[clang][Builtins][ARM] NFC updates in ARM.cpp (#180966)

Updates the logic in `CodeGenFunction::EmitAArch64BuiltinExpr` so that
we always start with the general code and we only fall-back to
specialised cases (i.e. `switch` stmts) for intrinsics for which the
general code does no apply.

BEFORE (only high-level:
```cpp
Value *CodeGenFunction::EmitAArch64BuiltinExpr() {
  (...)
  /// 1. SWITCH STMT FOR NON-OVERLOADED INTRINSIS
  switch (BuiltinID) {
    default break:
    case NEON::BI__builtin_neon_vabsh_f16:
    (...)
  }

  /// 2. GENERAL CODE
  Builtin = findARMVectorIntrinsicInMap(AArch64SIMDIntrinsicMap, BuiltinID,
                                        AArch64SIMDIntrinsicsProvenSorted);
  if (Builtin)
    return EmitCommonNeonBuiltinExpr(
        Builtin->BuiltinID, Builtin->LLVMIntrinsic, Builtin->AltLLVMIntrinsic,
        Builtin->NameHint, Builtin->TypeModifier, E, Ops,
        /*never use addresses*/ Address::invalid(), Address::invalid(), Arch);

  if (Value *V = EmitAArch64TblBuiltinExpr(*this, BuiltinID, E, Ops, Arch))
    return V;

  /// 3. SWITCH STMT FOR THE REMAINING INTRINSIS
  switch (BuiltinID) {
    default return nullptr:
    case NEON::BI__builtin_neon_vbsl_v:
    (...)
  }
}
```

AFTER:
```cpp
Value *CodeGenFunction::EmitAArch64BuiltinExpr() {

  /// 1. GENERAL CODE
  Builtin = findARMVectorIntrinsicInMap(AArch64SIMDIntrinsicMap, BuiltinID,
                                        AArch64SIMDIntrinsicsProvenSorted);

  if (Builtin)
    return EmitCommonNeonBuiltinExpr(
        Builtin->BuiltinID, Builtin->LLVMIntrinsic, Builtin->AltLLVMIntrinsic,
        Builtin->NameHint, Builtin->TypeModifier, E, Ops,
        /*never use addresses*/ Address::invalid(), Address::invalid(), Arch);

  if (Value *V = EmitAArch64TblBuiltinExpr(*this, BuiltinID, E, Ops, Arch))
    return V;

  /// 2. SWITCH STMT FOR NON-OVERLOADED INTRINSIS
  switch (BuiltinID) {
    default break:
    case NEON::BI__builtin_neon_vabsh_f16:
    (...)
  }

  /// 3. SWITCH STMT FOR THE REMAINING INTRINSIS
  switch (BuiltinID) {
    default return nullptr:
    case NEON::BI__builtin_neon_vbsl_v:
    (...)
  }
}
```

In addition:
  * Remove `vaddq_p128+ vcvtq_high_bf16_f32 + vcvtq_low_bf16_f32` from
   `AArch64SIMDIntrinsicMap`. Those were not required
    there (it's an array for intrinsics for which the general code-gen
    works, but that's not the case for those).
  * Extracted the declaration of `Int` so that it can be re-used.

0 files changed, 0 insertions, 0 deletions