src/librustc_codegen_llvm/intrinsic.rs

   1 use crate::llvm;
   2 use crate::llvm_util;
   3 use crate::abi::{Abi, FnAbi, LlvmType, PassMode};
   4 use crate::context::CodegenCx;
   5 use crate::type_::Type;
   6 use crate::type_of::LayoutLlvmExt;
   7 use crate::builder::Builder;
   8 use crate::value::Value;
   9 use crate::va_arg::emit_va_arg;
  10 use rustc_codegen_ssa::MemFlags;
  11 use rustc_codegen_ssa::mir::place::PlaceRef;
  12 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
  13 use rustc_codegen_ssa::glue;
  14 use rustc_codegen_ssa::base::{to_immediate, wants_msvc_seh, compare_simd_types};
  15 use rustc::ty::{self, Ty};
  16 use rustc::ty::layout::{self, FnAbiExt, LayoutOf, HasTyCtxt, Primitive};
  17 use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
  18 use rustc::hir;
  19 use rustc_target::abi::HasDataLayout;
  20 use syntax::ast;
  21 use rustc::{bug, span_bug};
  22
  23 use rustc_codegen_ssa::common::span_invalid_monomorphization_error;
  24 use rustc_codegen_ssa::traits::*;
  25
  26 use syntax_pos::Span;
  27
  28 use std::cmp::Ordering;
  29 use std::{iter, i128, u128};
  30
  31 fn get_simple_intrinsic(cx: &CodegenCx<'ll, '_>, name: &str) -> Option<&'ll Value> {
  32     let llvm_name = match name {
  33         "sqrtf32" => "llvm.sqrt.f32",
  34         "sqrtf64" => "llvm.sqrt.f64",
  35         "powif32" => "llvm.powi.f32",
  36         "powif64" => "llvm.powi.f64",
  37         "sinf32" => "llvm.sin.f32",
  38         "sinf64" => "llvm.sin.f64",
  39         "cosf32" => "llvm.cos.f32",
  40         "cosf64" => "llvm.cos.f64",
  41         "powf32" => "llvm.pow.f32",
  42         "powf64" => "llvm.pow.f64",
  43         "expf32" => "llvm.exp.f32",
  44         "expf64" => "llvm.exp.f64",
  45         "exp2f32" => "llvm.exp2.f32",
  46         "exp2f64" => "llvm.exp2.f64",
  47         "logf32" => "llvm.log.f32",
  48         "logf64" => "llvm.log.f64",
  49         "log10f32" => "llvm.log10.f32",
  50         "log10f64" => "llvm.log10.f64",
  51         "log2f32" => "llvm.log2.f32",
  52         "log2f64" => "llvm.log2.f64",
  53         "fmaf32" => "llvm.fma.f32",
  54         "fmaf64" => "llvm.fma.f64",
  55         "fabsf32" => "llvm.fabs.f32",
  56         "fabsf64" => "llvm.fabs.f64",
  57         "minnumf32" => "llvm.minnum.f32",
  58         "minnumf64" => "llvm.minnum.f64",
  59         "maxnumf32" => "llvm.maxnum.f32",
  60         "maxnumf64" => "llvm.maxnum.f64",
  61         "copysignf32" => "llvm.copysign.f32",
  62         "copysignf64" => "llvm.copysign.f64",
  63         "floorf32" => "llvm.floor.f32",
  64         "floorf64" => "llvm.floor.f64",
  65         "ceilf32" => "llvm.ceil.f32",
  66         "ceilf64" => "llvm.ceil.f64",
  67         "truncf32" => "llvm.trunc.f32",
  68         "truncf64" => "llvm.trunc.f64",
  69         "rintf32" => "llvm.rint.f32",
  70         "rintf64" => "llvm.rint.f64",
  71         "nearbyintf32" => "llvm.nearbyint.f32",
  72         "nearbyintf64" => "llvm.nearbyint.f64",
  73         "roundf32" => "llvm.round.f32",
  74         "roundf64" => "llvm.round.f64",
  75         "assume" => "llvm.assume",
  76         "abort" => "llvm.trap",
  77         _ => return None
  78     };
  79     Some(cx.get_intrinsic(&llvm_name))
  80 }
  81
  82 impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
  83     fn codegen_intrinsic_call(
  84         &mut self,
  85         instance: ty::Instance<'tcx>,
  86         fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
  87         args: &[OperandRef<'tcx, &'ll Value>],
  88         llresult: &'ll Value,
  89         span: Span,
  90     ) {
  91         let tcx = self.tcx;
  92         let callee_ty = instance.ty(tcx);
  93
  94         let (def_id, substs) = match callee_ty.kind {
  95             ty::FnDef(def_id, substs) => (def_id, substs),
  96             _ => bug!("expected fn item type, found {}", callee_ty)
  97         };
  98
  99         let sig = callee_ty.fn_sig(tcx);
 100         let sig = tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
 101         let arg_tys = sig.inputs();
 102         let ret_ty = sig.output();
 103         let name = &*tcx.item_name(def_id).as_str();
 104
 105         let llret_ty = self.layout_of(ret_ty).llvm_type(self);
 106         let result = PlaceRef::new_sized(llresult, fn_abi.ret.layout);
 107
 108         let simple = get_simple_intrinsic(self, name);
 109         let llval = match name {
 110             _ if simple.is_some() => {
 111                 self.call(simple.unwrap(),
 112                         &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
 113                         None)
 114             }
 115             "unreachable" => {
 116                 return;
 117             },
 118             "likely" => {
 119                 let expect = self.get_intrinsic(&("llvm.expect.i1"));
 120                 self.call(expect, &[args[0].immediate(), self.const_bool(true)], None)
 121             }
 122             "unlikely" => {
 123                 let expect = self.get_intrinsic(&("llvm.expect.i1"));
 124                 self.call(expect, &[args[0].immediate(), self.const_bool(false)], None)
 125             }
 126             "try" => {
 127                 try_intrinsic(self,
 128                               args[0].immediate(),
 129                               args[1].immediate(),
 130                               args[2].immediate(),
 131                               llresult);
 132                 return;
 133             }
 134             "breakpoint" => {
 135                 let llfn = self.get_intrinsic(&("llvm.debugtrap"));
 136                 self.call(llfn, &[], None)
 137             }
 138             "va_start" => {
 139                 self.va_start(args[0].immediate())
 140             }
 141             "va_end" => {
 142                 self.va_end(args[0].immediate())
 143             }
 144             "va_copy" => {
 145                 let intrinsic = self.cx().get_intrinsic(&("llvm.va_copy"));
 146                 self.call(intrinsic, &[args[0].immediate(), args[1].immediate()], None)
 147             }
 148             "va_arg" => {
 149                 match fn_abi.ret.layout.abi {
 150                     layout::Abi::Scalar(ref scalar) => {
 151                         match scalar.value {
 152                             Primitive::Int(..) => {
 153                                 if self.cx().size_of(ret_ty).bytes() < 4 {
 154                                     // `va_arg` should not be called on a integer type
 155                                     // less than 4 bytes in length. If it is, promote
 156                                     // the integer to a `i32` and truncate the result
 157                                     // back to the smaller type.
 158                                     let promoted_result = emit_va_arg(self, args[0],
 159                                                                       tcx.types.i32);
 160                                     self.trunc(promoted_result, llret_ty)
 161                                 } else {
 162                                     emit_va_arg(self, args[0], ret_ty)
 163                                 }
 164                             }
 165                             Primitive::F64 |
 166                             Primitive::Pointer => {
 167                                 emit_va_arg(self, args[0], ret_ty)
 168                             }
 169                             // `va_arg` should never be used with the return type f32.
 170                             Primitive::F32 => {
 171                                 bug!("the va_arg intrinsic does not work with `f32`")
 172                             }
 173                         }
 174                     }
 175                     _ => {
 176                         bug!("the va_arg intrinsic does not work with non-scalar types")
 177                     }
 178                 }
 179             }
 180             "size_of_val" => {
 181                 let tp_ty = substs.type_at(0);
 182                 if let OperandValue::Pair(_, meta) = args[0].val {
 183                     let (llsize, _) = glue::size_and_align_of_dst(self, tp_ty, Some(meta));
 184                     llsize
 185                 } else {
 186                     self.const_usize(self.size_of(tp_ty).bytes())
 187                 }
 188             }
 189             "min_align_of_val" => {
 190                 let tp_ty = substs.type_at(0);
 191                 if let OperandValue::Pair(_, meta) = args[0].val {
 192                     let (_, llalign) = glue::size_and_align_of_dst(self, tp_ty, Some(meta));
 193                     llalign
 194                 } else {
 195                     self.const_usize(self.align_of(tp_ty).bytes())
 196                 }
 197             }
 198             "size_of" |
 199             "pref_align_of" |
 200             "min_align_of" |
 201             "needs_drop" |
 202             "type_id" |
 203             "type_name" => {
 204                 let ty_name = self.tcx
 205                     .const_eval_instance(ty::ParamEnv::reveal_all(), instance, None)
 206                     .unwrap();
 207                 OperandRef::from_const(self, ty_name).immediate_or_packed_pair(self)
 208             }
 209             "init" => {
 210                 let ty = substs.type_at(0);
 211                 if !self.layout_of(ty).is_zst() {
 212                     // Just zero out the stack slot.
 213                     // If we store a zero constant, LLVM will drown in vreg allocation for large
 214                     // data structures, and the generated code will be awful. (A telltale sign of
 215                     // this is large quantities of `mov [byte ptr foo],0` in the generated code.)
 216                     memset_intrinsic(
 217                         self,
 218                         false,
 219                         ty,
 220                         llresult,
 221                         self.const_u8(0),
 222                         self.const_usize(1)
 223                     );
 224                 }
 225                 return;
 226             }
 227             // Effectively no-ops
 228             "uninit" | "forget" => {
 229                 return;
 230             }
 231             "offset" => {
 232                 let ptr = args[0].immediate();
 233                 let offset = args[1].immediate();
 234                 self.inbounds_gep(ptr, &[offset])
 235             }
 236             "arith_offset" => {
 237                 let ptr = args[0].immediate();
 238                 let offset = args[1].immediate();
 239                 self.gep(ptr, &[offset])
 240             }
 241
 242             "copy_nonoverlapping" => {
 243                 copy_intrinsic(self, false, false, substs.type_at(0),
 244                                args[1].immediate(), args[0].immediate(), args[2].immediate());
 245                 return;
 246             }
 247             "copy" => {
 248                 copy_intrinsic(self, true, false, substs.type_at(0),
 249                                args[1].immediate(), args[0].immediate(), args[2].immediate());
 250                 return;
 251             }
 252             "write_bytes" => {
 253                 memset_intrinsic(self, false, substs.type_at(0),
 254                                  args[0].immediate(), args[1].immediate(), args[2].immediate());
 255                 return;
 256             }
 257
 258             "volatile_copy_nonoverlapping_memory" => {
 259                 copy_intrinsic(self, false, true, substs.type_at(0),
 260                                args[0].immediate(), args[1].immediate(), args[2].immediate());
 261                 return;
 262             }
 263             "volatile_copy_memory" => {
 264                 copy_intrinsic(self, true, true, substs.type_at(0),
 265                                args[0].immediate(), args[1].immediate(), args[2].immediate());
 266                 return;
 267             }
 268             "volatile_set_memory" => {
 269                 memset_intrinsic(self, true, substs.type_at(0),
 270                                  args[0].immediate(), args[1].immediate(), args[2].immediate());
 271                 return;
 272             }
 273             "volatile_load" | "unaligned_volatile_load" => {
 274                 let tp_ty = substs.type_at(0);
 275                 let mut ptr = args[0].immediate();
 276                 if let PassMode::Cast(ty) = fn_abi.ret.mode {
 277                     ptr = self.pointercast(ptr, self.type_ptr_to(ty.llvm_type(self)));
 278                 }
 279                 let load = self.volatile_load(ptr);
 280                 let align = if name == "unaligned_volatile_load" {
 281                     1
 282                 } else {
 283                     self.align_of(tp_ty).bytes() as u32
 284                 };
 285                 unsafe {
 286                     llvm::LLVMSetAlignment(load, align);
 287                 }
 288                 to_immediate(self, load, self.layout_of(tp_ty))
 289             },
 290             "volatile_store" => {
 291                 let dst = args[0].deref(self.cx());
 292                 args[1].val.volatile_store(self, dst);
 293                 return;
 294             },
 295             "unaligned_volatile_store" => {
 296                 let dst = args[0].deref(self.cx());
 297                 args[1].val.unaligned_volatile_store(self, dst);
 298                 return;
 299             },
 300             "prefetch_read_data" | "prefetch_write_data" |
 301             "prefetch_read_instruction" | "prefetch_write_instruction" => {
 302                 let expect = self.get_intrinsic(&("llvm.prefetch"));
 303                 let (rw, cache_type) = match name {
 304                     "prefetch_read_data" => (0, 1),
 305                     "prefetch_write_data" => (1, 1),
 306                     "prefetch_read_instruction" => (0, 0),
 307                     "prefetch_write_instruction" => (1, 0),
 308                     _ => bug!()
 309                 };
 310                 self.call(expect, &[
 311                     args[0].immediate(),
 312                     self.const_i32(rw),
 313                     args[1].immediate(),
 314                     self.const_i32(cache_type)
 315                 ], None)
 316             },
 317             "ctlz" | "ctlz_nonzero" | "cttz" | "cttz_nonzero" | "ctpop" | "bswap" |
 318             "bitreverse" | "add_with_overflow" | "sub_with_overflow" |
 319             "mul_with_overflow" | "wrapping_add" | "wrapping_sub" | "wrapping_mul" |
 320             "unchecked_div" | "unchecked_rem" | "unchecked_shl" | "unchecked_shr" |
 321             "unchecked_add" | "unchecked_sub" | "unchecked_mul" | "exact_div" |
 322             "rotate_left" | "rotate_right" | "saturating_add" | "saturating_sub" => {
 323                 let ty = arg_tys[0];
 324                 match int_type_width_signed(ty, self) {
 325                     Some((width, signed)) =>
 326                         match name {
 327                             "ctlz" | "cttz" => {
 328                                 let y = self.const_bool(false);
 329                                 let llfn = self.get_intrinsic(
 330                                     &format!("llvm.{}.i{}", name, width),
 331                                 );
 332                                 self.call(llfn, &[args[0].immediate(), y], None)
 333                             }
 334                             "ctlz_nonzero" | "cttz_nonzero" => {
 335                                 let y = self.const_bool(true);
 336                                 let llvm_name = &format!("llvm.{}.i{}", &name[..4], width);
 337                                 let llfn = self.get_intrinsic(llvm_name);
 338                                 self.call(llfn, &[args[0].immediate(), y], None)
 339                             }
 340                             "ctpop" => self.call(
 341                                 self.get_intrinsic(&format!("llvm.ctpop.i{}", width)),
 342                                 &[args[0].immediate()],
 343                                 None
 344                             ),
 345                             "bswap" => {
 346                                 if width == 8 {
 347                                     args[0].immediate() // byte swap a u8/i8 is just a no-op
 348                                 } else {
 349                                     self.call(
 350                                         self.get_intrinsic(
 351                                             &format!("llvm.bswap.i{}", width),
 352                                         ),
 353                                         &[args[0].immediate()],
 354                                         None,
 355                                     )
 356                                 }
 357                             }
 358                             "bitreverse" => {
 359                                 self.call(
 360                                     self.get_intrinsic(
 361                                         &format!("llvm.bitreverse.i{}", width),
 362                                     ),
 363                                     &[args[0].immediate()],
 364                                     None,
 365                                 )
 366                             }
 367                             "add_with_overflow" | "sub_with_overflow" | "mul_with_overflow" => {
 368                                 let intrinsic = format!("llvm.{}{}.with.overflow.i{}",
 369                                                         if signed { 's' } else { 'u' },
 370                                                         &name[..3], width);
 371                                 let llfn = self.get_intrinsic(&intrinsic);
 372
 373                                 // Convert `i1` to a `bool`, and write it to the out parameter
 374                                 let pair = self.call(llfn, &[
 375                                     args[0].immediate(),
 376                                     args[1].immediate()
 377                                 ], None);
 378                                 let val = self.extract_value(pair, 0);
 379                                 let overflow = self.extract_value(pair, 1);
 380                                 let overflow = self.zext(overflow, self.type_bool());
 381
 382                                 let dest = result.project_field(self, 0);
 383                                 self.store(val, dest.llval, dest.align);
 384                                 let dest = result.project_field(self, 1);
 385                                 self.store(overflow, dest.llval, dest.align);
 386
 387                                 return;
 388                             },
 389                             "wrapping_add" => self.add(args[0].immediate(), args[1].immediate()),
 390                             "wrapping_sub" => self.sub(args[0].immediate(), args[1].immediate()),
 391                             "wrapping_mul" => self.mul(args[0].immediate(), args[1].immediate()),
 392                             "exact_div" =>
 393                                 if signed {
 394                                     self.exactsdiv(args[0].immediate(), args[1].immediate())
 395                                 } else {
 396                                     self.exactudiv(args[0].immediate(), args[1].immediate())
 397                                 },
 398                             "unchecked_div" =>
 399                                 if signed {
 400                                     self.sdiv(args[0].immediate(), args[1].immediate())
 401                                 } else {
 402                                     self.udiv(args[0].immediate(), args[1].immediate())
 403                                 },
 404                             "unchecked_rem" =>
 405                                 if signed {
 406                                     self.srem(args[0].immediate(), args[1].immediate())
 407                                 } else {
 408                                     self.urem(args[0].immediate(), args[1].immediate())
 409                                 },
 410                             "unchecked_shl" => self.shl(args[0].immediate(), args[1].immediate()),
 411                             "unchecked_shr" =>
 412                                 if signed {
 413                                     self.ashr(args[0].immediate(), args[1].immediate())
 414                                 } else {
 415                                     self.lshr(args[0].immediate(), args[1].immediate())
 416                                 },
 417                             "unchecked_add" => {
 418                                 if signed {
 419                                     self.unchecked_sadd(args[0].immediate(), args[1].immediate())
 420                                 } else {
 421                                     self.unchecked_uadd(args[0].immediate(), args[1].immediate())
 422                                 }
 423                             },
 424                             "unchecked_sub" => {
 425                                 if signed {
 426                                     self.unchecked_ssub(args[0].immediate(), args[1].immediate())
 427                                 } else {
 428                                     self.unchecked_usub(args[0].immediate(), args[1].immediate())
 429                                 }
 430                             },
 431                             "unchecked_mul" => {
 432                                 if signed {
 433                                     self.unchecked_smul(args[0].immediate(), args[1].immediate())
 434                                 } else {
 435                                     self.unchecked_umul(args[0].immediate(), args[1].immediate())
 436                                 }
 437                             },
 438                             "rotate_left" | "rotate_right" => {
 439                                 let is_left = name == "rotate_left";
 440                                 let val = args[0].immediate();
 441                                 let raw_shift = args[1].immediate();
 442                                 // rotate = funnel shift with first two args the same
 443                                 let llvm_name = &format!("llvm.fsh{}.i{}",
 444                                                         if is_left { 'l' } else { 'r' }, width);
 445                                 let llfn = self.get_intrinsic(llvm_name);
 446                                 self.call(llfn, &[val, val, raw_shift], None)
 447                             },
 448                             "saturating_add" | "saturating_sub" => {
 449                                 let is_add = name == "saturating_add";
 450                                 let lhs = args[0].immediate();
 451                                 let rhs = args[1].immediate();
 452                                 if llvm_util::get_major_version() >= 8 {
 453                                     let llvm_name = &format!("llvm.{}{}.sat.i{}",
 454                                                              if signed { 's' } else { 'u' },
 455                                                              if is_add { "add" } else { "sub" },
 456                                                              width);
 457                                     let llfn = self.get_intrinsic(llvm_name);
 458                                     self.call(llfn, &[lhs, rhs], None)
 459                                 } else {
 460                                     let llvm_name = &format!("llvm.{}{}.with.overflow.i{}",
 461                                                              if signed { 's' } else { 'u' },
 462                                                              if is_add { "add" } else { "sub" },
 463                                                              width);
 464                                     let llfn = self.get_intrinsic(llvm_name);
 465                                     let pair = self.call(llfn, &[lhs, rhs], None);
 466                                     let val = self.extract_value(pair, 0);
 467                                     let overflow = self.extract_value(pair, 1);
 468                                     let llty = self.type_ix(width);
 469
 470                                     let limit = if signed {
 471                                         let limit_lo = self.const_uint_big(
 472                                             llty, (i128::MIN >> (128 - width)) as u128);
 473                                         let limit_hi = self.const_uint_big(
 474                                             llty, (i128::MAX >> (128 - width)) as u128);
 475                                         let neg = self.icmp(
 476                                             IntPredicate::IntSLT, val, self.const_uint(llty, 0));
 477                                         self.select(neg, limit_hi, limit_lo)
 478                                     } else if is_add {
 479                                         self.const_uint_big(llty, u128::MAX >> (128 - width))
 480                                     } else {
 481                                         self.const_uint(llty, 0)
 482                                     };
 483                                     self.select(overflow, limit, val)
 484                                 }
 485                             },
 486                             _ => bug!(),
 487                         },
 488                     None => {
 489                         span_invalid_monomorphization_error(
 490                             tcx.sess, span,
 491                             &format!("invalid monomorphization of `{}` intrinsic: \
 492                                       expected basic integer type, found `{}`", name, ty));
 493                         return;
 494                     }
 495                 }
 496
 497             },
 498             "fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" => {
 499                 match float_type_width(arg_tys[0]) {
 500                     Some(_width) =>
 501                         match name {
 502                             "fadd_fast" => self.fadd_fast(args[0].immediate(), args[1].immediate()),
 503                             "fsub_fast" => self.fsub_fast(args[0].immediate(), args[1].immediate()),
 504                             "fmul_fast" => self.fmul_fast(args[0].immediate(), args[1].immediate()),
 505                             "fdiv_fast" => self.fdiv_fast(args[0].immediate(), args[1].immediate()),
 506                             "frem_fast" => self.frem_fast(args[0].immediate(), args[1].immediate()),
 507                             _ => bug!(),
 508                         },
 509                     None => {
 510                         span_invalid_monomorphization_error(
 511                             tcx.sess, span,
 512                             &format!("invalid monomorphization of `{}` intrinsic: \
 513                                       expected basic float type, found `{}`", name, arg_tys[0]));
 514                         return;
 515                     }
 516                 }
 517             },
 518
 519             "float_to_int_approx_unchecked" => {
 520                 if float_type_width(arg_tys[0]).is_none() {
 521                     span_invalid_monomorphization_error(
 522                         tcx.sess, span,
 523                         &format!("invalid monomorphization of `float_to_int_approx_unchecked` \
 524                                   intrinsic: expected basic float type, \
 525                                   found `{}`", arg_tys[0]));
 526                     return;
 527                 }
 528                 match int_type_width_signed(ret_ty, self.cx) {
 529                     Some((width, signed)) => {
 530                         if signed {
 531                             self.fptosi(args[0].immediate(), self.cx.type_ix(width))
 532                         } else {
 533                             self.fptoui(args[0].immediate(), self.cx.type_ix(width))
 534                         }
 535                     }
 536                     None => {
 537                         span_invalid_monomorphization_error(
 538                             tcx.sess, span,
 539                             &format!("invalid monomorphization of `float_to_int_approx_unchecked` \
 540                                       intrinsic:  expected basic integer type, \
 541                                       found `{}`", ret_ty));
 542                         return;
 543                     }
 544                 }
 545             }
 546
 547             "discriminant_value" => {
 548                 args[0].deref(self.cx()).codegen_get_discr(self, ret_ty)
 549             }
 550
 551             name if name.starts_with("simd_") => {
 552                 match generic_simd_intrinsic(self, name,
 553                                              callee_ty,
 554                                              args,
 555                                              ret_ty, llret_ty,
 556                                              span) {
 557                     Ok(llval) => llval,
 558                     Err(()) => return
 559                 }
 560             }
 561             // This requires that atomic intrinsics follow a specific naming pattern:
 562             // "atomic_<operation>[_<ordering>]", and no ordering means SeqCst
 563             name if name.starts_with("atomic_") => {
 564                 use rustc_codegen_ssa::common::AtomicOrdering::*;
 565                 use rustc_codegen_ssa::common::
 566                     {SynchronizationScope, AtomicRmwBinOp};
 567
 568                 let split: Vec<&str> = name.split('_').collect();
 569
 570                 let is_cxchg = split[1] == "cxchg" || split[1] == "cxchgweak";
 571                 let (order, failorder) = match split.len() {
 572                     2 => (SequentiallyConsistent, SequentiallyConsistent),
 573                     3 => match split[2] {
 574                         "unordered" => (Unordered, Unordered),
 575                         "relaxed" => (Monotonic, Monotonic),
 576                         "acq"     => (Acquire, Acquire),
 577                         "rel"     => (Release, Monotonic),
 578                         "acqrel"  => (AcquireRelease, Acquire),
 579                         "failrelaxed" if is_cxchg =>
 580                             (SequentiallyConsistent, Monotonic),
 581                         "failacq" if is_cxchg =>
 582                             (SequentiallyConsistent, Acquire),
 583                         _ => self.sess().fatal("unknown ordering in atomic intrinsic")
 584                     },
 585                     4 => match (split[2], split[3]) {
 586                         ("acq", "failrelaxed") if is_cxchg =>
 587                             (Acquire, Monotonic),
 588                         ("acqrel", "failrelaxed") if is_cxchg =>
 589                             (AcquireRelease, Monotonic),
 590                         _ => self.sess().fatal("unknown ordering in atomic intrinsic")
 591                     },
 592                     _ => self.sess().fatal("Atomic intrinsic not in correct format"),
 593                 };
 594
 595                 let invalid_monomorphization = |ty| {
 596                     span_invalid_monomorphization_error(tcx.sess, span,
 597                         &format!("invalid monomorphization of `{}` intrinsic: \
 598                                   expected basic integer type, found `{}`", name, ty));
 599                 };
 600
 601                 match split[1] {
 602                     "cxchg" | "cxchgweak" => {
 603                         let ty = substs.type_at(0);
 604                         if int_type_width_signed(ty, self).is_some() {
 605                             let weak = split[1] == "cxchgweak";
 606                             let pair = self.atomic_cmpxchg(
 607                                 args[0].immediate(),
 608                                 args[1].immediate(),
 609                                 args[2].immediate(),
 610                                 order,
 611                                 failorder,
 612                                 weak);
 613                             let val = self.extract_value(pair, 0);
 614                             let success = self.extract_value(pair, 1);
 615                             let success = self.zext(success, self.type_bool());
 616
 617                             let dest = result.project_field(self, 0);
 618                             self.store(val, dest.llval, dest.align);
 619                             let dest = result.project_field(self, 1);
 620                             self.store(success, dest.llval, dest.align);
 621                             return;
 622                         } else {
 623                             return invalid_monomorphization(ty);
 624                         }
 625                     }
 626
 627                     "load" => {
 628                         let ty = substs.type_at(0);
 629                         if int_type_width_signed(ty, self).is_some() {
 630                             let size = self.size_of(ty);
 631                             self.atomic_load(args[0].immediate(), order, size)
 632                         } else {
 633                             return invalid_monomorphization(ty);
 634                         }
 635                     }
 636
 637                     "store" => {
 638                         let ty = substs.type_at(0);
 639                         if int_type_width_signed(ty, self).is_some() {
 640                             let size = self.size_of(ty);
 641                             self.atomic_store(
 642                                 args[1].immediate(),
 643                                 args[0].immediate(),
 644                                 order,
 645                                 size
 646                             );
 647                             return;
 648                         } else {
 649                             return invalid_monomorphization(ty);
 650                         }
 651                     }
 652
 653                     "fence" => {
 654                         self.atomic_fence(order, SynchronizationScope::CrossThread);
 655                         return;
 656                     }
 657
 658                     "singlethreadfence" => {
 659                         self.atomic_fence(order, SynchronizationScope::SingleThread);
 660                         return;
 661                     }
 662
 663                     // These are all AtomicRMW ops
 664                     op => {
 665                         let atom_op = match op {
 666                             "xchg"  => AtomicRmwBinOp::AtomicXchg,
 667                             "xadd"  => AtomicRmwBinOp::AtomicAdd,
 668                             "xsub"  => AtomicRmwBinOp::AtomicSub,
 669                             "and"   => AtomicRmwBinOp::AtomicAnd,
 670                             "nand"  => AtomicRmwBinOp::AtomicNand,
 671                             "or"    => AtomicRmwBinOp::AtomicOr,
 672                             "xor"   => AtomicRmwBinOp::AtomicXor,
 673                             "max"   => AtomicRmwBinOp::AtomicMax,
 674                             "min"   => AtomicRmwBinOp::AtomicMin,
 675                             "umax"  => AtomicRmwBinOp::AtomicUMax,
 676                             "umin"  => AtomicRmwBinOp::AtomicUMin,
 677                             _ => self.sess().fatal("unknown atomic operation")
 678                         };
 679
 680                         let ty = substs.type_at(0);
 681                         if int_type_width_signed(ty, self).is_some() {
 682                             self.atomic_rmw(
 683                                 atom_op,
 684                                 args[0].immediate(),
 685                                 args[1].immediate(),
 686                                 order
 687                             )
 688                         } else {
 689                             return invalid_monomorphization(ty);
 690                         }
 691                     }
 692                 }
 693             }
 694
 695             "nontemporal_store" => {
 696                 let dst = args[0].deref(self.cx());
 697                 args[1].val.nontemporal_store(self, dst);
 698                 return;
 699             }
 700
 701             "ptr_offset_from" => {
 702                 let ty = substs.type_at(0);
 703                 let pointee_size = self.size_of(ty);
 704
 705                 // This is the same sequence that Clang emits for pointer subtraction.
 706                 // It can be neither `nsw` nor `nuw` because the input is treated as
 707                 // unsigned but then the output is treated as signed, so neither works.
 708                 let a = args[0].immediate();
 709                 let b = args[1].immediate();
 710                 let a = self.ptrtoint(a, self.type_isize());
 711                 let b = self.ptrtoint(b, self.type_isize());
 712                 let d = self.sub(a, b);
 713                 let pointee_size = self.const_usize(pointee_size.bytes());
 714                 // this is where the signed magic happens (notice the `s` in `exactsdiv`)
 715                 self.exactsdiv(d, pointee_size)
 716             }
 717
 718             _ => bug!("unknown intrinsic '{}'", name),
 719         };
 720
 721         if !fn_abi.ret.is_ignore() {
 722             if let PassMode::Cast(ty) = fn_abi.ret.mode {
 723                 let ptr_llty = self.type_ptr_to(ty.llvm_type(self));
 724                 let ptr = self.pointercast(result.llval, ptr_llty);
 725                 self.store(llval, ptr, result.align);
 726             } else {
 727                 OperandRef::from_immediate_or_packed_pair(self, llval, result.layout)
 728                     .val.store(self, result);
 729             }
 730         }
 731     }
 732
 733     fn abort(&mut self) {
 734         let fnname = self.get_intrinsic(&("llvm.trap"));
 735         self.call(fnname, &[], None);
 736     }
 737
 738     fn assume(&mut self, val: Self::Value) {
 739         let assume_intrinsic = self.get_intrinsic("llvm.assume");
 740         self.call(assume_intrinsic, &[val], None);
 741     }
 742
 743     fn expect(&mut self, cond: Self::Value, expected: bool) -> Self::Value {
 744         let expect = self.get_intrinsic(&"llvm.expect.i1");
 745         self.call(expect, &[cond, self.const_bool(expected)], None)
 746     }
 747
 748     fn sideeffect(&mut self) {
 749         if self.tcx.sess.opts.debugging_opts.insert_sideeffect {
 750             let fnname = self.get_intrinsic(&("llvm.sideeffect"));
 751             self.call(fnname, &[], None);
 752         }
 753     }
 754
 755     fn va_start(&mut self, va_list: &'ll Value) -> &'ll Value {
 756         let intrinsic = self.cx().get_intrinsic("llvm.va_start");
 757         self.call(intrinsic, &[va_list], None)
 758     }
 759
 760     fn va_end(&mut self, va_list: &'ll Value) -> &'ll Value {
 761         let intrinsic = self.cx().get_intrinsic("llvm.va_end");
 762         self.call(intrinsic, &[va_list], None)
 763     }
 764 }
 765
 766 fn copy_intrinsic(
 767     bx: &mut Builder<'a, 'll, 'tcx>,
 768     allow_overlap: bool,
 769     volatile: bool,
 770     ty: Ty<'tcx>,
 771     dst: &'ll Value,
 772     src: &'ll Value,
 773     count: &'ll Value,
 774 ) {
 775     let (size, align) = bx.size_and_align_of(ty);
 776     let size = bx.mul(bx.const_usize(size.bytes()), count);
 777     let flags = if volatile {
 778         MemFlags::VOLATILE
 779     } else {
 780         MemFlags::empty()
 781     };
 782     if allow_overlap {
 783         bx.memmove(dst, align, src, align, size, flags);
 784     } else {
 785         bx.memcpy(dst, align, src, align, size, flags);
 786     }
 787 }
 788
 789 fn memset_intrinsic(
 790     bx: &mut Builder<'a, 'll, 'tcx>,
 791     volatile: bool,
 792     ty: Ty<'tcx>,
 793     dst: &'ll Value,
 794     val: &'ll Value,
 795     count: &'ll Value
 796 ) {
 797     let (size, align) = bx.size_and_align_of(ty);
 798     let size = bx.mul(bx.const_usize(size.bytes()), count);
 799     let flags = if volatile {
 800         MemFlags::VOLATILE
 801     } else {
 802         MemFlags::empty()
 803     };
 804     bx.memset(dst, val, size, align, flags);
 805 }
 806
 807 fn try_intrinsic(
 808     bx: &mut Builder<'a, 'll, 'tcx>,
 809     func: &'ll Value,
 810     data: &'ll Value,
 811     local_ptr: &'ll Value,
 812     dest: &'ll Value,
 813 ) {
 814     if bx.sess().no_landing_pads() {
 815         bx.call(func, &[data], None);
 816         let ptr_align = bx.tcx().data_layout.pointer_align.abi;
 817         bx.store(bx.const_null(bx.type_i8p()), dest, ptr_align);
 818     } else if wants_msvc_seh(bx.sess()) {
 819         codegen_msvc_try(bx, func, data, local_ptr, dest);
 820     } else {
 821         codegen_gnu_try(bx, func, data, local_ptr, dest);
 822     }
 823 }
 824
 825 // MSVC's definition of the `rust_try` function.
 826 //
 827 // This implementation uses the new exception handling instructions in LLVM
 828 // which have support in LLVM for SEH on MSVC targets. Although these
 829 // instructions are meant to work for all targets, as of the time of this
 830 // writing, however, LLVM does not recommend the usage of these new instructions
 831 // as the old ones are still more optimized.
 832 fn codegen_msvc_try(
 833     bx: &mut Builder<'a, 'll, 'tcx>,
 834     func: &'ll Value,
 835     data: &'ll Value,
 836     local_ptr: &'ll Value,
 837     dest: &'ll Value,
 838 ) {
 839     let llfn = get_rust_try_fn(bx, &mut |mut bx| {
 840         bx.set_personality_fn(bx.eh_personality());
 841         bx.sideeffect();
 842
 843         let mut normal = bx.build_sibling_block("normal");
 844         let mut catchswitch = bx.build_sibling_block("catchswitch");
 845         let mut catchpad = bx.build_sibling_block("catchpad");
 846         let mut caught = bx.build_sibling_block("caught");
 847
 848         let func = llvm::get_param(bx.llfn(), 0);
 849         let data = llvm::get_param(bx.llfn(), 1);
 850         let local_ptr = llvm::get_param(bx.llfn(), 2);
 851
 852         // We're generating an IR snippet that looks like:
 853         //
 854         //   declare i32 @rust_try(%func, %data, %ptr) {
 855         //      %slot = alloca [2 x i64]
 856         //      invoke %func(%data) to label %normal unwind label %catchswitch
 857         //
 858         //   normal:
 859         //      ret i32 0
 860         //
 861         //   catchswitch:
 862         //      %cs = catchswitch within none [%catchpad] unwind to caller
 863         //
 864         //   catchpad:
 865         //      %tok = catchpad within %cs [%type_descriptor, 0, %slot]
 866         //      %ptr[0] = %slot[0]
 867         //      %ptr[1] = %slot[1]
 868         //      catchret from %tok to label %caught
 869         //
 870         //   caught:
 871         //      ret i32 1
 872         //   }
 873         //
 874         // This structure follows the basic usage of throw/try/catch in LLVM.
 875         // For example, compile this C++ snippet to see what LLVM generates:
 876         //
 877         //      #include <stdint.h>
 878         //
 879         //      struct rust_panic {
 880         //          uint64_t x[2];
 881         //      }
 882         //
 883         //      int bar(void (*foo)(void), uint64_t *ret) {
 884         //          try {
 885         //              foo();
 886         //              return 0;
 887         //          } catch(rust_panic a) {
 888         //              ret[0] = a.x[0];
 889         //              ret[1] = a.x[1];
 890         //              return 1;
 891         //          }
 892         //      }
 893         //
 894         // More information can be found in libstd's seh.rs implementation.
 895         let i64_2 = bx.type_array(bx.type_i64(), 2);
 896         let i64_align = bx.tcx().data_layout.i64_align.abi;
 897         let slot = bx.alloca(i64_2, i64_align);
 898         bx.invoke(func, &[data], normal.llbb(), catchswitch.llbb(), None);
 899
 900         normal.ret(bx.const_i32(0));
 901
 902         let cs = catchswitch.catch_switch(None, None, 1);
 903         catchswitch.add_handler(cs, catchpad.llbb());
 904
 905         let tydesc = match bx.tcx().lang_items().eh_catch_typeinfo() {
 906             Some(did) => bx.get_static(did),
 907             None => bug!("eh_catch_typeinfo not defined, but needed for SEH unwinding"),
 908         };
 909         let funclet = catchpad.catch_pad(cs, &[tydesc, bx.const_i32(0), slot]);
 910
 911         let payload = catchpad.load(slot, i64_align);
 912         let local_ptr = catchpad.bitcast(local_ptr, bx.type_ptr_to(i64_2));
 913         catchpad.store(payload, local_ptr, i64_align);
 914         catchpad.catch_ret(&funclet, caught.llbb());
 915
 916         caught.ret(bx.const_i32(1));
 917     });
 918
 919     // Note that no invoke is used here because by definition this function
 920     // can't panic (that's what it's catching).
 921     let ret = bx.call(llfn, &[func, data, local_ptr], None);
 922     let i32_align = bx.tcx().data_layout.i32_align.abi;
 923     bx.store(ret, dest, i32_align);
 924 }
 925
 926 // Definition of the standard `try` function for Rust using the GNU-like model
 927 // of exceptions (e.g., the normal semantics of LLVM's `landingpad` and `invoke`
 928 // instructions).
 929 //
 930 // This codegen is a little surprising because we always call a shim
 931 // function instead of inlining the call to `invoke` manually here. This is done
 932 // because in LLVM we're only allowed to have one personality per function
 933 // definition. The call to the `try` intrinsic is being inlined into the
 934 // function calling it, and that function may already have other personality
 935 // functions in play. By calling a shim we're guaranteed that our shim will have
 936 // the right personality function.
 937 fn codegen_gnu_try(
 938     bx: &mut Builder<'a, 'll, 'tcx>,
 939     func: &'ll Value,
 940     data: &'ll Value,
 941     local_ptr: &'ll Value,
 942     dest: &'ll Value,
 943 ) {
 944     let llfn = get_rust_try_fn(bx, &mut |mut bx| {
 945         // Codegens the shims described above:
 946         //
 947         //   bx:
 948         //      invoke %func(%args...) normal %normal unwind %catch
 949         //
 950         //   normal:
 951         //      ret 0
 952         //
 953         //   catch:
 954         //      (ptr, _) = landingpad
 955         //      store ptr, %local_ptr
 956         //      ret 1
 957         //
 958         // Note that the `local_ptr` data passed into the `try` intrinsic is
 959         // expected to be `*mut *mut u8` for this to actually work, but that's
 960         // managed by the standard library.
 961
 962         bx.sideeffect();
 963
 964         let mut then = bx.build_sibling_block("then");
 965         let mut catch = bx.build_sibling_block("catch");
 966
 967         let func = llvm::get_param(bx.llfn(), 0);
 968         let data = llvm::get_param(bx.llfn(), 1);
 969         let local_ptr = llvm::get_param(bx.llfn(), 2);
 970         bx.invoke(func, &[data], then.llbb(), catch.llbb(), None);
 971         then.ret(bx.const_i32(0));
 972
 973         // Type indicator for the exception being thrown.
 974         //
 975         // The first value in this tuple is a pointer to the exception object
 976         // being thrown.  The second value is a "selector" indicating which of
 977         // the landing pad clauses the exception's type had been matched to.
 978         // rust_try ignores the selector.
 979         let lpad_ty = bx.type_struct(&[bx.type_i8p(), bx.type_i32()], false);
 980         let vals = catch.landing_pad(lpad_ty, bx.eh_personality(), 1);
 981         let tydesc = match bx.tcx().lang_items().eh_catch_typeinfo() {
 982             Some(tydesc) => {
 983                 let tydesc = bx.get_static(tydesc);
 984                 bx.bitcast(tydesc, bx.type_i8p())
 985             }
 986             None => bx.const_null(bx.type_i8p()),
 987         };
 988         catch.add_clause(vals, tydesc);
 989         let ptr = catch.extract_value(vals, 0);
 990         let ptr_align = bx.tcx().data_layout.pointer_align.abi;
 991         let bitcast = catch.bitcast(local_ptr, bx.type_ptr_to(bx.type_i8p()));
 992         catch.store(ptr, bitcast, ptr_align);
 993         catch.ret(bx.const_i32(1));
 994     });
 995
 996     // Note that no invoke is used here because by definition this function
 997     // can't panic (that's what it's catching).
 998     let ret = bx.call(llfn, &[func, data, local_ptr], None);
 999     let i32_align = bx.tcx().data_layout.i32_align.abi;
1000     bx.store(ret, dest, i32_align);
1001 }
1002
1003 // Helper function to give a Block to a closure to codegen a shim function.
1004 // This is currently primarily used for the `try` intrinsic functions above.
1005 fn gen_fn<'ll, 'tcx>(
1006     cx: &CodegenCx<'ll, 'tcx>,
1007     name: &str,
1008     inputs: Vec<Ty<'tcx>>,
1009     output: Ty<'tcx>,
1010     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
1011 ) -> &'ll Value {
1012     let rust_fn_sig = ty::Binder::bind(cx.tcx.mk_fn_sig(
1013         inputs.into_iter(),
1014         output,
1015         false,
1016         hir::Unsafety::Unsafe,
1017         Abi::Rust
1018     ));
1019     let fn_abi = FnAbi::of_fn_ptr(cx, rust_fn_sig, &[]);
1020     let llfn = cx.declare_fn(name, &fn_abi);
1021     // FIXME(eddyb) find a nicer way to do this.
1022     unsafe { llvm::LLVMRustSetLinkage(llfn, llvm::Linkage::InternalLinkage) };
1023     let bx = Builder::new_block(cx, llfn, "entry-block");
1024     codegen(bx);
1025     llfn
1026 }
1027
1028 // Helper function used to get a handle to the `__rust_try` function used to
1029 // catch exceptions.
1030 //
1031 // This function is only generated once and is then cached.
1032 fn get_rust_try_fn<'ll, 'tcx>(
1033     cx: &CodegenCx<'ll, 'tcx>,
1034     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
1035 ) -> &'ll Value {
1036     if let Some(llfn) = cx.rust_try_fn.get() {
1037         return llfn;
1038     }
1039
1040     // Define the type up front for the signature of the rust_try function.
1041     let tcx = cx.tcx;
1042     let i8p = tcx.mk_mut_ptr(tcx.types.i8);
1043     let fn_ty = tcx.mk_fn_ptr(ty::Binder::bind(tcx.mk_fn_sig(
1044         iter::once(i8p),
1045         tcx.mk_unit(),
1046         false,
1047         hir::Unsafety::Unsafe,
1048         Abi::Rust
1049     )));
1050     let output = tcx.types.i32;
1051     let rust_try = gen_fn(cx, "__rust_try", vec![fn_ty, i8p, i8p], output, codegen);
1052     cx.rust_try_fn.set(Some(rust_try));
1053     rust_try
1054 }
1055
1056 fn generic_simd_intrinsic(
1057     bx: &mut Builder<'a, 'll, 'tcx>,
1058     name: &str,
1059     callee_ty: Ty<'tcx>,
1060     args: &[OperandRef<'tcx, &'ll Value>],
1061     ret_ty: Ty<'tcx>,
1062     llret_ty: &'ll Type,
1063     span: Span
1064 ) -> Result<&'ll Value, ()> {
1065     // macros for error handling:
1066     macro_rules! emit_error {
1067         ($msg: tt) => {
1068             emit_error!($msg, )
1069         };
1070         ($msg: tt, $($fmt: tt)*) => {
1071             span_invalid_monomorphization_error(
1072                 bx.sess(), span,
1073                 &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg),
1074                          name, $($fmt)*));
1075         }
1076     }
1077
1078     macro_rules! return_error {
1079         ($($fmt: tt)*) => {
1080             {
1081                 emit_error!($($fmt)*);
1082                 return Err(());
1083             }
1084         }
1085     }
1086
1087     macro_rules! require {
1088         ($cond: expr, $($fmt: tt)*) => {
1089             if !$cond {
1090                 return_error!($($fmt)*);
1091             }
1092         };
1093     }
1094
1095     macro_rules! require_simd {
1096         ($ty: expr, $position: expr) => {
1097             require!($ty.is_simd(), "expected SIMD {} type, found non-SIMD `{}`", $position, $ty)
1098         }
1099     }
1100
1101     let tcx = bx.tcx();
1102     let sig = tcx.normalize_erasing_late_bound_regions(
1103         ty::ParamEnv::reveal_all(),
1104         &callee_ty.fn_sig(tcx),
1105     );
1106     let arg_tys = sig.inputs();
1107
1108     if name == "simd_select_bitmask" {
1109         let in_ty = arg_tys[0];
1110         let m_len = match in_ty.kind {
1111             // Note that this `.unwrap()` crashes for isize/usize, that's sort
1112             // of intentional as there's not currently a use case for that.
1113             ty::Int(i) => i.bit_width().unwrap() as u64,
1114             ty::Uint(i) => i.bit_width().unwrap() as u64,
1115             _ => return_error!("`{}` is not an integral type", in_ty),
1116         };
1117         require_simd!(arg_tys[1], "argument");
1118         let v_len = arg_tys[1].simd_size(tcx);
1119         require!(m_len == v_len,
1120                  "mismatched lengths: mask length `{}` != other vector length `{}`",
1121                  m_len, v_len
1122         );
1123         let i1 = bx.type_i1();
1124         let i1xn = bx.type_vector(i1, m_len);
1125         let m_i1s = bx.bitcast(args[0].immediate(), i1xn);
1126         return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
1127     }
1128
1129     // every intrinsic below takes a SIMD vector as its first argument
1130     require_simd!(arg_tys[0], "input");
1131     let in_ty = arg_tys[0];
1132     let in_elem = arg_tys[0].simd_type(tcx);
1133     let in_len = arg_tys[0].simd_size(tcx);
1134
1135     let comparison = match name {
1136         "simd_eq" => Some(hir::BinOpKind::Eq),
1137         "simd_ne" => Some(hir::BinOpKind::Ne),
1138         "simd_lt" => Some(hir::BinOpKind::Lt),
1139         "simd_le" => Some(hir::BinOpKind::Le),
1140         "simd_gt" => Some(hir::BinOpKind::Gt),
1141         "simd_ge" => Some(hir::BinOpKind::Ge),
1142         _ => None
1143     };
1144
1145     if let Some(cmp_op) = comparison {
1146         require_simd!(ret_ty, "return");
1147
1148         let out_len = ret_ty.simd_size(tcx);
1149         require!(in_len == out_len,
1150                  "expected return type with length {} (same as input type `{}`), \
1151                   found `{}` with length {}",
1152                  in_len, in_ty,
1153                  ret_ty, out_len);
1154         require!(bx.type_kind(bx.element_type(llret_ty)) == TypeKind::Integer,
1155                  "expected return type with integer elements, found `{}` with non-integer `{}`",
1156                  ret_ty,
1157                  ret_ty.simd_type(tcx));
1158
1159         return Ok(compare_simd_types(bx,
1160                                      args[0].immediate(),
1161                                      args[1].immediate(),
1162                                      in_elem,
1163                                      llret_ty,
1164                                      cmp_op))
1165     }
1166
1167     if name.starts_with("simd_shuffle") {
1168         let n: u64 = name["simd_shuffle".len()..].parse().unwrap_or_else(|_|
1169             span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?"));
1170
1171         require_simd!(ret_ty, "return");
1172
1173         let out_len = ret_ty.simd_size(tcx);
1174         require!(out_len == n,
1175                  "expected return type of length {}, found `{}` with length {}",
1176                  n, ret_ty, out_len);
1177         require!(in_elem == ret_ty.simd_type(tcx),
1178                  "expected return element type `{}` (element of input `{}`), \
1179                   found `{}` with element type `{}`",
1180                  in_elem, in_ty,
1181                  ret_ty, ret_ty.simd_type(tcx));
1182
1183         let total_len = u128::from(in_len) * 2;
1184
1185         let vector = args[2].immediate();
1186
1187         let indices: Option<Vec<_>> = (0..n)
1188             .map(|i| {
1189                 let arg_idx = i;
1190                 let val = bx.const_get_elt(vector, i as u64);
1191                 match bx.const_to_opt_u128(val, true) {
1192                     None => {
1193                         emit_error!("shuffle index #{} is not a constant", arg_idx);
1194                         None
1195                     }
1196                     Some(idx) if idx >= total_len => {
1197                         emit_error!("shuffle index #{} is out of bounds (limit {})",
1198                                     arg_idx, total_len);
1199                         None
1200                     }
1201                     Some(idx) => Some(bx.const_i32(idx as i32)),
1202                 }
1203             })
1204             .collect();
1205         let indices = match indices {
1206             Some(i) => i,
1207             None => return Ok(bx.const_null(llret_ty))
1208         };
1209
1210         return Ok(bx.shuffle_vector(args[0].immediate(),
1211                                     args[1].immediate(),
1212                                     bx.const_vector(&indices)))
1213     }
1214
1215     if name == "simd_insert" {
1216         require!(in_elem == arg_tys[2],
1217                  "expected inserted type `{}` (element of input `{}`), found `{}`",
1218                  in_elem, in_ty, arg_tys[2]);
1219         return Ok(bx.insert_element(args[0].immediate(),
1220                                     args[2].immediate(),
1221                                     args[1].immediate()))
1222     }
1223     if name == "simd_extract" {
1224         require!(ret_ty == in_elem,
1225                  "expected return type `{}` (element of input `{}`), found `{}`",
1226                  in_elem, in_ty, ret_ty);
1227         return Ok(bx.extract_element(args[0].immediate(), args[1].immediate()))
1228     }
1229
1230     if name == "simd_select" {
1231         let m_elem_ty = in_elem;
1232         let m_len = in_len;
1233         require_simd!(arg_tys[1], "argument");
1234         let v_len = arg_tys[1].simd_size(tcx);
1235         require!(m_len == v_len,
1236                  "mismatched lengths: mask length `{}` != other vector length `{}`",
1237                  m_len, v_len
1238         );
1239         match m_elem_ty.kind {
1240             ty::Int(_) => {},
1241             _ => return_error!("mask element type is `{}`, expected `i_`", m_elem_ty)
1242         }
1243         // truncate the mask to a vector of i1s
1244         let i1 = bx.type_i1();
1245         let i1xn = bx.type_vector(i1, m_len as u64);
1246         let m_i1s = bx.trunc(args[0].immediate(), i1xn);
1247         return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
1248     }
1249
1250     if name == "simd_bitmask" {
1251         // The `fn simd_bitmask(vector) -> unsigned integer` intrinsic takes a
1252         // vector mask and returns an unsigned integer containing the most
1253         // significant bit (MSB) of each lane.
1254
1255         // If the vector has less than 8 lanes, an u8 is returned with zeroed
1256         // trailing bits.
1257         let expected_int_bits = in_len.max(8);
1258         match ret_ty.kind {
1259            ty::Uint(i) if i.bit_width() == Some(expected_int_bits as usize) => (),
1260             _ => return_error!(
1261                 "bitmask `{}`, expected `u{}`",
1262                 ret_ty, expected_int_bits
1263             ),
1264         }
1265
1266         // Integer vector <i{in_bitwidth} x in_len>:
1267         let (i_xn, in_elem_bitwidth) = match in_elem.kind {
1268             ty::Int(i) => (
1269                 args[0].immediate(),
1270                 i.bit_width().unwrap_or(bx.data_layout().pointer_size.bits() as _)
1271             ),
1272             ty::Uint(i) => (
1273                 args[0].immediate(),
1274                 i.bit_width().unwrap_or(bx.data_layout().pointer_size.bits() as _)
1275             ),
1276             _ => return_error!(
1277                 "vector argument `{}`'s element type `{}`, expected integer element type",
1278                 in_ty, in_elem
1279             ),
1280         };
1281
1282         // Shift the MSB to the right by "in_elem_bitwidth - 1" into the first bit position.
1283         let shift_indices = vec![
1284             bx.cx.const_int(bx.type_ix(in_elem_bitwidth as _), (in_elem_bitwidth - 1) as _);
1285             in_len as _
1286         ];
1287         let i_xn_msb = bx.lshr(i_xn, bx.const_vector(shift_indices.as_slice()));
1288         // Truncate vector to an <i1 x N>
1289         let i1xn = bx.trunc(i_xn_msb, bx.type_vector(bx.type_i1(), in_len as _));
1290         // Bitcast <i1 x N> to iN:
1291         let i_ = bx.bitcast(i1xn, bx.type_ix(in_len as _));
1292         // Zero-extend iN to the bitmask type:
1293         return Ok(bx.zext(i_, bx.type_ix(expected_int_bits as _)));
1294     }
1295
1296     fn simd_simple_float_intrinsic(
1297         name: &str,
1298         in_elem: &::rustc::ty::TyS<'_>,
1299         in_ty: &::rustc::ty::TyS<'_>,
1300         in_len: u64,
1301         bx: &mut Builder<'a, 'll, 'tcx>,
1302         span: Span,
1303         args: &[OperandRef<'tcx, &'ll Value>],
1304     ) -> Result<&'ll Value, ()> {
1305         macro_rules! emit_error {
1306             ($msg: tt) => {
1307                 emit_error!($msg, )
1308             };
1309             ($msg: tt, $($fmt: tt)*) => {
1310                 span_invalid_monomorphization_error(
1311                     bx.sess(), span,
1312                     &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg),
1313                              name, $($fmt)*));
1314             }
1315         }
1316         macro_rules! return_error {
1317             ($($fmt: tt)*) => {
1318                 {
1319                     emit_error!($($fmt)*);
1320                     return Err(());
1321                 }
1322             }
1323         }
1324         let ety = match in_elem.kind {
1325             ty::Float(f) if f.bit_width() == 32 => {
1326                 if in_len < 2 || in_len > 16 {
1327                     return_error!(
1328                         "unsupported floating-point vector `{}` with length `{}` \
1329                          out-of-range [2, 16]",
1330                         in_ty, in_len);
1331                 }
1332                 "f32"
1333             },
1334             ty::Float(f) if f.bit_width() == 64 => {
1335                 if in_len < 2 || in_len > 8 {
1336                     return_error!("unsupported floating-point vector `{}` with length `{}` \
1337                                    out-of-range [2, 8]",
1338                                   in_ty, in_len);
1339                 }
1340                 "f64"
1341             },
1342             ty::Float(f) => {
1343                 return_error!("unsupported element type `{}` of floating-point vector `{}`",
1344                               f.name_str(), in_ty);
1345             },
1346             _ => {
1347                 return_error!("`{}` is not a floating-point type", in_ty);
1348             }
1349         };
1350
1351         let llvm_name = &format!("llvm.{0}.v{1}{2}", name, in_len, ety);
1352         let intrinsic = bx.get_intrinsic(&llvm_name);
1353         let c = bx.call(intrinsic,
1354                         &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
1355                         None);
1356         unsafe { llvm::LLVMRustSetHasUnsafeAlgebra(c) };
1357         Ok(c)
1358     }
1359
1360     match name {
1361         "simd_fsqrt" => {
1362             return simd_simple_float_intrinsic("sqrt", in_elem, in_ty, in_len, bx, span, args);
1363         }
1364         "simd_fsin" => {
1365             return simd_simple_float_intrinsic("sin", in_elem, in_ty, in_len, bx, span, args);
1366         }
1367         "simd_fcos" => {
1368             return simd_simple_float_intrinsic("cos", in_elem, in_ty, in_len, bx, span, args);
1369         }
1370         "simd_fabs" => {
1371             return simd_simple_float_intrinsic("fabs", in_elem, in_ty, in_len, bx, span, args);
1372         }
1373         "simd_floor" => {
1374             return simd_simple_float_intrinsic("floor", in_elem, in_ty, in_len, bx, span, args);
1375         }
1376         "simd_ceil" => {
1377             return simd_simple_float_intrinsic("ceil", in_elem, in_ty, in_len, bx, span, args);
1378         }
1379         "simd_fexp" => {
1380             return simd_simple_float_intrinsic("exp", in_elem, in_ty, in_len, bx, span, args);
1381         }
1382         "simd_fexp2" => {
1383             return simd_simple_float_intrinsic("exp2", in_elem, in_ty, in_len, bx, span, args);
1384         }
1385         "simd_flog10" => {
1386             return simd_simple_float_intrinsic("log10", in_elem, in_ty, in_len, bx, span, args);
1387         }
1388         "simd_flog2" => {
1389             return simd_simple_float_intrinsic("log2", in_elem, in_ty, in_len, bx, span, args);
1390         }
1391         "simd_flog" => {
1392             return simd_simple_float_intrinsic("log", in_elem, in_ty, in_len, bx, span, args);
1393         }
1394         "simd_fpowi" => {
1395             return simd_simple_float_intrinsic("powi", in_elem, in_ty, in_len, bx, span, args);
1396         }
1397         "simd_fpow" => {
1398             return simd_simple_float_intrinsic("pow", in_elem, in_ty, in_len, bx, span, args);
1399         }
1400         "simd_fma" => {
1401             return simd_simple_float_intrinsic("fma", in_elem, in_ty, in_len, bx, span, args);
1402         }
1403         _ => { /* fallthrough */ }
1404     }
1405
1406     // FIXME: use:
1407     //  https://github.com/llvm-mirror/llvm/blob/master/include/llvm/IR/Function.h#L182
1408     //  https://github.com/llvm-mirror/llvm/blob/master/include/llvm/IR/Intrinsics.h#L81
1409     fn llvm_vector_str(elem_ty: Ty<'_>, vec_len: u64, no_pointers: usize) -> String {
1410         let p0s: String = "p0".repeat(no_pointers);
1411         match elem_ty.kind {
1412             ty::Int(v) => format!("v{}{}i{}", vec_len, p0s, v.bit_width().unwrap()),
1413             ty::Uint(v) => format!("v{}{}i{}", vec_len, p0s, v.bit_width().unwrap()),
1414             ty::Float(v) => format!("v{}{}f{}", vec_len, p0s, v.bit_width()),
1415             _ => unreachable!(),
1416         }
1417     }
1418
1419     fn llvm_vector_ty(cx: &CodegenCx<'ll, '_>, elem_ty: Ty<'_>, vec_len: u64,
1420                       mut no_pointers: usize) -> &'ll Type {
1421         // FIXME: use cx.layout_of(ty).llvm_type() ?
1422         let mut elem_ty = match elem_ty.kind {
1423             ty::Int(v) => cx.type_int_from_ty( v),
1424             ty::Uint(v) => cx.type_uint_from_ty( v),
1425             ty::Float(v) => cx.type_float_from_ty( v),
1426             _ => unreachable!(),
1427         };
1428         while no_pointers > 0 {
1429             elem_ty = cx.type_ptr_to(elem_ty);
1430             no_pointers -= 1;
1431         }
1432         cx.type_vector(elem_ty, vec_len)
1433     }
1434
1435
1436     if name == "simd_gather" {
1437         // simd_gather(values: <N x T>, pointers: <N x *_ T>,
1438         //             mask: <N x i{M}>) -> <N x T>
1439         // * N: number of elements in the input vectors
1440         // * T: type of the element to load
1441         // * M: any integer width is supported, will be truncated to i1
1442
1443         // All types must be simd vector types
1444         require_simd!(in_ty, "first");
1445         require_simd!(arg_tys[1], "second");
1446         require_simd!(arg_tys[2], "third");
1447         require_simd!(ret_ty, "return");
1448
1449         // Of the same length:
1450         require!(in_len == arg_tys[1].simd_size(tcx),
1451                  "expected {} argument with length {} (same as input type `{}`), \
1452                   found `{}` with length {}", "second", in_len, in_ty, arg_tys[1],
1453                  arg_tys[1].simd_size(tcx));
1454         require!(in_len == arg_tys[2].simd_size(tcx),
1455                  "expected {} argument with length {} (same as input type `{}`), \
1456                   found `{}` with length {}", "third", in_len, in_ty, arg_tys[2],
1457                  arg_tys[2].simd_size(tcx));
1458
1459         // The return type must match the first argument type
1460         require!(ret_ty == in_ty,
1461                  "expected return type `{}`, found `{}`",
1462                  in_ty, ret_ty);
1463
1464         // This counts how many pointers
1465         fn ptr_count(t: Ty<'_>) -> usize {
1466             match t.kind {
1467                 ty::RawPtr(p) => 1 + ptr_count(p.ty),
1468                 _ => 0,
1469             }
1470         }
1471
1472         // Non-ptr type
1473         fn non_ptr(t: Ty<'_>) -> Ty<'_> {
1474             match t.kind {
1475                 ty::RawPtr(p) => non_ptr(p.ty),
1476                 _ => t,
1477             }
1478         }
1479
1480         // The second argument must be a simd vector with an element type that's a pointer
1481         // to the element type of the first argument
1482         let (pointer_count, underlying_ty) = match arg_tys[1].simd_type(tcx).kind {
1483             ty::RawPtr(p) if p.ty == in_elem => (ptr_count(arg_tys[1].simd_type(tcx)),
1484                                                  non_ptr(arg_tys[1].simd_type(tcx))),
1485             _ => {
1486                 require!(false, "expected element type `{}` of second argument `{}` \
1487                                  to be a pointer to the element type `{}` of the first \
1488                                  argument `{}`, found `{}` != `*_ {}`",
1489                          arg_tys[1].simd_type(tcx), arg_tys[1], in_elem, in_ty,
1490                          arg_tys[1].simd_type(tcx), in_elem);
1491                 unreachable!();
1492             }
1493         };
1494         assert!(pointer_count > 0);
1495         assert_eq!(pointer_count - 1, ptr_count(arg_tys[0].simd_type(tcx)));
1496         assert_eq!(underlying_ty, non_ptr(arg_tys[0].simd_type(tcx)));
1497
1498         // The element type of the third argument must be a signed integer type of any width:
1499         match arg_tys[2].simd_type(tcx).kind {
1500             ty::Int(_) => (),
1501             _ => {
1502                 require!(false, "expected element type `{}` of third argument `{}` \
1503                                  to be a signed integer type",
1504                          arg_tys[2].simd_type(tcx), arg_tys[2]);
1505             }
1506         }
1507
1508         // Alignment of T, must be a constant integer value:
1509         let alignment_ty = bx.type_i32();
1510         let alignment = bx.const_i32(bx.align_of(in_elem).bytes() as i32);
1511
1512         // Truncate the mask vector to a vector of i1s:
1513         let (mask, mask_ty) = {
1514             let i1 = bx.type_i1();
1515             let i1xn = bx.type_vector(i1, in_len);
1516             (bx.trunc(args[2].immediate(), i1xn), i1xn)
1517         };
1518
1519         // Type of the vector of pointers:
1520         let llvm_pointer_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count);
1521         let llvm_pointer_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count);
1522
1523         // Type of the vector of elements:
1524         let llvm_elem_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count - 1);
1525         let llvm_elem_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count - 1);
1526
1527         let llvm_intrinsic = format!("llvm.masked.gather.{}.{}",
1528                                      llvm_elem_vec_str, llvm_pointer_vec_str);
1529         let f = bx.declare_cfn(&llvm_intrinsic,
1530                                      bx.type_func(&[
1531                                          llvm_pointer_vec_ty,
1532                                          alignment_ty,
1533                                          mask_ty,
1534                                          llvm_elem_vec_ty], llvm_elem_vec_ty));
1535         llvm::SetUnnamedAddr(f, false);
1536         let v = bx.call(f, &[args[1].immediate(), alignment, mask, args[0].immediate()],
1537                         None);
1538         return Ok(v);
1539     }
1540
1541     if name == "simd_scatter" {
1542         // simd_scatter(values: <N x T>, pointers: <N x *mut T>,
1543         //             mask: <N x i{M}>) -> ()
1544         // * N: number of elements in the input vectors
1545         // * T: type of the element to load
1546         // * M: any integer width is supported, will be truncated to i1
1547
1548         // All types must be simd vector types
1549         require_simd!(in_ty, "first");
1550         require_simd!(arg_tys[1], "second");
1551         require_simd!(arg_tys[2], "third");
1552
1553         // Of the same length:
1554         require!(in_len == arg_tys[1].simd_size(tcx),
1555                  "expected {} argument with length {} (same as input type `{}`), \
1556                   found `{}` with length {}", "second", in_len, in_ty, arg_tys[1],
1557                  arg_tys[1].simd_size(tcx));
1558         require!(in_len == arg_tys[2].simd_size(tcx),
1559                  "expected {} argument with length {} (same as input type `{}`), \
1560                   found `{}` with length {}", "third", in_len, in_ty, arg_tys[2],
1561                  arg_tys[2].simd_size(tcx));
1562
1563         // This counts how many pointers
1564         fn ptr_count(t: Ty<'_>) -> usize {
1565             match t.kind {
1566                 ty::RawPtr(p) => 1 + ptr_count(p.ty),
1567                 _ => 0,
1568             }
1569         }
1570
1571         // Non-ptr type
1572         fn non_ptr(t: Ty<'_>) -> Ty<'_> {
1573             match t.kind {
1574                 ty::RawPtr(p) => non_ptr(p.ty),
1575                 _ => t,
1576             }
1577         }
1578
1579         // The second argument must be a simd vector with an element type that's a pointer
1580         // to the element type of the first argument
1581         let (pointer_count, underlying_ty) = match arg_tys[1].simd_type(tcx).kind {
1582             ty::RawPtr(p) if p.ty == in_elem && p.mutbl == hir::Mutability::Mut
1583                 => (ptr_count(arg_tys[1].simd_type(tcx)),
1584                     non_ptr(arg_tys[1].simd_type(tcx))),
1585             _ => {
1586                 require!(false, "expected element type `{}` of second argument `{}` \
1587                                  to be a pointer to the element type `{}` of the first \
1588                                  argument `{}`, found `{}` != `*mut {}`",
1589                          arg_tys[1].simd_type(tcx), arg_tys[1], in_elem, in_ty,
1590                          arg_tys[1].simd_type(tcx), in_elem);
1591                 unreachable!();
1592             }
1593         };
1594         assert!(pointer_count > 0);
1595         assert_eq!(pointer_count - 1, ptr_count(arg_tys[0].simd_type(tcx)));
1596         assert_eq!(underlying_ty, non_ptr(arg_tys[0].simd_type(tcx)));
1597
1598         // The element type of the third argument must be a signed integer type of any width:
1599         match arg_tys[2].simd_type(tcx).kind {
1600             ty::Int(_) => (),
1601             _ => {
1602                 require!(false, "expected element type `{}` of third argument `{}` \
1603                                  to be a signed integer type",
1604                          arg_tys[2].simd_type(tcx), arg_tys[2]);
1605             }
1606         }
1607
1608         // Alignment of T, must be a constant integer value:
1609         let alignment_ty = bx.type_i32();
1610         let alignment = bx.const_i32(bx.align_of(in_elem).bytes() as i32);
1611
1612         // Truncate the mask vector to a vector of i1s:
1613         let (mask, mask_ty) = {
1614             let i1 = bx.type_i1();
1615             let i1xn = bx.type_vector(i1, in_len);
1616             (bx.trunc(args[2].immediate(), i1xn), i1xn)
1617         };
1618
1619         let ret_t = bx.type_void();
1620
1621         // Type of the vector of pointers:
1622         let llvm_pointer_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count);
1623         let llvm_pointer_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count);
1624
1625         // Type of the vector of elements:
1626         let llvm_elem_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count - 1);
1627         let llvm_elem_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count - 1);
1628
1629         let llvm_intrinsic = format!("llvm.masked.scatter.{}.{}",
1630                                      llvm_elem_vec_str, llvm_pointer_vec_str);
1631         let f = bx.declare_cfn(&llvm_intrinsic,
1632                                      bx.type_func(&[llvm_elem_vec_ty,
1633                                                   llvm_pointer_vec_ty,
1634                                                   alignment_ty,
1635                                                   mask_ty], ret_t));
1636         llvm::SetUnnamedAddr(f, false);
1637         let v = bx.call(f, &[args[0].immediate(), args[1].immediate(), alignment, mask],
1638                         None);
1639         return Ok(v);
1640     }
1641
1642     macro_rules! arith_red {
1643         ($name:tt : $integer_reduce:ident, $float_reduce:ident, $ordered:expr) => {
1644             if name == $name {
1645                 require!(ret_ty == in_elem,
1646                          "expected return type `{}` (element of input `{}`), found `{}`",
1647                          in_elem, in_ty, ret_ty);
1648                 return match in_elem.kind {
1649                     ty::Int(_) | ty::Uint(_) => {
1650                         let r = bx.$integer_reduce(args[0].immediate());
1651                         if $ordered {
1652                             // if overflow occurs, the result is the
1653                             // mathematical result modulo 2^n:
1654                             if name.contains("mul") {
1655                                 Ok(bx.mul(args[1].immediate(), r))
1656                             } else {
1657                                 Ok(bx.add(args[1].immediate(), r))
1658                             }
1659                         } else {
1660                             Ok(bx.$integer_reduce(args[0].immediate()))
1661                         }
1662                     },
1663                     ty::Float(f) => {
1664                         let acc = if $ordered {
1665                             // ordered arithmetic reductions take an accumulator
1666                             args[1].immediate()
1667                         } else {
1668                             // unordered arithmetic reductions use the identity accumulator
1669                             let identity_acc = if $name.contains("mul") { 1.0 } else { 0.0 };
1670                             match f.bit_width() {
1671                                 32 => bx.const_real(bx.type_f32(), identity_acc),
1672                                 64 => bx.const_real(bx.type_f64(), identity_acc),
1673                                 v => {
1674                                     return_error!(r#"
1675 unsupported {} from `{}` with element `{}` of size `{}` to `{}`"#,
1676                                         $name, in_ty, in_elem, v, ret_ty
1677                                     )
1678                                 }
1679                             }
1680                         };
1681                         Ok(bx.$float_reduce(acc, args[0].immediate()))
1682                     }
1683                     _ => {
1684                         return_error!(
1685                             "unsupported {} from `{}` with element `{}` to `{}`",
1686                             $name, in_ty, in_elem, ret_ty
1687                         )
1688                     },
1689                 }
1690             }
1691         }
1692     }
1693
1694     arith_red!("simd_reduce_add_ordered": vector_reduce_add, vector_reduce_fadd, true);
1695     arith_red!("simd_reduce_mul_ordered": vector_reduce_mul, vector_reduce_fmul, true);
1696     arith_red!("simd_reduce_add_unordered": vector_reduce_add, vector_reduce_fadd_fast, false);
1697     arith_red!("simd_reduce_mul_unordered": vector_reduce_mul, vector_reduce_fmul_fast, false);
1698
1699     macro_rules! minmax_red {
1700         ($name:tt: $int_red:ident, $float_red:ident) => {
1701             if name == $name {
1702                 require!(ret_ty == in_elem,
1703                          "expected return type `{}` (element of input `{}`), found `{}`",
1704                          in_elem, in_ty, ret_ty);
1705                 return match in_elem.kind {
1706                     ty::Int(_i) => {
1707                         Ok(bx.$int_red(args[0].immediate(), true))
1708                     },
1709                     ty::Uint(_u) => {
1710                         Ok(bx.$int_red(args[0].immediate(), false))
1711                     },
1712                     ty::Float(_f) => {
1713                         Ok(bx.$float_red(args[0].immediate()))
1714                     }
1715                     _ => {
1716                         return_error!("unsupported {} from `{}` with element `{}` to `{}`",
1717                                       $name, in_ty, in_elem, ret_ty)
1718                     },
1719                 }
1720             }
1721
1722         }
1723     }
1724
1725     minmax_red!("simd_reduce_min": vector_reduce_min, vector_reduce_fmin);
1726     minmax_red!("simd_reduce_max": vector_reduce_max, vector_reduce_fmax);
1727
1728     minmax_red!("simd_reduce_min_nanless": vector_reduce_min, vector_reduce_fmin_fast);
1729     minmax_red!("simd_reduce_max_nanless": vector_reduce_max, vector_reduce_fmax_fast);
1730
1731     macro_rules! bitwise_red {
1732         ($name:tt : $red:ident, $boolean:expr) => {
1733             if name == $name {
1734                 let input = if !$boolean {
1735                     require!(ret_ty == in_elem,
1736                              "expected return type `{}` (element of input `{}`), found `{}`",
1737                              in_elem, in_ty, ret_ty);
1738                     args[0].immediate()
1739                 } else {
1740                     match in_elem.kind {
1741                         ty::Int(_) | ty::Uint(_) => {},
1742                         _ => {
1743                             return_error!("unsupported {} from `{}` with element `{}` to `{}`",
1744                                           $name, in_ty, in_elem, ret_ty)
1745                         }
1746                     }
1747
1748                     // boolean reductions operate on vectors of i1s:
1749                     let i1 = bx.type_i1();
1750                     let i1xn = bx.type_vector(i1, in_len as u64);
1751                     bx.trunc(args[0].immediate(), i1xn)
1752                 };
1753                 return match in_elem.kind {
1754                     ty::Int(_) | ty::Uint(_) => {
1755                         let r = bx.$red(input);
1756                         Ok(
1757                             if !$boolean {
1758                                 r
1759                             } else {
1760                                 bx.zext(r, bx.type_bool())
1761                             }
1762                         )
1763                     },
1764                     _ => {
1765                         return_error!("unsupported {} from `{}` with element `{}` to `{}`",
1766                                       $name, in_ty, in_elem, ret_ty)
1767                     },
1768                 }
1769             }
1770         }
1771     }
1772
1773     bitwise_red!("simd_reduce_and": vector_reduce_and, false);
1774     bitwise_red!("simd_reduce_or": vector_reduce_or, false);
1775     bitwise_red!("simd_reduce_xor": vector_reduce_xor, false);
1776     bitwise_red!("simd_reduce_all": vector_reduce_and, true);
1777     bitwise_red!("simd_reduce_any": vector_reduce_or, true);
1778
1779     if name == "simd_cast" {
1780         require_simd!(ret_ty, "return");
1781         let out_len = ret_ty.simd_size(tcx);
1782         require!(in_len == out_len,
1783                  "expected return type with length {} (same as input type `{}`), \
1784                   found `{}` with length {}",
1785                  in_len, in_ty,
1786                  ret_ty, out_len);
1787         // casting cares about nominal type, not just structural type
1788         let out_elem = ret_ty.simd_type(tcx);
1789
1790         if in_elem == out_elem { return Ok(args[0].immediate()); }
1791
1792         enum Style { Float, Int(/* is signed? */ bool), Unsupported }
1793
1794         let (in_style, in_width) = match in_elem.kind {
1795             // vectors of pointer-sized integers should've been
1796             // disallowed before here, so this unwrap is safe.
1797             ty::Int(i) => (Style::Int(true), i.bit_width().unwrap()),
1798             ty::Uint(u) => (Style::Int(false), u.bit_width().unwrap()),
1799             ty::Float(f) => (Style::Float, f.bit_width()),
1800             _ => (Style::Unsupported, 0)
1801         };
1802         let (out_style, out_width) = match out_elem.kind {
1803             ty::Int(i) => (Style::Int(true), i.bit_width().unwrap()),
1804             ty::Uint(u) => (Style::Int(false), u.bit_width().unwrap()),
1805             ty::Float(f) => (Style::Float, f.bit_width()),
1806             _ => (Style::Unsupported, 0)
1807         };
1808
1809         match (in_style, out_style) {
1810             (Style::Int(in_is_signed), Style::Int(_)) => {
1811                 return Ok(match in_width.cmp(&out_width) {
1812                     Ordering::Greater => bx.trunc(args[0].immediate(), llret_ty),
1813                     Ordering::Equal => args[0].immediate(),
1814                     Ordering::Less => if in_is_signed {
1815                         bx.sext(args[0].immediate(), llret_ty)
1816                     } else {
1817                         bx.zext(args[0].immediate(), llret_ty)
1818                     }
1819                 })
1820             }
1821             (Style::Int(in_is_signed), Style::Float) => {
1822                 return Ok(if in_is_signed {
1823                     bx.sitofp(args[0].immediate(), llret_ty)
1824                 } else {
1825                     bx.uitofp(args[0].immediate(), llret_ty)
1826                 })
1827             }
1828             (Style::Float, Style::Int(out_is_signed)) => {
1829                 return Ok(if out_is_signed {
1830                     bx.fptosi(args[0].immediate(), llret_ty)
1831                 } else {
1832                     bx.fptoui(args[0].immediate(), llret_ty)
1833                 })
1834             }
1835             (Style::Float, Style::Float) => {
1836                 return Ok(match in_width.cmp(&out_width) {
1837                     Ordering::Greater => bx.fptrunc(args[0].immediate(), llret_ty),
1838                     Ordering::Equal => args[0].immediate(),
1839                     Ordering::Less => bx.fpext(args[0].immediate(), llret_ty)
1840                 })
1841             }
1842             _ => {/* Unsupported. Fallthrough. */}
1843         }
1844         require!(false,
1845                  "unsupported cast from `{}` with element `{}` to `{}` with element `{}`",
1846                  in_ty, in_elem,
1847                  ret_ty, out_elem);
1848     }
1849     macro_rules! arith {
1850         ($($name: ident: $($($p: ident),* => $call: ident),*;)*) => {
1851             $(if name == stringify!($name) {
1852                 match in_elem.kind {
1853                     $($(ty::$p(_))|* => {
1854                         return Ok(bx.$call(args[0].immediate(), args[1].immediate()))
1855                     })*
1856                     _ => {},
1857                 }
1858                 require!(false,
1859                          "unsupported operation on `{}` with element `{}`",
1860                          in_ty,
1861                          in_elem)
1862             })*
1863         }
1864     }
1865     arith! {
1866         simd_add: Uint, Int => add, Float => fadd;
1867         simd_sub: Uint, Int => sub, Float => fsub;
1868         simd_mul: Uint, Int => mul, Float => fmul;
1869         simd_div: Uint => udiv, Int => sdiv, Float => fdiv;
1870         simd_rem: Uint => urem, Int => srem, Float => frem;
1871         simd_shl: Uint, Int => shl;
1872         simd_shr: Uint => lshr, Int => ashr;
1873         simd_and: Uint, Int => and;
1874         simd_or: Uint, Int => or;
1875         simd_xor: Uint, Int => xor;
1876         simd_fmax: Float => maxnum;
1877         simd_fmin: Float => minnum;
1878
1879     }
1880
1881     if name == "simd_saturating_add" || name == "simd_saturating_sub" {
1882         let lhs = args[0].immediate();
1883         let rhs = args[1].immediate();
1884         let is_add = name == "simd_saturating_add";
1885         let ptr_bits = bx.tcx().data_layout.pointer_size.bits() as _;
1886         let (signed, elem_width, elem_ty) = match in_elem.kind {
1887             ty::Int(i) =>
1888                 (
1889                     true,
1890                     i.bit_width().unwrap_or(ptr_bits),
1891                     bx.cx.type_int_from_ty(i)
1892                 ),
1893             ty::Uint(i) =>
1894                 (
1895                     false,
1896                     i.bit_width().unwrap_or(ptr_bits),
1897                     bx.cx.type_uint_from_ty(i)
1898                 ),
1899             _ => {
1900                 return_error!(
1901                     "expected element type `{}` of vector type `{}` \
1902                      to be a signed or unsigned integer type",
1903                     arg_tys[0].simd_type(tcx), arg_tys[0]
1904                 );
1905             }
1906         };
1907         let llvm_intrinsic = &format!(
1908             "llvm.{}{}.sat.v{}i{}",
1909             if signed { 's' } else { 'u' },
1910             if is_add { "add" } else { "sub" },
1911             in_len, elem_width
1912         );
1913         let vec_ty = bx.cx.type_vector(elem_ty, in_len as u64);
1914
1915         let f = bx.declare_cfn(
1916             &llvm_intrinsic,
1917             bx.type_func(&[vec_ty, vec_ty], vec_ty)
1918         );
1919         llvm::SetUnnamedAddr(f, false);
1920         let v = bx.call(f, &[lhs, rhs], None);
1921         return Ok(v);
1922     }
1923
1924     span_bug!(span, "unknown SIMD intrinsic");
1925 }
1926
1927 // Returns the width of an int Ty, and if it's signed or not
1928 // Returns None if the type is not an integer
1929 // FIXME: there’s multiple of this functions, investigate using some of the already existing
1930 // stuffs.
1931 fn int_type_width_signed(ty: Ty<'_>, cx: &CodegenCx<'_, '_>) -> Option<(u64, bool)> {
1932     match ty.kind {
1933         ty::Int(t) => Some((match t {
1934             ast::IntTy::Isize => cx.tcx.sess.target.ptr_width as u64,
1935             ast::IntTy::I8 => 8,
1936             ast::IntTy::I16 => 16,
1937             ast::IntTy::I32 => 32,
1938             ast::IntTy::I64 => 64,
1939             ast::IntTy::I128 => 128,
1940         }, true)),
1941         ty::Uint(t) => Some((match t {
1942             ast::UintTy::Usize => cx.tcx.sess.target.ptr_width as u64,
1943             ast::UintTy::U8 => 8,
1944             ast::UintTy::U16 => 16,
1945             ast::UintTy::U32 => 32,
1946             ast::UintTy::U64 => 64,
1947             ast::UintTy::U128 => 128,
1948         }, false)),
1949         _ => None,
1950     }
1951 }
1952
1953 // Returns the width of a float Ty
1954 // Returns None if the type is not a float
1955 fn float_type_width(ty: Ty<'_>) -> Option<u64> {
1956     match ty.kind {
1957         ty::Float(t) => Some(t.bit_width() as u64),
1958         _ => None,
1959     }
1960 }