[Attributor] Manifest load/store alignment generally

[jdoerfert]

Summary

Any pointer could have load/store users not only floating ones so we
move the manifest logic for alignment into the AAAlignImpl class.

[uenoku]

LGTM

llvm/trunk/lib/Transforms/IPO/Attributor.cpp

void initialize(Attributor &A) override {
     takeAssumedMinimum(MAX_ALIGN);
 
     SmallVector<Attribute, 4> Attrs;
     getAttrs({Attribute::Alignment}, Attrs);
     for (const Attribute &Attr : Attrs)
       takeKnownMaximum(Attr.getValueAsInt());
   }
 
-  // TODO: Provide a helper to determine the implied ABI alignment and check in
-  //       the existing manifest method and a new one for AAAlignImpl that value
-  //       to avoid making the alignment explicit if it did not improve.
-
-  /// See AbstractAttribute::getDeducedAttributes
-  virtual void
-  getDeducedAttributes(LLVMContext &Ctx,
-                       SmallVectorImpl<Attribute> &Attrs) const override {
-    if (getAssumedAlign() > 1)
-      Attrs.emplace_back(Attribute::getWithAlignment(Ctx, getAssumedAlign()));
-  }
-
-  /// See AbstractAttribute::getAsStr().
-  const std::string getAsStr() const override {
-    return getAssumedAlign() ? ("align<" + std::to_string(getKnownAlign()) +
-                                "-" + std::to_string(getAssumedAlign()) + ">")
-                             : "unknown-align";
-  }
-};
-
-/// Align attribute for a floating value.
-struct AAAlignFloating : AAAlignImpl {
-  AAAlignFloating(const IRPosition &IRP) : AAAlignImpl(IRP) {}
-
   /// See AbstractAttribute::manifest(...).
   ChangeStatus manifest(Attributor &A) override {
     ChangeStatus Changed = ChangeStatus::UNCHANGED;
 
     // Check for users that allow alignment annotations.
     Value &AnchorVal = getIRPosition().getAnchorValue();
     for (const Use &U : AnchorVal.uses()) {
       if (auto *SI = dyn_cast<StoreInst>(U.getUser())) {
for (const Use &U : AnchorVal.uses()) {
             LI->setAlignment(getAssumedAlign());
             STATS_DECLTRACK(AAAlign, Load,
                             "Number of times alignemnt added to a load");
             Changed = ChangeStatus::CHANGED;
           }
       }
     }
 
-    return AAAlignImpl::manifest(A) | Changed;
+    return AAAlign::manifest(A) | Changed;
   }
 
+  // TODO: Provide a helper to determine the implied ABI alignment and check in
+  //       the existing manifest method and a new one for AAAlignImpl that value
+  //       to avoid making the alignment explicit if it did not improve.
+
+  /// See AbstractAttribute::getDeducedAttributes
+  virtual void
+  getDeducedAttributes(LLVMContext &Ctx,
+                       SmallVectorImpl<Attribute> &Attrs) const override {
+    if (getAssumedAlign() > 1)
+      Attrs.emplace_back(Attribute::getWithAlignment(Ctx, getAssumedAlign()));
+  }
+
+  /// See AbstractAttribute::getAsStr().
+  const std::string getAsStr() const override {
+    return getAssumedAlign() ? ("align<" + std::to_string(getKnownAlign()) +
+                                "-" + std::to_string(getAssumedAlign()) + ">")
+                             : "unknown-align";
+  }
+};
+
+/// Align attribute for a floating value.
+struct AAAlignFloating : AAAlignImpl {
+  AAAlignFloating(const IRPosition &IRP) : AAAlignImpl(IRP) {}
+
   /// See AbstractAttribute::updateImpl(...).
   ChangeStatus updateImpl(Attributor &A) override {
     const DataLayout &DL = A.getDataLayout();
 
     auto VisitValueCB = [&](Value &V, AAAlign::StateType &T,
                             bool Stripped) -> bool {
       const auto &AA = A.getAAFor<AAAlign>(*this, IRPosition::value(V));
       if (!Stripped && this == &AA) {

llvm/trunk/test/Transforms/FunctionAttrs/align.ll

 define internal i8* @f1(i8* readnone %0) local_unnamed_addr #0 {
 ; ATTRIBUTOR: define internal nonnull align 8 dereferenceable(1) i8* @f1(i8* nonnull readnone align 8 dereferenceable(1) %0)
   %2 = icmp eq i8* %0, null
   br i1 %2, label %3, label %5
 
 ; <label>:3:                                      ; preds = %1
 ; ATTRIBUTOR: %4 = tail call i8* @f2(i8* nonnull align 8 dereferenceable(1) @a1)
   %4 = tail call i8* @f2(i8* nonnull @a1)
+; ATTRIBUTOR: %l = load i8, i8* %4, align 8
+  %l = load i8, i8* %4
   br label %5
 
 ; <label>:5:                                      ; preds = %1, %3
   %6 = phi i8* [ %4, %3 ], [ %0, %1 ]
   ret i8* %6
 }
 
 ; Function Attrs: nounwind readnone ssp uwtable