[Alignment] Get DataLayout::StackAlignment as Align

Summary:
Internally it is needed to know if StackAlignment is set but we can
expose it as llvm::Align.

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

Reviewers: courbet

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67852

llvm-svn: 372585

llvm/include/llvm/IR/DataLayout.h

@@ -266,7 +266,11 @@ public:
     return StackNaturalAlign && (Align > StackNaturalAlign);
   }
 
-  unsigned getStackAlignment() const { return StackNaturalAlign ? StackNaturalAlign->value() : 0; }
+  llvm::Align getStackAlignment() const {
+    assert(StackNaturalAlign && "StackNaturalAlign must be defined");
+    return *StackNaturalAlign;
+  }
+
   unsigned getAllocaAddrSpace() const { return AllocaAddrSpace; }
 
   /// Returns the alignment of function pointers, which may or may not be

llvm/lib/Target/AArch64/AArch64CallingConvention.cpp

@@ -40,12 +40,14 @@ static bool finishStackBlock(SmallVectorImpl<CCValAssign> &PendingMembers,
                              MVT LocVT, ISD::ArgFlagsTy &ArgFlags,
                              CCState &State, unsigned SlotAlign) {
   unsigned Size = LocVT.getSizeInBits() / 8;
-  unsigned StackAlign =
+  const llvm::Align StackAlign =
       State.getMachineFunction().getDataLayout().getStackAlignment();
-  unsigned Align = std::min(ArgFlags.getOrigAlign(), StackAlign);
+  const llvm::Align OrigAlign(ArgFlags.getOrigAlign());
+  const llvm::Align Align = std::min(OrigAlign, StackAlign);
 
   for (auto &It : PendingMembers) {
-    It.convertToMem(State.AllocateStack(Size, std::max(Align, SlotAlign)));
+    It.convertToMem(State.AllocateStack(
+        Size, std::max((unsigned)Align.value(), SlotAlign)));
     State.addLoc(It);
     SlotAlign = 1;
   }

llvm/lib/Target/ARM/ARMCallingConv.cpp

@@ -193,7 +193,7 @@ static bool CC_ARM_AAPCS_Custom_Aggregate(unsigned &ValNo, MVT &ValVT,
   // Try to allocate a contiguous block of registers, each of the correct
   // size to hold one member.
   auto &DL = State.getMachineFunction().getDataLayout();
-  unsigned StackAlign = DL.getStackAlignment();
+  unsigned StackAlign = DL.getStackAlignment().value();
   unsigned Align = std::min(PendingMembers[0].getExtraInfo(), StackAlign);
 
   ArrayRef<MCPhysReg> RegList;

llvm/lib/Target/ARM/ARMISelLowering.cpp

@@ -16771,7 +16771,8 @@ ARMTargetLowering::getABIAlignmentForCallingConv(Type *ArgTy,
 
   // Avoid over-aligning vector parameters. It would require realigning the
   // stack and waste space for no real benefit.
-  return std::min(DL.getABITypeAlignment(ArgTy), DL.getStackAlignment());
+  return std::min(DL.getABITypeAlignment(ArgTy),
+                  (unsigned)DL.getStackAlignment().value());
 }
 
 /// Return true if a type is an AAPCS-VFP homogeneous aggregate or one of