[llvm][TypeSize] Fix addition/subtraction in TypeSize. (#72979)

It seems TypeSize is currently broken in the sense that:

  TypeSize::Fixed(4) + TypeSize::Scalable(4) => TypeSize::Fixed(8)

without failing its assert that explicitly tests for this case:

  assert(LHS.Scalable == RHS.Scalable && ...);

The reason this fails is that `Scalable` is a static method of class
TypeSize,
and LHS and RHS are both objects of class TypeSize. So this is
evaluating
if the pointer to the function Scalable == the pointer to the function
Scalable,
which is always true because LHS and RHS have the same class.

This patch fixes the issue by renaming `TypeSize::Scalable` ->
`TypeSize::getScalable`, as well as `TypeSize::Fixed` to
`TypeSize::getFixed`,
so that it no longer clashes with the variable in
FixedOrScalableQuantity.

The new methods now also better match the coding standard, which
specifies that:
* Variable names should be nouns (as they represent state)
* Function names should be verb phrases (as they represent actions)

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp b/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
index e1375f0..605a540 100644
--- a/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
@@ -92,7 +92,7 @@ void RISCVDAGToDAGISel::PreprocessISelDAG() {
 
       // Create temporary stack for each expanding node.
       SDValue StackSlot =
-          CurDAG->CreateStackTemporary(TypeSize::Fixed(8), Align(8));
+          CurDAG->CreateStackTemporary(TypeSize::getFixed(8), Align(8));
       int FI = cast<FrameIndexSDNode>(StackSlot.getNode())->getIndex();
       MachinePointerInfo MPI = MachinePointerInfo::getFixedStack(MF, FI);
 
@@ -100,7 +100,7 @@ void RISCVDAGToDAGISel::PreprocessISelDAG() {
       Lo = CurDAG->getStore(Chain, DL, Lo, StackSlot, MPI, Align(8));
 
       SDValue OffsetSlot =
-          CurDAG->getMemBasePlusOffset(StackSlot, TypeSize::Fixed(4), DL);
+          CurDAG->getMemBasePlusOffset(StackSlot, TypeSize::getFixed(4), DL);
       Hi = CurDAG->getStore(Chain, DL, Hi, OffsetSlot, MPI.getWithOffset(4),
                             Align(8));