src/librustc_codegen_llvm/intrinsic.rs

   1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 #![allow(non_upper_case_globals)]
  12
  13 use attributes;
  14 use intrinsics::{self, Intrinsic};
  15 use llvm;
  16 use llvm_util;
  17 use abi::{Abi, FnType, LlvmType, PassMode};
  18 use mir::place::PlaceRef;
  19 use mir::operand::{OperandRef, OperandValue};
  20 use base::*;
  21 use context::CodegenCx;
  22 use glue;
  23 use type_::Type;
  24 use type_of::LayoutLlvmExt;
  25 use rustc::ty::{self, Ty};
  26 use rustc::ty::layout::{LayoutOf, HasTyCtxt};
  27 use rustc_codegen_ssa::common::TypeKind;
  28 use rustc::hir;
  29 use syntax::ast;
  30 use syntax::symbol::Symbol;
  31 use builder::{Builder, MemFlags};
  32 use value::Value;
  33
  34 use interfaces::*;
  35
  36 use rustc::session::Session;
  37 use syntax_pos::Span;
  38
  39 use std::cmp::Ordering;
  40 use std::iter;
  41
  42 fn get_simple_intrinsic(cx: &CodegenCx<'ll, '_>, name: &str) -> Option<&'ll Value> {
  43     let llvm_name = match name {
  44         "sqrtf32" => "llvm.sqrt.f32",
  45         "sqrtf64" => "llvm.sqrt.f64",
  46         "powif32" => "llvm.powi.f32",
  47         "powif64" => "llvm.powi.f64",
  48         "sinf32" => "llvm.sin.f32",
  49         "sinf64" => "llvm.sin.f64",
  50         "cosf32" => "llvm.cos.f32",
  51         "cosf64" => "llvm.cos.f64",
  52         "powf32" => "llvm.pow.f32",
  53         "powf64" => "llvm.pow.f64",
  54         "expf32" => "llvm.exp.f32",
  55         "expf64" => "llvm.exp.f64",
  56         "exp2f32" => "llvm.exp2.f32",
  57         "exp2f64" => "llvm.exp2.f64",
  58         "logf32" => "llvm.log.f32",
  59         "logf64" => "llvm.log.f64",
  60         "log10f32" => "llvm.log10.f32",
  61         "log10f64" => "llvm.log10.f64",
  62         "log2f32" => "llvm.log2.f32",
  63         "log2f64" => "llvm.log2.f64",
  64         "fmaf32" => "llvm.fma.f32",
  65         "fmaf64" => "llvm.fma.f64",
  66         "fabsf32" => "llvm.fabs.f32",
  67         "fabsf64" => "llvm.fabs.f64",
  68         "copysignf32" => "llvm.copysign.f32",
  69         "copysignf64" => "llvm.copysign.f64",
  70         "floorf32" => "llvm.floor.f32",
  71         "floorf64" => "llvm.floor.f64",
  72         "ceilf32" => "llvm.ceil.f32",
  73         "ceilf64" => "llvm.ceil.f64",
  74         "truncf32" => "llvm.trunc.f32",
  75         "truncf64" => "llvm.trunc.f64",
  76         "rintf32" => "llvm.rint.f32",
  77         "rintf64" => "llvm.rint.f64",
  78         "nearbyintf32" => "llvm.nearbyint.f32",
  79         "nearbyintf64" => "llvm.nearbyint.f64",
  80         "roundf32" => "llvm.round.f32",
  81         "roundf64" => "llvm.round.f64",
  82         "assume" => "llvm.assume",
  83         "abort" => "llvm.trap",
  84         _ => return None
  85     };
  86     Some(cx.get_intrinsic(&llvm_name))
  87 }
  88
  89 impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
  90     fn codegen_intrinsic_call(
  91         &self,
  92         callee_ty: Ty<'tcx>,
  93         fn_ty: &FnType<'tcx, Ty<'tcx>>,
  94         args: &[OperandRef<'tcx, &'ll Value>],
  95         llresult: &'ll Value,
  96         span: Span,
  97     ) {
  98         let cx = self.cx();
  99         let tcx = cx.tcx;
 100
 101         let (def_id, substs) = match callee_ty.sty {
 102             ty::FnDef(def_id, substs) => (def_id, substs),
 103             _ => bug!("expected fn item type, found {}", callee_ty)
 104         };
 105
 106         let sig = callee_ty.fn_sig(tcx);
 107         let sig = tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
 108         let arg_tys = sig.inputs();
 109         let ret_ty = sig.output();
 110         let name = &*tcx.item_name(def_id).as_str();
 111
 112         let llret_ty = cx.layout_of(ret_ty).llvm_type(cx);
 113         let result = PlaceRef::new_sized(llresult, fn_ty.ret.layout, fn_ty.ret.layout.align);
 114
 115         let simple = get_simple_intrinsic(cx, name);
 116         let llval = match name {
 117             _ if simple.is_some() => {
 118                 self.call(simple.unwrap(),
 119                         &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
 120                         None)
 121             }
 122             "unreachable" => {
 123                 return;
 124             },
 125             "likely" => {
 126                 let expect = cx.get_intrinsic(&("llvm.expect.i1"));
 127                 self.call(expect, &[args[0].immediate(), cx.const_bool(true)], None)
 128             }
 129             "unlikely" => {
 130                 let expect = cx.get_intrinsic(&("llvm.expect.i1"));
 131                 self.call(expect, &[args[0].immediate(), cx.const_bool(false)], None)
 132             }
 133             "try" => {
 134                 try_intrinsic(self, cx,
 135                               args[0].immediate(),
 136                               args[1].immediate(),
 137                               args[2].immediate(),
 138                               llresult);
 139                 return;
 140             }
 141             "breakpoint" => {
 142                 let llfn = cx.get_intrinsic(&("llvm.debugtrap"));
 143                 self.call(llfn, &[], None)
 144             }
 145             "size_of" => {
 146                 let tp_ty = substs.type_at(0);
 147                 cx.const_usize(cx.size_of(tp_ty).bytes())
 148             }
 149             "size_of_val" => {
 150                 let tp_ty = substs.type_at(0);
 151                 if let OperandValue::Pair(_, meta) = args[0].val {
 152                     let (llsize, _) =
 153                         glue::size_and_align_of_dst(self, tp_ty, Some(meta));
 154                     llsize
 155                 } else {
 156                     cx.const_usize(cx.size_of(tp_ty).bytes())
 157                 }
 158             }
 159             "min_align_of" => {
 160                 let tp_ty = substs.type_at(0);
 161                 cx.const_usize(cx.align_of(tp_ty).abi())
 162             }
 163             "min_align_of_val" => {
 164                 let tp_ty = substs.type_at(0);
 165                 if let OperandValue::Pair(_, meta) = args[0].val {
 166                     let (_, llalign) =
 167                         glue::size_and_align_of_dst(self, tp_ty, Some(meta));
 168                     llalign
 169                 } else {
 170                     cx.const_usize(cx.align_of(tp_ty).abi())
 171                 }
 172             }
 173             "pref_align_of" => {
 174                 let tp_ty = substs.type_at(0);
 175                 cx.const_usize(cx.align_of(tp_ty).pref())
 176             }
 177             "type_name" => {
 178                 let tp_ty = substs.type_at(0);
 179                 let ty_name = Symbol::intern(&tp_ty.to_string()).as_str();
 180                 cx.const_str_slice(ty_name)
 181             }
 182             "type_id" => {
 183                 cx.const_u64(cx.tcx.type_id_hash(substs.type_at(0)))
 184             }
 185             "init" => {
 186                 let ty = substs.type_at(0);
 187                 if !cx.layout_of(ty).is_zst() {
 188                     // Just zero out the stack slot.
 189                     // If we store a zero constant, LLVM will drown in vreg allocation for large
 190                     // data structures, and the generated code will be awful. (A telltale sign of
 191                     // this is large quantities of `mov [byte ptr foo],0` in the generated code.)
 192                     memset_intrinsic(
 193                         &self,
 194                         false,
 195                         ty,
 196                         llresult,
 197                         cx.const_u8(0),
 198                         cx.const_usize(1)
 199                     );
 200                 }
 201                 return;
 202             }
 203             // Effectively no-ops
 204             "uninit" | "forget" => {
 205                 return;
 206             }
 207             "needs_drop" => {
 208                 let tp_ty = substs.type_at(0);
 209
 210                 cx.const_bool(cx.type_needs_drop(tp_ty))
 211             }
 212             "offset" => {
 213                 let ptr = args[0].immediate();
 214                 let offset = args[1].immediate();
 215                 self.inbounds_gep(ptr, &[offset])
 216             }
 217             "arith_offset" => {
 218                 let ptr = args[0].immediate();
 219                 let offset = args[1].immediate();
 220                 self.gep(ptr, &[offset])
 221             }
 222
 223             "copy_nonoverlapping" => {
 224                 copy_intrinsic(&self, false, false, substs.type_at(0),
 225                                args[1].immediate(), args[0].immediate(), args[2].immediate());
 226                 return;
 227             }
 228             "copy" => {
 229                 copy_intrinsic(&self, true, false, substs.type_at(0),
 230                                args[1].immediate(), args[0].immediate(), args[2].immediate());
 231                 return;
 232             }
 233             "write_bytes" => {
 234                 memset_intrinsic(&self, false, substs.type_at(0),
 235                                  args[0].immediate(), args[1].immediate(), args[2].immediate());
 236                 return;
 237             }
 238
 239             "volatile_copy_nonoverlapping_memory" => {
 240                 copy_intrinsic(&self, false, true, substs.type_at(0),
 241                                args[0].immediate(), args[1].immediate(), args[2].immediate());
 242                 return;
 243             }
 244             "volatile_copy_memory" => {
 245                 copy_intrinsic(&self, true, true, substs.type_at(0),
 246                                args[0].immediate(), args[1].immediate(), args[2].immediate());
 247                 return;
 248             }
 249             "volatile_set_memory" => {
 250                 memset_intrinsic(&self, true, substs.type_at(0),
 251                                  args[0].immediate(), args[1].immediate(), args[2].immediate());
 252                 return;
 253             }
 254             "volatile_load" | "unaligned_volatile_load" => {
 255                 let tp_ty = substs.type_at(0);
 256                 let mut ptr = args[0].immediate();
 257                 if let PassMode::Cast(ty) = fn_ty.ret.mode {
 258                     ptr = self.pointercast(ptr, cx.type_ptr_to(ty.llvm_type(cx)));
 259                 }
 260                 let load = self.volatile_load(ptr);
 261                 let align = if name == "unaligned_volatile_load" {
 262                     1
 263                 } else {
 264                     cx.align_of(tp_ty).abi() as u32
 265                 };
 266                 unsafe {
 267                     llvm::LLVMSetAlignment(load, align);
 268                 }
 269                 to_immediate(self, load, cx.layout_of(tp_ty))
 270             },
 271             "volatile_store" => {
 272                 let dst = args[0].deref(cx);
 273                 args[1].val.volatile_store(self, dst);
 274                 return;
 275             },
 276             "unaligned_volatile_store" => {
 277                 let dst = args[0].deref(cx);
 278                 args[1].val.unaligned_volatile_store(self, dst);
 279                 return;
 280             },
 281             "prefetch_read_data" | "prefetch_write_data" |
 282             "prefetch_read_instruction" | "prefetch_write_instruction" => {
 283                 let expect = cx.get_intrinsic(&("llvm.prefetch"));
 284                 let (rw, cache_type) = match name {
 285                     "prefetch_read_data" => (0, 1),
 286                     "prefetch_write_data" => (1, 1),
 287                     "prefetch_read_instruction" => (0, 0),
 288                     "prefetch_write_instruction" => (1, 0),
 289                     _ => bug!()
 290                 };
 291                 self.call(expect, &[
 292                     args[0].immediate(),
 293                     cx.const_i32(rw),
 294                     args[1].immediate(),
 295                     cx.const_i32(cache_type)
 296                 ], None)
 297             },
 298             "ctlz" | "ctlz_nonzero" | "cttz" | "cttz_nonzero" | "ctpop" | "bswap" |
 299             "bitreverse" | "add_with_overflow" | "sub_with_overflow" |
 300             "mul_with_overflow" | "overflowing_add" | "overflowing_sub" | "overflowing_mul" |
 301             "unchecked_div" | "unchecked_rem" | "unchecked_shl" | "unchecked_shr" | "exact_div" |
 302             "rotate_left" | "rotate_right" => {
 303                 let ty = arg_tys[0];
 304                 match int_type_width_signed(ty, cx) {
 305                     Some((width, signed)) =>
 306                         match name {
 307                             "ctlz" | "cttz" => {
 308                                 let y = cx.const_bool(false);
 309                                 let llfn = cx.get_intrinsic(&format!("llvm.{}.i{}", name, width));
 310                                 self.call(llfn, &[args[0].immediate(), y], None)
 311                             }
 312                             "ctlz_nonzero" | "cttz_nonzero" => {
 313                                 let y = cx.const_bool(true);
 314                                 let llvm_name = &format!("llvm.{}.i{}", &name[..4], width);
 315                                 let llfn = cx.get_intrinsic(llvm_name);
 316                                 self.call(llfn, &[args[0].immediate(), y], None)
 317                             }
 318                             "ctpop" => self.call(
 319                                 cx.get_intrinsic(&format!("llvm.ctpop.i{}", width)),
 320                                 &[args[0].immediate()],
 321                                 None
 322                             ),
 323                             "bswap" => {
 324                                 if width == 8 {
 325                                     args[0].immediate() // byte swap a u8/i8 is just a no-op
 326                                 } else {
 327                                     self.call(cx.get_intrinsic(&format!("llvm.bswap.i{}", width)),
 328                                             &[args[0].immediate()], None)
 329                                 }
 330                             }
 331                             "bitreverse" => {
 332                                 self.call(cx.get_intrinsic(&format!("llvm.bitreverse.i{}", width)),
 333                                     &[args[0].immediate()], None)
 334                             }
 335                             "add_with_overflow" | "sub_with_overflow" | "mul_with_overflow" => {
 336                                 let intrinsic = format!("llvm.{}{}.with.overflow.i{}",
 337                                                         if signed { 's' } else { 'u' },
 338                                                         &name[..3], width);
 339                                 let llfn = cx.get_intrinsic(&intrinsic);
 340
 341                                 // Convert `i1` to a `bool`, and write it to the out parameter
 342                                 let pair = self.call(llfn, &[
 343                                     args[0].immediate(),
 344                                     args[1].immediate()
 345                                 ], None);
 346                                 let val = self.extract_value(pair, 0);
 347                                 let overflow = self.zext(
 348                                     self.extract_value(pair, 1),
 349                                     cx.type_bool()
 350                                 );
 351
 352                                 let dest = result.project_field(self, 0);
 353                                 self.store(val, dest.llval, dest.align);
 354                                 let dest = result.project_field(self, 1);
 355                                 self.store(overflow, dest.llval, dest.align);
 356
 357                                 return;
 358                             },
 359                             "overflowing_add" => self.add(args[0].immediate(), args[1].immediate()),
 360                             "overflowing_sub" => self.sub(args[0].immediate(), args[1].immediate()),
 361                             "overflowing_mul" => self.mul(args[0].immediate(), args[1].immediate()),
 362                             "exact_div" =>
 363                                 if signed {
 364                                     self.exactsdiv(args[0].immediate(), args[1].immediate())
 365                                 } else {
 366                                     self.exactudiv(args[0].immediate(), args[1].immediate())
 367                                 },
 368                             "unchecked_div" =>
 369                                 if signed {
 370                                     self.sdiv(args[0].immediate(), args[1].immediate())
 371                                 } else {
 372                                     self.udiv(args[0].immediate(), args[1].immediate())
 373                                 },
 374                             "unchecked_rem" =>
 375                                 if signed {
 376                                     self.srem(args[0].immediate(), args[1].immediate())
 377                                 } else {
 378                                     self.urem(args[0].immediate(), args[1].immediate())
 379                                 },
 380                             "unchecked_shl" => self.shl(args[0].immediate(), args[1].immediate()),
 381                             "unchecked_shr" =>
 382                                 if signed {
 383                                     self.ashr(args[0].immediate(), args[1].immediate())
 384                                 } else {
 385                                     self.lshr(args[0].immediate(), args[1].immediate())
 386                                 },
 387                             "rotate_left" | "rotate_right" => {
 388                                 let is_left = name == "rotate_left";
 389                                 let val = args[0].immediate();
 390                                 let raw_shift = args[1].immediate();
 391                                 if llvm_util::get_major_version() >= 7 {
 392                                     // rotate = funnel shift with first two args the same
 393                                     let llvm_name = &format!("llvm.fsh{}.i{}",
 394                                                             if is_left { 'l' } else { 'r' }, width);
 395                                     let llfn = cx.get_intrinsic(llvm_name);
 396                                     self.call(llfn, &[val, val, raw_shift], None)
 397                                 } else {
 398                                     // rotate_left: (X << (S % BW)) | (X >> ((BW - S) % BW))
 399                                     // rotate_right: (X << ((BW - S) % BW)) | (X >> (S % BW))
 400                                     let width = cx.const_uint(cx.type_ix(width), width);
 401                                     let shift = self.urem(raw_shift, width);
 402                                     let inv_shift = self.urem(self.sub(width, raw_shift), width);
 403                                     let shift1 = self.shl(
 404                                         val,
 405                                         if is_left { shift } else { inv_shift },
 406                                     );
 407                                     let shift2 = self.lshr(
 408                                         val,
 409                                         if !is_left { shift } else { inv_shift },
 410                                     );
 411                                     self.or(shift1, shift2)
 412                                 }
 413                             },
 414                             _ => bug!(),
 415                         },
 416                     None => {
 417                         span_invalid_monomorphization_error(
 418                             tcx.sess, span,
 419                             &format!("invalid monomorphization of `{}` intrinsic: \
 420                                       expected basic integer type, found `{}`", name, ty));
 421                         return;
 422                     }
 423                 }
 424
 425             },
 426             "fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" => {
 427                 let sty = &arg_tys[0].sty;
 428                 match float_type_width(sty) {
 429                     Some(_width) =>
 430                         match name {
 431                             "fadd_fast" => self.fadd_fast(args[0].immediate(), args[1].immediate()),
 432                             "fsub_fast" => self.fsub_fast(args[0].immediate(), args[1].immediate()),
 433                             "fmul_fast" => self.fmul_fast(args[0].immediate(), args[1].immediate()),
 434                             "fdiv_fast" => self.fdiv_fast(args[0].immediate(), args[1].immediate()),
 435                             "frem_fast" => self.frem_fast(args[0].immediate(), args[1].immediate()),
 436                             _ => bug!(),
 437                         },
 438                     None => {
 439                         span_invalid_monomorphization_error(
 440                             tcx.sess, span,
 441                             &format!("invalid monomorphization of `{}` intrinsic: \
 442                                       expected basic float type, found `{}`", name, sty));
 443                         return;
 444                     }
 445                 }
 446
 447             },
 448
 449             "discriminant_value" => {
 450                 args[0].deref(cx).codegen_get_discr(self, ret_ty)
 451             }
 452
 453             name if name.starts_with("simd_") => {
 454                 match generic_simd_intrinsic(&self, name,
 455                                              callee_ty,
 456                                              args,
 457                                              ret_ty, llret_ty,
 458                                              span) {
 459                     Ok(llval) => llval,
 460                     Err(()) => return
 461                 }
 462             }
 463             // This requires that atomic intrinsics follow a specific naming pattern:
 464             // "atomic_<operation>[_<ordering>]", and no ordering means SeqCst
 465             name if name.starts_with("atomic_") => {
 466                 use rustc_codegen_ssa::common::AtomicOrdering::*;
 467                 use rustc_codegen_ssa::common::
 468                     {SynchronizationScope, AtomicRmwBinOp};
 469
 470                 let split: Vec<&str> = name.split('_').collect();
 471
 472                 let is_cxchg = split[1] == "cxchg" || split[1] == "cxchgweak";
 473                 let (order, failorder) = match split.len() {
 474                     2 => (SequentiallyConsistent, SequentiallyConsistent),
 475                     3 => match split[2] {
 476                         "unordered" => (Unordered, Unordered),
 477                         "relaxed" => (Monotonic, Monotonic),
 478                         "acq"     => (Acquire, Acquire),
 479                         "rel"     => (Release, Monotonic),
 480                         "acqrel"  => (AcquireRelease, Acquire),
 481                         "failrelaxed" if is_cxchg =>
 482                             (SequentiallyConsistent, Monotonic),
 483                         "failacq" if is_cxchg =>
 484                             (SequentiallyConsistent, Acquire),
 485                         _ => cx.sess().fatal("unknown ordering in atomic intrinsic")
 486                     },
 487                     4 => match (split[2], split[3]) {
 488                         ("acq", "failrelaxed") if is_cxchg =>
 489                             (Acquire, Monotonic),
 490                         ("acqrel", "failrelaxed") if is_cxchg =>
 491                             (AcquireRelease, Monotonic),
 492                         _ => cx.sess().fatal("unknown ordering in atomic intrinsic")
 493                     },
 494                     _ => cx.sess().fatal("Atomic intrinsic not in correct format"),
 495                 };
 496
 497                 let invalid_monomorphization = |ty| {
 498                     span_invalid_monomorphization_error(tcx.sess, span,
 499                         &format!("invalid monomorphization of `{}` intrinsic: \
 500                                   expected basic integer type, found `{}`", name, ty));
 501                 };
 502
 503                 match split[1] {
 504                     "cxchg" | "cxchgweak" => {
 505                         let ty = substs.type_at(0);
 506                         if int_type_width_signed(ty, cx).is_some() {
 507                             let weak = split[1] == "cxchgweak";
 508                             let pair = self.atomic_cmpxchg(
 509                                 args[0].immediate(),
 510                                 args[1].immediate(),
 511                                 args[2].immediate(),
 512                                 order,
 513                                 failorder,
 514                                 weak);
 515                             let val = self.extract_value(pair, 0);
 516                             let success = self.zext(
 517                                 self.extract_value(pair, 1),
 518                                 cx.type_bool()
 519                             );
 520
 521                             let dest = result.project_field(self, 0);
 522                             self.store(val, dest.llval, dest.align);
 523                             let dest = result.project_field(self, 1);
 524                             self.store(success, dest.llval, dest.align);
 525                             return;
 526                         } else {
 527                             return invalid_monomorphization(ty);
 528                         }
 529                     }
 530
 531                     "load" => {
 532                         let ty = substs.type_at(0);
 533                         if int_type_width_signed(ty, cx).is_some() {
 534                             let size = cx.size_of(ty);
 535                             self.atomic_load(args[0].immediate(), order, size)
 536                         } else {
 537                             return invalid_monomorphization(ty);
 538                         }
 539                     }
 540
 541                     "store" => {
 542                         let ty = substs.type_at(0);
 543                         if int_type_width_signed(ty, cx).is_some() {
 544                             let size = cx.size_of(ty);
 545                             self.atomic_store(
 546                                 args[1].immediate(),
 547                                 args[0].immediate(),
 548                                 order,
 549                                 size
 550                             );
 551                             return;
 552                         } else {
 553                             return invalid_monomorphization(ty);
 554                         }
 555                     }
 556
 557                     "fence" => {
 558                         self.atomic_fence(order, SynchronizationScope::CrossThread);
 559                         return;
 560                     }
 561
 562                     "singlethreadfence" => {
 563                         self.atomic_fence(order, SynchronizationScope::SingleThread);
 564                         return;
 565                     }
 566
 567                     // These are all AtomicRMW ops
 568                     op => {
 569                         let atom_op = match op {
 570                             "xchg"  => AtomicRmwBinOp::AtomicXchg,
 571                             "xadd"  => AtomicRmwBinOp::AtomicAdd,
 572                             "xsub"  => AtomicRmwBinOp::AtomicSub,
 573                             "and"   => AtomicRmwBinOp::AtomicAnd,
 574                             "nand"  => AtomicRmwBinOp::AtomicNand,
 575                             "or"    => AtomicRmwBinOp::AtomicOr,
 576                             "xor"   => AtomicRmwBinOp::AtomicXor,
 577                             "max"   => AtomicRmwBinOp::AtomicMax,
 578                             "min"   => AtomicRmwBinOp::AtomicMin,
 579                             "umax"  => AtomicRmwBinOp::AtomicUMax,
 580                             "umin"  => AtomicRmwBinOp::AtomicUMin,
 581                             _ => cx.sess().fatal("unknown atomic operation")
 582                         };
 583
 584                         let ty = substs.type_at(0);
 585                         if int_type_width_signed(ty, cx).is_some() {
 586                             self.atomic_rmw(
 587                                 atom_op,
 588                                 args[0].immediate(),
 589                                 args[1].immediate(),
 590                                 order
 591                             )
 592                         } else {
 593                             return invalid_monomorphization(ty);
 594                         }
 595                     }
 596                 }
 597             }
 598
 599             "nontemporal_store" => {
 600                 let dst = args[0].deref(cx);
 601                 args[1].val.nontemporal_store(self, dst);
 602                 return;
 603             }
 604
 605             _ => {
 606                 let intr = match Intrinsic::find(&name) {
 607                     Some(intr) => intr,
 608                     None => bug!("unknown intrinsic '{}'", name),
 609                 };
 610                 fn one<T>(x: Vec<T>) -> T {
 611                     assert_eq!(x.len(), 1);
 612                     x.into_iter().next().unwrap()
 613                 }
 614                 fn ty_to_type<'ll>(
 615                     cx: &CodegenCx<'ll, '_>,
 616                      t: &intrinsics::Type
 617                  ) -> Vec<&'ll Type> {
 618                     use intrinsics::Type::*;
 619                     match *t {
 620                         Void => vec![cx.type_void()],
 621                         Integer(_signed, _width, llvm_width) => {
 622                             vec![cx.type_ix( llvm_width as u64)]
 623                         }
 624                         Float(x) => {
 625                             match x {
 626                                 32 => vec![cx.type_f32()],
 627                                 64 => vec![cx.type_f64()],
 628                                 _ => bug!()
 629                             }
 630                         }
 631                         Pointer(ref t, ref llvm_elem, _const) => {
 632                             let t = llvm_elem.as_ref().unwrap_or(t);
 633                             let elem = one(ty_to_type(cx, t));
 634                             vec![cx.type_ptr_to(elem)]
 635                         }
 636                         Vector(ref t, ref llvm_elem, length) => {
 637                             let t = llvm_elem.as_ref().unwrap_or(t);
 638                             let elem = one(ty_to_type(cx, t));
 639                             vec![cx.type_vector(elem, length as u64)]
 640                         }
 641                         Aggregate(false, ref contents) => {
 642                             let elems = contents.iter()
 643                                                 .map(|t| one(ty_to_type(cx, t)))
 644                                                 .collect::<Vec<_>>();
 645                             vec![cx.type_struct( &elems, false)]
 646                         }
 647                         Aggregate(true, ref contents) => {
 648                             contents.iter()
 649                                     .flat_map(|t| ty_to_type(cx, t))
 650                                     .collect()
 651                         }
 652                     }
 653                 }
 654
 655                 // This allows an argument list like `foo, (bar, baz),
 656                 // qux` to be converted into `foo, bar, baz, qux`, integer
 657                 // arguments to be truncated as needed and pointers to be
 658                 // cast.
 659                 fn modify_as_needed<'ll, 'tcx>(
 660                     bx: &Builder<'_, 'll, 'tcx>,
 661                     t: &intrinsics::Type,
 662                     arg: &OperandRef<'tcx, &'ll Value>,
 663                 ) -> Vec<&'ll Value> {
 664                     match *t {
 665                         intrinsics::Type::Aggregate(true, ref contents) => {
 666                             // We found a tuple that needs squishing! So
 667                             // run over the tuple and load each field.
 668                             //
 669                             // This assumes the type is "simple", i.e. no
 670                             // destructors, and the contents are SIMD
 671                             // etc.
 672                             assert!(!bx.cx().type_needs_drop(arg.layout.ty));
 673                             let (ptr, align) = match arg.val {
 674                                 OperandValue::Ref(ptr, None, align) => (ptr, align),
 675                                 _ => bug!()
 676                             };
 677                             let arg = PlaceRef::new_sized(ptr, arg.layout, align);
 678                             (0..contents.len()).map(|i| {
 679                                 bx.load_operand(arg.project_field(bx, i)).immediate()
 680                             }).collect()
 681                         }
 682                         intrinsics::Type::Pointer(_, Some(ref llvm_elem), _) => {
 683                             let llvm_elem = one(ty_to_type(bx.cx(), llvm_elem));
 684                             vec![bx.pointercast(arg.immediate(), bx.cx().type_ptr_to(llvm_elem))]
 685                         }
 686                         intrinsics::Type::Vector(_, Some(ref llvm_elem), length) => {
 687                             let llvm_elem = one(ty_to_type(bx.cx(), llvm_elem));
 688                             vec![
 689                                 bx.bitcast(arg.immediate(),
 690                                 bx.cx().type_vector(llvm_elem, length as u64))
 691                             ]
 692                         }
 693                         intrinsics::Type::Integer(_, width, llvm_width) if width != llvm_width => {
 694                             // the LLVM intrinsic uses a smaller integer
 695                             // size than the C intrinsic's signature, so
 696                             // we have to trim it down here.
 697                             vec![bx.trunc(arg.immediate(), bx.cx().type_ix(llvm_width as u64))]
 698                         }
 699                         _ => vec![arg.immediate()],
 700                     }
 701                 }
 702
 703
 704                 let inputs = intr.inputs.iter()
 705                                         .flat_map(|t| ty_to_type(cx, t))
 706                                         .collect::<Vec<_>>();
 707
 708                 let outputs = one(ty_to_type(cx, &intr.output));
 709
 710                 let llargs: Vec<_> = intr.inputs.iter().zip(args).flat_map(|(t, arg)| {
 711                     modify_as_needed(&self, t, arg)
 712                 }).collect();
 713                 assert_eq!(inputs.len(), llargs.len());
 714
 715                 let val = match intr.definition {
 716                     intrinsics::IntrinsicDef::Named(name) => {
 717                         let f = cx.declare_cfn(
 718                             name,
 719                             cx.type_func(&inputs, outputs),
 720                         );
 721                         self.call(f, &llargs, None)
 722                     }
 723                 };
 724
 725                 match *intr.output {
 726                     intrinsics::Type::Aggregate(flatten, ref elems) => {
 727                         // the output is a tuple so we need to munge it properly
 728                         assert!(!flatten);
 729
 730                         for i in 0..elems.len() {
 731                             let dest = result.project_field(self, i);
 732                             let val = self.extract_value(val, i as u64);
 733                             self.store(val, dest.llval, dest.align);
 734                         }
 735                         return;
 736                     }
 737                     _ => val,
 738                 }
 739             }
 740         };
 741
 742         if !fn_ty.ret.is_ignore() {
 743             if let PassMode::Cast(ty) = fn_ty.ret.mode {
 744                 let ptr = self.pointercast(result.llval, cx.type_ptr_to(ty.llvm_type(cx)));
 745                 self.store(llval, ptr, result.align);
 746             } else {
 747                 OperandRef::from_immediate_or_packed_pair(self, llval, result.layout)
 748                     .val.store(self, result);
 749             }
 750         }
 751     }
 752 }
 753
 754 fn copy_intrinsic(
 755     bx: &Builder<'a, 'll, 'tcx>,
 756     allow_overlap: bool,
 757     volatile: bool,
 758     ty: Ty<'tcx>,
 759     dst: &'ll Value,
 760     src: &'ll Value,
 761     count: &'ll Value,
 762 ) {
 763     let (size, align) = bx.cx().size_and_align_of(ty);
 764     let size = bx.mul(bx.cx().const_usize(size.bytes()), count);
 765     let flags = if volatile {
 766         MemFlags::VOLATILE
 767     } else {
 768         MemFlags::empty()
 769     };
 770     if allow_overlap {
 771         bx.memmove(dst, align, src, align, size, flags);
 772     } else {
 773         bx.memcpy(dst, align, src, align, size, flags);
 774     }
 775 }
 776
 777 fn memset_intrinsic(
 778     bx: &Builder<'a, 'll, 'tcx>,
 779     volatile: bool,
 780     ty: Ty<'tcx>,
 781     dst: &'ll Value,
 782     val: &'ll Value,
 783     count: &'ll Value
 784 ) {
 785     let (size, align) = bx.cx().size_and_align_of(ty);
 786     let size = bx.cx().const_usize(size.bytes());
 787     let flags = if volatile {
 788         MemFlags::VOLATILE
 789     } else {
 790         MemFlags::empty()
 791     };
 792     bx.memset(dst, val, bx.mul(size, count), align, flags);
 793 }
 794
 795 fn try_intrinsic(
 796     bx: &Builder<'a, 'll, 'tcx>,
 797     cx: &CodegenCx<'ll, 'tcx>,
 798     func: &'ll Value,
 799     data: &'ll Value,
 800     local_ptr: &'ll Value,
 801     dest: &'ll Value,
 802 ) {
 803     if bx.cx().sess().no_landing_pads() {
 804         bx.call(func, &[data], None);
 805         let ptr_align = bx.tcx().data_layout.pointer_align;
 806         bx.store(cx.const_null(cx.type_i8p()), dest, ptr_align);
 807     } else if wants_msvc_seh(bx.cx().sess()) {
 808         codegen_msvc_try(bx, cx, func, data, local_ptr, dest);
 809     } else {
 810         codegen_gnu_try(bx, cx, func, data, local_ptr, dest);
 811     }
 812 }
 813
 814 // MSVC's definition of the `rust_try` function.
 815 //
 816 // This implementation uses the new exception handling instructions in LLVM
 817 // which have support in LLVM for SEH on MSVC targets. Although these
 818 // instructions are meant to work for all targets, as of the time of this
 819 // writing, however, LLVM does not recommend the usage of these new instructions
 820 // as the old ones are still more optimized.
 821 fn codegen_msvc_try(
 822     bx: &Builder<'a, 'll, 'tcx>,
 823     cx: &CodegenCx<'ll, 'tcx>,
 824     func: &'ll Value,
 825     data: &'ll Value,
 826     local_ptr: &'ll Value,
 827     dest: &'ll Value,
 828 ) {
 829     let llfn = get_rust_try_fn(cx, &mut |bx| {
 830         let cx = bx.cx();
 831
 832         bx.set_personality_fn(bx.cx().eh_personality());
 833
 834         let normal = bx.build_sibling_block("normal");
 835         let catchswitch = bx.build_sibling_block("catchswitch");
 836         let catchpad = bx.build_sibling_block("catchpad");
 837         let caught = bx.build_sibling_block("caught");
 838
 839         let func = llvm::get_param(bx.llfn(), 0);
 840         let data = llvm::get_param(bx.llfn(), 1);
 841         let local_ptr = llvm::get_param(bx.llfn(), 2);
 842
 843         // We're generating an IR snippet that looks like:
 844         //
 845         //   declare i32 @rust_try(%func, %data, %ptr) {
 846         //      %slot = alloca i64*
 847         //      invoke %func(%data) to label %normal unwind label %catchswitch
 848         //
 849         //   normal:
 850         //      ret i32 0
 851         //
 852         //   catchswitch:
 853         //      %cs = catchswitch within none [%catchpad] unwind to caller
 854         //
 855         //   catchpad:
 856         //      %tok = catchpad within %cs [%type_descriptor, 0, %slot]
 857         //      %ptr[0] = %slot[0]
 858         //      %ptr[1] = %slot[1]
 859         //      catchret from %tok to label %caught
 860         //
 861         //   caught:
 862         //      ret i32 1
 863         //   }
 864         //
 865         // This structure follows the basic usage of throw/try/catch in LLVM.
 866         // For example, compile this C++ snippet to see what LLVM generates:
 867         //
 868         //      #include <stdint.h>
 869         //
 870         //      int bar(void (*foo)(void), uint64_t *ret) {
 871         //          try {
 872         //              foo();
 873         //              return 0;
 874         //          } catch(uint64_t a[2]) {
 875         //              ret[0] = a[0];
 876         //              ret[1] = a[1];
 877         //              return 1;
 878         //          }
 879         //      }
 880         //
 881         // More information can be found in libstd's seh.rs implementation.
 882         let i64p = cx.type_ptr_to(cx.type_i64());
 883         let ptr_align = bx.tcx().data_layout.pointer_align;
 884         let slot = bx.alloca(i64p, "slot", ptr_align);
 885         bx.invoke(func, &[data], normal.llbb(), catchswitch.llbb(), None);
 886
 887         normal.ret(cx.const_i32(0));
 888
 889         let cs = catchswitch.catch_switch(None, None, 1);
 890         catchswitch.add_handler(cs, catchpad.llbb());
 891
 892         let tcx = cx.tcx;
 893         let tydesc = match tcx.lang_items().msvc_try_filter() {
 894             Some(did) => cx.get_static(did),
 895             None => bug!("msvc_try_filter not defined"),
 896         };
 897         let funclet = catchpad.catch_pad(cs, &[tydesc, cx.const_i32(0), slot]);
 898         let addr = catchpad.load(slot, ptr_align);
 899
 900         let i64_align = bx.tcx().data_layout.i64_align;
 901         let arg1 = catchpad.load(addr, i64_align);
 902         let val1 = cx.const_i32(1);
 903         let arg2 = catchpad.load(catchpad.inbounds_gep(addr, &[val1]), i64_align);
 904         let local_ptr = catchpad.bitcast(local_ptr, i64p);
 905         catchpad.store(arg1, local_ptr, i64_align);
 906         catchpad.store(arg2, catchpad.inbounds_gep(local_ptr, &[val1]), i64_align);
 907         catchpad.catch_ret(&funclet, caught.llbb());
 908
 909         caught.ret(cx.const_i32(1));
 910     });
 911
 912     // Note that no invoke is used here because by definition this function
 913     // can't panic (that's what it's catching).
 914     let ret = bx.call(llfn, &[func, data, local_ptr], None);
 915     let i32_align = bx.tcx().data_layout.i32_align;
 916     bx.store(ret, dest, i32_align);
 917 }
 918
 919 // Definition of the standard "try" function for Rust using the GNU-like model
 920 // of exceptions (e.g. the normal semantics of LLVM's landingpad and invoke
 921 // instructions).
 922 //
 923 // This codegen is a little surprising because we always call a shim
 924 // function instead of inlining the call to `invoke` manually here. This is done
 925 // because in LLVM we're only allowed to have one personality per function
 926 // definition. The call to the `try` intrinsic is being inlined into the
 927 // function calling it, and that function may already have other personality
 928 // functions in play. By calling a shim we're guaranteed that our shim will have
 929 // the right personality function.
 930 fn codegen_gnu_try(
 931     bx: &Builder<'a, 'll, 'tcx>,
 932     cx: &CodegenCx<'ll, 'tcx>,
 933     func: &'ll Value,
 934     data: &'ll Value,
 935     local_ptr: &'ll Value,
 936     dest: &'ll Value,
 937 ) {
 938     let llfn = get_rust_try_fn(cx, &mut |bx| {
 939         let cx = bx.cx();
 940
 941         // Codegens the shims described above:
 942         //
 943         //   bx:
 944         //      invoke %func(%args...) normal %normal unwind %catch
 945         //
 946         //   normal:
 947         //      ret 0
 948         //
 949         //   catch:
 950         //      (ptr, _) = landingpad
 951         //      store ptr, %local_ptr
 952         //      ret 1
 953         //
 954         // Note that the `local_ptr` data passed into the `try` intrinsic is
 955         // expected to be `*mut *mut u8` for this to actually work, but that's
 956         // managed by the standard library.
 957
 958         let then = bx.build_sibling_block("then");
 959         let catch = bx.build_sibling_block("catch");
 960
 961         let func = llvm::get_param(bx.llfn(), 0);
 962         let data = llvm::get_param(bx.llfn(), 1);
 963         let local_ptr = llvm::get_param(bx.llfn(), 2);
 964         bx.invoke(func, &[data], then.llbb(), catch.llbb(), None);
 965         then.ret(cx.const_i32(0));
 966
 967         // Type indicator for the exception being thrown.
 968         //
 969         // The first value in this tuple is a pointer to the exception object
 970         // being thrown.  The second value is a "selector" indicating which of
 971         // the landing pad clauses the exception's type had been matched to.
 972         // rust_try ignores the selector.
 973         let lpad_ty = cx.type_struct(&[cx.type_i8p(), cx.type_i32()], false);
 974         let vals = catch.landing_pad(lpad_ty, bx.cx().eh_personality(), 1);
 975         catch.add_clause(vals, bx.cx().const_null(cx.type_i8p()));
 976         let ptr = catch.extract_value(vals, 0);
 977         let ptr_align = bx.tcx().data_layout.pointer_align;
 978         catch.store(ptr, catch.bitcast(local_ptr, cx.type_ptr_to(cx.type_i8p())), ptr_align);
 979         catch.ret(cx.const_i32(1));
 980     });
 981
 982     // Note that no invoke is used here because by definition this function
 983     // can't panic (that's what it's catching).
 984     let ret = bx.call(llfn, &[func, data, local_ptr], None);
 985     let i32_align = bx.tcx().data_layout.i32_align;
 986     bx.store(ret, dest, i32_align);
 987 }
 988
 989 // Helper function to give a Block to a closure to codegen a shim function.
 990 // This is currently primarily used for the `try` intrinsic functions above.
 991 fn gen_fn<'ll, 'tcx>(
 992     cx: &CodegenCx<'ll, 'tcx>,
 993     name: &str,
 994     inputs: Vec<Ty<'tcx>>,
 995     output: Ty<'tcx>,
 996     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
 997 ) -> &'ll Value {
 998     let rust_fn_sig = ty::Binder::bind(cx.tcx.mk_fn_sig(
 999         inputs.into_iter(),
1000         output,
1001         false,
1002         hir::Unsafety::Unsafe,
1003         Abi::Rust
1004     ));
1005     let llfn = cx.define_internal_fn(name, rust_fn_sig);
1006     attributes::from_fn_attrs(cx, llfn, None);
1007     let bx = Builder::new_block(cx, llfn, "entry-block");
1008     codegen(bx);
1009     llfn
1010 }
1011
1012 // Helper function used to get a handle to the `__rust_try` function used to
1013 // catch exceptions.
1014 //
1015 // This function is only generated once and is then cached.
1016 fn get_rust_try_fn<'ll, 'tcx>(
1017     cx: &CodegenCx<'ll, 'tcx>,
1018     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
1019 ) -> &'ll Value {
1020     if let Some(llfn) = cx.rust_try_fn.get() {
1021         return llfn;
1022     }
1023
1024     // Define the type up front for the signature of the rust_try function.
1025     let tcx = cx.tcx;
1026     let i8p = tcx.mk_mut_ptr(tcx.types.i8);
1027     let fn_ty = tcx.mk_fn_ptr(ty::Binder::bind(tcx.mk_fn_sig(
1028         iter::once(i8p),
1029         tcx.mk_unit(),
1030         false,
1031         hir::Unsafety::Unsafe,
1032         Abi::Rust
1033     )));
1034     let output = tcx.types.i32;
1035     let rust_try = gen_fn(cx, "__rust_try", vec![fn_ty, i8p, i8p], output, codegen);
1036     cx.rust_try_fn.set(Some(rust_try));
1037     rust_try
1038 }
1039
1040 fn span_invalid_monomorphization_error(a: &Session, b: Span, c: &str) {
1041     span_err!(a, b, E0511, "{}", c);
1042 }
1043
1044 fn generic_simd_intrinsic(
1045     bx: &Builder<'a, 'll, 'tcx>,
1046     name: &str,
1047     callee_ty: Ty<'tcx>,
1048     args: &[OperandRef<'tcx, &'ll Value>],
1049     ret_ty: Ty<'tcx>,
1050     llret_ty: &'ll Type,
1051     span: Span
1052 ) -> Result<&'ll Value, ()> {
1053     // macros for error handling:
1054     macro_rules! emit_error {
1055         ($msg: tt) => {
1056             emit_error!($msg, )
1057         };
1058         ($msg: tt, $($fmt: tt)*) => {
1059             span_invalid_monomorphization_error(
1060                 bx.cx().sess(), span,
1061                 &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg),
1062                          name, $($fmt)*));
1063         }
1064     }
1065
1066     macro_rules! return_error {
1067         ($($fmt: tt)*) => {
1068             {
1069                 emit_error!($($fmt)*);
1070                 return Err(());
1071             }
1072         }
1073     }
1074
1075     macro_rules! require {
1076         ($cond: expr, $($fmt: tt)*) => {
1077             if !$cond {
1078                 return_error!($($fmt)*);
1079             }
1080         };
1081     }
1082
1083     macro_rules! require_simd {
1084         ($ty: expr, $position: expr) => {
1085             require!($ty.is_simd(), "expected SIMD {} type, found non-SIMD `{}`", $position, $ty)
1086         }
1087     }
1088
1089     let tcx = bx.tcx();
1090     let sig = tcx.normalize_erasing_late_bound_regions(
1091         ty::ParamEnv::reveal_all(),
1092         &callee_ty.fn_sig(tcx),
1093     );
1094     let arg_tys = sig.inputs();
1095
1096     // every intrinsic takes a SIMD vector as its first argument
1097     require_simd!(arg_tys[0], "input");
1098     let in_ty = arg_tys[0];
1099     let in_elem = arg_tys[0].simd_type(tcx);
1100     let in_len = arg_tys[0].simd_size(tcx);
1101
1102     let comparison = match name {
1103         "simd_eq" => Some(hir::BinOpKind::Eq),
1104         "simd_ne" => Some(hir::BinOpKind::Ne),
1105         "simd_lt" => Some(hir::BinOpKind::Lt),
1106         "simd_le" => Some(hir::BinOpKind::Le),
1107         "simd_gt" => Some(hir::BinOpKind::Gt),
1108         "simd_ge" => Some(hir::BinOpKind::Ge),
1109         _ => None
1110     };
1111
1112     if let Some(cmp_op) = comparison {
1113         require_simd!(ret_ty, "return");
1114
1115         let out_len = ret_ty.simd_size(tcx);
1116         require!(in_len == out_len,
1117                  "expected return type with length {} (same as input type `{}`), \
1118                   found `{}` with length {}",
1119                  in_len, in_ty,
1120                  ret_ty, out_len);
1121         require!(bx.cx().type_kind(bx.cx().element_type(llret_ty)) == TypeKind::Integer,
1122                  "expected return type with integer elements, found `{}` with non-integer `{}`",
1123                  ret_ty,
1124                  ret_ty.simd_type(tcx));
1125
1126         return Ok(compare_simd_types(bx,
1127                                      args[0].immediate(),
1128                                      args[1].immediate(),
1129                                      in_elem,
1130                                      llret_ty,
1131                                      cmp_op))
1132     }
1133
1134     if name.starts_with("simd_shuffle") {
1135         let n: usize = name["simd_shuffle".len()..].parse().unwrap_or_else(|_|
1136             span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?"));
1137
1138         require_simd!(ret_ty, "return");
1139
1140         let out_len = ret_ty.simd_size(tcx);
1141         require!(out_len == n,
1142                  "expected return type of length {}, found `{}` with length {}",
1143                  n, ret_ty, out_len);
1144         require!(in_elem == ret_ty.simd_type(tcx),
1145                  "expected return element type `{}` (element of input `{}`), \
1146                   found `{}` with element type `{}`",
1147                  in_elem, in_ty,
1148                  ret_ty, ret_ty.simd_type(tcx));
1149
1150         let total_len = in_len as u128 * 2;
1151
1152         let vector = args[2].immediate();
1153
1154         let indices: Option<Vec<_>> = (0..n)
1155             .map(|i| {
1156                 let arg_idx = i;
1157                 let val = bx.cx().const_get_elt(vector, i as u64);
1158                 match bx.cx().const_to_opt_u128(val, true) {
1159                     None => {
1160                         emit_error!("shuffle index #{} is not a constant", arg_idx);
1161                         None
1162                     }
1163                     Some(idx) if idx >= total_len => {
1164                         emit_error!("shuffle index #{} is out of bounds (limit {})",
1165                                     arg_idx, total_len);
1166                         None
1167                     }
1168                     Some(idx) => Some(bx.cx().const_i32(idx as i32)),
1169                 }
1170             })
1171             .collect();
1172         let indices = match indices {
1173             Some(i) => i,
1174             None => return Ok(bx.cx().const_null(llret_ty))
1175         };
1176
1177         return Ok(bx.shuffle_vector(args[0].immediate(),
1178                                     args[1].immediate(),
1179                                     bx.cx().const_vector(&indices)))
1180     }
1181
1182     if name == "simd_insert" {
1183         require!(in_elem == arg_tys[2],
1184                  "expected inserted type `{}` (element of input `{}`), found `{}`",
1185                  in_elem, in_ty, arg_tys[2]);
1186         return Ok(bx.insert_element(args[0].immediate(),
1187                                     args[2].immediate(),
1188                                     args[1].immediate()))
1189     }
1190     if name == "simd_extract" {
1191         require!(ret_ty == in_elem,
1192                  "expected return type `{}` (element of input `{}`), found `{}`",
1193                  in_elem, in_ty, ret_ty);
1194         return Ok(bx.extract_element(args[0].immediate(), args[1].immediate()))
1195     }
1196
1197     if name == "simd_select" {
1198         let m_elem_ty = in_elem;
1199         let m_len = in_len;
1200         let v_len = arg_tys[1].simd_size(tcx);
1201         require!(m_len == v_len,
1202                  "mismatched lengths: mask length `{}` != other vector length `{}`",
1203                  m_len, v_len
1204         );
1205         match m_elem_ty.sty {
1206             ty::Int(_) => {},
1207             _ => return_error!("mask element type is `{}`, expected `i_`", m_elem_ty)
1208         }
1209         // truncate the mask to a vector of i1s
1210         let i1 = bx.cx().type_i1();
1211         let i1xn = bx.cx().type_vector(i1, m_len as u64);
1212         let m_i1s = bx.trunc(args[0].immediate(), i1xn);
1213         return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
1214     }
1215
1216     fn simd_simple_float_intrinsic(
1217         name: &str,
1218         in_elem: &::rustc::ty::TyS,
1219         in_ty: &::rustc::ty::TyS,
1220         in_len: usize,
1221         bx: &Builder<'a, 'll, 'tcx>,
1222         span: Span,
1223         args: &[OperandRef<'tcx, &'ll Value>],
1224     ) -> Result<&'ll Value, ()> {
1225         macro_rules! emit_error {
1226             ($msg: tt) => {
1227                 emit_error!($msg, )
1228             };
1229             ($msg: tt, $($fmt: tt)*) => {
1230                 span_invalid_monomorphization_error(
1231                     bx.cx().sess(), span,
1232                     &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg),
1233                              name, $($fmt)*));
1234             }
1235         }
1236         macro_rules! return_error {
1237             ($($fmt: tt)*) => {
1238                 {
1239                     emit_error!($($fmt)*);
1240                     return Err(());
1241                 }
1242             }
1243         }
1244         let ety = match in_elem.sty {
1245             ty::Float(f) if f.bit_width() == 32 => {
1246                 if in_len < 2 || in_len > 16 {
1247                     return_error!(
1248                         "unsupported floating-point vector `{}` with length `{}` \
1249                          out-of-range [2, 16]",
1250                         in_ty, in_len);
1251                 }
1252                 "f32"
1253             },
1254             ty::Float(f) if f.bit_width() == 64 => {
1255                 if in_len < 2 || in_len > 8 {
1256                     return_error!("unsupported floating-point vector `{}` with length `{}` \
1257                                    out-of-range [2, 8]",
1258                                   in_ty, in_len);
1259                 }
1260                 "f64"
1261             },
1262             ty::Float(f) => {
1263                 return_error!("unsupported element type `{}` of floating-point vector `{}`",
1264                               f, in_ty);
1265             },
1266             _ => {
1267                 return_error!("`{}` is not a floating-point type", in_ty);
1268             }
1269         };
1270
1271         let llvm_name = &format!("llvm.{0}.v{1}{2}", name, in_len, ety);
1272         let intrinsic = bx.cx().get_intrinsic(&llvm_name);
1273         let c = bx.call(intrinsic,
1274                         &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
1275                         None);
1276         unsafe { llvm::LLVMRustSetHasUnsafeAlgebra(c) };
1277         Ok(c)
1278     }
1279
1280     match name {
1281         "simd_fsqrt" => {
1282             return simd_simple_float_intrinsic("sqrt", in_elem, in_ty, in_len, bx, span, args);
1283         }
1284         "simd_fsin" => {
1285             return simd_simple_float_intrinsic("sin", in_elem, in_ty, in_len, bx, span, args);
1286         }
1287         "simd_fcos" => {
1288             return simd_simple_float_intrinsic("cos", in_elem, in_ty, in_len, bx, span, args);
1289         }
1290         "simd_fabs" => {
1291             return simd_simple_float_intrinsic("fabs", in_elem, in_ty, in_len, bx, span, args);
1292         }
1293         "simd_floor" => {
1294             return simd_simple_float_intrinsic("floor", in_elem, in_ty, in_len, bx, span, args);
1295         }
1296         "simd_ceil" => {
1297             return simd_simple_float_intrinsic("ceil", in_elem, in_ty, in_len, bx, span, args);
1298         }
1299         "simd_fexp" => {
1300             return simd_simple_float_intrinsic("exp", in_elem, in_ty, in_len, bx, span, args);
1301         }
1302         "simd_fexp2" => {
1303             return simd_simple_float_intrinsic("exp2", in_elem, in_ty, in_len, bx, span, args);
1304         }
1305         "simd_flog10" => {
1306             return simd_simple_float_intrinsic("log10", in_elem, in_ty, in_len, bx, span, args);
1307         }
1308         "simd_flog2" => {
1309             return simd_simple_float_intrinsic("log2", in_elem, in_ty, in_len, bx, span, args);
1310         }
1311         "simd_flog" => {
1312             return simd_simple_float_intrinsic("log", in_elem, in_ty, in_len, bx, span, args);
1313         }
1314         "simd_fpowi" => {
1315             return simd_simple_float_intrinsic("powi", in_elem, in_ty, in_len, bx, span, args);
1316         }
1317         "simd_fpow" => {
1318             return simd_simple_float_intrinsic("pow", in_elem, in_ty, in_len, bx, span, args);
1319         }
1320         "simd_fma" => {
1321             return simd_simple_float_intrinsic("fma", in_elem, in_ty, in_len, bx, span, args);
1322         }
1323         _ => { /* fallthrough */ }
1324     }
1325
1326     // FIXME: use:
1327     //  https://github.com/llvm-mirror/llvm/blob/master/include/llvm/IR/Function.h#L182
1328     //  https://github.com/llvm-mirror/llvm/blob/master/include/llvm/IR/Intrinsics.h#L81
1329     fn llvm_vector_str(elem_ty: ty::Ty, vec_len: usize, no_pointers: usize) -> String {
1330         let p0s: String = "p0".repeat(no_pointers);
1331         match elem_ty.sty {
1332             ty::Int(v) => format!("v{}{}i{}", vec_len, p0s, v.bit_width().unwrap()),
1333             ty::Uint(v) => format!("v{}{}i{}", vec_len, p0s, v.bit_width().unwrap()),
1334             ty::Float(v) => format!("v{}{}f{}", vec_len, p0s, v.bit_width()),
1335             _ => unreachable!(),
1336         }
1337     }
1338
1339     fn llvm_vector_ty(cx: &CodegenCx<'ll, '_>, elem_ty: ty::Ty, vec_len: usize,
1340                       mut no_pointers: usize) -> &'ll Type {
1341         // FIXME: use cx.layout_of(ty).llvm_type() ?
1342         let mut elem_ty = match elem_ty.sty {
1343             ty::Int(v) => cx.type_int_from_ty( v),
1344             ty::Uint(v) => cx.type_uint_from_ty( v),
1345             ty::Float(v) => cx.type_float_from_ty( v),
1346             _ => unreachable!(),
1347         };
1348         while no_pointers > 0 {
1349             elem_ty = cx.type_ptr_to(elem_ty);
1350             no_pointers -= 1;
1351         }
1352         cx.type_vector(elem_ty, vec_len as u64)
1353     }
1354
1355
1356     if name == "simd_gather" {
1357         // simd_gather(values: <N x T>, pointers: <N x *_ T>,
1358         //             mask: <N x i{M}>) -> <N x T>
1359         // * N: number of elements in the input vectors
1360         // * T: type of the element to load
1361         // * M: any integer width is supported, will be truncated to i1
1362
1363         // All types must be simd vector types
1364         require_simd!(in_ty, "first");
1365         require_simd!(arg_tys[1], "second");
1366         require_simd!(arg_tys[2], "third");
1367         require_simd!(ret_ty, "return");
1368
1369         // Of the same length:
1370         require!(in_len == arg_tys[1].simd_size(tcx),
1371                  "expected {} argument with length {} (same as input type `{}`), \
1372                   found `{}` with length {}", "second", in_len, in_ty, arg_tys[1],
1373                  arg_tys[1].simd_size(tcx));
1374         require!(in_len == arg_tys[2].simd_size(tcx),
1375                  "expected {} argument with length {} (same as input type `{}`), \
1376                   found `{}` with length {}", "third", in_len, in_ty, arg_tys[2],
1377                  arg_tys[2].simd_size(tcx));
1378
1379         // The return type must match the first argument type
1380         require!(ret_ty == in_ty,
1381                  "expected return type `{}`, found `{}`",
1382                  in_ty, ret_ty);
1383
1384         // This counts how many pointers
1385         fn ptr_count(t: ty::Ty) -> usize {
1386             match t.sty {
1387                 ty::RawPtr(p) => 1 + ptr_count(p.ty),
1388                 _ => 0,
1389             }
1390         }
1391
1392         // Non-ptr type
1393         fn non_ptr(t: ty::Ty) -> ty::Ty {
1394             match t.sty {
1395                 ty::RawPtr(p) => non_ptr(p.ty),
1396                 _ => t,
1397             }
1398         }
1399
1400         // The second argument must be a simd vector with an element type that's a pointer
1401         // to the element type of the first argument
1402         let (pointer_count, underlying_ty) = match arg_tys[1].simd_type(tcx).sty {
1403             ty::RawPtr(p) if p.ty == in_elem => (ptr_count(arg_tys[1].simd_type(tcx)),
1404                                                  non_ptr(arg_tys[1].simd_type(tcx))),
1405             _ => {
1406                 require!(false, "expected element type `{}` of second argument `{}` \
1407                                  to be a pointer to the element type `{}` of the first \
1408                                  argument `{}`, found `{}` != `*_ {}`",
1409                          arg_tys[1].simd_type(tcx).sty, arg_tys[1], in_elem, in_ty,
1410                          arg_tys[1].simd_type(tcx).sty, in_elem);
1411                 unreachable!();
1412             }
1413         };
1414         assert!(pointer_count > 0);
1415         assert_eq!(pointer_count - 1, ptr_count(arg_tys[0].simd_type(tcx)));
1416         assert_eq!(underlying_ty, non_ptr(arg_tys[0].simd_type(tcx)));
1417
1418         // The element type of the third argument must be a signed integer type of any width:
1419         match arg_tys[2].simd_type(tcx).sty {
1420             ty::Int(_) => (),
1421             _ => {
1422                 require!(false, "expected element type `{}` of third argument `{}` \
1423                                  to be a signed integer type",
1424                          arg_tys[2].simd_type(tcx).sty, arg_tys[2]);
1425             }
1426         }
1427
1428         // Alignment of T, must be a constant integer value:
1429         let alignment_ty = bx.cx().type_i32();
1430         let alignment = bx.cx().const_i32(bx.cx().align_of(in_elem).abi() as i32);
1431
1432         // Truncate the mask vector to a vector of i1s:
1433         let (mask, mask_ty) = {
1434             let i1 = bx.cx().type_i1();
1435             let i1xn = bx.cx().type_vector(i1, in_len as u64);
1436             (bx.trunc(args[2].immediate(), i1xn), i1xn)
1437         };
1438
1439         // Type of the vector of pointers:
1440         let llvm_pointer_vec_ty = llvm_vector_ty(bx.cx(), underlying_ty, in_len, pointer_count);
1441         let llvm_pointer_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count);
1442
1443         // Type of the vector of elements:
1444         let llvm_elem_vec_ty = llvm_vector_ty(bx.cx(), underlying_ty, in_len, pointer_count - 1);
1445         let llvm_elem_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count - 1);
1446
1447         let llvm_intrinsic = format!("llvm.masked.gather.{}.{}",
1448                                      llvm_elem_vec_str, llvm_pointer_vec_str);
1449         let f = bx.cx().declare_cfn(&llvm_intrinsic,
1450                                      bx.cx().type_func(&[
1451                                          llvm_pointer_vec_ty,
1452                                          alignment_ty,
1453                                          mask_ty,
1454                                          llvm_elem_vec_ty], llvm_elem_vec_ty));
1455         llvm::SetUnnamedAddr(f, false);
1456         let v = bx.call(f, &[args[1].immediate(), alignment, mask, args[0].immediate()],
1457                         None);
1458         return Ok(v);
1459     }
1460
1461     if name == "simd_scatter" {
1462         // simd_scatter(values: <N x T>, pointers: <N x *mut T>,
1463         //             mask: <N x i{M}>) -> ()
1464         // * N: number of elements in the input vectors
1465         // * T: type of the element to load
1466         // * M: any integer width is supported, will be truncated to i1
1467
1468         // All types must be simd vector types
1469         require_simd!(in_ty, "first");
1470         require_simd!(arg_tys[1], "second");
1471         require_simd!(arg_tys[2], "third");
1472
1473         // Of the same length:
1474         require!(in_len == arg_tys[1].simd_size(tcx),
1475                  "expected {} argument with length {} (same as input type `{}`), \
1476                   found `{}` with length {}", "second", in_len, in_ty, arg_tys[1],
1477                  arg_tys[1].simd_size(tcx));
1478         require!(in_len == arg_tys[2].simd_size(tcx),
1479                  "expected {} argument with length {} (same as input type `{}`), \
1480                   found `{}` with length {}", "third", in_len, in_ty, arg_tys[2],
1481                  arg_tys[2].simd_size(tcx));
1482
1483         // This counts how many pointers
1484         fn ptr_count(t: ty::Ty) -> usize {
1485             match t.sty {
1486                 ty::RawPtr(p) => 1 + ptr_count(p.ty),
1487                 _ => 0,
1488             }
1489         }
1490
1491         // Non-ptr type
1492         fn non_ptr(t: ty::Ty) -> ty::Ty {
1493             match t.sty {
1494                 ty::RawPtr(p) => non_ptr(p.ty),
1495                 _ => t,
1496             }
1497         }
1498
1499         // The second argument must be a simd vector with an element type that's a pointer
1500         // to the element type of the first argument
1501         let (pointer_count, underlying_ty) = match arg_tys[1].simd_type(tcx).sty {
1502             ty::RawPtr(p) if p.ty == in_elem && p.mutbl == hir::MutMutable
1503                 => (ptr_count(arg_tys[1].simd_type(tcx)),
1504                     non_ptr(arg_tys[1].simd_type(tcx))),
1505             _ => {
1506                 require!(false, "expected element type `{}` of second argument `{}` \
1507                                  to be a pointer to the element type `{}` of the first \
1508                                  argument `{}`, found `{}` != `*mut {}`",
1509                          arg_tys[1].simd_type(tcx).sty, arg_tys[1], in_elem, in_ty,
1510                          arg_tys[1].simd_type(tcx).sty, in_elem);
1511                 unreachable!();
1512             }
1513         };
1514         assert!(pointer_count > 0);
1515         assert_eq!(pointer_count - 1, ptr_count(arg_tys[0].simd_type(tcx)));
1516         assert_eq!(underlying_ty, non_ptr(arg_tys[0].simd_type(tcx)));
1517
1518         // The element type of the third argument must be a signed integer type of any width:
1519         match arg_tys[2].simd_type(tcx).sty {
1520             ty::Int(_) => (),
1521             _ => {
1522                 require!(false, "expected element type `{}` of third argument `{}` \
1523                                  to be a signed integer type",
1524                          arg_tys[2].simd_type(tcx).sty, arg_tys[2]);
1525             }
1526         }
1527
1528         // Alignment of T, must be a constant integer value:
1529         let alignment_ty = bx.cx().type_i32();
1530         let alignment = bx.cx().const_i32(bx.cx().align_of(in_elem).abi() as i32);
1531
1532         // Truncate the mask vector to a vector of i1s:
1533         let (mask, mask_ty) = {
1534             let i1 = bx.cx().type_i1();
1535             let i1xn = bx.cx().type_vector(i1, in_len as u64);
1536             (bx.trunc(args[2].immediate(), i1xn), i1xn)
1537         };
1538
1539         let ret_t = bx.cx().type_void();
1540
1541         // Type of the vector of pointers:
1542         let llvm_pointer_vec_ty = llvm_vector_ty(bx.cx(), underlying_ty, in_len, pointer_count);
1543         let llvm_pointer_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count);
1544
1545         // Type of the vector of elements:
1546         let llvm_elem_vec_ty = llvm_vector_ty(bx.cx(), underlying_ty, in_len, pointer_count - 1);
1547         let llvm_elem_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count - 1);
1548
1549         let llvm_intrinsic = format!("llvm.masked.scatter.{}.{}",
1550                                      llvm_elem_vec_str, llvm_pointer_vec_str);
1551         let f = bx.cx().declare_cfn(&llvm_intrinsic,
1552                                      bx.cx().type_func(&[llvm_elem_vec_ty,
1553                                                   llvm_pointer_vec_ty,
1554                                                   alignment_ty,
1555                                                   mask_ty], ret_t));
1556         llvm::SetUnnamedAddr(f, false);
1557         let v = bx.call(f, &[args[0].immediate(), args[1].immediate(), alignment, mask],
1558                         None);
1559         return Ok(v);
1560     }
1561
1562     macro_rules! arith_red {
1563         ($name:tt : $integer_reduce:ident, $float_reduce:ident, $ordered:expr) => {
1564             if name == $name {
1565                 require!(ret_ty == in_elem,
1566                          "expected return type `{}` (element of input `{}`), found `{}`",
1567                          in_elem, in_ty, ret_ty);
1568                 return match in_elem.sty {
1569                     ty::Int(_) | ty::Uint(_) => {
1570                         let r = bx.$integer_reduce(args[0].immediate());
1571                         if $ordered {
1572                             // if overflow occurs, the result is the
1573                             // mathematical result modulo 2^n:
1574                             if name.contains("mul") {
1575                                 Ok(bx.mul(args[1].immediate(), r))
1576                             } else {
1577                                 Ok(bx.add(args[1].immediate(), r))
1578                             }
1579                         } else {
1580                             Ok(bx.$integer_reduce(args[0].immediate()))
1581                         }
1582                     },
1583                     ty::Float(f) => {
1584                         // ordered arithmetic reductions take an accumulator
1585                         let acc = if $ordered {
1586                             let acc = args[1].immediate();
1587                             // FIXME: https://bugs.llvm.org/show_bug.cgi?id=36734
1588                             // * if the accumulator of the fadd isn't 0, incorrect
1589                             //   code is generated
1590                             // * if the accumulator of the fmul isn't 1, incorrect
1591                             //   code is generated
1592                             match bx.cx().const_get_real(acc) {
1593                                 None => return_error!("accumulator of {} is not a constant", $name),
1594                                 Some((v, loses_info)) => {
1595                                     if $name.contains("mul") && v != 1.0_f64 {
1596                                         return_error!("accumulator of {} is not 1.0", $name);
1597                                     } else if $name.contains("add") && v != 0.0_f64 {
1598                                         return_error!("accumulator of {} is not 0.0", $name);
1599                                     } else if loses_info {
1600                                         return_error!("accumulator of {} loses information", $name);
1601                                     }
1602                                 }
1603                             }
1604                             acc
1605                         } else {
1606                             // unordered arithmetic reductions do not:
1607                             match f.bit_width() {
1608                                 32 => bx.cx().const_undef(bx.cx().type_f32()),
1609                                 64 => bx.cx().const_undef(bx.cx().type_f64()),
1610                                 v => {
1611                                     return_error!(r#"
1612 unsupported {} from `{}` with element `{}` of size `{}` to `{}`"#,
1613                                         $name, in_ty, in_elem, v, ret_ty
1614                                     )
1615                                 }
1616                             }
1617                         };
1618                         Ok(bx.$float_reduce(acc, args[0].immediate()))
1619                     }
1620                     _ => {
1621                         return_error!(
1622                             "unsupported {} from `{}` with element `{}` to `{}`",
1623                             $name, in_ty, in_elem, ret_ty
1624                         )
1625                     },
1626                 }
1627             }
1628         }
1629     }
1630
1631     arith_red!("simd_reduce_add_ordered": vector_reduce_add, vector_reduce_fadd_fast, true);
1632     arith_red!("simd_reduce_mul_ordered": vector_reduce_mul, vector_reduce_fmul_fast, true);
1633     arith_red!("simd_reduce_add_unordered": vector_reduce_add, vector_reduce_fadd_fast, false);
1634     arith_red!("simd_reduce_mul_unordered": vector_reduce_mul, vector_reduce_fmul_fast, false);
1635
1636     macro_rules! minmax_red {
1637         ($name:tt: $int_red:ident, $float_red:ident) => {
1638             if name == $name {
1639                 require!(ret_ty == in_elem,
1640                          "expected return type `{}` (element of input `{}`), found `{}`",
1641                          in_elem, in_ty, ret_ty);
1642                 return match in_elem.sty {
1643                     ty::Int(_i) => {
1644                         Ok(bx.$int_red(args[0].immediate(), true))
1645                     },
1646                     ty::Uint(_u) => {
1647                         Ok(bx.$int_red(args[0].immediate(), false))
1648                     },
1649                     ty::Float(_f) => {
1650                         Ok(bx.$float_red(args[0].immediate()))
1651                     }
1652                     _ => {
1653                         return_error!("unsupported {} from `{}` with element `{}` to `{}`",
1654                                       $name, in_ty, in_elem, ret_ty)
1655                     },
1656                 }
1657             }
1658
1659         }
1660     }
1661
1662     minmax_red!("simd_reduce_min": vector_reduce_min, vector_reduce_fmin);
1663     minmax_red!("simd_reduce_max": vector_reduce_max, vector_reduce_fmax);
1664
1665     minmax_red!("simd_reduce_min_nanless": vector_reduce_min, vector_reduce_fmin_fast);
1666     minmax_red!("simd_reduce_max_nanless": vector_reduce_max, vector_reduce_fmax_fast);
1667
1668     macro_rules! bitwise_red {
1669         ($name:tt : $red:ident, $boolean:expr) => {
1670             if name == $name {
1671                 let input = if !$boolean {
1672                     require!(ret_ty == in_elem,
1673                              "expected return type `{}` (element of input `{}`), found `{}`",
1674                              in_elem, in_ty, ret_ty);
1675                     args[0].immediate()
1676                 } else {
1677                     match in_elem.sty {
1678                         ty::Int(_) | ty::Uint(_) => {},
1679                         _ => {
1680                             return_error!("unsupported {} from `{}` with element `{}` to `{}`",
1681                                           $name, in_ty, in_elem, ret_ty)
1682                         }
1683                     }
1684
1685                     // boolean reductions operate on vectors of i1s:
1686                     let i1 = bx.cx().type_i1();
1687                     let i1xn = bx.cx().type_vector(i1, in_len as u64);
1688                     bx.trunc(args[0].immediate(), i1xn)
1689                 };
1690                 return match in_elem.sty {
1691                     ty::Int(_) | ty::Uint(_) => {
1692                         let r = bx.$red(input);
1693                         Ok(
1694                             if !$boolean {
1695                                 r
1696                             } else {
1697                                 bx.zext(r, bx.cx().type_bool())
1698                             }
1699                         )
1700                     },
1701                     _ => {
1702                         return_error!("unsupported {} from `{}` with element `{}` to `{}`",
1703                                       $name, in_ty, in_elem, ret_ty)
1704                     },
1705                 }
1706             }
1707         }
1708     }
1709
1710     bitwise_red!("simd_reduce_and": vector_reduce_and, false);
1711     bitwise_red!("simd_reduce_or": vector_reduce_or, false);
1712     bitwise_red!("simd_reduce_xor": vector_reduce_xor, false);
1713     bitwise_red!("simd_reduce_all": vector_reduce_and, true);
1714     bitwise_red!("simd_reduce_any": vector_reduce_or, true);
1715
1716     if name == "simd_cast" {
1717         require_simd!(ret_ty, "return");
1718         let out_len = ret_ty.simd_size(tcx);
1719         require!(in_len == out_len,
1720                  "expected return type with length {} (same as input type `{}`), \
1721                   found `{}` with length {}",
1722                  in_len, in_ty,
1723                  ret_ty, out_len);
1724         // casting cares about nominal type, not just structural type
1725         let out_elem = ret_ty.simd_type(tcx);
1726
1727         if in_elem == out_elem { return Ok(args[0].immediate()); }
1728
1729         enum Style { Float, Int(/* is signed? */ bool), Unsupported }
1730
1731         let (in_style, in_width) = match in_elem.sty {
1732             // vectors of pointer-sized integers should've been
1733             // disallowed before here, so this unwrap is safe.
1734             ty::Int(i) => (Style::Int(true), i.bit_width().unwrap()),
1735             ty::Uint(u) => (Style::Int(false), u.bit_width().unwrap()),
1736             ty::Float(f) => (Style::Float, f.bit_width()),
1737             _ => (Style::Unsupported, 0)
1738         };
1739         let (out_style, out_width) = match out_elem.sty {
1740             ty::Int(i) => (Style::Int(true), i.bit_width().unwrap()),
1741             ty::Uint(u) => (Style::Int(false), u.bit_width().unwrap()),
1742             ty::Float(f) => (Style::Float, f.bit_width()),
1743             _ => (Style::Unsupported, 0)
1744         };
1745
1746         match (in_style, out_style) {
1747             (Style::Int(in_is_signed), Style::Int(_)) => {
1748                 return Ok(match in_width.cmp(&out_width) {
1749                     Ordering::Greater => bx.trunc(args[0].immediate(), llret_ty),
1750                     Ordering::Equal => args[0].immediate(),
1751                     Ordering::Less => if in_is_signed {
1752                         bx.sext(args[0].immediate(), llret_ty)
1753                     } else {
1754                         bx.zext(args[0].immediate(), llret_ty)
1755                     }
1756                 })
1757             }
1758             (Style::Int(in_is_signed), Style::Float) => {
1759                 return Ok(if in_is_signed {
1760                     bx.sitofp(args[0].immediate(), llret_ty)
1761                 } else {
1762                     bx.uitofp(args[0].immediate(), llret_ty)
1763                 })
1764             }
1765             (Style::Float, Style::Int(out_is_signed)) => {
1766                 return Ok(if out_is_signed {
1767                     bx.fptosi(args[0].immediate(), llret_ty)
1768                 } else {
1769                     bx.fptoui(args[0].immediate(), llret_ty)
1770                 })
1771             }
1772             (Style::Float, Style::Float) => {
1773                 return Ok(match in_width.cmp(&out_width) {
1774                     Ordering::Greater => bx.fptrunc(args[0].immediate(), llret_ty),
1775                     Ordering::Equal => args[0].immediate(),
1776                     Ordering::Less => bx.fpext(args[0].immediate(), llret_ty)
1777                 })
1778             }
1779             _ => {/* Unsupported. Fallthrough. */}
1780         }
1781         require!(false,
1782                  "unsupported cast from `{}` with element `{}` to `{}` with element `{}`",
1783                  in_ty, in_elem,
1784                  ret_ty, out_elem);
1785     }
1786     macro_rules! arith {
1787         ($($name: ident: $($($p: ident),* => $call: ident),*;)*) => {
1788             $(if name == stringify!($name) {
1789                 match in_elem.sty {
1790                     $($(ty::$p(_))|* => {
1791                         return Ok(bx.$call(args[0].immediate(), args[1].immediate()))
1792                     })*
1793                     _ => {},
1794                 }
1795                 require!(false,
1796                          "unsupported operation on `{}` with element `{}`",
1797                          in_ty,
1798                          in_elem)
1799             })*
1800         }
1801     }
1802     arith! {
1803         simd_add: Uint, Int => add, Float => fadd;
1804         simd_sub: Uint, Int => sub, Float => fsub;
1805         simd_mul: Uint, Int => mul, Float => fmul;
1806         simd_div: Uint => udiv, Int => sdiv, Float => fdiv;
1807         simd_rem: Uint => urem, Int => srem, Float => frem;
1808         simd_shl: Uint, Int => shl;
1809         simd_shr: Uint => lshr, Int => ashr;
1810         simd_and: Uint, Int => and;
1811         simd_or: Uint, Int => or;
1812         simd_xor: Uint, Int => xor;
1813         simd_fmax: Float => maxnum;
1814         simd_fmin: Float => minnum;
1815     }
1816     span_bug!(span, "unknown SIMD intrinsic");
1817 }
1818
1819 // Returns the width of an int Ty, and if it's signed or not
1820 // Returns None if the type is not an integer
1821 // FIXME: there’s multiple of this functions, investigate using some of the already existing
1822 // stuffs.
1823 fn int_type_width_signed(ty: Ty, cx: &CodegenCx) -> Option<(u64, bool)> {
1824     match ty.sty {
1825         ty::Int(t) => Some((match t {
1826             ast::IntTy::Isize => cx.tcx.sess.target.isize_ty.bit_width().unwrap() as u64,
1827             ast::IntTy::I8 => 8,
1828             ast::IntTy::I16 => 16,
1829             ast::IntTy::I32 => 32,
1830             ast::IntTy::I64 => 64,
1831             ast::IntTy::I128 => 128,
1832         }, true)),
1833         ty::Uint(t) => Some((match t {
1834             ast::UintTy::Usize => cx.tcx.sess.target.usize_ty.bit_width().unwrap() as u64,
1835             ast::UintTy::U8 => 8,
1836             ast::UintTy::U16 => 16,
1837             ast::UintTy::U32 => 32,
1838             ast::UintTy::U64 => 64,
1839             ast::UintTy::U128 => 128,
1840         }, false)),
1841         _ => None,
1842     }
1843 }
1844
1845 // Returns the width of a float TypeVariant
1846 // Returns None if the type is not a float
1847 fn float_type_width<'tcx>(sty: &ty::TyKind<'tcx>) -> Option<u64> {
1848     match *sty {
1849         ty::Float(t) => Some(t.bit_width() as u64),
1850         _ => None,
1851     }
1852 }