compiler/rustc_codegen_llvm/src/intrinsic.rs

   1 use crate::abi::{Abi, FnAbi, LlvmType, PassMode};
   2 use crate::builder::Builder;
   3 use crate::context::CodegenCx;
   4 use crate::llvm;
   5 use crate::type_::Type;
   6 use crate::type_of::LayoutLlvmExt;
   7 use crate::va_arg::emit_va_arg;
   8 use crate::value::Value;
   9
  10 use rustc_codegen_ssa::base::{compare_simd_types, wants_msvc_seh};
  11 use rustc_codegen_ssa::common::span_invalid_monomorphization_error;
  12 use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
  13 use rustc_codegen_ssa::mir::operand::OperandRef;
  14 use rustc_codegen_ssa::mir::place::PlaceRef;
  15 use rustc_codegen_ssa::traits::*;
  16 use rustc_hir as hir;
  17 use rustc_middle::ty::layout::{FnAbiExt, HasTyCtxt};
  18 use rustc_middle::ty::{self, Ty};
  19 use rustc_middle::{bug, span_bug};
  20 use rustc_span::{sym, symbol::kw, Span, Symbol};
  21 use rustc_target::abi::{self, HasDataLayout, LayoutOf, Primitive};
  22 use rustc_target::spec::PanicStrategy;
  23
  24 use std::cmp::Ordering;
  25 use std::iter;
  26
  27 fn get_simple_intrinsic(cx: &CodegenCx<'ll, '_>, name: Symbol) -> Option<&'ll Value> {
  28     let llvm_name = match name {
  29         sym::sqrtf32 => "llvm.sqrt.f32",
  30         sym::sqrtf64 => "llvm.sqrt.f64",
  31         sym::powif32 => "llvm.powi.f32",
  32         sym::powif64 => "llvm.powi.f64",
  33         sym::sinf32 => "llvm.sin.f32",
  34         sym::sinf64 => "llvm.sin.f64",
  35         sym::cosf32 => "llvm.cos.f32",
  36         sym::cosf64 => "llvm.cos.f64",
  37         sym::powf32 => "llvm.pow.f32",
  38         sym::powf64 => "llvm.pow.f64",
  39         sym::expf32 => "llvm.exp.f32",
  40         sym::expf64 => "llvm.exp.f64",
  41         sym::exp2f32 => "llvm.exp2.f32",
  42         sym::exp2f64 => "llvm.exp2.f64",
  43         sym::logf32 => "llvm.log.f32",
  44         sym::logf64 => "llvm.log.f64",
  45         sym::log10f32 => "llvm.log10.f32",
  46         sym::log10f64 => "llvm.log10.f64",
  47         sym::log2f32 => "llvm.log2.f32",
  48         sym::log2f64 => "llvm.log2.f64",
  49         sym::fmaf32 => "llvm.fma.f32",
  50         sym::fmaf64 => "llvm.fma.f64",
  51         sym::fabsf32 => "llvm.fabs.f32",
  52         sym::fabsf64 => "llvm.fabs.f64",
  53         sym::minnumf32 => "llvm.minnum.f32",
  54         sym::minnumf64 => "llvm.minnum.f64",
  55         sym::maxnumf32 => "llvm.maxnum.f32",
  56         sym::maxnumf64 => "llvm.maxnum.f64",
  57         sym::copysignf32 => "llvm.copysign.f32",
  58         sym::copysignf64 => "llvm.copysign.f64",
  59         sym::floorf32 => "llvm.floor.f32",
  60         sym::floorf64 => "llvm.floor.f64",
  61         sym::ceilf32 => "llvm.ceil.f32",
  62         sym::ceilf64 => "llvm.ceil.f64",
  63         sym::truncf32 => "llvm.trunc.f32",
  64         sym::truncf64 => "llvm.trunc.f64",
  65         sym::rintf32 => "llvm.rint.f32",
  66         sym::rintf64 => "llvm.rint.f64",
  67         sym::nearbyintf32 => "llvm.nearbyint.f32",
  68         sym::nearbyintf64 => "llvm.nearbyint.f64",
  69         sym::roundf32 => "llvm.round.f32",
  70         sym::roundf64 => "llvm.round.f64",
  71         _ => return None,
  72     };
  73     Some(cx.get_intrinsic(&llvm_name))
  74 }
  75
  76 impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
  77     fn codegen_intrinsic_call(
  78         &mut self,
  79         instance: ty::Instance<'tcx>,
  80         fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
  81         args: &[OperandRef<'tcx, &'ll Value>],
  82         llresult: &'ll Value,
  83         span: Span,
  84     ) {
  85         let tcx = self.tcx;
  86         let callee_ty = instance.ty(tcx, ty::ParamEnv::reveal_all());
  87
  88         let (def_id, substs) = match *callee_ty.kind() {
  89             ty::FnDef(def_id, substs) => (def_id, substs),
  90             _ => bug!("expected fn item type, found {}", callee_ty),
  91         };
  92
  93         let sig = callee_ty.fn_sig(tcx);
  94         let sig = tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), sig);
  95         let arg_tys = sig.inputs();
  96         let ret_ty = sig.output();
  97         let name = tcx.item_name(def_id);
  98         let name_str = &*name.as_str();
  99
 100         let llret_ty = self.layout_of(ret_ty).llvm_type(self);
 101         let result = PlaceRef::new_sized(llresult, fn_abi.ret.layout);
 102
 103         let simple = get_simple_intrinsic(self, name);
 104         let llval = match name {
 105             _ if simple.is_some() => self.call(
 106                 simple.unwrap(),
 107                 &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
 108                 None,
 109             ),
 110             sym::likely => {
 111                 let expect = self.get_intrinsic(&("llvm.expect.i1"));
 112                 self.call(expect, &[args[0].immediate(), self.const_bool(true)], None)
 113             }
 114             sym::unlikely => {
 115                 let expect = self.get_intrinsic(&("llvm.expect.i1"));
 116                 self.call(expect, &[args[0].immediate(), self.const_bool(false)], None)
 117             }
 118             kw::Try => {
 119                 try_intrinsic(
 120                     self,
 121                     args[0].immediate(),
 122                     args[1].immediate(),
 123                     args[2].immediate(),
 124                     llresult,
 125                 );
 126                 return;
 127             }
 128             sym::breakpoint => {
 129                 let llfn = self.get_intrinsic(&("llvm.debugtrap"));
 130                 self.call(llfn, &[], None)
 131             }
 132             sym::va_copy => {
 133                 let intrinsic = self.cx().get_intrinsic(&("llvm.va_copy"));
 134                 self.call(intrinsic, &[args[0].immediate(), args[1].immediate()], None)
 135             }
 136             sym::va_arg => {
 137                 match fn_abi.ret.layout.abi {
 138                     abi::Abi::Scalar(ref scalar) => {
 139                         match scalar.value {
 140                             Primitive::Int(..) => {
 141                                 if self.cx().size_of(ret_ty).bytes() < 4 {
 142                                     // `va_arg` should not be called on a integer type
 143                                     // less than 4 bytes in length. If it is, promote
 144                                     // the integer to a `i32` and truncate the result
 145                                     // back to the smaller type.
 146                                     let promoted_result = emit_va_arg(self, args[0], tcx.types.i32);
 147                                     self.trunc(promoted_result, llret_ty)
 148                                 } else {
 149                                     emit_va_arg(self, args[0], ret_ty)
 150                                 }
 151                             }
 152                             Primitive::F64 | Primitive::Pointer => {
 153                                 emit_va_arg(self, args[0], ret_ty)
 154                             }
 155                             // `va_arg` should never be used with the return type f32.
 156                             Primitive::F32 => bug!("the va_arg intrinsic does not work with `f32`"),
 157                         }
 158                     }
 159                     _ => bug!("the va_arg intrinsic does not work with non-scalar types"),
 160                 }
 161             }
 162
 163             sym::volatile_load | sym::unaligned_volatile_load => {
 164                 let tp_ty = substs.type_at(0);
 165                 let mut ptr = args[0].immediate();
 166                 if let PassMode::Cast(ty) = fn_abi.ret.mode {
 167                     ptr = self.pointercast(ptr, self.type_ptr_to(ty.llvm_type(self)));
 168                 }
 169                 let load = self.volatile_load(ptr);
 170                 let align = if name == sym::unaligned_volatile_load {
 171                     1
 172                 } else {
 173                     self.align_of(tp_ty).bytes() as u32
 174                 };
 175                 unsafe {
 176                     llvm::LLVMSetAlignment(load, align);
 177                 }
 178                 self.to_immediate(load, self.layout_of(tp_ty))
 179             }
 180             sym::volatile_store => {
 181                 let dst = args[0].deref(self.cx());
 182                 args[1].val.volatile_store(self, dst);
 183                 return;
 184             }
 185             sym::unaligned_volatile_store => {
 186                 let dst = args[0].deref(self.cx());
 187                 args[1].val.unaligned_volatile_store(self, dst);
 188                 return;
 189             }
 190             sym::prefetch_read_data
 191             | sym::prefetch_write_data
 192             | sym::prefetch_read_instruction
 193             | sym::prefetch_write_instruction => {
 194                 let expect = self.get_intrinsic(&("llvm.prefetch"));
 195                 let (rw, cache_type) = match name {
 196                     sym::prefetch_read_data => (0, 1),
 197                     sym::prefetch_write_data => (1, 1),
 198                     sym::prefetch_read_instruction => (0, 0),
 199                     sym::prefetch_write_instruction => (1, 0),
 200                     _ => bug!(),
 201                 };
 202                 self.call(
 203                     expect,
 204                     &[
 205                         args[0].immediate(),
 206                         self.const_i32(rw),
 207                         args[1].immediate(),
 208                         self.const_i32(cache_type),
 209                     ],
 210                     None,
 211                 )
 212             }
 213             sym::ctlz
 214             | sym::ctlz_nonzero
 215             | sym::cttz
 216             | sym::cttz_nonzero
 217             | sym::ctpop
 218             | sym::bswap
 219             | sym::bitreverse
 220             | sym::rotate_left
 221             | sym::rotate_right
 222             | sym::saturating_add
 223             | sym::saturating_sub => {
 224                 let ty = arg_tys[0];
 225                 match int_type_width_signed(ty, self) {
 226                     Some((width, signed)) => match name {
 227                         sym::ctlz | sym::cttz => {
 228                             let y = self.const_bool(false);
 229                             let llfn = self.get_intrinsic(&format!("llvm.{}.i{}", name, width));
 230                             self.call(llfn, &[args[0].immediate(), y], None)
 231                         }
 232                         sym::ctlz_nonzero | sym::cttz_nonzero => {
 233                             let y = self.const_bool(true);
 234                             let llvm_name = &format!("llvm.{}.i{}", &name_str[..4], width);
 235                             let llfn = self.get_intrinsic(llvm_name);
 236                             self.call(llfn, &[args[0].immediate(), y], None)
 237                         }
 238                         sym::ctpop => self.call(
 239                             self.get_intrinsic(&format!("llvm.ctpop.i{}", width)),
 240                             &[args[0].immediate()],
 241                             None,
 242                         ),
 243                         sym::bswap => {
 244                             if width == 8 {
 245                                 args[0].immediate() // byte swap a u8/i8 is just a no-op
 246                             } else {
 247                                 self.call(
 248                                     self.get_intrinsic(&format!("llvm.bswap.i{}", width)),
 249                                     &[args[0].immediate()],
 250                                     None,
 251                                 )
 252                             }
 253                         }
 254                         sym::bitreverse => self.call(
 255                             self.get_intrinsic(&format!("llvm.bitreverse.i{}", width)),
 256                             &[args[0].immediate()],
 257                             None,
 258                         ),
 259                         sym::rotate_left | sym::rotate_right => {
 260                             let is_left = name == sym::rotate_left;
 261                             let val = args[0].immediate();
 262                             let raw_shift = args[1].immediate();
 263                             // rotate = funnel shift with first two args the same
 264                             let llvm_name =
 265                                 &format!("llvm.fsh{}.i{}", if is_left { 'l' } else { 'r' }, width);
 266                             let llfn = self.get_intrinsic(llvm_name);
 267                             self.call(llfn, &[val, val, raw_shift], None)
 268                         }
 269                         sym::saturating_add | sym::saturating_sub => {
 270                             let is_add = name == sym::saturating_add;
 271                             let lhs = args[0].immediate();
 272                             let rhs = args[1].immediate();
 273                             let llvm_name = &format!(
 274                                 "llvm.{}{}.sat.i{}",
 275                                 if signed { 's' } else { 'u' },
 276                                 if is_add { "add" } else { "sub" },
 277                                 width
 278                             );
 279                             let llfn = self.get_intrinsic(llvm_name);
 280                             self.call(llfn, &[lhs, rhs], None)
 281                         }
 282                         _ => bug!(),
 283                     },
 284                     None => {
 285                         span_invalid_monomorphization_error(
 286                             tcx.sess,
 287                             span,
 288                             &format!(
 289                                 "invalid monomorphization of `{}` intrinsic: \
 290                                       expected basic integer type, found `{}`",
 291                                 name, ty
 292                             ),
 293                         );
 294                         return;
 295                     }
 296                 }
 297             }
 298
 299             _ if name_str.starts_with("simd_") => {
 300                 match generic_simd_intrinsic(self, name, callee_ty, args, ret_ty, llret_ty, span) {
 301                     Ok(llval) => llval,
 302                     Err(()) => return,
 303                 }
 304             }
 305
 306             _ => bug!("unknown intrinsic '{}'", name),
 307         };
 308
 309         if !fn_abi.ret.is_ignore() {
 310             if let PassMode::Cast(ty) = fn_abi.ret.mode {
 311                 let ptr_llty = self.type_ptr_to(ty.llvm_type(self));
 312                 let ptr = self.pointercast(result.llval, ptr_llty);
 313                 self.store(llval, ptr, result.align);
 314             } else {
 315                 OperandRef::from_immediate_or_packed_pair(self, llval, result.layout)
 316                     .val
 317                     .store(self, result);
 318             }
 319         }
 320     }
 321
 322     fn abort(&mut self) {
 323         let fnname = self.get_intrinsic(&("llvm.trap"));
 324         self.call(fnname, &[], None);
 325     }
 326
 327     fn assume(&mut self, val: Self::Value) {
 328         let assume_intrinsic = self.get_intrinsic("llvm.assume");
 329         self.call(assume_intrinsic, &[val], None);
 330     }
 331
 332     fn expect(&mut self, cond: Self::Value, expected: bool) -> Self::Value {
 333         let expect = self.get_intrinsic(&"llvm.expect.i1");
 334         self.call(expect, &[cond, self.const_bool(expected)], None)
 335     }
 336
 337     fn sideeffect(&mut self) {
 338         // This kind of check would make a ton of sense in the caller, but currently the only
 339         // caller of this function is in `rustc_codegen_ssa`, which is agnostic to whether LLVM
 340         // codegen backend being used, and so is unable to check the LLVM version.
 341         if unsafe { llvm::LLVMRustVersionMajor() } < 12 {
 342             let fnname = self.get_intrinsic(&("llvm.sideeffect"));
 343             self.call(fnname, &[], None);
 344         }
 345     }
 346
 347     fn va_start(&mut self, va_list: &'ll Value) -> &'ll Value {
 348         let intrinsic = self.cx().get_intrinsic("llvm.va_start");
 349         self.call(intrinsic, &[va_list], None)
 350     }
 351
 352     fn va_end(&mut self, va_list: &'ll Value) -> &'ll Value {
 353         let intrinsic = self.cx().get_intrinsic("llvm.va_end");
 354         self.call(intrinsic, &[va_list], None)
 355     }
 356 }
 357
 358 fn try_intrinsic(
 359     bx: &mut Builder<'a, 'll, 'tcx>,
 360     try_func: &'ll Value,
 361     data: &'ll Value,
 362     catch_func: &'ll Value,
 363     dest: &'ll Value,
 364 ) {
 365     if bx.sess().panic_strategy() == PanicStrategy::Abort {
 366         bx.call(try_func, &[data], None);
 367         // Return 0 unconditionally from the intrinsic call;
 368         // we can never unwind.
 369         let ret_align = bx.tcx().data_layout.i32_align.abi;
 370         bx.store(bx.const_i32(0), dest, ret_align);
 371     } else if wants_msvc_seh(bx.sess()) {
 372         codegen_msvc_try(bx, try_func, data, catch_func, dest);
 373     } else if bx.sess().target.is_like_emscripten {
 374         codegen_emcc_try(bx, try_func, data, catch_func, dest);
 375     } else {
 376         codegen_gnu_try(bx, try_func, data, catch_func, dest);
 377     }
 378 }
 379
 380 // MSVC's definition of the `rust_try` function.
 381 //
 382 // This implementation uses the new exception handling instructions in LLVM
 383 // which have support in LLVM for SEH on MSVC targets. Although these
 384 // instructions are meant to work for all targets, as of the time of this
 385 // writing, however, LLVM does not recommend the usage of these new instructions
 386 // as the old ones are still more optimized.
 387 fn codegen_msvc_try(
 388     bx: &mut Builder<'a, 'll, 'tcx>,
 389     try_func: &'ll Value,
 390     data: &'ll Value,
 391     catch_func: &'ll Value,
 392     dest: &'ll Value,
 393 ) {
 394     let llfn = get_rust_try_fn(bx, &mut |mut bx| {
 395         bx.set_personality_fn(bx.eh_personality());
 396
 397         let mut normal = bx.build_sibling_block("normal");
 398         let mut catchswitch = bx.build_sibling_block("catchswitch");
 399         let mut catchpad_rust = bx.build_sibling_block("catchpad_rust");
 400         let mut catchpad_foreign = bx.build_sibling_block("catchpad_foreign");
 401         let mut caught = bx.build_sibling_block("caught");
 402
 403         let try_func = llvm::get_param(bx.llfn(), 0);
 404         let data = llvm::get_param(bx.llfn(), 1);
 405         let catch_func = llvm::get_param(bx.llfn(), 2);
 406
 407         // We're generating an IR snippet that looks like:
 408         //
 409         //   declare i32 @rust_try(%try_func, %data, %catch_func) {
 410         //      %slot = alloca i8*
 411         //      invoke %try_func(%data) to label %normal unwind label %catchswitch
 412         //
 413         //   normal:
 414         //      ret i32 0
 415         //
 416         //   catchswitch:
 417         //      %cs = catchswitch within none [%catchpad_rust, %catchpad_foreign] unwind to caller
 418         //
 419         //   catchpad_rust:
 420         //      %tok = catchpad within %cs [%type_descriptor, 8, %slot]
 421         //      %ptr = load %slot
 422         //      call %catch_func(%data, %ptr)
 423         //      catchret from %tok to label %caught
 424         //
 425         //   catchpad_foreign:
 426         //      %tok = catchpad within %cs [null, 64, null]
 427         //      call %catch_func(%data, null)
 428         //      catchret from %tok to label %caught
 429         //
 430         //   caught:
 431         //      ret i32 1
 432         //   }
 433         //
 434         // This structure follows the basic usage of throw/try/catch in LLVM.
 435         // For example, compile this C++ snippet to see what LLVM generates:
 436         //
 437         //      struct rust_panic {
 438         //          rust_panic(const rust_panic&);
 439         //          ~rust_panic();
 440         //
 441         //          void* x[2];
 442         //      };
 443         //
 444         //      int __rust_try(
 445         //          void (*try_func)(void*),
 446         //          void *data,
 447         //          void (*catch_func)(void*, void*) noexcept
 448         //      ) {
 449         //          try {
 450         //              try_func(data);
 451         //              return 0;
 452         //          } catch(rust_panic& a) {
 453         //              catch_func(data, &a);
 454         //              return 1;
 455         //          } catch(...) {
 456         //              catch_func(data, NULL);
 457         //              return 1;
 458         //          }
 459         //      }
 460         //
 461         // More information can be found in libstd's seh.rs implementation.
 462         let ptr_align = bx.tcx().data_layout.pointer_align.abi;
 463         let slot = bx.alloca(bx.type_i8p(), ptr_align);
 464         bx.invoke(try_func, &[data], normal.llbb(), catchswitch.llbb(), None);
 465
 466         normal.ret(bx.const_i32(0));
 467
 468         let cs = catchswitch.catch_switch(None, None, 2);
 469         catchswitch.add_handler(cs, catchpad_rust.llbb());
 470         catchswitch.add_handler(cs, catchpad_foreign.llbb());
 471
 472         // We can't use the TypeDescriptor defined in libpanic_unwind because it
 473         // might be in another DLL and the SEH encoding only supports specifying
 474         // a TypeDescriptor from the current module.
 475         //
 476         // However this isn't an issue since the MSVC runtime uses string
 477         // comparison on the type name to match TypeDescriptors rather than
 478         // pointer equality.
 479         //
 480         // So instead we generate a new TypeDescriptor in each module that uses
 481         // `try` and let the linker merge duplicate definitions in the same
 482         // module.
 483         //
 484         // When modifying, make sure that the type_name string exactly matches
 485         // the one used in src/libpanic_unwind/seh.rs.
 486         let type_info_vtable = bx.declare_global("??_7type_info@@6B@", bx.type_i8p());
 487         let type_name = bx.const_bytes(b"rust_panic\0");
 488         let type_info =
 489             bx.const_struct(&[type_info_vtable, bx.const_null(bx.type_i8p()), type_name], false);
 490         let tydesc = bx.declare_global("__rust_panic_type_info", bx.val_ty(type_info));
 491         unsafe {
 492             llvm::LLVMRustSetLinkage(tydesc, llvm::Linkage::LinkOnceODRLinkage);
 493             llvm::SetUniqueComdat(bx.llmod, tydesc);
 494             llvm::LLVMSetInitializer(tydesc, type_info);
 495         }
 496
 497         // The flag value of 8 indicates that we are catching the exception by
 498         // reference instead of by value. We can't use catch by value because
 499         // that requires copying the exception object, which we don't support
 500         // since our exception object effectively contains a Box.
 501         //
 502         // Source: MicrosoftCXXABI::getAddrOfCXXCatchHandlerType in clang
 503         let flags = bx.const_i32(8);
 504         let funclet = catchpad_rust.catch_pad(cs, &[tydesc, flags, slot]);
 505         let ptr = catchpad_rust.load(slot, ptr_align);
 506         catchpad_rust.call(catch_func, &[data, ptr], Some(&funclet));
 507         catchpad_rust.catch_ret(&funclet, caught.llbb());
 508
 509         // The flag value of 64 indicates a "catch-all".
 510         let flags = bx.const_i32(64);
 511         let null = bx.const_null(bx.type_i8p());
 512         let funclet = catchpad_foreign.catch_pad(cs, &[null, flags, null]);
 513         catchpad_foreign.call(catch_func, &[data, null], Some(&funclet));
 514         catchpad_foreign.catch_ret(&funclet, caught.llbb());
 515
 516         caught.ret(bx.const_i32(1));
 517     });
 518
 519     // Note that no invoke is used here because by definition this function
 520     // can't panic (that's what it's catching).
 521     let ret = bx.call(llfn, &[try_func, data, catch_func], None);
 522     let i32_align = bx.tcx().data_layout.i32_align.abi;
 523     bx.store(ret, dest, i32_align);
 524 }
 525
 526 // Definition of the standard `try` function for Rust using the GNU-like model
 527 // of exceptions (e.g., the normal semantics of LLVM's `landingpad` and `invoke`
 528 // instructions).
 529 //
 530 // This codegen is a little surprising because we always call a shim
 531 // function instead of inlining the call to `invoke` manually here. This is done
 532 // because in LLVM we're only allowed to have one personality per function
 533 // definition. The call to the `try` intrinsic is being inlined into the
 534 // function calling it, and that function may already have other personality
 535 // functions in play. By calling a shim we're guaranteed that our shim will have
 536 // the right personality function.
 537 fn codegen_gnu_try(
 538     bx: &mut Builder<'a, 'll, 'tcx>,
 539     try_func: &'ll Value,
 540     data: &'ll Value,
 541     catch_func: &'ll Value,
 542     dest: &'ll Value,
 543 ) {
 544     let llfn = get_rust_try_fn(bx, &mut |mut bx| {
 545         // Codegens the shims described above:
 546         //
 547         //   bx:
 548         //      invoke %try_func(%data) normal %normal unwind %catch
 549         //
 550         //   normal:
 551         //      ret 0
 552         //
 553         //   catch:
 554         //      (%ptr, _) = landingpad
 555         //      call %catch_func(%data, %ptr)
 556         //      ret 1
 557         let mut then = bx.build_sibling_block("then");
 558         let mut catch = bx.build_sibling_block("catch");
 559
 560         let try_func = llvm::get_param(bx.llfn(), 0);
 561         let data = llvm::get_param(bx.llfn(), 1);
 562         let catch_func = llvm::get_param(bx.llfn(), 2);
 563         bx.invoke(try_func, &[data], then.llbb(), catch.llbb(), None);
 564         then.ret(bx.const_i32(0));
 565
 566         // Type indicator for the exception being thrown.
 567         //
 568         // The first value in this tuple is a pointer to the exception object
 569         // being thrown.  The second value is a "selector" indicating which of
 570         // the landing pad clauses the exception's type had been matched to.
 571         // rust_try ignores the selector.
 572         let lpad_ty = bx.type_struct(&[bx.type_i8p(), bx.type_i32()], false);
 573         let vals = catch.landing_pad(lpad_ty, bx.eh_personality(), 1);
 574         let tydesc = bx.const_null(bx.type_i8p());
 575         catch.add_clause(vals, tydesc);
 576         let ptr = catch.extract_value(vals, 0);
 577         catch.call(catch_func, &[data, ptr], None);
 578         catch.ret(bx.const_i32(1));
 579     });
 580
 581     // Note that no invoke is used here because by definition this function
 582     // can't panic (that's what it's catching).
 583     let ret = bx.call(llfn, &[try_func, data, catch_func], None);
 584     let i32_align = bx.tcx().data_layout.i32_align.abi;
 585     bx.store(ret, dest, i32_align);
 586 }
 587
 588 // Variant of codegen_gnu_try used for emscripten where Rust panics are
 589 // implemented using C++ exceptions. Here we use exceptions of a specific type
 590 // (`struct rust_panic`) to represent Rust panics.
 591 fn codegen_emcc_try(
 592     bx: &mut Builder<'a, 'll, 'tcx>,
 593     try_func: &'ll Value,
 594     data: &'ll Value,
 595     catch_func: &'ll Value,
 596     dest: &'ll Value,
 597 ) {
 598     let llfn = get_rust_try_fn(bx, &mut |mut bx| {
 599         // Codegens the shims described above:
 600         //
 601         //   bx:
 602         //      invoke %try_func(%data) normal %normal unwind %catch
 603         //
 604         //   normal:
 605         //      ret 0
 606         //
 607         //   catch:
 608         //      (%ptr, %selector) = landingpad
 609         //      %rust_typeid = @llvm.eh.typeid.for(@_ZTI10rust_panic)
 610         //      %is_rust_panic = %selector == %rust_typeid
 611         //      %catch_data = alloca { i8*, i8 }
 612         //      %catch_data[0] = %ptr
 613         //      %catch_data[1] = %is_rust_panic
 614         //      call %catch_func(%data, %catch_data)
 615         //      ret 1
 616         let mut then = bx.build_sibling_block("then");
 617         let mut catch = bx.build_sibling_block("catch");
 618
 619         let try_func = llvm::get_param(bx.llfn(), 0);
 620         let data = llvm::get_param(bx.llfn(), 1);
 621         let catch_func = llvm::get_param(bx.llfn(), 2);
 622         bx.invoke(try_func, &[data], then.llbb(), catch.llbb(), None);
 623         then.ret(bx.const_i32(0));
 624
 625         // Type indicator for the exception being thrown.
 626         //
 627         // The first value in this tuple is a pointer to the exception object
 628         // being thrown.  The second value is a "selector" indicating which of
 629         // the landing pad clauses the exception's type had been matched to.
 630         let tydesc = bx.eh_catch_typeinfo();
 631         let lpad_ty = bx.type_struct(&[bx.type_i8p(), bx.type_i32()], false);
 632         let vals = catch.landing_pad(lpad_ty, bx.eh_personality(), 2);
 633         catch.add_clause(vals, tydesc);
 634         catch.add_clause(vals, bx.const_null(bx.type_i8p()));
 635         let ptr = catch.extract_value(vals, 0);
 636         let selector = catch.extract_value(vals, 1);
 637
 638         // Check if the typeid we got is the one for a Rust panic.
 639         let llvm_eh_typeid_for = bx.get_intrinsic("llvm.eh.typeid.for");
 640         let rust_typeid = catch.call(llvm_eh_typeid_for, &[tydesc], None);
 641         let is_rust_panic = catch.icmp(IntPredicate::IntEQ, selector, rust_typeid);
 642         let is_rust_panic = catch.zext(is_rust_panic, bx.type_bool());
 643
 644         // We need to pass two values to catch_func (ptr and is_rust_panic), so
 645         // create an alloca and pass a pointer to that.
 646         let ptr_align = bx.tcx().data_layout.pointer_align.abi;
 647         let i8_align = bx.tcx().data_layout.i8_align.abi;
 648         let catch_data =
 649             catch.alloca(bx.type_struct(&[bx.type_i8p(), bx.type_bool()], false), ptr_align);
 650         let catch_data_0 = catch.inbounds_gep(catch_data, &[bx.const_usize(0), bx.const_usize(0)]);
 651         catch.store(ptr, catch_data_0, ptr_align);
 652         let catch_data_1 = catch.inbounds_gep(catch_data, &[bx.const_usize(0), bx.const_usize(1)]);
 653         catch.store(is_rust_panic, catch_data_1, i8_align);
 654         let catch_data = catch.bitcast(catch_data, bx.type_i8p());
 655
 656         catch.call(catch_func, &[data, catch_data], None);
 657         catch.ret(bx.const_i32(1));
 658     });
 659
 660     // Note that no invoke is used here because by definition this function
 661     // can't panic (that's what it's catching).
 662     let ret = bx.call(llfn, &[try_func, data, catch_func], None);
 663     let i32_align = bx.tcx().data_layout.i32_align.abi;
 664     bx.store(ret, dest, i32_align);
 665 }
 666
 667 // Helper function to give a Block to a closure to codegen a shim function.
 668 // This is currently primarily used for the `try` intrinsic functions above.
 669 fn gen_fn<'ll, 'tcx>(
 670     cx: &CodegenCx<'ll, 'tcx>,
 671     name: &str,
 672     rust_fn_sig: ty::PolyFnSig<'tcx>,
 673     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
 674 ) -> &'ll Value {
 675     let fn_abi = FnAbi::of_fn_ptr(cx, rust_fn_sig, &[]);
 676     let llfn = cx.declare_fn(name, &fn_abi);
 677     cx.set_frame_pointer_type(llfn);
 678     cx.apply_target_cpu_attr(llfn);
 679     // FIXME(eddyb) find a nicer way to do this.
 680     unsafe { llvm::LLVMRustSetLinkage(llfn, llvm::Linkage::InternalLinkage) };
 681     let llbb = Builder::append_block(cx, llfn, "entry-block");
 682     let bx = Builder::build(cx, llbb);
 683     codegen(bx);
 684     llfn
 685 }
 686
 687 // Helper function used to get a handle to the `__rust_try` function used to
 688 // catch exceptions.
 689 //
 690 // This function is only generated once and is then cached.
 691 fn get_rust_try_fn<'ll, 'tcx>(
 692     cx: &CodegenCx<'ll, 'tcx>,
 693     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
 694 ) -> &'ll Value {
 695     if let Some(llfn) = cx.rust_try_fn.get() {
 696         return llfn;
 697     }
 698
 699     // Define the type up front for the signature of the rust_try function.
 700     let tcx = cx.tcx;
 701     let i8p = tcx.mk_mut_ptr(tcx.types.i8);
 702     // `unsafe fn(*mut i8) -> ()`
 703     let try_fn_ty = tcx.mk_fn_ptr(ty::Binder::dummy(tcx.mk_fn_sig(
 704         iter::once(i8p),
 705         tcx.mk_unit(),
 706         false,
 707         hir::Unsafety::Unsafe,
 708         Abi::Rust,
 709     )));
 710     // `unsafe fn(*mut i8, *mut i8) -> ()`
 711     let catch_fn_ty = tcx.mk_fn_ptr(ty::Binder::dummy(tcx.mk_fn_sig(
 712         [i8p, i8p].iter().cloned(),
 713         tcx.mk_unit(),
 714         false,
 715         hir::Unsafety::Unsafe,
 716         Abi::Rust,
 717     )));
 718     // `unsafe fn(unsafe fn(*mut i8) -> (), *mut i8, unsafe fn(*mut i8, *mut i8) -> ()) -> i32`
 719     let rust_fn_sig = ty::Binder::dummy(cx.tcx.mk_fn_sig(
 720         vec![try_fn_ty, i8p, catch_fn_ty].into_iter(),
 721         tcx.types.i32,
 722         false,
 723         hir::Unsafety::Unsafe,
 724         Abi::Rust,
 725     ));
 726     let rust_try = gen_fn(cx, "__rust_try", rust_fn_sig, codegen);
 727     cx.rust_try_fn.set(Some(rust_try));
 728     rust_try
 729 }
 730
 731 fn generic_simd_intrinsic(
 732     bx: &mut Builder<'a, 'll, 'tcx>,
 733     name: Symbol,
 734     callee_ty: Ty<'tcx>,
 735     args: &[OperandRef<'tcx, &'ll Value>],
 736     ret_ty: Ty<'tcx>,
 737     llret_ty: &'ll Type,
 738     span: Span,
 739 ) -> Result<&'ll Value, ()> {
 740     // macros for error handling:
 741     macro_rules! emit_error {
 742         ($msg: tt) => {
 743             emit_error!($msg, )
 744         };
 745         ($msg: tt, $($fmt: tt)*) => {
 746             span_invalid_monomorphization_error(
 747                 bx.sess(), span,
 748                 &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg),
 749                          name, $($fmt)*));
 750         }
 751     }
 752
 753     macro_rules! return_error {
 754         ($($fmt: tt)*) => {
 755             {
 756                 emit_error!($($fmt)*);
 757                 return Err(());
 758             }
 759         }
 760     }
 761
 762     macro_rules! require {
 763         ($cond: expr, $($fmt: tt)*) => {
 764             if !$cond {
 765                 return_error!($($fmt)*);
 766             }
 767         };
 768     }
 769
 770     macro_rules! require_simd {
 771         ($ty: expr, $position: expr) => {
 772             require!($ty.is_simd(), "expected SIMD {} type, found non-SIMD `{}`", $position, $ty)
 773         };
 774     }
 775
 776     let tcx = bx.tcx();
 777     let sig =
 778         tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), callee_ty.fn_sig(tcx));
 779     let arg_tys = sig.inputs();
 780     let name_str = &*name.as_str();
 781
 782     if name == sym::simd_select_bitmask {
 783         let in_ty = arg_tys[0];
 784         let m_len = match in_ty.kind() {
 785             // Note that this `.unwrap()` crashes for isize/usize, that's sort
 786             // of intentional as there's not currently a use case for that.
 787             ty::Int(i) => i.bit_width().unwrap(),
 788             ty::Uint(i) => i.bit_width().unwrap(),
 789             _ => return_error!("`{}` is not an integral type", in_ty),
 790         };
 791         require_simd!(arg_tys[1], "argument");
 792         let (v_len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
 793         require!(
 794             // Allow masks for vectors with fewer than 8 elements to be
 795             // represented with a u8 or i8.
 796             m_len == v_len || (m_len == 8 && v_len < 8),
 797             "mismatched lengths: mask length `{}` != other vector length `{}`",
 798             m_len,
 799             v_len
 800         );
 801         let i1 = bx.type_i1();
 802         let im = bx.type_ix(v_len);
 803         let i1xn = bx.type_vector(i1, v_len);
 804         let m_im = bx.trunc(args[0].immediate(), im);
 805         let m_i1s = bx.bitcast(m_im, i1xn);
 806         return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
 807     }
 808
 809     // every intrinsic below takes a SIMD vector as its first argument
 810     require_simd!(arg_tys[0], "input");
 811     let in_ty = arg_tys[0];
 812
 813     let comparison = match name {
 814         sym::simd_eq => Some(hir::BinOpKind::Eq),
 815         sym::simd_ne => Some(hir::BinOpKind::Ne),
 816         sym::simd_lt => Some(hir::BinOpKind::Lt),
 817         sym::simd_le => Some(hir::BinOpKind::Le),
 818         sym::simd_gt => Some(hir::BinOpKind::Gt),
 819         sym::simd_ge => Some(hir::BinOpKind::Ge),
 820         _ => None,
 821     };
 822
 823     let (in_len, in_elem) = arg_tys[0].simd_size_and_type(bx.tcx());
 824     if let Some(cmp_op) = comparison {
 825         require_simd!(ret_ty, "return");
 826
 827         let (out_len, out_ty) = ret_ty.simd_size_and_type(bx.tcx());
 828         require!(
 829             in_len == out_len,
 830             "expected return type with length {} (same as input type `{}`), \
 831              found `{}` with length {}",
 832             in_len,
 833             in_ty,
 834             ret_ty,
 835             out_len
 836         );
 837         require!(
 838             bx.type_kind(bx.element_type(llret_ty)) == TypeKind::Integer,
 839             "expected return type with integer elements, found `{}` with non-integer `{}`",
 840             ret_ty,
 841             out_ty
 842         );
 843
 844         return Ok(compare_simd_types(
 845             bx,
 846             args[0].immediate(),
 847             args[1].immediate(),
 848             in_elem,
 849             llret_ty,
 850             cmp_op,
 851         ));
 852     }
 853
 854     if let Some(stripped) = name_str.strip_prefix("simd_shuffle") {
 855         let n: u64 = stripped.parse().unwrap_or_else(|_| {
 856             span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?")
 857         });
 858
 859         require_simd!(ret_ty, "return");
 860
 861         let (out_len, out_ty) = ret_ty.simd_size_and_type(bx.tcx());
 862         require!(
 863             out_len == n,
 864             "expected return type of length {}, found `{}` with length {}",
 865             n,
 866             ret_ty,
 867             out_len
 868         );
 869         require!(
 870             in_elem == out_ty,
 871             "expected return element type `{}` (element of input `{}`), \
 872              found `{}` with element type `{}`",
 873             in_elem,
 874             in_ty,
 875             ret_ty,
 876             out_ty
 877         );
 878
 879         let total_len = u128::from(in_len) * 2;
 880
 881         let vector = args[2].immediate();
 882
 883         let indices: Option<Vec<_>> = (0..n)
 884             .map(|i| {
 885                 let arg_idx = i;
 886                 let val = bx.const_get_elt(vector, i as u64);
 887                 match bx.const_to_opt_u128(val, true) {
 888                     None => {
 889                         emit_error!("shuffle index #{} is not a constant", arg_idx);
 890                         None
 891                     }
 892                     Some(idx) if idx >= total_len => {
 893                         emit_error!(
 894                             "shuffle index #{} is out of bounds (limit {})",
 895                             arg_idx,
 896                             total_len
 897                         );
 898                         None
 899                     }
 900                     Some(idx) => Some(bx.const_i32(idx as i32)),
 901                 }
 902             })
 903             .collect();
 904         let indices = match indices {
 905             Some(i) => i,
 906             None => return Ok(bx.const_null(llret_ty)),
 907         };
 908
 909         return Ok(bx.shuffle_vector(
 910             args[0].immediate(),
 911             args[1].immediate(),
 912             bx.const_vector(&indices),
 913         ));
 914     }
 915
 916     if name == sym::simd_insert {
 917         require!(
 918             in_elem == arg_tys[2],
 919             "expected inserted type `{}` (element of input `{}`), found `{}`",
 920             in_elem,
 921             in_ty,
 922             arg_tys[2]
 923         );
 924         return Ok(bx.insert_element(
 925             args[0].immediate(),
 926             args[2].immediate(),
 927             args[1].immediate(),
 928         ));
 929     }
 930     if name == sym::simd_extract {
 931         require!(
 932             ret_ty == in_elem,
 933             "expected return type `{}` (element of input `{}`), found `{}`",
 934             in_elem,
 935             in_ty,
 936             ret_ty
 937         );
 938         return Ok(bx.extract_element(args[0].immediate(), args[1].immediate()));
 939     }
 940
 941     if name == sym::simd_select {
 942         let m_elem_ty = in_elem;
 943         let m_len = in_len;
 944         require_simd!(arg_tys[1], "argument");
 945         let (v_len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
 946         require!(
 947             m_len == v_len,
 948             "mismatched lengths: mask length `{}` != other vector length `{}`",
 949             m_len,
 950             v_len
 951         );
 952         match m_elem_ty.kind() {
 953             ty::Int(_) => {}
 954             _ => return_error!("mask element type is `{}`, expected `i_`", m_elem_ty),
 955         }
 956         // truncate the mask to a vector of i1s
 957         let i1 = bx.type_i1();
 958         let i1xn = bx.type_vector(i1, m_len as u64);
 959         let m_i1s = bx.trunc(args[0].immediate(), i1xn);
 960         return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
 961     }
 962
 963     if name == sym::simd_bitmask {
 964         // The `fn simd_bitmask(vector) -> unsigned integer` intrinsic takes a
 965         // vector mask and returns an unsigned integer containing the most
 966         // significant bit (MSB) of each lane.
 967
 968         // If the vector has less than 8 lanes, an u8 is returned with zeroed
 969         // trailing bits.
 970         let expected_int_bits = in_len.max(8);
 971         match ret_ty.kind() {
 972             ty::Uint(i) if i.bit_width() == Some(expected_int_bits) => (),
 973             _ => return_error!("bitmask `{}`, expected `u{}`", ret_ty, expected_int_bits),
 974         }
 975
 976         // Integer vector <i{in_bitwidth} x in_len>:
 977         let (i_xn, in_elem_bitwidth) = match in_elem.kind() {
 978             ty::Int(i) => (
 979                 args[0].immediate(),
 980                 i.bit_width().unwrap_or_else(|| bx.data_layout().pointer_size.bits()),
 981             ),
 982             ty::Uint(i) => (
 983                 args[0].immediate(),
 984                 i.bit_width().unwrap_or_else(|| bx.data_layout().pointer_size.bits()),
 985             ),
 986             _ => return_error!(
 987                 "vector argument `{}`'s element type `{}`, expected integer element type",
 988                 in_ty,
 989                 in_elem
 990             ),
 991         };
 992
 993         // Shift the MSB to the right by "in_elem_bitwidth - 1" into the first bit position.
 994         let shift_indices =
 995             vec![
 996                 bx.cx.const_int(bx.type_ix(in_elem_bitwidth), (in_elem_bitwidth - 1) as _);
 997                 in_len as _
 998             ];
 999         let i_xn_msb = bx.lshr(i_xn, bx.const_vector(shift_indices.as_slice()));
1000         // Truncate vector to an <i1 x N>
1001         let i1xn = bx.trunc(i_xn_msb, bx.type_vector(bx.type_i1(), in_len));
1002         // Bitcast <i1 x N> to iN:
1003         let i_ = bx.bitcast(i1xn, bx.type_ix(in_len));
1004         // Zero-extend iN to the bitmask type:
1005         return Ok(bx.zext(i_, bx.type_ix(expected_int_bits)));
1006     }
1007
1008     fn simd_simple_float_intrinsic(
1009         name: Symbol,
1010         in_elem: &::rustc_middle::ty::TyS<'_>,
1011         in_ty: &::rustc_middle::ty::TyS<'_>,
1012         in_len: u64,
1013         bx: &mut Builder<'a, 'll, 'tcx>,
1014         span: Span,
1015         args: &[OperandRef<'tcx, &'ll Value>],
1016     ) -> Result<&'ll Value, ()> {
1017         macro_rules! emit_error {
1018             ($msg: tt) => {
1019                 emit_error!($msg, )
1020             };
1021             ($msg: tt, $($fmt: tt)*) => {
1022                 span_invalid_monomorphization_error(
1023                     bx.sess(), span,
1024                     &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg),
1025                              name, $($fmt)*));
1026             }
1027         }
1028         macro_rules! return_error {
1029             ($($fmt: tt)*) => {
1030                 {
1031                     emit_error!($($fmt)*);
1032                     return Err(());
1033                 }
1034             }
1035         }
1036
1037         let (elem_ty_str, elem_ty) = if let ty::Float(f) = in_elem.kind() {
1038             let elem_ty = bx.cx.type_float_from_ty(*f);
1039             match f.bit_width() {
1040                 32 => ("f32", elem_ty),
1041                 64 => ("f64", elem_ty),
1042                 _ => {
1043                     return_error!(
1044                         "unsupported element type `{}` of floating-point vector `{}`",
1045                         f.name_str(),
1046                         in_ty
1047                     );
1048                 }
1049             }
1050         } else {
1051             return_error!("`{}` is not a floating-point type", in_ty);
1052         };
1053
1054         let vec_ty = bx.type_vector(elem_ty, in_len);
1055
1056         let (intr_name, fn_ty) = match name {
1057             sym::simd_ceil => ("ceil", bx.type_func(&[vec_ty], vec_ty)),
1058             sym::simd_fabs => ("fabs", bx.type_func(&[vec_ty], vec_ty)),
1059             sym::simd_fcos => ("cos", bx.type_func(&[vec_ty], vec_ty)),
1060             sym::simd_fexp2 => ("exp2", bx.type_func(&[vec_ty], vec_ty)),
1061             sym::simd_fexp => ("exp", bx.type_func(&[vec_ty], vec_ty)),
1062             sym::simd_flog10 => ("log10", bx.type_func(&[vec_ty], vec_ty)),
1063             sym::simd_flog2 => ("log2", bx.type_func(&[vec_ty], vec_ty)),
1064             sym::simd_flog => ("log", bx.type_func(&[vec_ty], vec_ty)),
1065             sym::simd_floor => ("floor", bx.type_func(&[vec_ty], vec_ty)),
1066             sym::simd_fma => ("fma", bx.type_func(&[vec_ty, vec_ty, vec_ty], vec_ty)),
1067             sym::simd_fpowi => ("powi", bx.type_func(&[vec_ty, bx.type_i32()], vec_ty)),
1068             sym::simd_fpow => ("pow", bx.type_func(&[vec_ty, vec_ty], vec_ty)),
1069             sym::simd_fsin => ("sin", bx.type_func(&[vec_ty], vec_ty)),
1070             sym::simd_fsqrt => ("sqrt", bx.type_func(&[vec_ty], vec_ty)),
1071             sym::simd_round => ("round", bx.type_func(&[vec_ty], vec_ty)),
1072             sym::simd_trunc => ("trunc", bx.type_func(&[vec_ty], vec_ty)),
1073             _ => return_error!("unrecognized intrinsic `{}`", name),
1074         };
1075         let llvm_name = &format!("llvm.{0}.v{1}{2}", intr_name, in_len, elem_ty_str);
1076         let f = bx.declare_cfn(&llvm_name, llvm::UnnamedAddr::No, fn_ty);
1077         let c = bx.call(f, &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(), None);
1078         Ok(c)
1079     }
1080
1081     if std::matches!(
1082         name,
1083         sym::simd_ceil
1084             | sym::simd_fabs
1085             | sym::simd_fcos
1086             | sym::simd_fexp2
1087             | sym::simd_fexp
1088             | sym::simd_flog10
1089             | sym::simd_flog2
1090             | sym::simd_flog
1091             | sym::simd_floor
1092             | sym::simd_fma
1093             | sym::simd_fpow
1094             | sym::simd_fpowi
1095             | sym::simd_fsin
1096             | sym::simd_fsqrt
1097             | sym::simd_round
1098             | sym::simd_trunc
1099     ) {
1100         return simd_simple_float_intrinsic(name, in_elem, in_ty, in_len, bx, span, args);
1101     }
1102
1103     // FIXME: use:
1104     //  https://github.com/llvm-mirror/llvm/blob/master/include/llvm/IR/Function.h#L182
1105     //  https://github.com/llvm-mirror/llvm/blob/master/include/llvm/IR/Intrinsics.h#L81
1106     fn llvm_vector_str(elem_ty: Ty<'_>, vec_len: u64, no_pointers: usize) -> String {
1107         let p0s: String = "p0".repeat(no_pointers);
1108         match *elem_ty.kind() {
1109             ty::Int(v) => format!("v{}{}i{}", vec_len, p0s, v.bit_width().unwrap()),
1110             ty::Uint(v) => format!("v{}{}i{}", vec_len, p0s, v.bit_width().unwrap()),
1111             ty::Float(v) => format!("v{}{}f{}", vec_len, p0s, v.bit_width()),
1112             _ => unreachable!(),
1113         }
1114     }
1115
1116     fn llvm_vector_ty(
1117         cx: &CodegenCx<'ll, '_>,
1118         elem_ty: Ty<'_>,
1119         vec_len: u64,
1120         mut no_pointers: usize,
1121     ) -> &'ll Type {
1122         // FIXME: use cx.layout_of(ty).llvm_type() ?
1123         let mut elem_ty = match *elem_ty.kind() {
1124             ty::Int(v) => cx.type_int_from_ty(v),
1125             ty::Uint(v) => cx.type_uint_from_ty(v),
1126             ty::Float(v) => cx.type_float_from_ty(v),
1127             _ => unreachable!(),
1128         };
1129         while no_pointers > 0 {
1130             elem_ty = cx.type_ptr_to(elem_ty);
1131             no_pointers -= 1;
1132         }
1133         cx.type_vector(elem_ty, vec_len)
1134     }
1135
1136     if name == sym::simd_gather {
1137         // simd_gather(values: <N x T>, pointers: <N x *_ T>,
1138         //             mask: <N x i{M}>) -> <N x T>
1139         // * N: number of elements in the input vectors
1140         // * T: type of the element to load
1141         // * M: any integer width is supported, will be truncated to i1
1142
1143         // All types must be simd vector types
1144         require_simd!(in_ty, "first");
1145         require_simd!(arg_tys[1], "second");
1146         require_simd!(arg_tys[2], "third");
1147         require_simd!(ret_ty, "return");
1148
1149         // Of the same length:
1150         let (out_len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
1151         let (out_len2, _) = arg_tys[2].simd_size_and_type(bx.tcx());
1152         require!(
1153             in_len == out_len,
1154             "expected {} argument with length {} (same as input type `{}`), \
1155              found `{}` with length {}",
1156             "second",
1157             in_len,
1158             in_ty,
1159             arg_tys[1],
1160             out_len
1161         );
1162         require!(
1163             in_len == out_len2,
1164             "expected {} argument with length {} (same as input type `{}`), \
1165              found `{}` with length {}",
1166             "third",
1167             in_len,
1168             in_ty,
1169             arg_tys[2],
1170             out_len2
1171         );
1172
1173         // The return type must match the first argument type
1174         require!(ret_ty == in_ty, "expected return type `{}`, found `{}`", in_ty, ret_ty);
1175
1176         // This counts how many pointers
1177         fn ptr_count(t: Ty<'_>) -> usize {
1178             match t.kind() {
1179                 ty::RawPtr(p) => 1 + ptr_count(p.ty),
1180                 _ => 0,
1181             }
1182         }
1183
1184         // Non-ptr type
1185         fn non_ptr(t: Ty<'_>) -> Ty<'_> {
1186             match t.kind() {
1187                 ty::RawPtr(p) => non_ptr(p.ty),
1188                 _ => t,
1189             }
1190         }
1191
1192         // The second argument must be a simd vector with an element type that's a pointer
1193         // to the element type of the first argument
1194         let (_, element_ty0) = arg_tys[0].simd_size_and_type(bx.tcx());
1195         let (_, element_ty1) = arg_tys[1].simd_size_and_type(bx.tcx());
1196         let (pointer_count, underlying_ty) = match element_ty1.kind() {
1197             ty::RawPtr(p) if p.ty == in_elem => (ptr_count(element_ty1), non_ptr(element_ty1)),
1198             _ => {
1199                 require!(
1200                     false,
1201                     "expected element type `{}` of second argument `{}` \
1202                         to be a pointer to the element type `{}` of the first \
1203                         argument `{}`, found `{}` != `*_ {}`",
1204                     element_ty1,
1205                     arg_tys[1],
1206                     in_elem,
1207                     in_ty,
1208                     element_ty1,
1209                     in_elem
1210                 );
1211                 unreachable!();
1212             }
1213         };
1214         assert!(pointer_count > 0);
1215         assert_eq!(pointer_count - 1, ptr_count(element_ty0));
1216         assert_eq!(underlying_ty, non_ptr(element_ty0));
1217
1218         // The element type of the third argument must be a signed integer type of any width:
1219         let (_, element_ty2) = arg_tys[2].simd_size_and_type(bx.tcx());
1220         match element_ty2.kind() {
1221             ty::Int(_) => (),
1222             _ => {
1223                 require!(
1224                     false,
1225                     "expected element type `{}` of third argument `{}` \
1226                                  to be a signed integer type",
1227                     element_ty2,
1228                     arg_tys[2]
1229                 );
1230             }
1231         }
1232
1233         // Alignment of T, must be a constant integer value:
1234         let alignment_ty = bx.type_i32();
1235         let alignment = bx.const_i32(bx.align_of(in_elem).bytes() as i32);
1236
1237         // Truncate the mask vector to a vector of i1s:
1238         let (mask, mask_ty) = {
1239             let i1 = bx.type_i1();
1240             let i1xn = bx.type_vector(i1, in_len);
1241             (bx.trunc(args[2].immediate(), i1xn), i1xn)
1242         };
1243
1244         // Type of the vector of pointers:
1245         let llvm_pointer_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count);
1246         let llvm_pointer_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count);
1247
1248         // Type of the vector of elements:
1249         let llvm_elem_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count - 1);
1250         let llvm_elem_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count - 1);
1251
1252         let llvm_intrinsic =
1253             format!("llvm.masked.gather.{}.{}", llvm_elem_vec_str, llvm_pointer_vec_str);
1254         let f = bx.declare_cfn(
1255             &llvm_intrinsic,
1256             llvm::UnnamedAddr::No,
1257             bx.type_func(
1258                 &[llvm_pointer_vec_ty, alignment_ty, mask_ty, llvm_elem_vec_ty],
1259                 llvm_elem_vec_ty,
1260             ),
1261         );
1262         let v = bx.call(f, &[args[1].immediate(), alignment, mask, args[0].immediate()], None);
1263         return Ok(v);
1264     }
1265
1266     if name == sym::simd_scatter {
1267         // simd_scatter(values: <N x T>, pointers: <N x *mut T>,
1268         //             mask: <N x i{M}>) -> ()
1269         // * N: number of elements in the input vectors
1270         // * T: type of the element to load
1271         // * M: any integer width is supported, will be truncated to i1
1272
1273         // All types must be simd vector types
1274         require_simd!(in_ty, "first");
1275         require_simd!(arg_tys[1], "second");
1276         require_simd!(arg_tys[2], "third");
1277
1278         // Of the same length:
1279         let (element_len1, _) = arg_tys[1].simd_size_and_type(bx.tcx());
1280         let (element_len2, _) = arg_tys[2].simd_size_and_type(bx.tcx());
1281         require!(
1282             in_len == element_len1,
1283             "expected {} argument with length {} (same as input type `{}`), \
1284             found `{}` with length {}",
1285             "second",
1286             in_len,
1287             in_ty,
1288             arg_tys[1],
1289             element_len1
1290         );
1291         require!(
1292             in_len == element_len2,
1293             "expected {} argument with length {} (same as input type `{}`), \
1294             found `{}` with length {}",
1295             "third",
1296             in_len,
1297             in_ty,
1298             arg_tys[2],
1299             element_len2
1300         );
1301
1302         // This counts how many pointers
1303         fn ptr_count(t: Ty<'_>) -> usize {
1304             match t.kind() {
1305                 ty::RawPtr(p) => 1 + ptr_count(p.ty),
1306                 _ => 0,
1307             }
1308         }
1309
1310         // Non-ptr type
1311         fn non_ptr(t: Ty<'_>) -> Ty<'_> {
1312             match t.kind() {
1313                 ty::RawPtr(p) => non_ptr(p.ty),
1314                 _ => t,
1315             }
1316         }
1317
1318         // The second argument must be a simd vector with an element type that's a pointer
1319         // to the element type of the first argument
1320         let (_, element_ty0) = arg_tys[0].simd_size_and_type(bx.tcx());
1321         let (_, element_ty1) = arg_tys[1].simd_size_and_type(bx.tcx());
1322         let (_, element_ty2) = arg_tys[2].simd_size_and_type(bx.tcx());
1323         let (pointer_count, underlying_ty) = match element_ty1.kind() {
1324             ty::RawPtr(p) if p.ty == in_elem && p.mutbl == hir::Mutability::Mut => {
1325                 (ptr_count(element_ty1), non_ptr(element_ty1))
1326             }
1327             _ => {
1328                 require!(
1329                     false,
1330                     "expected element type `{}` of second argument `{}` \
1331                         to be a pointer to the element type `{}` of the first \
1332                         argument `{}`, found `{}` != `*mut {}`",
1333                     element_ty1,
1334                     arg_tys[1],
1335                     in_elem,
1336                     in_ty,
1337                     element_ty1,
1338                     in_elem
1339                 );
1340                 unreachable!();
1341             }
1342         };
1343         assert!(pointer_count > 0);
1344         assert_eq!(pointer_count - 1, ptr_count(element_ty0));
1345         assert_eq!(underlying_ty, non_ptr(element_ty0));
1346
1347         // The element type of the third argument must be a signed integer type of any width:
1348         match element_ty2.kind() {
1349             ty::Int(_) => (),
1350             _ => {
1351                 require!(
1352                     false,
1353                     "expected element type `{}` of third argument `{}` \
1354                          be a signed integer type",
1355                     element_ty2,
1356                     arg_tys[2]
1357                 );
1358             }
1359         }
1360
1361         // Alignment of T, must be a constant integer value:
1362         let alignment_ty = bx.type_i32();
1363         let alignment = bx.const_i32(bx.align_of(in_elem).bytes() as i32);
1364
1365         // Truncate the mask vector to a vector of i1s:
1366         let (mask, mask_ty) = {
1367             let i1 = bx.type_i1();
1368             let i1xn = bx.type_vector(i1, in_len);
1369             (bx.trunc(args[2].immediate(), i1xn), i1xn)
1370         };
1371
1372         let ret_t = bx.type_void();
1373
1374         // Type of the vector of pointers:
1375         let llvm_pointer_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count);
1376         let llvm_pointer_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count);
1377
1378         // Type of the vector of elements:
1379         let llvm_elem_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count - 1);
1380         let llvm_elem_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count - 1);
1381
1382         let llvm_intrinsic =
1383             format!("llvm.masked.scatter.{}.{}", llvm_elem_vec_str, llvm_pointer_vec_str);
1384         let f = bx.declare_cfn(
1385             &llvm_intrinsic,
1386             llvm::UnnamedAddr::No,
1387             bx.type_func(&[llvm_elem_vec_ty, llvm_pointer_vec_ty, alignment_ty, mask_ty], ret_t),
1388         );
1389         let v = bx.call(f, &[args[0].immediate(), args[1].immediate(), alignment, mask], None);
1390         return Ok(v);
1391     }
1392
1393     macro_rules! arith_red {
1394         ($name:ident : $integer_reduce:ident, $float_reduce:ident, $ordered:expr, $op:ident,
1395          $identity:expr) => {
1396             if name == sym::$name {
1397                 require!(
1398                     ret_ty == in_elem,
1399                     "expected return type `{}` (element of input `{}`), found `{}`",
1400                     in_elem,
1401                     in_ty,
1402                     ret_ty
1403                 );
1404                 return match in_elem.kind() {
1405                     ty::Int(_) | ty::Uint(_) => {
1406                         let r = bx.$integer_reduce(args[0].immediate());
1407                         if $ordered {
1408                             // if overflow occurs, the result is the
1409                             // mathematical result modulo 2^n:
1410                             Ok(bx.$op(args[1].immediate(), r))
1411                         } else {
1412                             Ok(bx.$integer_reduce(args[0].immediate()))
1413                         }
1414                     }
1415                     ty::Float(f) => {
1416                         let acc = if $ordered {
1417                             // ordered arithmetic reductions take an accumulator
1418                             args[1].immediate()
1419                         } else {
1420                             // unordered arithmetic reductions use the identity accumulator
1421                             match f.bit_width() {
1422                                 32 => bx.const_real(bx.type_f32(), $identity),
1423                                 64 => bx.const_real(bx.type_f64(), $identity),
1424                                 v => return_error!(
1425                                     r#"
1426 unsupported {} from `{}` with element `{}` of size `{}` to `{}`"#,
1427                                     sym::$name,
1428                                     in_ty,
1429                                     in_elem,
1430                                     v,
1431                                     ret_ty
1432                                 ),
1433                             }
1434                         };
1435                         Ok(bx.$float_reduce(acc, args[0].immediate()))
1436                     }
1437                     _ => return_error!(
1438                         "unsupported {} from `{}` with element `{}` to `{}`",
1439                         sym::$name,
1440                         in_ty,
1441                         in_elem,
1442                         ret_ty
1443                     ),
1444                 };
1445             }
1446         };
1447     }
1448
1449     arith_red!(simd_reduce_add_ordered: vector_reduce_add, vector_reduce_fadd, true, add, 0.0);
1450     arith_red!(simd_reduce_mul_ordered: vector_reduce_mul, vector_reduce_fmul, true, mul, 1.0);
1451     arith_red!(
1452         simd_reduce_add_unordered: vector_reduce_add,
1453         vector_reduce_fadd_fast,
1454         false,
1455         add,
1456         0.0
1457     );
1458     arith_red!(
1459         simd_reduce_mul_unordered: vector_reduce_mul,
1460         vector_reduce_fmul_fast,
1461         false,
1462         mul,
1463         1.0
1464     );
1465
1466     macro_rules! minmax_red {
1467         ($name:ident: $int_red:ident, $float_red:ident) => {
1468             if name == sym::$name {
1469                 require!(
1470                     ret_ty == in_elem,
1471                     "expected return type `{}` (element of input `{}`), found `{}`",
1472                     in_elem,
1473                     in_ty,
1474                     ret_ty
1475                 );
1476                 return match in_elem.kind() {
1477                     ty::Int(_i) => Ok(bx.$int_red(args[0].immediate(), true)),
1478                     ty::Uint(_u) => Ok(bx.$int_red(args[0].immediate(), false)),
1479                     ty::Float(_f) => Ok(bx.$float_red(args[0].immediate())),
1480                     _ => return_error!(
1481                         "unsupported {} from `{}` with element `{}` to `{}`",
1482                         sym::$name,
1483                         in_ty,
1484                         in_elem,
1485                         ret_ty
1486                     ),
1487                 };
1488             }
1489         };
1490     }
1491
1492     minmax_red!(simd_reduce_min: vector_reduce_min, vector_reduce_fmin);
1493     minmax_red!(simd_reduce_max: vector_reduce_max, vector_reduce_fmax);
1494
1495     minmax_red!(simd_reduce_min_nanless: vector_reduce_min, vector_reduce_fmin_fast);
1496     minmax_red!(simd_reduce_max_nanless: vector_reduce_max, vector_reduce_fmax_fast);
1497
1498     macro_rules! bitwise_red {
1499         ($name:ident : $red:ident, $boolean:expr) => {
1500             if name == sym::$name {
1501                 let input = if !$boolean {
1502                     require!(
1503                         ret_ty == in_elem,
1504                         "expected return type `{}` (element of input `{}`), found `{}`",
1505                         in_elem,
1506                         in_ty,
1507                         ret_ty
1508                     );
1509                     args[0].immediate()
1510                 } else {
1511                     match in_elem.kind() {
1512                         ty::Int(_) | ty::Uint(_) => {}
1513                         _ => return_error!(
1514                             "unsupported {} from `{}` with element `{}` to `{}`",
1515                             sym::$name,
1516                             in_ty,
1517                             in_elem,
1518                             ret_ty
1519                         ),
1520                     }
1521
1522                     // boolean reductions operate on vectors of i1s:
1523                     let i1 = bx.type_i1();
1524                     let i1xn = bx.type_vector(i1, in_len as u64);
1525                     bx.trunc(args[0].immediate(), i1xn)
1526                 };
1527                 return match in_elem.kind() {
1528                     ty::Int(_) | ty::Uint(_) => {
1529                         let r = bx.$red(input);
1530                         Ok(if !$boolean { r } else { bx.zext(r, bx.type_bool()) })
1531                     }
1532                     _ => return_error!(
1533                         "unsupported {} from `{}` with element `{}` to `{}`",
1534                         sym::$name,
1535                         in_ty,
1536                         in_elem,
1537                         ret_ty
1538                     ),
1539                 };
1540             }
1541         };
1542     }
1543
1544     bitwise_red!(simd_reduce_and: vector_reduce_and, false);
1545     bitwise_red!(simd_reduce_or: vector_reduce_or, false);
1546     bitwise_red!(simd_reduce_xor: vector_reduce_xor, false);
1547     bitwise_red!(simd_reduce_all: vector_reduce_and, true);
1548     bitwise_red!(simd_reduce_any: vector_reduce_or, true);
1549
1550     if name == sym::simd_cast {
1551         require_simd!(ret_ty, "return");
1552         let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
1553         require!(
1554             in_len == out_len,
1555             "expected return type with length {} (same as input type `{}`), \
1556                   found `{}` with length {}",
1557             in_len,
1558             in_ty,
1559             ret_ty,
1560             out_len
1561         );
1562         // casting cares about nominal type, not just structural type
1563         if in_elem == out_elem {
1564             return Ok(args[0].immediate());
1565         }
1566
1567         enum Style {
1568             Float,
1569             Int(/* is signed? */ bool),
1570             Unsupported,
1571         }
1572
1573         let (in_style, in_width) = match in_elem.kind() {
1574             // vectors of pointer-sized integers should've been
1575             // disallowed before here, so this unwrap is safe.
1576             ty::Int(i) => (Style::Int(true), i.bit_width().unwrap()),
1577             ty::Uint(u) => (Style::Int(false), u.bit_width().unwrap()),
1578             ty::Float(f) => (Style::Float, f.bit_width()),
1579             _ => (Style::Unsupported, 0),
1580         };
1581         let (out_style, out_width) = match out_elem.kind() {
1582             ty::Int(i) => (Style::Int(true), i.bit_width().unwrap()),
1583             ty::Uint(u) => (Style::Int(false), u.bit_width().unwrap()),
1584             ty::Float(f) => (Style::Float, f.bit_width()),
1585             _ => (Style::Unsupported, 0),
1586         };
1587
1588         match (in_style, out_style) {
1589             (Style::Int(in_is_signed), Style::Int(_)) => {
1590                 return Ok(match in_width.cmp(&out_width) {
1591                     Ordering::Greater => bx.trunc(args[0].immediate(), llret_ty),
1592                     Ordering::Equal => args[0].immediate(),
1593                     Ordering::Less => {
1594                         if in_is_signed {
1595                             bx.sext(args[0].immediate(), llret_ty)
1596                         } else {
1597                             bx.zext(args[0].immediate(), llret_ty)
1598                         }
1599                     }
1600                 });
1601             }
1602             (Style::Int(in_is_signed), Style::Float) => {
1603                 return Ok(if in_is_signed {
1604                     bx.sitofp(args[0].immediate(), llret_ty)
1605                 } else {
1606                     bx.uitofp(args[0].immediate(), llret_ty)
1607                 });
1608             }
1609             (Style::Float, Style::Int(out_is_signed)) => {
1610                 return Ok(if out_is_signed {
1611                     bx.fptosi(args[0].immediate(), llret_ty)
1612                 } else {
1613                     bx.fptoui(args[0].immediate(), llret_ty)
1614                 });
1615             }
1616             (Style::Float, Style::Float) => {
1617                 return Ok(match in_width.cmp(&out_width) {
1618                     Ordering::Greater => bx.fptrunc(args[0].immediate(), llret_ty),
1619                     Ordering::Equal => args[0].immediate(),
1620                     Ordering::Less => bx.fpext(args[0].immediate(), llret_ty),
1621                 });
1622             }
1623             _ => { /* Unsupported. Fallthrough. */ }
1624         }
1625         require!(
1626             false,
1627             "unsupported cast from `{}` with element `{}` to `{}` with element `{}`",
1628             in_ty,
1629             in_elem,
1630             ret_ty,
1631             out_elem
1632         );
1633     }
1634     macro_rules! arith_binary {
1635         ($($name: ident: $($($p: ident),* => $call: ident),*;)*) => {
1636             $(if name == sym::$name {
1637                 match in_elem.kind() {
1638                     $($(ty::$p(_))|* => {
1639                         return Ok(bx.$call(args[0].immediate(), args[1].immediate()))
1640                     })*
1641                     _ => {},
1642                 }
1643                 require!(false,
1644                          "unsupported operation on `{}` with element `{}`",
1645                          in_ty,
1646                          in_elem)
1647             })*
1648         }
1649     }
1650     arith_binary! {
1651         simd_add: Uint, Int => add, Float => fadd;
1652         simd_sub: Uint, Int => sub, Float => fsub;
1653         simd_mul: Uint, Int => mul, Float => fmul;
1654         simd_div: Uint => udiv, Int => sdiv, Float => fdiv;
1655         simd_rem: Uint => urem, Int => srem, Float => frem;
1656         simd_shl: Uint, Int => shl;
1657         simd_shr: Uint => lshr, Int => ashr;
1658         simd_and: Uint, Int => and;
1659         simd_or: Uint, Int => or;
1660         simd_xor: Uint, Int => xor;
1661         simd_fmax: Float => maxnum;
1662         simd_fmin: Float => minnum;
1663
1664     }
1665     macro_rules! arith_unary {
1666         ($($name: ident: $($($p: ident),* => $call: ident),*;)*) => {
1667             $(if name == sym::$name {
1668                 match in_elem.kind() {
1669                     $($(ty::$p(_))|* => {
1670                         return Ok(bx.$call(args[0].immediate()))
1671                     })*
1672                     _ => {},
1673                 }
1674                 require!(false,
1675                          "unsupported operation on `{}` with element `{}`",
1676                          in_ty,
1677                          in_elem)
1678             })*
1679         }
1680     }
1681     arith_unary! {
1682         simd_neg: Int => neg, Float => fneg;
1683     }
1684
1685     if name == sym::simd_saturating_add || name == sym::simd_saturating_sub {
1686         let lhs = args[0].immediate();
1687         let rhs = args[1].immediate();
1688         let is_add = name == sym::simd_saturating_add;
1689         let ptr_bits = bx.tcx().data_layout.pointer_size.bits() as _;
1690         let (signed, elem_width, elem_ty) = match *in_elem.kind() {
1691             ty::Int(i) => (true, i.bit_width().unwrap_or(ptr_bits), bx.cx.type_int_from_ty(i)),
1692             ty::Uint(i) => (false, i.bit_width().unwrap_or(ptr_bits), bx.cx.type_uint_from_ty(i)),
1693             _ => {
1694                 return_error!(
1695                     "expected element type `{}` of vector type `{}` \
1696                      to be a signed or unsigned integer type",
1697                     arg_tys[0].simd_size_and_type(bx.tcx()).1,
1698                     arg_tys[0]
1699                 );
1700             }
1701         };
1702         let llvm_intrinsic = &format!(
1703             "llvm.{}{}.sat.v{}i{}",
1704             if signed { 's' } else { 'u' },
1705             if is_add { "add" } else { "sub" },
1706             in_len,
1707             elem_width
1708         );
1709         let vec_ty = bx.cx.type_vector(elem_ty, in_len as u64);
1710
1711         let f = bx.declare_cfn(
1712             &llvm_intrinsic,
1713             llvm::UnnamedAddr::No,
1714             bx.type_func(&[vec_ty, vec_ty], vec_ty),
1715         );
1716         let v = bx.call(f, &[lhs, rhs], None);
1717         return Ok(v);
1718     }
1719
1720     span_bug!(span, "unknown SIMD intrinsic");
1721 }
1722
1723 // Returns the width of an int Ty, and if it's signed or not
1724 // Returns None if the type is not an integer
1725 // FIXME: there’s multiple of this functions, investigate using some of the already existing
1726 // stuffs.
1727 fn int_type_width_signed(ty: Ty<'_>, cx: &CodegenCx<'_, '_>) -> Option<(u64, bool)> {
1728     match ty.kind() {
1729         ty::Int(t) => {
1730             Some((t.bit_width().unwrap_or(u64::from(cx.tcx.sess.target.pointer_width)), true))
1731         }
1732         ty::Uint(t) => {
1733             Some((t.bit_width().unwrap_or(u64::from(cx.tcx.sess.target.pointer_width)), false))
1734         }
1735         _ => None,
1736     }
1737 }