[clang][aarch64] Fix ILP32 ABI for arm_sve_vector_bits

The element types of scalable vectors are defined in terms of stdint
types in the ACLE. This patch fixes the mapping to builtin types for the
ILP32 ABI when creating VLS types with the arm_sve_vector_bits, where
the mapping is as follows:

  int32_t -> LongTy
  int64_t -> LongLongTy
  uint32_t -> UnsignedLongTy
  uint64_t -> UnsignedLongLongTy

This is implemented by leveraging getBuiltinVectorTypeInfo which is
target agnostic since it calls ASTContext::getIntTypeForBitwidth for
integer types. The element type for svfloat16_t is changed from
Float16Ty to HalfTy when creating VLS types since this is what is used
elsewhere.

For more information, see:

https://github.com/ARM-software/abi-aa/blob/master/aapcs64/aapcs64.rst#types-varying-by-data-model
https://github.com/ARM-software/abi-aa/blob/master/aapcs64/aapcs64.rst#appendix-support-for-scalable-vectors

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D87358

Author: c-rhodes

clang/lib/AST/ItaniumMangle.cpp

@@ -3388,7 +3388,7 @@ void CXXNameMangler::mangleAArch64FixedSveVectorType(const VectorType *T) {
   case BuiltinType::ULong:
     TypeName = "__SVUint64_t";
     break;
-  case BuiltinType::Float16:
+  case BuiltinType::Half:
     TypeName = "__SVFloat16_t";
     break;
   case BuiltinType::Float:

clang/lib/AST/Type.cpp

@@ -2317,38 +2317,13 @@ QualType Type::getSveEltType(const ASTContext &Ctx) const {
   assert(isVLSTBuiltinType() && "unsupported type!");
 
   const BuiltinType *BTy = getAs<BuiltinType>();
-  switch (BTy->getKind()) {
-  default:
-    llvm_unreachable("Unknown builtin SVE type!");
-  case BuiltinType::SveInt8:
-    return Ctx.SignedCharTy;
-  case BuiltinType::SveUint8:
-  case BuiltinType::SveBool:
+  if (BTy->getKind() == BuiltinType::SveBool)
     // Represent predicates as i8 rather than i1 to avoid any layout issues.
     // The type is bitcasted to a scalable predicate type when casting between
     // scalable and fixed-length vectors.
     return Ctx.UnsignedCharTy;
-  case BuiltinType::SveInt16:
-    return Ctx.ShortTy;
-  case BuiltinType::SveUint16:
-    return Ctx.UnsignedShortTy;
-  case BuiltinType::SveInt32:
-    return Ctx.IntTy;
-  case BuiltinType::SveUint32:
-    return Ctx.UnsignedIntTy;
-  case BuiltinType::SveInt64:
-    return Ctx.LongTy;
-  case BuiltinType::SveUint64:
-    return Ctx.UnsignedLongTy;
-  case BuiltinType::SveFloat16:
-    return Ctx.Float16Ty;
-  case BuiltinType::SveBFloat16:
-    return Ctx.BFloat16Ty;
-  case BuiltinType::SveFloat32:
-    return Ctx.FloatTy;
-  case BuiltinType::SveFloat64:
-    return Ctx.DoubleTy;
-  }
+  else
+    return Ctx.getBuiltinVectorTypeInfo(BTy).ElementType;
 }
 
 bool QualType::isPODType(const ASTContext &Context) const {

clang/lib/CodeGen/TargetInfo.cpp

@@ -5627,7 +5627,7 @@ ABIArgInfo AArch64ABIInfo::coerceIllegalVector(QualType Ty) const {
       ResType = llvm::ScalableVectorType::get(
           llvm::Type::getInt64Ty(getVMContext()), 2);
       break;
-    case BuiltinType::Float16:
+    case BuiltinType::Half:
       ResType = llvm::ScalableVectorType::get(
           llvm::Type::getHalfTy(getVMContext()), 8);
       break;

clang/test/CodeGen/attr-arm-sve-vector-bits-types.c

@@ -4,6 +4,7 @@
 // RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sve -target-feature +bf16 -msve-vector-bits=512 -fallow-half-arguments-and-returns -S -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-512
 // RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sve -target-feature +bf16 -msve-vector-bits=1024 -fallow-half-arguments-and-returns -S -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-1024
 // RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sve -target-feature +bf16 -msve-vector-bits=2048 -fallow-half-arguments-and-returns -S -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-2048
+// RUN: %clang_cc1 -triple aarch64_32-unknown-darwin -target-feature +sve -target-feature +bf16 -msve-vector-bits=512 -fallow-half-arguments-and-returns -S -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK-ILP32
 
 #include <arm_sve.h>
 
@@ -579,3 +580,11 @@ void f() {
 // CHECK-2048-NEXT:  %local_arr_f64 = alloca [3 x <32 x double>], align 16
 // CHECK-2048-NEXT:  %local_arr_bf16 = alloca [3 x <128 x bfloat>], align 16
 // CHECK-2048-NEXT:  %local_arr_bool = alloca [3 x <32 x i8>], align 2
+
+//===----------------------------------------------------------------------===//
+// ILP32 ABI
+//===----------------------------------------------------------------------===//
+// CHECK-ILP32: @global_i32 = global <16 x i32> zeroinitializer, align 16
+// CHECK-ILP32: @global_i64 = global <8 x i64> zeroinitializer, align 16
+// CHECK-ILP32: @global_u32 = global <16 x i32> zeroinitializer, align 16
+// CHECK-ILP32: @global_u64 = global <8 x i64> zeroinitializer, align 16