[DataLayout] Remove getMaxIndexSizeInBits() API

The last use was removed in #119365, and we should not add more
uses of this concept in the future either.

Author: nikic

llvm/include/llvm/IR/DataLayout.h

@@ -365,9 +365,6 @@ class DataLayout {
     return getPointerSpec(AS).BitWidth;
   }
 
-  /// Returns the maximum index size over all address spaces.
-  unsigned getMaxIndexSizeInBits() const;
-
   /// Size in bits of index used for address calculation in getelementptr.
   unsigned getIndexSizeInBits(unsigned AS) const {
     return getPointerSpec(AS).IndexBitWidth;

llvm/lib/IR/DataLayout.cpp

@@ -740,13 +740,6 @@ unsigned DataLayout::getPointerSize(unsigned AS) const {
   return divideCeil(getPointerSpec(AS).BitWidth, 8);
 }
 
-unsigned DataLayout::getMaxIndexSizeInBits() const {
-  unsigned MaxIndexSize = 0;
-  for (const PointerSpec &Spec : PointerSpecs)
-    MaxIndexSize = std::max(MaxIndexSize, Spec.IndexBitWidth);
-  return MaxIndexSize;
-}
-
 unsigned DataLayout::getPointerTypeSizeInBits(Type *Ty) const {
   assert(Ty->isPtrOrPtrVectorTy() &&
          "This should only be called with a pointer or pointer vector type");