Fix f16/f128 TypeKind UB causing SIGTRAP on aarch64

The `TypeKind` repr(C) enum was missing `X86_FP80`, `FP128`, and
`PPC_FP128` variants (values 4, 5, 6). When `compiler_builtins` is
compiled with `--cfg f128_enabled` (new in recent nightlies), the C FFI
function `LLVMRustGetTypeKind` returns 5 for fp128 types. The Rust enum
had no variant for that discriminant, causing instant undefined behavior
(manifesting as SIGTRAP).

Also adds f16 and f128 cases to the ABI `Reg::llvm_type` float match,
which previously only handled 32 and 64-bit floats.

Author: LegNeato

crates/rustc_codegen_nvvm/src/abi.rs

@@ -213,8 +213,10 @@ impl LlvmType for Reg {
         match self.kind {
             RegKind::Integer => cx.type_ix(self.size.bits()),
             RegKind::Float => match self.size.bits() {
+                16 => cx.type_f16(),
                 32 => cx.type_f32(),
                 64 => cx.type_f64(),
+                128 => cx.type_f128(),
                 _ => bug!("unsupported float: {:?}", self),
             },
             RegKind::Vector => cx.type_vector(cx.type_i8(), self.size.bytes()),

crates/rustc_codegen_nvvm/src/llvm.rs

@@ -292,6 +292,9 @@ pub(crate) enum TypeKind {
     Half = 1,
     Float = 2,
     Double = 3,
+    X86_FP80 = 4,
+    FP128 = 5,
+    PPC_FP128 = 6,
     Label = 7,
     Integer = 8,
     Function = 9,
@@ -312,6 +315,9 @@ impl TypeKind {
             TypeKind::Half => rustc_codegen_ssa::common::TypeKind::Half,
             TypeKind::Float => rustc_codegen_ssa::common::TypeKind::Float,
             TypeKind::Double => rustc_codegen_ssa::common::TypeKind::Double,
+            TypeKind::X86_FP80 => rustc_codegen_ssa::common::TypeKind::X86_FP80,
+            TypeKind::FP128 => rustc_codegen_ssa::common::TypeKind::FP128,
+            TypeKind::PPC_FP128 => rustc_codegen_ssa::common::TypeKind::PPC_FP128,
             TypeKind::Label => rustc_codegen_ssa::common::TypeKind::Label,
             TypeKind::Integer => rustc_codegen_ssa::common::TypeKind::Integer,
             TypeKind::Function => rustc_codegen_ssa::common::TypeKind::Function,