[Alignment][NFC] Migrate Instructions to Align

[gchatelet]

Summary

This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

llvm/trunk/include/llvm/IR/Instructions.h

public:
   Type *getAllocatedType() const { return AllocatedType; }
   /// for use only in special circumstances that need to generically
   /// transform a whole instruction (eg: IR linking and vectorization).
   void setAllocatedType(Type *Ty) { AllocatedType = Ty; }
 
   /// Return the alignment of the memory that is being allocated by the
   /// instruction.
   unsigned getAlignment() const {
-    return (1u << (getSubclassDataFromInstruction() & 31)) >> 1;
+    if (const auto MA = decodeMaybeAlign(getSubclassDataFromInstruction() & 31))
+      return MA->value();
+    return 0;
   }
+  // FIXME: Remove once migration to llvm::Align is over.
   void setAlignment(unsigned Align);
+  void setAlignment(llvm::MaybeAlign Align);
 
   /// Return true if this alloca is in the entry block of the function and is a
   /// constant size. If so, the code generator will fold it into the
   /// prolog/epilog code, so it is basically free.
   bool isStaticAlloca() const;
 
   /// Return true if this alloca is used as an inalloca argument to a call. Such
   /// allocas are never considered static even if they are in the entry block.
public:
   /// Specify whether this is a volatile load or not.
   void setVolatile(bool V) {
     setInstructionSubclassData((getSubclassDataFromInstruction() & ~1) |
                                (V ? 1 : 0));
   }
 
   /// Return the alignment of the access that is being performed.
   unsigned getAlignment() const {
-    return (1 << ((getSubclassDataFromInstruction() >> 1) & 31)) >> 1;
+    if (const auto MA =
+            decodeMaybeAlign((getSubclassDataFromInstruction() >> 1) & 31))
+      return MA->value();
+    return 0;
   }
 
+  // FIXME: Remove once migration to llvm::Align is over.
   void setAlignment(unsigned Align);
+  void setAlignment(llvm::MaybeAlign Align);
 
   /// Returns the ordering constraint of this load instruction.
   AtomicOrdering getOrdering() const {
     return AtomicOrdering((getSubclassDataFromInstruction() >> 7) & 7);
   }
 
   /// Sets the ordering constraint of this load instruction.  May not be Release
   /// or AcquireRelease.
setInstructionSubclassData((getSubclassDataFromInstruction() & ~1) |
                                (V ? 1 : 0));
   }
 
   /// Transparently provide more efficient getOperand methods.
   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 
   /// Return the alignment of the access that is being performed
   unsigned getAlignment() const {
-    return (1 << ((getSubclassDataFromInstruction() >> 1) & 31)) >> 1;
+    if (const auto MA =
+            decodeMaybeAlign((getSubclassDataFromInstruction() >> 1) & 31))
+      return MA->value();
+    return 0;
   }
 
+  // FIXME: Remove once migration to llvm::Align is over.
   void setAlignment(unsigned Align);
+  void setAlignment(llvm::MaybeAlign Align);
 
   /// Returns the ordering constraint of this store instruction.
   AtomicOrdering getOrdering() const {
     return AtomicOrdering((getSubclassDataFromInstruction() >> 7) & 7);
   }
 
   /// Sets the ordering constraint of this store instruction.  May not be
   /// Acquire or AcquireRelease.

llvm/trunk/lib/IR/Instructions.cpp

: UnaryInstruction(PointerType::get(Ty, AddrSpace), Alloca,
                      getAISize(Ty->getContext(), ArraySize), InsertAtEnd),
       AllocatedType(Ty) {
   setAlignment(Align);
   assert(!Ty->isVoidTy() && "Cannot allocate void!");
   setName(Name);
 }
 
 void AllocaInst::setAlignment(unsigned Align) {
-  assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
-  assert(Align <= MaximumAlignment &&
+  setAlignment(llvm::MaybeAlign(Align));
+}
+
+void AllocaInst::setAlignment(llvm::MaybeAlign Align) {
+  assert((!Align || *Align <= MaximumAlignment) &&
          "Alignment is greater than MaximumAlignment!");
   setInstructionSubclassData((getSubclassDataFromInstruction() & ~31) |
-                             (Log2_32(Align) + 1));
-  assert(getAlignment() == Align && "Alignment representation error!");
+                             encode(Align));
+  if (Align)
+    assert(getAlignment() == Align->value() &&
+           "Alignment representation error!");
+  else
+    assert(getAlignment() == 0 && "Alignment representation error!");
 }
 
 bool AllocaInst::isArrayAllocation() const {
   if (ConstantInt *CI = dyn_cast<ConstantInt>(getOperand(0)))
     return !CI->isOne();
   return true;
 }
 
LoadInst::LoadInst(Type *Ty, Value *Ptr, const Twine &Name, bool isVolatile,
   setVolatile(isVolatile);
   setAlignment(Align);
   setAtomic(Order, SSID);
   AssertOK();
   setName(Name);
 }
 
 void LoadInst::setAlignment(unsigned Align) {
-  assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
-  assert(Align <= MaximumAlignment &&
+  setAlignment(llvm::MaybeAlign(Align));
+}
+
+void LoadInst::setAlignment(llvm::MaybeAlign Align) {
+  assert((!Align || *Align <= MaximumAlignment) &&
          "Alignment is greater than MaximumAlignment!");
   setInstructionSubclassData((getSubclassDataFromInstruction() & ~(31 << 1)) |
-                             ((Log2_32(Align)+1)<<1));
-  assert(getAlignment() == Align && "Alignment representation error!");
+                             (encode(Align) << 1));
+  if (Align)
+    assert(getAlignment() == Align->value() &&
+           "Alignment representation error!");
+  else
+    assert(getAlignment() == 0 && "Alignment representation error!");
 }
 
 //===----------------------------------------------------------------------===//
 //                           StoreInst Implementation
 //===----------------------------------------------------------------------===//
 
 void StoreInst::AssertOK() {
   assert(getOperand(0) && getOperand(1) && "Both operands must be non-null!");
StoreInst::StoreInst(Value *val, Value *addr, bool isVolatile,
   Op<1>() = addr;
   setVolatile(isVolatile);
   setAlignment(Align);
   setAtomic(Order, SSID);
   AssertOK();
 }
 
 void StoreInst::setAlignment(unsigned Align) {
-  assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
-  assert(Align <= MaximumAlignment &&
+  setAlignment(llvm::MaybeAlign(Align));
+}
+
+void StoreInst::setAlignment(llvm::MaybeAlign Align) {
+  assert((!Align || *Align <= MaximumAlignment) &&
          "Alignment is greater than MaximumAlignment!");
   setInstructionSubclassData((getSubclassDataFromInstruction() & ~(31 << 1)) |
-                             ((Log2_32(Align)+1) << 1));
-  assert(getAlignment() == Align && "Alignment representation error!");
+                             (encode(Align) << 1));
+  if (Align)
+    assert(getAlignment() == Align->value() &&
+           "Alignment representation error!");
+  else
+    assert(getAlignment() == 0 && "Alignment representation error!");
 }
 
 //===----------------------------------------------------------------------===//
 //                       AtomicCmpXchgInst Implementation
 //===----------------------------------------------------------------------===//
 
 void AtomicCmpXchgInst::Init(Value *Ptr, Value *Cmp, Value *NewVal,
                              AtomicOrdering SuccessOrdering,