GlobalISel: Add isPointer legality predicates

[volkan]

LGTM.

[arsenm]

r351699

include/llvm/CodeGen/GlobalISel/LegalizerInfo.h

 /// specified type pairs.
 LegalityPredicate typePairAndMemSizeInSet(
     unsigned TypeIdx0, unsigned TypeIdx1, unsigned MMOIdx,
     std::initializer_list<TypePairAndMemSize> TypesAndMemSizeInit);
 /// True iff the specified type index is a scalar.
 LegalityPredicate isScalar(unsigned TypeIdx);
 /// True iff the specified type index is a vector.
 LegalityPredicate isVector(unsigned TypeIdx);
+/// True iff the specified type index is a pointer (with any address space).
+LegalityPredicate isPointer(unsigned TypeIdx);
+
+/// True iff the specified type index is a pointer with the specified address
+/// space.
+LegalityPredicate isPointer(unsigned TypeIdx, unsigned AddrSpace);
 
 /// True iff the specified type index is a scalar that's narrower than the given
 /// size.
 LegalityPredicate narrowerThan(unsigned TypeIdx, unsigned Size);
 /// True iff the specified type index is a scalar that's wider than the given
 /// size.
 LegalityPredicate widerThan(unsigned TypeIdx, unsigned Size);
 /// True iff the specified type index is a scalar whose size is not a power of

lib/CodeGen/GlobalISel/LegalityPredicates.cpp

 }
 
 LegalityPredicate LegalityPredicates::isVector(unsigned TypeIdx) {
   return [=](const LegalityQuery &Query) {
     return Query.Types[TypeIdx].isVector();
   };
 }
 
+LegalityPredicate LegalityPredicates::isPointer(unsigned TypeIdx) {
+  return [=](const LegalityQuery &Query) {
+    return Query.Types[TypeIdx].isPointer();
+  };
+}
+
+LegalityPredicate LegalityPredicates::isPointer(unsigned TypeIdx,
+                                                unsigned AddrSpace) {
+  return [=](const LegalityQuery &Query) {
+    LLT Ty = Query.Types[TypeIdx];
+    return Ty.isPointer() && Ty.getAddressSpace() == AddrSpace;
+  };
+}
+
 LegalityPredicate LegalityPredicates::narrowerThan(unsigned TypeIdx,
                                                    unsigned Size) {
   return [=](const LegalityQuery &Query) {
     const LLT &QueryTy = Query.Types[TypeIdx];
     return QueryTy.isScalar() && QueryTy.getSizeInBits() < Size;
   };
 }