src/shims/intrinsics.rs

   1 use std::iter;
   2
   3 use log::trace;
   4
   5 use rustc_apfloat::{Float, Round};
   6 use rustc_middle::ty::layout::{HasParamEnv, IntegerExt, LayoutOf};
   7 use rustc_middle::{mir, mir::BinOp, ty, ty::FloatTy};
   8 use rustc_target::abi::{Align, Integer};
   9
  10 use crate::*;
  11 use helpers::{bool_to_simd_element, check_arg_count, simd_element_to_bool};
  12
  13 pub enum AtomicOp {
  14     MirOp(mir::BinOp, bool),
  15     Max,
  16     Min,
  17 }
  18
  19 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
  20 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
  21     fn call_intrinsic(
  22         &mut self,
  23         instance: ty::Instance<'tcx>,
  24         args: &[OpTy<'tcx, Tag>],
  25         ret: Option<(&PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
  26         _unwind: StackPopUnwind,
  27     ) -> InterpResult<'tcx> {
  28         let this = self.eval_context_mut();
  29
  30         if this.emulate_intrinsic(instance, args, ret)? {
  31             return Ok(());
  32         }
  33
  34         // All supported intrinsics have a return place.
  35         let intrinsic_name = this.tcx.item_name(instance.def_id());
  36         let intrinsic_name = intrinsic_name.as_str();
  37         let (dest, ret) = match ret {
  38             None => throw_unsup_format!("unimplemented (diverging) intrinsic: {}", intrinsic_name),
  39             Some(p) => p,
  40         };
  41
  42         // Then handle terminating intrinsics.
  43         match intrinsic_name {
  44             // Miri overwriting CTFE intrinsics.
  45             "ptr_guaranteed_eq" => {
  46                 let &[ref left, ref right] = check_arg_count(args)?;
  47                 let left = this.read_immediate(left)?;
  48                 let right = this.read_immediate(right)?;
  49                 this.binop_ignore_overflow(mir::BinOp::Eq, &left, &right, dest)?;
  50             }
  51             "ptr_guaranteed_ne" => {
  52                 let &[ref left, ref right] = check_arg_count(args)?;
  53                 let left = this.read_immediate(left)?;
  54                 let right = this.read_immediate(right)?;
  55                 this.binop_ignore_overflow(mir::BinOp::Ne, &left, &right, dest)?;
  56             }
  57             "const_allocate" => {
  58                 // For now, for compatibility with the run-time implementation of this, we just return null.
  59                 // See <https://github.com/rust-lang/rust/issues/93935>.
  60                 this.write_null(dest)?;
  61             }
  62             "const_deallocate" => {
  63                 // complete NOP
  64             }
  65
  66             // Raw memory accesses
  67             "volatile_load" => {
  68                 let &[ref place] = check_arg_count(args)?;
  69                 let place = this.deref_operand(place)?;
  70                 this.copy_op(&place.into(), dest)?;
  71             }
  72             "volatile_store" => {
  73                 let &[ref place, ref dest] = check_arg_count(args)?;
  74                 let place = this.deref_operand(place)?;
  75                 this.copy_op(dest, &place.into())?;
  76             }
  77
  78             "write_bytes" | "volatile_set_memory" => {
  79                 let &[ref ptr, ref val_byte, ref count] = check_arg_count(args)?;
  80                 let ty = instance.substs.type_at(0);
  81                 let ty_layout = this.layout_of(ty)?;
  82                 let val_byte = this.read_scalar(val_byte)?.to_u8()?;
  83                 let ptr = this.read_pointer(ptr)?;
  84                 let count = this.read_scalar(count)?.to_machine_usize(this)?;
  85                 let byte_count = ty_layout.size.checked_mul(count, this).ok_or_else(|| {
  86                     err_ub_format!("overflow computing total size of `{}`", intrinsic_name)
  87                 })?;
  88                 this.memory
  89                     .write_bytes(ptr, iter::repeat(val_byte).take(byte_count.bytes() as usize))?;
  90             }
  91
  92             // Floating-point operations
  93             "fabsf32" => {
  94                 let &[ref f] = check_arg_count(args)?;
  95                 let f = this.read_scalar(f)?.to_f32()?;
  96                 // Can be implemented in soft-floats.
  97                 this.write_scalar(Scalar::from_f32(f.abs()), dest)?;
  98             }
  99             "fabsf64" => {
 100                 let &[ref f] = check_arg_count(args)?;
 101                 let f = this.read_scalar(f)?.to_f64()?;
 102                 // Can be implemented in soft-floats.
 103                 this.write_scalar(Scalar::from_f64(f.abs()), dest)?;
 104             }
 105             #[rustfmt::skip]
 106             | "sinf32"
 107             | "cosf32"
 108             | "sqrtf32"
 109             | "expf32"
 110             | "exp2f32"
 111             | "logf32"
 112             | "log10f32"
 113             | "log2f32"
 114             | "floorf32"
 115             | "ceilf32"
 116             | "truncf32"
 117             | "roundf32"
 118             => {
 119                 let &[ref f] = check_arg_count(args)?;
 120                 // FIXME: Using host floats.
 121                 let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
 122                 let f = match intrinsic_name {
 123                     "sinf32" => f.sin(),
 124                     "cosf32" => f.cos(),
 125                     "sqrtf32" => f.sqrt(),
 126                     "expf32" => f.exp(),
 127                     "exp2f32" => f.exp2(),
 128                     "logf32" => f.ln(),
 129                     "log10f32" => f.log10(),
 130                     "log2f32" => f.log2(),
 131                     "floorf32" => f.floor(),
 132                     "ceilf32" => f.ceil(),
 133                     "truncf32" => f.trunc(),
 134                     "roundf32" => f.round(),
 135                     _ => bug!(),
 136                 };
 137                 this.write_scalar(Scalar::from_u32(f.to_bits()), dest)?;
 138             }
 139
 140             #[rustfmt::skip]
 141             | "sinf64"
 142             | "cosf64"
 143             | "sqrtf64"
 144             | "expf64"
 145             | "exp2f64"
 146             | "logf64"
 147             | "log10f64"
 148             | "log2f64"
 149             | "floorf64"
 150             | "ceilf64"
 151             | "truncf64"
 152             | "roundf64"
 153             => {
 154                 let &[ref f] = check_arg_count(args)?;
 155                 // FIXME: Using host floats.
 156                 let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
 157                 let f = match intrinsic_name {
 158                     "sinf64" => f.sin(),
 159                     "cosf64" => f.cos(),
 160                     "sqrtf64" => f.sqrt(),
 161                     "expf64" => f.exp(),
 162                     "exp2f64" => f.exp2(),
 163                     "logf64" => f.ln(),
 164                     "log10f64" => f.log10(),
 165                     "log2f64" => f.log2(),
 166                     "floorf64" => f.floor(),
 167                     "ceilf64" => f.ceil(),
 168                     "truncf64" => f.trunc(),
 169                     "roundf64" => f.round(),
 170                     _ => bug!(),
 171                 };
 172                 this.write_scalar(Scalar::from_u64(f.to_bits()), dest)?;
 173             }
 174
 175             #[rustfmt::skip]
 176             | "fadd_fast"
 177             | "fsub_fast"
 178             | "fmul_fast"
 179             | "fdiv_fast"
 180             | "frem_fast"
 181             => {
 182                 let &[ref a, ref b] = check_arg_count(args)?;
 183                 let a = this.read_immediate(a)?;
 184                 let b = this.read_immediate(b)?;
 185                 let op = match intrinsic_name {
 186                     "fadd_fast" => mir::BinOp::Add,
 187                     "fsub_fast" => mir::BinOp::Sub,
 188                     "fmul_fast" => mir::BinOp::Mul,
 189                     "fdiv_fast" => mir::BinOp::Div,
 190                     "frem_fast" => mir::BinOp::Rem,
 191                     _ => bug!(),
 192                 };
 193                 let float_finite = |x: ImmTy<'tcx, _>| -> InterpResult<'tcx, bool> {
 194                     Ok(match x.layout.ty.kind() {
 195                         ty::Float(FloatTy::F32) => x.to_scalar()?.to_f32()?.is_finite(),
 196                         ty::Float(FloatTy::F64) => x.to_scalar()?.to_f64()?.is_finite(),
 197                         _ => bug!(
 198                             "`{}` called with non-float input type {:?}",
 199                             intrinsic_name,
 200                             x.layout.ty
 201                         ),
 202                     })
 203                 };
 204                 match (float_finite(a)?, float_finite(b)?) {
 205                     (false, false) => throw_ub_format!(
 206                         "`{}` intrinsic called with non-finite value as both parameters",
 207                         intrinsic_name,
 208                     ),
 209                     (false, _) => throw_ub_format!(
 210                         "`{}` intrinsic called with non-finite value as first parameter",
 211                         intrinsic_name,
 212                     ),
 213                     (_, false) => throw_ub_format!(
 214                         "`{}` intrinsic called with non-finite value as second parameter",
 215                         intrinsic_name,
 216                     ),
 217                     _ => {}
 218                 }
 219                 this.binop_ignore_overflow(op, &a, &b, dest)?;
 220             }
 221
 222             #[rustfmt::skip]
 223             | "minnumf32"
 224             | "maxnumf32"
 225             | "copysignf32"
 226             => {
 227                 let &[ref a, ref b] = check_arg_count(args)?;
 228                 let a = this.read_scalar(a)?.to_f32()?;
 229                 let b = this.read_scalar(b)?.to_f32()?;
 230                 let res = match intrinsic_name {
 231                     "minnumf32" => a.min(b),
 232                     "maxnumf32" => a.max(b),
 233                     "copysignf32" => a.copy_sign(b),
 234                     _ => bug!(),
 235                 };
 236                 this.write_scalar(Scalar::from_f32(res), dest)?;
 237             }
 238
 239             #[rustfmt::skip]
 240             | "minnumf64"
 241             | "maxnumf64"
 242             | "copysignf64"
 243             => {
 244                 let &[ref a, ref b] = check_arg_count(args)?;
 245                 let a = this.read_scalar(a)?.to_f64()?;
 246                 let b = this.read_scalar(b)?.to_f64()?;
 247                 let res = match intrinsic_name {
 248                     "minnumf64" => a.min(b),
 249                     "maxnumf64" => a.max(b),
 250                     "copysignf64" => a.copy_sign(b),
 251                     _ => bug!(),
 252                 };
 253                 this.write_scalar(Scalar::from_f64(res), dest)?;
 254             }
 255
 256             "powf32" => {
 257                 let &[ref f, ref f2] = check_arg_count(args)?;
 258                 // FIXME: Using host floats.
 259                 let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
 260                 let f2 = f32::from_bits(this.read_scalar(f2)?.to_u32()?);
 261                 this.write_scalar(Scalar::from_u32(f.powf(f2).to_bits()), dest)?;
 262             }
 263
 264             "powf64" => {
 265                 let &[ref f, ref f2] = check_arg_count(args)?;
 266                 // FIXME: Using host floats.
 267                 let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
 268                 let f2 = f64::from_bits(this.read_scalar(f2)?.to_u64()?);
 269                 this.write_scalar(Scalar::from_u64(f.powf(f2).to_bits()), dest)?;
 270             }
 271
 272             "fmaf32" => {
 273                 let &[ref a, ref b, ref c] = check_arg_count(args)?;
 274                 let a = this.read_scalar(a)?.to_f32()?;
 275                 let b = this.read_scalar(b)?.to_f32()?;
 276                 let c = this.read_scalar(c)?.to_f32()?;
 277                 let res = a.mul_add(b, c).value;
 278                 this.write_scalar(Scalar::from_f32(res), dest)?;
 279             }
 280
 281             "fmaf64" => {
 282                 let &[ref a, ref b, ref c] = check_arg_count(args)?;
 283                 let a = this.read_scalar(a)?.to_f64()?;
 284                 let b = this.read_scalar(b)?.to_f64()?;
 285                 let c = this.read_scalar(c)?.to_f64()?;
 286                 let res = a.mul_add(b, c).value;
 287                 this.write_scalar(Scalar::from_f64(res), dest)?;
 288             }
 289
 290             "powif32" => {
 291                 let &[ref f, ref i] = check_arg_count(args)?;
 292                 // FIXME: Using host floats.
 293                 let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
 294                 let i = this.read_scalar(i)?.to_i32()?;
 295                 this.write_scalar(Scalar::from_u32(f.powi(i).to_bits()), dest)?;
 296             }
 297
 298             "powif64" => {
 299                 let &[ref f, ref i] = check_arg_count(args)?;
 300                 // FIXME: Using host floats.
 301                 let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
 302                 let i = this.read_scalar(i)?.to_i32()?;
 303                 this.write_scalar(Scalar::from_u64(f.powi(i).to_bits()), dest)?;
 304             }
 305
 306             "float_to_int_unchecked" => {
 307                 let &[ref val] = check_arg_count(args)?;
 308                 let val = this.read_immediate(val)?;
 309
 310                 let res = match val.layout.ty.kind() {
 311                     ty::Float(FloatTy::F32) =>
 312                         this.float_to_int_unchecked(val.to_scalar()?.to_f32()?, dest.layout.ty)?,
 313                     ty::Float(FloatTy::F64) =>
 314                         this.float_to_int_unchecked(val.to_scalar()?.to_f64()?, dest.layout.ty)?,
 315                     _ =>
 316                         bug!(
 317                             "`float_to_int_unchecked` called with non-float input type {:?}",
 318                             val.layout.ty
 319                         ),
 320                 };
 321
 322                 this.write_scalar(res, dest)?;
 323             }
 324
 325             // SIMD operations
 326             #[rustfmt::skip]
 327             | "simd_neg"
 328             | "simd_fabs"
 329             | "simd_ceil"
 330             | "simd_floor"
 331             | "simd_round"
 332             | "simd_trunc" => {
 333                 let &[ref op] = check_arg_count(args)?;
 334                 let (op, op_len) = this.operand_to_simd(op)?;
 335                 let (dest, dest_len) = this.place_to_simd(dest)?;
 336
 337                 assert_eq!(dest_len, op_len);
 338
 339                 #[derive(Copy, Clone)]
 340                 enum HostFloatOp {
 341                     Ceil,
 342                     Floor,
 343                     Round,
 344                     Trunc,
 345                 }
 346                 #[derive(Copy, Clone)]
 347                 enum Op {
 348                     MirOp(mir::UnOp),
 349                     Abs,
 350                     HostOp(HostFloatOp),
 351                 }
 352                 let which = match intrinsic_name {
 353                     "simd_neg" => Op::MirOp(mir::UnOp::Neg),
 354                     "simd_fabs" => Op::Abs,
 355                     "simd_ceil" => Op::HostOp(HostFloatOp::Ceil),
 356                     "simd_floor" => Op::HostOp(HostFloatOp::Floor),
 357                     "simd_round" => Op::HostOp(HostFloatOp::Round),
 358                     "simd_trunc" => Op::HostOp(HostFloatOp::Trunc),
 359                     _ => unreachable!(),
 360                 };
 361
 362                 for i in 0..dest_len {
 363                     let op = this.read_immediate(&this.mplace_index(&op, i)?.into())?;
 364                     let dest = this.mplace_index(&dest, i)?;
 365                     let val = match which {
 366                         Op::MirOp(mir_op) => this.unary_op(mir_op, &op)?.to_scalar()?,
 367                         Op::Abs => {
 368                             // Works for f32 and f64.
 369                             let ty::Float(float_ty) = op.layout.ty.kind() else {
 370                                 bug!("{} operand is not a float", intrinsic_name)
 371                             };
 372                             let op = op.to_scalar()?;
 373                             match float_ty {
 374                                 FloatTy::F32 => Scalar::from_f32(op.to_f32()?.abs()),
 375                                 FloatTy::F64 => Scalar::from_f64(op.to_f64()?.abs()),
 376                             }
 377                         }
 378                         Op::HostOp(host_op) => {
 379                             let ty::Float(float_ty) = op.layout.ty.kind() else {
 380                                 bug!("{} operand is not a float", intrinsic_name)
 381                             };
 382                             // FIXME using host floats
 383                             match float_ty {
 384                                 FloatTy::F32 => {
 385                                     let f = f32::from_bits(op.to_scalar()?.to_u32()?);
 386                                     let res = match host_op {
 387                                         HostFloatOp::Ceil => f.ceil(),
 388                                         HostFloatOp::Floor => f.floor(),
 389                                         HostFloatOp::Round => f.round(),
 390                                         HostFloatOp::Trunc => f.trunc(),
 391                                     };
 392                                     Scalar::from_u32(res.to_bits())
 393                                 }
 394                                 FloatTy::F64 => {
 395                                     let f = f64::from_bits(op.to_scalar()?.to_u64()?);
 396                                     let res = match host_op {
 397                                         HostFloatOp::Ceil => f.ceil(),
 398                                         HostFloatOp::Floor => f.floor(),
 399                                         HostFloatOp::Round => f.round(),
 400                                         HostFloatOp::Trunc => f.trunc(),
 401                                     };
 402                                     Scalar::from_u64(res.to_bits())
 403                                 }
 404                             }
 405
 406                         }
 407                     };
 408                     this.write_scalar(val, &dest.into())?;
 409                 }
 410             }
 411             #[rustfmt::skip]
 412             | "simd_add"
 413             | "simd_sub"
 414             | "simd_mul"
 415             | "simd_div"
 416             | "simd_rem"
 417             | "simd_shl"
 418             | "simd_shr"
 419             | "simd_and"
 420             | "simd_or"
 421             | "simd_xor"
 422             | "simd_eq"
 423             | "simd_ne"
 424             | "simd_lt"
 425             | "simd_le"
 426             | "simd_gt"
 427             | "simd_ge"
 428             | "simd_fmax"
 429             | "simd_fmin"
 430             | "simd_saturating_add"
 431             | "simd_saturating_sub" => {
 432                 use mir::BinOp;
 433
 434                 let &[ref left, ref right] = check_arg_count(args)?;
 435                 let (left, left_len) = this.operand_to_simd(left)?;
 436                 let (right, right_len) = this.operand_to_simd(right)?;
 437                 let (dest, dest_len) = this.place_to_simd(dest)?;
 438
 439                 assert_eq!(dest_len, left_len);
 440                 assert_eq!(dest_len, right_len);
 441
 442                 enum Op {
 443                     MirOp(BinOp),
 444                     SaturatingOp(BinOp),
 445                     FMax,
 446                     FMin,
 447                 }
 448                 let which = match intrinsic_name {
 449                     "simd_add" => Op::MirOp(BinOp::Add),
 450                     "simd_sub" => Op::MirOp(BinOp::Sub),
 451                     "simd_mul" => Op::MirOp(BinOp::Mul),
 452                     "simd_div" => Op::MirOp(BinOp::Div),
 453                     "simd_rem" => Op::MirOp(BinOp::Rem),
 454                     "simd_shl" => Op::MirOp(BinOp::Shl),
 455                     "simd_shr" => Op::MirOp(BinOp::Shr),
 456                     "simd_and" => Op::MirOp(BinOp::BitAnd),
 457                     "simd_or" => Op::MirOp(BinOp::BitOr),
 458                     "simd_xor" => Op::MirOp(BinOp::BitXor),
 459                     "simd_eq" => Op::MirOp(BinOp::Eq),
 460                     "simd_ne" => Op::MirOp(BinOp::Ne),
 461                     "simd_lt" => Op::MirOp(BinOp::Lt),
 462                     "simd_le" => Op::MirOp(BinOp::Le),
 463                     "simd_gt" => Op::MirOp(BinOp::Gt),
 464                     "simd_ge" => Op::MirOp(BinOp::Ge),
 465                     "simd_fmax" => Op::FMax,
 466                     "simd_fmin" => Op::FMin,
 467                     "simd_saturating_add" => Op::SaturatingOp(BinOp::Add),
 468                     "simd_saturating_sub" => Op::SaturatingOp(BinOp::Sub),
 469                     _ => unreachable!(),
 470                 };
 471
 472                 for i in 0..dest_len {
 473                     let left = this.read_immediate(&this.mplace_index(&left, i)?.into())?;
 474                     let right = this.read_immediate(&this.mplace_index(&right, i)?.into())?;
 475                     let dest = this.mplace_index(&dest, i)?;
 476                     let val = match which {
 477                         Op::MirOp(mir_op) => {
 478                             let (val, overflowed, ty) = this.overflowing_binary_op(mir_op, &left, &right)?;
 479                             if matches!(mir_op, BinOp::Shl | BinOp::Shr) {
 480                                 // Shifts have extra UB as SIMD operations that the MIR binop does not have.
 481                                 // See <https://github.com/rust-lang/rust/issues/91237>.
 482                                 if overflowed {
 483                                     let r_val = right.to_scalar()?.to_bits(right.layout.size)?;
 484                                     throw_ub_format!("overflowing shift by {} in `{}` in SIMD lane {}", r_val, intrinsic_name, i);
 485                                 }
 486                             }
 487                             if matches!(mir_op, BinOp::Eq | BinOp::Ne | BinOp::Lt | BinOp::Le | BinOp::Gt | BinOp::Ge) {
 488                                 // Special handling for boolean-returning operations
 489                                 assert_eq!(ty, this.tcx.types.bool);
 490                                 let val = val.to_bool().unwrap();
 491                                 bool_to_simd_element(val, dest.layout.size)
 492                             } else {
 493                                 assert_ne!(ty, this.tcx.types.bool);
 494                                 assert_eq!(ty, dest.layout.ty);
 495                                 val
 496                             }
 497                         }
 498                         Op::FMax => {
 499                             fmax_op(&left, &right)?
 500                         }
 501                         Op::FMin => {
 502                             fmin_op(&left, &right)?
 503                         }
 504                         Op::SaturatingOp(mir_op) => {
 505                             this.saturating_arith(mir_op, &left, &right)?
 506                         }
 507                     };
 508                     this.write_scalar(val, &dest.into())?;
 509                 }
 510             }
 511             #[rustfmt::skip]
 512             | "simd_reduce_and"
 513             | "simd_reduce_or"
 514             | "simd_reduce_xor"
 515             | "simd_reduce_any"
 516             | "simd_reduce_all"
 517             | "simd_reduce_max"
 518             | "simd_reduce_min" => {
 519                 use mir::BinOp;
 520
 521                 let &[ref op] = check_arg_count(args)?;
 522                 let (op, op_len) = this.operand_to_simd(op)?;
 523
 524                 let imm_from_bool =
 525                     |b| ImmTy::from_scalar(Scalar::from_bool(b), this.machine.layouts.bool);
 526
 527                 enum Op {
 528                     MirOp(BinOp),
 529                     MirOpBool(BinOp),
 530                     Max,
 531                     Min,
 532                 }
 533                 let which = match intrinsic_name {
 534                     "simd_reduce_and" => Op::MirOp(BinOp::BitAnd),
 535                     "simd_reduce_or" => Op::MirOp(BinOp::BitOr),
 536                     "simd_reduce_xor" => Op::MirOp(BinOp::BitXor),
 537                     "simd_reduce_any" => Op::MirOpBool(BinOp::BitOr),
 538                     "simd_reduce_all" => Op::MirOpBool(BinOp::BitAnd),
 539                     "simd_reduce_max" => Op::Max,
 540                     "simd_reduce_min" => Op::Min,
 541                     _ => unreachable!(),
 542                 };
 543
 544                 // Initialize with first lane, then proceed with the rest.
 545                 let mut res = this.read_immediate(&this.mplace_index(&op, 0)?.into())?;
 546                 if matches!(which, Op::MirOpBool(_)) {
 547                     // Convert to `bool` scalar.
 548                     res = imm_from_bool(simd_element_to_bool(res)?);
 549                 }
 550                 for i in 1..op_len {
 551                     let op = this.read_immediate(&this.mplace_index(&op, i)?.into())?;
 552                     res = match which {
 553                         Op::MirOp(mir_op) => {
 554                             this.binary_op(mir_op, &res, &op)?
 555                         }
 556                         Op::MirOpBool(mir_op) => {
 557                             let op = imm_from_bool(simd_element_to_bool(op)?);
 558                             this.binary_op(mir_op, &res, &op)?
 559                         }
 560                         Op::Max => {
 561                             if matches!(res.layout.ty.kind(), ty::Float(_)) {
 562                                 ImmTy::from_scalar(fmax_op(&res, &op)?, res.layout)
 563                             } else {
 564                                 // Just boring integers, so NaNs to worry about
 565                                 if this.binary_op(BinOp::Ge, &res, &op)?.to_scalar()?.to_bool()? {
 566                                     res
 567                                 } else {
 568                                     op
 569                                 }
 570                             }
 571                         }
 572                         Op::Min => {
 573                             if matches!(res.layout.ty.kind(), ty::Float(_)) {
 574                                 ImmTy::from_scalar(fmin_op(&res, &op)?, res.layout)
 575                             } else {
 576                                 // Just boring integers, so NaNs to worry about
 577                                 if this.binary_op(BinOp::Le, &res, &op)?.to_scalar()?.to_bool()? {
 578                                     res
 579                                 } else {
 580                                     op
 581                                 }
 582                             }
 583                         }
 584                     };
 585                 }
 586                 this.write_immediate(*res, dest)?;
 587             }
 588             #[rustfmt::skip]
 589             | "simd_reduce_add_ordered"
 590             | "simd_reduce_mul_ordered" => {
 591                 use mir::BinOp;
 592
 593                 let &[ref op, ref init] = check_arg_count(args)?;
 594                 let (op, op_len) = this.operand_to_simd(op)?;
 595                 let init = this.read_immediate(init)?;
 596
 597                 let mir_op = match intrinsic_name {
 598                     "simd_reduce_add_ordered" => BinOp::Add,
 599                     "simd_reduce_mul_ordered" => BinOp::Mul,
 600                     _ => unreachable!(),
 601                 };
 602
 603                 let mut res = init;
 604                 for i in 0..op_len {
 605                     let op = this.read_immediate(&this.mplace_index(&op, i)?.into())?;
 606                     res = this.binary_op(mir_op, &res, &op)?;
 607                 }
 608                 this.write_immediate(*res, dest)?;
 609             }
 610             "simd_select" => {
 611                 let &[ref mask, ref yes, ref no] = check_arg_count(args)?;
 612                 let (mask, mask_len) = this.operand_to_simd(mask)?;
 613                 let (yes, yes_len) = this.operand_to_simd(yes)?;
 614                 let (no, no_len) = this.operand_to_simd(no)?;
 615                 let (dest, dest_len) = this.place_to_simd(dest)?;
 616
 617                 assert_eq!(dest_len, mask_len);
 618                 assert_eq!(dest_len, yes_len);
 619                 assert_eq!(dest_len, no_len);
 620
 621                 for i in 0..dest_len {
 622                     let mask = this.read_immediate(&this.mplace_index(&mask, i)?.into())?;
 623                     let yes = this.read_immediate(&this.mplace_index(&yes, i)?.into())?;
 624                     let no = this.read_immediate(&this.mplace_index(&no, i)?.into())?;
 625                     let dest = this.mplace_index(&dest, i)?;
 626
 627                     let val = if simd_element_to_bool(mask)? { yes } else { no };
 628                     this.write_immediate(*val, &dest.into())?;
 629                 }
 630             }
 631             #[rustfmt::skip]
 632             "simd_cast" | "simd_as" => {
 633                 let &[ref op] = check_arg_count(args)?;
 634                 let (op, op_len) = this.operand_to_simd(op)?;
 635                 let (dest, dest_len) = this.place_to_simd(dest)?;
 636
 637                 assert_eq!(dest_len, op_len);
 638
 639                 let safe_cast = intrinsic_name == "simd_as";
 640
 641                 for i in 0..dest_len {
 642                     let op = this.read_immediate(&this.mplace_index(&op, i)?.into())?;
 643                     let dest = this.mplace_index(&dest, i)?;
 644
 645                     let val = match (op.layout.ty.kind(), dest.layout.ty.kind()) {
 646                         // Int-to-(int|float): always safe
 647                         (ty::Int(_) | ty::Uint(_), ty::Int(_) | ty::Uint(_) | ty::Float(_)) =>
 648                             this.misc_cast(&op, dest.layout.ty)?,
 649                         // Float-to-float: always safe
 650                         (ty::Float(_), ty::Float(_)) =>
 651                             this.misc_cast(&op, dest.layout.ty)?,
 652                         // Float-to-int in safe mode
 653                         (ty::Float(_), ty::Int(_) | ty::Uint(_)) if safe_cast =>
 654                             this.misc_cast(&op, dest.layout.ty)?,
 655                         // Float-to-int in unchecked mode
 656                         (ty::Float(FloatTy::F32), ty::Int(_) | ty::Uint(_)) if !safe_cast =>
 657                             this.float_to_int_unchecked(op.to_scalar()?.to_f32()?, dest.layout.ty)?.into(),
 658                         (ty::Float(FloatTy::F64), ty::Int(_) | ty::Uint(_)) if !safe_cast =>
 659                             this.float_to_int_unchecked(op.to_scalar()?.to_f64()?, dest.layout.ty)?.into(),
 660                         _ =>
 661                             throw_unsup_format!(
 662                                 "Unsupported SIMD cast from element type {} to {}",
 663                                 op.layout.ty,
 664                                 dest.layout.ty
 665                             ),
 666                     };
 667                     this.write_immediate(val, &dest.into())?;
 668                 }
 669             }
 670             "simd_shuffle" => {
 671                 let &[ref left, ref right, ref index] = check_arg_count(args)?;
 672                 let (left, left_len) = this.operand_to_simd(left)?;
 673                 let (right, right_len) = this.operand_to_simd(right)?;
 674                 let (dest, dest_len) = this.place_to_simd(dest)?;
 675
 676                 // `index` is an array, not a SIMD type
 677                 let ty::Array(_, index_len) = index.layout.ty.kind() else {
 678                     bug!("simd_shuffle index argument has non-array type {}", index.layout.ty)
 679                 };
 680                 let index_len = index_len.eval_usize(*this.tcx, this.param_env());
 681
 682                 assert_eq!(left_len, right_len);
 683                 assert_eq!(index_len, dest_len);
 684
 685                 for i in 0..dest_len {
 686                     let src_index: u64 = this
 687                         .read_immediate(&this.operand_index(&index, i)?.into())?
 688                         .to_scalar()?
 689                         .to_u32()?
 690                         .into();
 691                     let dest = this.mplace_index(&dest, i)?;
 692
 693                     let val = if src_index < left_len {
 694                         this.read_immediate(&this.mplace_index(&left, src_index)?.into())?
 695                     } else if src_index < left_len.checked_add(right_len).unwrap() {
 696                         this.read_immediate(
 697                             &this.mplace_index(&right, src_index - left_len)?.into(),
 698                         )?
 699                     } else {
 700                         bug!(
 701                             "simd_shuffle index {} is out of bounds for 2 vectors of size {}",
 702                             src_index,
 703                             left_len
 704                         );
 705                     };
 706                     this.write_immediate(*val, &dest.into())?;
 707                 }
 708             }
 709             "simd_gather" => {
 710                 let &[ref passthru, ref ptrs, ref mask] = check_arg_count(args)?;
 711                 let (passthru, passthru_len) = this.operand_to_simd(passthru)?;
 712                 let (ptrs, ptrs_len) = this.operand_to_simd(ptrs)?;
 713                 let (mask, mask_len) = this.operand_to_simd(mask)?;
 714                 let (dest, dest_len) = this.place_to_simd(dest)?;
 715
 716                 assert_eq!(dest_len, passthru_len);
 717                 assert_eq!(dest_len, ptrs_len);
 718                 assert_eq!(dest_len, mask_len);
 719
 720                 for i in 0..dest_len {
 721                     let passthru = this.read_immediate(&this.mplace_index(&passthru, i)?.into())?;
 722                     let ptr = this.read_immediate(&this.mplace_index(&ptrs, i)?.into())?;
 723                     let mask = this.read_immediate(&this.mplace_index(&mask, i)?.into())?;
 724                     let dest = this.mplace_index(&dest, i)?;
 725
 726                     let val = if simd_element_to_bool(mask)? {
 727                         let place = this.deref_operand(&ptr.into())?;
 728                         this.read_immediate(&place.into())?
 729                     } else {
 730                         passthru
 731                     };
 732                     this.write_immediate(*val, &dest.into())?;
 733                 }
 734             }
 735             "simd_scatter" => {
 736                 let &[ref value, ref ptrs, ref mask] = check_arg_count(args)?;
 737                 let (value, value_len) = this.operand_to_simd(value)?;
 738                 let (ptrs, ptrs_len) = this.operand_to_simd(ptrs)?;
 739                 let (mask, mask_len) = this.operand_to_simd(mask)?;
 740
 741                 assert_eq!(ptrs_len, value_len);
 742                 assert_eq!(ptrs_len, mask_len);
 743
 744                 for i in 0..ptrs_len {
 745                     let value = this.read_immediate(&this.mplace_index(&value, i)?.into())?;
 746                     let ptr = this.read_immediate(&this.mplace_index(&ptrs, i)?.into())?;
 747                     let mask = this.read_immediate(&this.mplace_index(&mask, i)?.into())?;
 748
 749                     if simd_element_to_bool(mask)? {
 750                         let place = this.deref_operand(&ptr.into())?;
 751                         this.write_immediate(*value, &place.into())?;
 752                     }
 753                 }
 754             }
 755
 756             // Atomic operations
 757             "atomic_load" => this.atomic_load(args, dest, AtomicReadOp::SeqCst)?,
 758             "atomic_load_relaxed" => this.atomic_load(args, dest, AtomicReadOp::Relaxed)?,
 759             "atomic_load_acq" => this.atomic_load(args, dest, AtomicReadOp::Acquire)?,
 760
 761             "atomic_store" => this.atomic_store(args, AtomicWriteOp::SeqCst)?,
 762             "atomic_store_relaxed" => this.atomic_store(args, AtomicWriteOp::Relaxed)?,
 763             "atomic_store_rel" => this.atomic_store(args, AtomicWriteOp::Release)?,
 764
 765             "atomic_fence_acq" => this.atomic_fence(args, AtomicFenceOp::Acquire)?,
 766             "atomic_fence_rel" => this.atomic_fence(args, AtomicFenceOp::Release)?,
 767             "atomic_fence_acqrel" => this.atomic_fence(args, AtomicFenceOp::AcqRel)?,
 768             "atomic_fence" => this.atomic_fence(args, AtomicFenceOp::SeqCst)?,
 769
 770             "atomic_singlethreadfence_acq" => this.compiler_fence(args, AtomicFenceOp::Acquire)?,
 771             "atomic_singlethreadfence_rel" => this.compiler_fence(args, AtomicFenceOp::Release)?,
 772             "atomic_singlethreadfence_acqrel" =>
 773                 this.compiler_fence(args, AtomicFenceOp::AcqRel)?,
 774             "atomic_singlethreadfence" => this.compiler_fence(args, AtomicFenceOp::SeqCst)?,
 775
 776             "atomic_xchg" => this.atomic_exchange(args, dest, AtomicRwOp::SeqCst)?,
 777             "atomic_xchg_acq" => this.atomic_exchange(args, dest, AtomicRwOp::Acquire)?,
 778             "atomic_xchg_rel" => this.atomic_exchange(args, dest, AtomicRwOp::Release)?,
 779             "atomic_xchg_acqrel" => this.atomic_exchange(args, dest, AtomicRwOp::AcqRel)?,
 780             "atomic_xchg_relaxed" => this.atomic_exchange(args, dest, AtomicRwOp::Relaxed)?,
 781
 782             #[rustfmt::skip]
 783             "atomic_cxchg" =>
 784                 this.atomic_compare_exchange(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::SeqCst)?,
 785             #[rustfmt::skip]
 786             "atomic_cxchg_acq" =>
 787                 this.atomic_compare_exchange(args, dest, AtomicRwOp::Acquire, AtomicReadOp::Acquire)?,
 788             #[rustfmt::skip]
 789             "atomic_cxchg_rel" =>
 790                 this.atomic_compare_exchange(args, dest, AtomicRwOp::Release, AtomicReadOp::Relaxed)?,
 791             #[rustfmt::skip]
 792             "atomic_cxchg_acqrel" =>
 793                 this.atomic_compare_exchange(args, dest, AtomicRwOp::AcqRel, AtomicReadOp::Acquire)?,
 794             #[rustfmt::skip]
 795             "atomic_cxchg_relaxed" =>
 796                 this.atomic_compare_exchange(args, dest, AtomicRwOp::Relaxed, AtomicReadOp::Relaxed)?,
 797             #[rustfmt::skip]
 798             "atomic_cxchg_acq_failrelaxed" =>
 799                 this.atomic_compare_exchange(args, dest, AtomicRwOp::Acquire, AtomicReadOp::Relaxed)?,
 800             #[rustfmt::skip]
 801             "atomic_cxchg_acqrel_failrelaxed" =>
 802                 this.atomic_compare_exchange(args, dest, AtomicRwOp::AcqRel, AtomicReadOp::Relaxed)?,
 803             #[rustfmt::skip]
 804             "atomic_cxchg_failrelaxed" =>
 805                 this.atomic_compare_exchange(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::Relaxed)?,
 806             #[rustfmt::skip]
 807             "atomic_cxchg_failacq" =>
 808                 this.atomic_compare_exchange(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::Acquire)?,
 809
 810             #[rustfmt::skip]
 811             "atomic_cxchgweak" =>
 812                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::SeqCst)?,
 813             #[rustfmt::skip]
 814             "atomic_cxchgweak_acq" =>
 815                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::Acquire, AtomicReadOp::Acquire)?,
 816             #[rustfmt::skip]
 817             "atomic_cxchgweak_rel" =>
 818                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::Release, AtomicReadOp::Relaxed)?,
 819             #[rustfmt::skip]
 820             "atomic_cxchgweak_acqrel" =>
 821                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::AcqRel, AtomicReadOp::Acquire)?,
 822             #[rustfmt::skip]
 823             "atomic_cxchgweak_relaxed" =>
 824                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::Relaxed, AtomicReadOp::Relaxed)?,
 825             #[rustfmt::skip]
 826             "atomic_cxchgweak_acq_failrelaxed" =>
 827                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::Acquire, AtomicReadOp::Relaxed)?,
 828             #[rustfmt::skip]
 829             "atomic_cxchgweak_acqrel_failrelaxed" =>
 830                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::AcqRel, AtomicReadOp::Relaxed)?,
 831             #[rustfmt::skip]
 832             "atomic_cxchgweak_failrelaxed" =>
 833                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::Relaxed)?,
 834             #[rustfmt::skip]
 835             "atomic_cxchgweak_failacq" =>
 836                 this.atomic_compare_exchange_weak(args, dest, AtomicRwOp::SeqCst, AtomicReadOp::Acquire)?,
 837
 838             #[rustfmt::skip]
 839             "atomic_or" =>
 840                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::SeqCst)?,
 841             #[rustfmt::skip]
 842             "atomic_or_acq" =>
 843                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::Acquire)?,
 844             #[rustfmt::skip]
 845             "atomic_or_rel" =>
 846                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::Release)?,
 847             #[rustfmt::skip]
 848             "atomic_or_acqrel" =>
 849                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::AcqRel)?,
 850             #[rustfmt::skip]
 851             "atomic_or_relaxed" =>
 852                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitOr, false), AtomicRwOp::Relaxed)?,
 853             #[rustfmt::skip]
 854             "atomic_xor" =>
 855                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::SeqCst)?,
 856             #[rustfmt::skip]
 857             "atomic_xor_acq" =>
 858                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::Acquire)?,
 859             #[rustfmt::skip]
 860             "atomic_xor_rel" =>
 861                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::Release)?,
 862             #[rustfmt::skip]
 863             "atomic_xor_acqrel" =>
 864                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::AcqRel)?,
 865             #[rustfmt::skip]
 866             "atomic_xor_relaxed" =>
 867                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitXor, false), AtomicRwOp::Relaxed)?,
 868             #[rustfmt::skip]
 869             "atomic_and" =>
 870                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::SeqCst)?,
 871             #[rustfmt::skip]
 872             "atomic_and_acq" =>
 873                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::Acquire)?,
 874             #[rustfmt::skip]
 875             "atomic_and_rel" =>
 876                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::Release)?,
 877             #[rustfmt::skip]
 878             "atomic_and_acqrel" =>
 879                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::AcqRel)?,
 880             #[rustfmt::skip]
 881             "atomic_and_relaxed" =>
 882                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, false), AtomicRwOp::Relaxed)?,
 883             #[rustfmt::skip]
 884             "atomic_nand" =>
 885                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::SeqCst)?,
 886             #[rustfmt::skip]
 887             "atomic_nand_acq" =>
 888                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::Acquire)?,
 889             #[rustfmt::skip]
 890             "atomic_nand_rel" =>
 891                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::Release)?,
 892             #[rustfmt::skip]
 893             "atomic_nand_acqrel" =>
 894                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::AcqRel)?,
 895             #[rustfmt::skip]
 896             "atomic_nand_relaxed" =>
 897                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::BitAnd, true), AtomicRwOp::Relaxed)?,
 898             #[rustfmt::skip]
 899             "atomic_xadd" =>
 900                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::SeqCst)?,
 901             #[rustfmt::skip]
 902             "atomic_xadd_acq" =>
 903                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::Acquire)?,
 904             #[rustfmt::skip]
 905             "atomic_xadd_rel" =>
 906                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::Release)?,
 907             #[rustfmt::skip]
 908             "atomic_xadd_acqrel" =>
 909                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::AcqRel)?,
 910             #[rustfmt::skip]
 911             "atomic_xadd_relaxed" =>
 912                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Add, false), AtomicRwOp::Relaxed)?,
 913             #[rustfmt::skip]
 914             "atomic_xsub" =>
 915                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::SeqCst)?,
 916             #[rustfmt::skip]
 917             "atomic_xsub_acq" =>
 918                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::Acquire)?,
 919             #[rustfmt::skip]
 920             "atomic_xsub_rel" =>
 921                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::Release)?,
 922             #[rustfmt::skip]
 923             "atomic_xsub_acqrel" =>
 924                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::AcqRel)?,
 925             #[rustfmt::skip]
 926             "atomic_xsub_relaxed" =>
 927                 this.atomic_op(args, dest, AtomicOp::MirOp(BinOp::Sub, false), AtomicRwOp::Relaxed)?,
 928             "atomic_min" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::SeqCst)?,
 929             "atomic_min_acq" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Acquire)?,
 930             "atomic_min_rel" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Release)?,
 931             "atomic_min_acqrel" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::AcqRel)?,
 932             "atomic_min_relaxed" =>
 933                 this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Relaxed)?,
 934             "atomic_max" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::SeqCst)?,
 935             "atomic_max_acq" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Acquire)?,
 936             "atomic_max_rel" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Release)?,
 937             "atomic_max_acqrel" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::AcqRel)?,
 938             "atomic_max_relaxed" =>
 939                 this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Relaxed)?,
 940             "atomic_umin" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::SeqCst)?,
 941             "atomic_umin_acq" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Acquire)?,
 942             "atomic_umin_rel" => this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Release)?,
 943             "atomic_umin_acqrel" =>
 944                 this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::AcqRel)?,
 945             "atomic_umin_relaxed" =>
 946                 this.atomic_op(args, dest, AtomicOp::Min, AtomicRwOp::Relaxed)?,
 947             "atomic_umax" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::SeqCst)?,
 948             "atomic_umax_acq" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Acquire)?,
 949             "atomic_umax_rel" => this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Release)?,
 950             "atomic_umax_acqrel" =>
 951                 this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::AcqRel)?,
 952             "atomic_umax_relaxed" =>
 953                 this.atomic_op(args, dest, AtomicOp::Max, AtomicRwOp::Relaxed)?,
 954
 955             // Other
 956             "exact_div" => {
 957                 let &[ref num, ref denom] = check_arg_count(args)?;
 958                 this.exact_div(&this.read_immediate(num)?, &this.read_immediate(denom)?, dest)?;
 959             }
 960
 961             "try" => return this.handle_try(args, dest, ret),
 962
 963             "breakpoint" => {
 964                 let &[] = check_arg_count(args)?;
 965                 // normally this would raise a SIGTRAP, which aborts if no debugger is connected
 966                 throw_machine_stop!(TerminationInfo::Abort("Trace/breakpoint trap".to_string()))
 967             }
 968
 969             name => throw_unsup_format!("unimplemented intrinsic: {}", name),
 970         }
 971
 972         trace!("{:?}", this.dump_place(**dest));
 973         this.go_to_block(ret);
 974         Ok(())
 975     }
 976
 977     fn atomic_load(
 978         &mut self,
 979         args: &[OpTy<'tcx, Tag>],
 980         dest: &PlaceTy<'tcx, Tag>,
 981         atomic: AtomicReadOp,
 982     ) -> InterpResult<'tcx> {
 983         let this = self.eval_context_mut();
 984
 985         let &[ref place] = check_arg_count(args)?;
 986         let place = this.deref_operand(place)?;
 987
 988         // make sure it fits into a scalar; otherwise it cannot be atomic
 989         let val = this.read_scalar_atomic(&place, atomic)?;
 990
 991         // Check alignment requirements. Atomics must always be aligned to their size,
 992         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
 993         // be 8-aligned).
 994         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
 995         this.memory.check_ptr_access_align(
 996             place.ptr,
 997             place.layout.size,
 998             align,
 999             CheckInAllocMsg::MemoryAccessTest,
1000         )?;
1001         // Perform regular access.
1002         this.write_scalar(val, dest)?;
1003         Ok(())
1004     }
1005
1006     fn atomic_store(
1007         &mut self,
1008         args: &[OpTy<'tcx, Tag>],
1009         atomic: AtomicWriteOp,
1010     ) -> InterpResult<'tcx> {
1011         let this = self.eval_context_mut();
1012
1013         let &[ref place, ref val] = check_arg_count(args)?;
1014         let place = this.deref_operand(place)?;
1015         let val = this.read_scalar(val)?; // make sure it fits into a scalar; otherwise it cannot be atomic
1016
1017         // Check alignment requirements. Atomics must always be aligned to their size,
1018         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
1019         // be 8-aligned).
1020         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
1021         this.memory.check_ptr_access_align(
1022             place.ptr,
1023             place.layout.size,
1024             align,
1025             CheckInAllocMsg::MemoryAccessTest,
1026         )?;
1027
1028         // Perform atomic store
1029         this.write_scalar_atomic(val, &place, atomic)?;
1030         Ok(())
1031     }
1032
1033     fn compiler_fence(
1034         &mut self,
1035         args: &[OpTy<'tcx, Tag>],
1036         atomic: AtomicFenceOp,
1037     ) -> InterpResult<'tcx> {
1038         let &[] = check_arg_count(args)?;
1039         let _ = atomic;
1040         //FIXME: compiler fences are currently ignored
1041         Ok(())
1042     }
1043
1044     fn atomic_fence(
1045         &mut self,
1046         args: &[OpTy<'tcx, Tag>],
1047         atomic: AtomicFenceOp,
1048     ) -> InterpResult<'tcx> {
1049         let this = self.eval_context_mut();
1050         let &[] = check_arg_count(args)?;
1051         this.validate_atomic_fence(atomic)?;
1052         Ok(())
1053     }
1054
1055     fn atomic_op(
1056         &mut self,
1057         args: &[OpTy<'tcx, Tag>],
1058         dest: &PlaceTy<'tcx, Tag>,
1059         atomic_op: AtomicOp,
1060         atomic: AtomicRwOp,
1061     ) -> InterpResult<'tcx> {
1062         let this = self.eval_context_mut();
1063
1064         let &[ref place, ref rhs] = check_arg_count(args)?;
1065         let place = this.deref_operand(place)?;
1066
1067         if !place.layout.ty.is_integral() {
1068             bug!("Atomic arithmetic operations only work on integer types");
1069         }
1070         let rhs = this.read_immediate(rhs)?;
1071
1072         // Check alignment requirements. Atomics must always be aligned to their size,
1073         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
1074         // be 8-aligned).
1075         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
1076         this.memory.check_ptr_access_align(
1077             place.ptr,
1078             place.layout.size,
1079             align,
1080             CheckInAllocMsg::MemoryAccessTest,
1081         )?;
1082
1083         match atomic_op {
1084             AtomicOp::Min => {
1085                 let old = this.atomic_min_max_scalar(&place, rhs, true, atomic)?;
1086                 this.write_immediate(*old, &dest)?; // old value is returned
1087                 Ok(())
1088             }
1089             AtomicOp::Max => {
1090                 let old = this.atomic_min_max_scalar(&place, rhs, false, atomic)?;
1091                 this.write_immediate(*old, &dest)?; // old value is returned
1092                 Ok(())
1093             }
1094             AtomicOp::MirOp(op, neg) => {
1095                 let old = this.atomic_op_immediate(&place, &rhs, op, neg, atomic)?;
1096                 this.write_immediate(*old, dest)?; // old value is returned
1097                 Ok(())
1098             }
1099         }
1100     }
1101
1102     fn atomic_exchange(
1103         &mut self,
1104         args: &[OpTy<'tcx, Tag>],
1105         dest: &PlaceTy<'tcx, Tag>,
1106         atomic: AtomicRwOp,
1107     ) -> InterpResult<'tcx> {
1108         let this = self.eval_context_mut();
1109
1110         let &[ref place, ref new] = check_arg_count(args)?;
1111         let place = this.deref_operand(place)?;
1112         let new = this.read_scalar(new)?;
1113
1114         // Check alignment requirements. Atomics must always be aligned to their size,
1115         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
1116         // be 8-aligned).
1117         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
1118         this.memory.check_ptr_access_align(
1119             place.ptr,
1120             place.layout.size,
1121             align,
1122             CheckInAllocMsg::MemoryAccessTest,
1123         )?;
1124
1125         let old = this.atomic_exchange_scalar(&place, new, atomic)?;
1126         this.write_scalar(old, dest)?; // old value is returned
1127         Ok(())
1128     }
1129
1130     fn atomic_compare_exchange_impl(
1131         &mut self,
1132         args: &[OpTy<'tcx, Tag>],
1133         dest: &PlaceTy<'tcx, Tag>,
1134         success: AtomicRwOp,
1135         fail: AtomicReadOp,
1136         can_fail_spuriously: bool,
1137     ) -> InterpResult<'tcx> {
1138         let this = self.eval_context_mut();
1139
1140         let &[ref place, ref expect_old, ref new] = check_arg_count(args)?;
1141         let place = this.deref_operand(place)?;
1142         let expect_old = this.read_immediate(expect_old)?; // read as immediate for the sake of `binary_op()`
1143         let new = this.read_scalar(new)?;
1144
1145         // Check alignment requirements. Atomics must always be aligned to their size,
1146         // even if the type they wrap would be less aligned (e.g. AtomicU64 on 32bit must
1147         // be 8-aligned).
1148         let align = Align::from_bytes(place.layout.size.bytes()).unwrap();
1149         this.memory.check_ptr_access_align(
1150             place.ptr,
1151             place.layout.size,
1152             align,
1153             CheckInAllocMsg::MemoryAccessTest,
1154         )?;
1155
1156         let old = this.atomic_compare_exchange_scalar(
1157             &place,
1158             &expect_old,
1159             new,
1160             success,
1161             fail,
1162             can_fail_spuriously,
1163         )?;
1164
1165         // Return old value.
1166         this.write_immediate(old, dest)?;
1167         Ok(())
1168     }
1169
1170     fn atomic_compare_exchange(
1171         &mut self,
1172         args: &[OpTy<'tcx, Tag>],
1173         dest: &PlaceTy<'tcx, Tag>,
1174         success: AtomicRwOp,
1175         fail: AtomicReadOp,
1176     ) -> InterpResult<'tcx> {
1177         self.atomic_compare_exchange_impl(args, dest, success, fail, false)
1178     }
1179
1180     fn atomic_compare_exchange_weak(
1181         &mut self,
1182         args: &[OpTy<'tcx, Tag>],
1183         dest: &PlaceTy<'tcx, Tag>,
1184         success: AtomicRwOp,
1185         fail: AtomicReadOp,
1186     ) -> InterpResult<'tcx> {
1187         self.atomic_compare_exchange_impl(args, dest, success, fail, true)
1188     }
1189
1190     fn float_to_int_unchecked<F>(
1191         &self,
1192         f: F,
1193         dest_ty: ty::Ty<'tcx>,
1194     ) -> InterpResult<'tcx, Scalar<Tag>>
1195     where
1196         F: Float + Into<Scalar<Tag>>,
1197     {
1198         let this = self.eval_context_ref();
1199
1200         // Step 1: cut off the fractional part of `f`. The result of this is
1201         // guaranteed to be precisely representable in IEEE floats.
1202         let f = f.round_to_integral(Round::TowardZero).value;
1203
1204         // Step 2: Cast the truncated float to the target integer type and see if we lose any information in this step.
1205         Ok(match dest_ty.kind() {
1206             // Unsigned
1207             ty::Uint(t) => {
1208                 let size = Integer::from_uint_ty(this, *t).size();
1209                 let res = f.to_u128(size.bits_usize());
1210                 if res.status.is_empty() {
1211                     // No status flags means there was no further rounding or other loss of precision.
1212                     Scalar::from_uint(res.value, size)
1213                 } else {
1214                     // `f` was not representable in this integer type.
1215                     throw_ub_format!(
1216                         "`float_to_int_unchecked` intrinsic called on {} which cannot be represented in target type `{:?}`",
1217                         f,
1218                         dest_ty,
1219                     );
1220                 }
1221             }
1222             // Signed
1223             ty::Int(t) => {
1224                 let size = Integer::from_int_ty(this, *t).size();
1225                 let res = f.to_i128(size.bits_usize());
1226                 if res.status.is_empty() {
1227                     // No status flags means there was no further rounding or other loss of precision.
1228                     Scalar::from_int(res.value, size)
1229                 } else {
1230                     // `f` was not representable in this integer type.
1231                     throw_ub_format!(
1232                         "`float_to_int_unchecked` intrinsic called on {} which cannot be represented in target type `{:?}`",
1233                         f,
1234                         dest_ty,
1235                     );
1236                 }
1237             }
1238             // Nothing else
1239             _ => bug!("`float_to_int_unchecked` called with non-int output type {:?}", dest_ty),
1240         })
1241     }
1242 }
1243
1244 fn fmax_op<'tcx>(
1245     left: &ImmTy<'tcx, Tag>,
1246     right: &ImmTy<'tcx, Tag>,
1247 ) -> InterpResult<'tcx, Scalar<Tag>> {
1248     assert_eq!(left.layout.ty, right.layout.ty);
1249     let ty::Float(float_ty) = left.layout.ty.kind() else {
1250         bug!("fmax operand is not a float")
1251     };
1252     let left = left.to_scalar()?;
1253     let right = right.to_scalar()?;
1254     Ok(match float_ty {
1255         FloatTy::F32 => Scalar::from_f32(left.to_f32()?.max(right.to_f32()?)),
1256         FloatTy::F64 => Scalar::from_f64(left.to_f64()?.max(right.to_f64()?)),
1257     })
1258 }
1259
1260 fn fmin_op<'tcx>(
1261     left: &ImmTy<'tcx, Tag>,
1262     right: &ImmTy<'tcx, Tag>,
1263 ) -> InterpResult<'tcx, Scalar<Tag>> {
1264     assert_eq!(left.layout.ty, right.layout.ty);
1265     let ty::Float(float_ty) = left.layout.ty.kind() else {
1266         bug!("fmin operand is not a float")
1267     };
1268     let left = left.to_scalar()?;
1269     let right = right.to_scalar()?;
1270     Ok(match float_ty {
1271         FloatTy::F32 => Scalar::from_f32(left.to_f32()?.min(right.to_f32()?)),
1272         FloatTy::F64 => Scalar::from_f64(left.to_f64()?.min(right.to_f64()?)),
1273     })
1274 }