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