handle both volatile and atomic
+  // loads here but it isn't clear that this is important.
+  if (!LI.isSimple())
+    return nullptr;
+
+  if (LI.use_empty())
+    return nullptr;
+
+
+  // Fold away bit casts of the loaded value by loading the desired type.
+  if (LI.hasOneUse())
+    if (auto *BC = dyn_cast<BitCastInst>(LI.user_back())) {
+      LoadInst *NewLoad = combineLoadToNewType(IC, LI, BC->getDestTy());
+      BC->replaceAllUsesWith(NewLoad);
+      IC.EraseInstFromFunction(*BC);
+      return &LI;
+    }
+
+  // FIXME: We should also canonicalize loads of vectors when their elements are
+  // cast to other types.
   return nullptr;
 }
 
 Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
   Value *Op = LI.getOperand(0);
 
+  // Try to canonicalize the loaded type.
+  if (Instruction *Res = combineLoadToOperationType(*this, LI))
+    return Res;
+
   // Attempt to improve the alignment.
   if (DL) {
-    unsigned KnownAlign =
-      getOrEnforceKnownAlignment(Op, DL->getPrefTypeAlignment(LI.getType()),DL);
+    unsigned KnownAlign = getOrEnforceKnownAlignment(
+        Op, DL->getPrefTypeAlignment(LI.getType()), DL, AC, &LI, DT);
     unsigned LoadAlign = LI.getAlignment();
     unsigned EffectiveLoadAlign = LoadAlign != 0 ? LoadAlign :
       DL->getABITypeAlignment(LI.getType());
@@ -374,11 +406,6 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
       LI.setAlignment(EffectiveLoadAlign);
   }
 
-  // load (cast X) --> cast (load X) iff safe.
-  if (isa<CastInst>(Op))
-    if (Instruction *Res = InstCombineLoadCast(*this, LI, DL))
-      return Res;
-
   // None of the following transforms are legal for volatile/atomic loads.
   // FIXME: Some of it is okay for atomic loads; needs refactoring.
   if (!LI.isSimple()) return nullptr;
@@ -388,7 +415,9 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
   // separated by a few arithmetic operations.
   BasicBlock::iterator BBI = &LI;
   if (Value *AvailableVal = FindAvailableLoadedValue(Op, LI.getParent(), BBI,6))
-    return ReplaceInstUsesWith(LI, AvailableVal);
+    return ReplaceInstUsesWith(
+        LI, Builder->CreateBitOrPointerCast(AvailableVal, LI.getType(),
+                                            LI.getName() + ".cast"));
 
   // load(gep null, ...) -> unreachable
   if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(Op)) {
@@ -417,12 +446,6 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
     return ReplaceInstUsesWith(LI, UndefValue::get(LI.getType()));
   }
 
-  // Instcombine load (constantexpr_cast global) -> cast (load global)
-  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Op))
-    if (CE->isCast())
-      if (Instruction *Res = InstCombineLoadCast(*this, LI, DL))
-        return Res;
-
   if (Op->hasOneUse()) {
     // Change select and PHI nodes to select values instead of addresses: this
     // helps alias analysis out a lot, allows many others simplifications, and
@@ -449,119 +472,98 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
       }
 
       // load (select (cond, null, P)) -> load P
-      if (Constant *C = dyn_cast<Constant>(SI->getOperand(1)))
-        if (C->isNullValue()) {
-          LI.setOperand(0, SI->getOperand(2));
-          return &LI;
-        }
+      if (isa<ConstantPointerNull>(SI->getOperand(1)) && 
+          LI.getPointerAddressSpace() == 0) {
+        LI.setOperand(0, SI->getOperand(2));
+        return &LI;
+      }
 
       // load (select (cond, P, null)) -> load P
-      if (Constant *C = dyn_cast<Constant>(SI->getOperand(2)))
-        if (C->isNullValue()) {
-          LI.setOperand(0, SI->getOperand(1));
-          return &LI;
-        }
+      if (isa<ConstantPointerNull>(SI->getOperand(2)) &&
+          LI.getPointerAddressSpace() == 0) {
+        LI.setOperand(0, SI->getOperand(1));
+        return &LI;
+      }
     }
   }
   return nullptr;
 }
 
-/// InstCombineStoreToCast - Fold store V, (cast P) -> store (cast V), P
-/// when possible.  This makes it generally easy to do alias analysis and/or
-/// SROA/mem2reg of the memory object.
-static Instruction *InstCombineStoreToCast(InstCombiner &IC, StoreInst &SI) {
-  User *CI = cast<User>(SI.getOperand(1));
-  Value *CastOp = CI->getOperand(0);
-
-  Type *DestPTy = CI->getType()->getPointerElementType();
-  PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType());
-  if (!SrcTy) return nullptr;
-
-  Type *SrcPTy = SrcTy->getElementType();
+/// \brief Combine stores to match the type of value being stored.
+///
+/// The core idea here is that the memory does not have any intrinsic type and
+/// where we can we should match the type of a store to the type of value being
+/// stored.
+///
+/// However, this routine must never change the width of a store or the number of
+/// stores as that would introduce a semantic change. This combine is expected to
+/// be a semantic no-op which just allows stores to more closely model the types
+/// of their incoming values.
+///
+/// Currently, we also refuse to change the precise type used for an atomic or
+/// volatile store. This is debatable, and might be reasonable to change later.
+/// However, it is risky in case some backend or other part of LLVM is relying
+/// on the exact type stored to select appropriate atomic operations.
+///
+/// \returns true if the store was successfully combined away. This indicates
+/// the caller must erase the store instruction. We have to let the caller erase
+/// the store instruction sas otherwise there is no way to signal whether it was
+/// combined or not: IC.EraseInstFromFunction returns a null pointer.
+static bool combineStoreToValueType(InstCombiner &IC, StoreInst &SI) {
+  // FIXME: We could probably with some care handle both volatile and atomic
+  // stores here but it isn't clear that this is important.
+  if (!SI.isSimple())
+    return false;
 
-  if (!DestPTy->isIntegerTy() && !DestPTy->isPointerTy())
-    return nullptr;
+  Value *Ptr = SI.getPointerOperand();
+  Value *V = SI.getValueOperand();
+  unsigned AS = SI.getPointerAddressSpace();
+  SmallVector<std::pair<unsigned, MDNode *>, 8> MD;
+  SI.getAllMetadata(MD);
+
+  // Fold away bit casts of the stored value by storing the original type.
+  if (auto *BC = dyn_cast<BitCastInst>(V)) {
+    V = BC->getOperand(0);
+    StoreInst *NewStore = IC.Builder->CreateAlignedStore(
+        V, IC.Builder->CreateBitCast(Ptr, V->getType()->getPointerTo(AS)),
+        SI.getAlignment());
+    for (const auto &MDPair : MD) {
+      unsigned ID = MDPair.first;
+      MDNode *N = MDPair.second;
+      // Note, essentially every kind of metadata should be preserved here! This
+      // routine is supposed to clone a store instruction changing *only its
+      // type*. The only metadata it makes sense to drop is metadata which is
+      // invalidated when the pointer type changes. This should essentially
+      // never be the case in LLVM, but we explicitly switch over only known
+      // metadata to be conservatively correct. If you are adding metadata to
+      // LLVM which pertains to stores, you almost certainly want to add it
+      // here.
+      switch (ID) {
+      case LLVMContext::MD_dbg:
+      case LLVMContext::MD_tbaa:
+      case LLVMContext::MD_prof:
+      case LLVMContext::MD_fpmath:
+      case LLVMContext::MD_tbaa_struct:
+      case LLVMContext::MD_alias_scope:
+      case LLVMContext::MD_noalias:
+      case LLVMContext::MD_nontemporal:
+      case LLVMContext::MD_mem_parallel_loop_access:
+      case LLVMContext::MD_nonnull:
+        // All of these directly apply.
+        NewStore->setMetadata(ID, N);
+        break;
 
-  /// NewGEPIndices - If SrcPTy is an aggregate type, we can emit a "noop gep"
-  /// to its first element.  This allows us to handle things like:
-  ///   store i32 xxx, (bitcast {foo*, float}* %P to i32*)
-  /// on 32-bit hosts.
-  SmallVector<Value*, 4> NewGEPIndices;
-
-  // If the source is an array, the code below will not succeed.  Check to
-  // see if a trivial 'gep P, 0, 0' will help matters.  Only do this for
-  // constants.
-  if (SrcPTy->isArrayTy() || SrcPTy->isStructTy()) {
-    // Index through pointer.
-    Constant *Zero = Constant::getNullValue(Type::getInt32Ty(SI.getContext()));
-    NewGEPIndices.push_back(Zero);
-
-    while (1) {
-      if (StructType *STy = dyn_cast<StructType>(SrcPTy)) {
-        if (!STy->getNumElements()) /* Struct can be empty {} */
-          break;
-        NewGEPIndices.push_back(Zero);
-        SrcPTy = STy->getElementType(0);
-      } else if (ArrayType *ATy = dyn_cast<ArrayType>(SrcPTy)) {
-        NewGEPIndices.push_back(Zero);
-        SrcPTy = ATy->getElementType();
-      } else {
+      case LLVMContext::MD_invariant_load:
+      case LLVMContext::MD_range:
         break;
       }
     }
-
-    SrcTy = PointerType::get(SrcPTy, SrcTy->getAddressSpace());
-  }
-
-  if (!SrcPTy->isIntegerTy() && !SrcPTy->isPointerTy())
-    return nullptr;
-
-  // If the pointers point into different address spaces don't do the
-  // transformation.
-  if (SrcTy->getAddressSpace() != CI->getType()->getPointerAddressSpace())
-    return nullptr;
-
-  // If the pointers point to values of different sizes don't do the
-  // transformation.
-  if (!IC.getDataLayout() ||
-      IC.getDataLayout()->getTypeSizeInBits(SrcPTy) !=
-      IC.getDataLayout()->getTypeSizeInBits(DestPTy))
-    return nullptr;
-
-  // If the pointers point to pointers to different address spaces don't do the
-  // transformation. It is not safe to introduce an addrspacecast instruction in
-  // this case since, depending on the target, addrspacecast may not be a no-op
-  // cast.
-  if (SrcPTy->isPointerTy() && DestPTy->isPointerTy() &&
-      SrcPTy->getPointerAddressSpace() != DestPTy->getPointerAddressSpace())
-    return nullptr;
-
-  // Okay, we are casting from one integer or pointer type to another of
-  // the same size.  Instead of casting the pointer before
-  // the store, cast the value to be stored.
-  Value *NewCast;
-  Instruction::CastOps opcode = Instruction::BitCast;
-  Type* CastSrcTy = DestPTy;
-  Type* CastDstTy = SrcPTy;
-  if (CastDstTy->isPointerTy()) {
-    if (CastSrcTy->isIntegerTy())
-      opcode = Instruction::IntToPtr;
-  } else if (CastDstTy->isIntegerTy()) {
-    if (CastSrcTy->isPointerTy())
-      opcode = Instruction::PtrToInt;
+    return true;
   }
 
-  // SIOp0 is a pointer to aggregate and this is a store to the first field,
-  // emit a GEP to index into its first field.
-  if (!NewGEPIndices.empty())
-    CastOp = IC.Builder->CreateInBoundsGEP(CastOp, NewGEPIndices);
-
-  Value *SIOp0 = SI.getOperand(0);
-  NewCast = IC.Builder->CreateCast(opcode, SIOp0, CastDstTy,
-                                   SIOp0->getName()+".c");
-  SI.setOperand(0, NewCast);
-  SI.setOperand(1, CastOp);
-  return &SI;
+  // FIXME: We should also canonicalize loads of vectors when their elements are
+  // cast to other types.
+  return false;
 }
 
 /// equivalentAddressValues - Test if A and B will obviously have the same
@@ -597,11 +599,14 @@ Instruction *InstCombiner::visitStoreInst(StoreInst &SI) {
   Value *Val = SI.getOperand(0);
   Value *Ptr = SI.getOperand(1);
 
+  // Try to canonicalize the stored type.
+  if (combineStoreToValueType(*this, SI))
+    return EraseInstFromFunction(SI);
+
   // Attempt to improve the alignment.
   if (DL) {
-    unsigned KnownAlign =
-      getOrEnforceKnownAlignment(Ptr, DL->getPrefTypeAlignment(Val->getType()),
-                                 DL);
+    unsigned KnownAlign = getOrEnforceKnownAlignment(
+        Ptr, DL->getPrefTypeAlignment(Val->getType()), DL, AC, &SI, DT);
     unsigned StoreAlign = SI.getAlignment();
     unsigned EffectiveStoreAlign = StoreAlign != 0 ? StoreAlign :
       DL->getABITypeAlignment(Val->getType());
@@ -688,17 +693,6 @@ Instruction *InstCombiner::visitStoreInst(StoreInst &SI) {
   if (isa<UndefValue>(Val))
     return EraseInstFromFunction(SI);
 
-  // If the pointer destination is a cast, see if we can fold the cast into the
-  // source instead.
-  if (isa<CastInst>(Ptr))
-    if (Instruction *Res = InstCombineStoreToCast(*this, SI))
-      return Res;
-  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr))
-    if (CE->isCast())
-      if (Instruction *Res = InstCombineStoreToCast(*this, SI))
-        return Res;
-
-
   // If this store is the last instruction in the basic block (possibly
   // excepting debug info instructions), and if the block ends with an
   // unconditional branch, try to move it to the successor block.
@@ -836,12 +830,13 @@ bool InstCombiner::SimplifyStoreAtEndOfBlock(StoreInst &SI) {
   InsertNewInstBefore(NewSI, *BBI);
   NewSI->setDebugLoc(OtherStore->getDebugLoc());
 
-  // If the two stores had the same TBAA tag, preserve it.
-  if (MDNode *TBAATag = SI.getMetadata(LLVMContext::MD_tbaa))
-    if ((TBAATag = MDNode::getMostGenericTBAA(TBAATag,
-                               OtherStore->getMetadata(LLVMContext::MD_tbaa))))
-      NewSI->setMetadata(LLVMContext::MD_tbaa, TBAATag);
-
+  // If the two stores had AA tags, merge them.
+  AAMDNodes AATags;
+  SI.getAAMetadata(AATags);
+  if (AATags) {
+    OtherStore->getAAMetadata(AATags, /* Merge = */ true);
+    NewSI->setAAMetadata(AATags);
+  }
 
   // Nuke the old stores.
   EraseInstFromFunction(SI);