rustc_codegen_ssa/mir/
rvalue.rs

1use rustc_abi::{self as abi, FIRST_VARIANT};
2use rustc_middle::ty::adjustment::PointerCoercion;
3use rustc_middle::ty::layout::{HasTyCtxt, HasTypingEnv, LayoutOf, TyAndLayout};
4use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
5use rustc_middle::{bug, mir};
6use rustc_session::config::OptLevel;
7use rustc_span::{DUMMY_SP, Span};
8use tracing::{debug, instrument};
9
10use super::operand::{OperandRef, OperandValue};
11use super::place::{PlaceRef, codegen_tag_value};
12use super::{FunctionCx, LocalRef};
13use crate::common::{IntPredicate, TypeKind};
14use crate::traits::*;
15use crate::{MemFlags, base};
16
17impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
18    #[instrument(level = "trace", skip(self, bx))]
19    pub(crate) fn codegen_rvalue(
20        &mut self,
21        bx: &mut Bx,
22        dest: PlaceRef<'tcx, Bx::Value>,
23        rvalue: &mir::Rvalue<'tcx>,
24    ) {
25        match *rvalue {
26            mir::Rvalue::Use(ref operand) => {
27                let cg_operand = self.codegen_operand(bx, operand);
28                // FIXME: consider not copying constants through stack. (Fixable by codegen'ing
29                // constants into `OperandValue::Ref`; why don’t we do that yet if we don’t?)
30                cg_operand.val.store(bx, dest);
31            }
32
33            mir::Rvalue::Cast(
34                mir::CastKind::PointerCoercion(PointerCoercion::Unsize, _),
35                ref source,
36                _,
37            ) => {
38                // The destination necessarily contains a wide pointer, so if
39                // it's a scalar pair, it's a wide pointer or newtype thereof.
40                if bx.cx().is_backend_scalar_pair(dest.layout) {
41                    // Into-coerce of a thin pointer to a wide pointer -- just
42                    // use the operand path.
43                    let temp = self.codegen_rvalue_operand(bx, rvalue);
44                    temp.val.store(bx, dest);
45                    return;
46                }
47
48                // Unsize of a nontrivial struct. I would prefer for
49                // this to be eliminated by MIR building, but
50                // `CoerceUnsized` can be passed by a where-clause,
51                // so the (generic) MIR may not be able to expand it.
52                let operand = self.codegen_operand(bx, source);
53                match operand.val {
54                    OperandValue::Pair(..) | OperandValue::Immediate(_) => {
55                        // Unsize from an immediate structure. We don't
56                        // really need a temporary alloca here, but
57                        // avoiding it would require us to have
58                        // `coerce_unsized_into` use `extractvalue` to
59                        // index into the struct, and this case isn't
60                        // important enough for it.
61                        debug!("codegen_rvalue: creating ugly alloca");
62                        let scratch = PlaceRef::alloca(bx, operand.layout);
63                        scratch.storage_live(bx);
64                        operand.val.store(bx, scratch);
65                        base::coerce_unsized_into(bx, scratch, dest);
66                        scratch.storage_dead(bx);
67                    }
68                    OperandValue::Ref(val) => {
69                        if val.llextra.is_some() {
70                            bug!("unsized coercion on an unsized rvalue");
71                        }
72                        base::coerce_unsized_into(bx, val.with_type(operand.layout), dest);
73                    }
74                    OperandValue::ZeroSized => {
75                        bug!("unsized coercion on a ZST rvalue");
76                    }
77                }
78            }
79
80            mir::Rvalue::Cast(mir::CastKind::Transmute, ref operand, _ty) => {
81                let src = self.codegen_operand(bx, operand);
82                self.codegen_transmute(bx, src, dest);
83            }
84
85            mir::Rvalue::Repeat(ref elem, count) => {
86                // Do not generate the loop for zero-sized elements or empty arrays.
87                if dest.layout.is_zst() {
88                    return;
89                }
90
91                // When the element is a const with all bytes uninit, emit a single memset that
92                // writes undef to the entire destination.
93                if let mir::Operand::Constant(const_op) = elem {
94                    let val = self.eval_mir_constant(const_op);
95                    if val.all_bytes_uninit(self.cx.tcx()) {
96                        let size = bx.const_usize(dest.layout.size.bytes());
97                        bx.memset(
98                            dest.val.llval,
99                            bx.const_undef(bx.type_i8()),
100                            size,
101                            dest.val.align,
102                            MemFlags::empty(),
103                        );
104                        return;
105                    }
106                }
107
108                let cg_elem = self.codegen_operand(bx, elem);
109
110                let try_init_all_same = |bx: &mut Bx, v| {
111                    let start = dest.val.llval;
112                    let size = bx.const_usize(dest.layout.size.bytes());
113
114                    // Use llvm.memset.p0i8.* to initialize all same byte arrays
115                    if let Some(int) = bx.cx().const_to_opt_u128(v, false) {
116                        let bytes = &int.to_le_bytes()[..cg_elem.layout.size.bytes_usize()];
117                        let first = bytes[0];
118                        if bytes[1..].iter().all(|&b| b == first) {
119                            let fill = bx.cx().const_u8(first);
120                            bx.memset(start, fill, size, dest.val.align, MemFlags::empty());
121                            return true;
122                        }
123                    }
124
125                    // Use llvm.memset.p0i8.* to initialize byte arrays
126                    let v = bx.from_immediate(v);
127                    if bx.cx().val_ty(v) == bx.cx().type_i8() {
128                        bx.memset(start, v, size, dest.val.align, MemFlags::empty());
129                        return true;
130                    }
131                    false
132                };
133
134                match cg_elem.val {
135                    OperandValue::Immediate(v) => {
136                        if try_init_all_same(bx, v) {
137                            return;
138                        }
139                    }
140                    _ => (),
141                }
142
143                let count = self
144                    .monomorphize(count)
145                    .try_to_target_usize(bx.tcx())
146                    .expect("expected monomorphic const in codegen");
147
148                bx.write_operand_repeatedly(cg_elem, count, dest);
149            }
150
151            // This implementation does field projection, so never use it for `RawPtr`,
152            // which will always be fine with the `codegen_rvalue_operand` path below.
153            mir::Rvalue::Aggregate(ref kind, ref operands)
154                if !matches!(**kind, mir::AggregateKind::RawPtr(..)) =>
155            {
156                let (variant_index, variant_dest, active_field_index) = match **kind {
157                    mir::AggregateKind::Adt(_, variant_index, _, _, active_field_index) => {
158                        let variant_dest = dest.project_downcast(bx, variant_index);
159                        (variant_index, variant_dest, active_field_index)
160                    }
161                    _ => (FIRST_VARIANT, dest, None),
162                };
163                if active_field_index.is_some() {
164                    assert_eq!(operands.len(), 1);
165                }
166                for (i, operand) in operands.iter_enumerated() {
167                    let op = self.codegen_operand(bx, operand);
168                    // Do not generate stores and GEPis for zero-sized fields.
169                    if !op.layout.is_zst() {
170                        let field_index = active_field_index.unwrap_or(i);
171                        let field = if let mir::AggregateKind::Array(_) = **kind {
172                            let llindex = bx.cx().const_usize(field_index.as_u32().into());
173                            variant_dest.project_index(bx, llindex)
174                        } else {
175                            variant_dest.project_field(bx, field_index.as_usize())
176                        };
177                        op.val.store(bx, field);
178                    }
179                }
180                dest.codegen_set_discr(bx, variant_index);
181            }
182
183            _ => {
184                assert!(self.rvalue_creates_operand(rvalue, DUMMY_SP));
185                let temp = self.codegen_rvalue_operand(bx, rvalue);
186                temp.val.store(bx, dest);
187            }
188        }
189    }
190
191    /// Transmutes the `src` value to the destination type by writing it to `dst`.
192    ///
193    /// See also [`Self::codegen_transmute_operand`] for cases that can be done
194    /// without needing a pre-allocated place for the destination.
195    fn codegen_transmute(
196        &mut self,
197        bx: &mut Bx,
198        src: OperandRef<'tcx, Bx::Value>,
199        dst: PlaceRef<'tcx, Bx::Value>,
200    ) {
201        // The MIR validator enforces no unsized transmutes.
202        assert!(src.layout.is_sized());
203        assert!(dst.layout.is_sized());
204
205        if src.layout.size != dst.layout.size
206            || src.layout.is_uninhabited()
207            || dst.layout.is_uninhabited()
208        {
209            // These cases are all UB to actually hit, so don't emit code for them.
210            // (The size mismatches are reachable via `transmute_unchecked`.)
211            // We can't use unreachable because that's a terminator, and we
212            // need something that can be in the middle of a basic block.
213            bx.assume(bx.cx().const_bool(false))
214        } else {
215            // Since in this path we have a place anyway, we can store or copy to it,
216            // making sure we use the destination place's alignment even if the
217            // source would normally have a higher one.
218            src.val.store(bx, dst.val.with_type(src.layout));
219        }
220    }
221
222    /// Transmutes an `OperandValue` to another `OperandValue`.
223    ///
224    /// This is supported only for cases where [`Self::rvalue_creates_operand`]
225    /// returns `true`, and will ICE otherwise. (In particular, anything that
226    /// would need to `alloca` in order to return a `PlaceValue` will ICE,
227    /// expecting those to go via [`Self::codegen_transmute`] instead where
228    /// the destination place is already allocated.)
229    pub(crate) fn codegen_transmute_operand(
230        &mut self,
231        bx: &mut Bx,
232        operand: OperandRef<'tcx, Bx::Value>,
233        cast: TyAndLayout<'tcx>,
234    ) -> OperandValue<Bx::Value> {
235        // Check for transmutes that are always UB.
236        if operand.layout.size != cast.size
237            || operand.layout.is_uninhabited()
238            || cast.is_uninhabited()
239        {
240            if !operand.layout.is_uninhabited() {
241                // Since this is known statically and the input could have existed
242                // without already having hit UB, might as well trap for it.
243                bx.abort();
244            }
245
246            // Because this transmute is UB, return something easy to generate,
247            // since it's fine that later uses of the value are probably UB.
248            return OperandValue::poison(bx, cast);
249        }
250
251        match (operand.val, operand.layout.backend_repr, cast.backend_repr) {
252            _ if cast.is_zst() => OperandValue::ZeroSized,
253            (_, _, abi::BackendRepr::Memory { .. }) => {
254                bug!("Cannot `codegen_transmute_operand` to non-ZST memory-ABI output {cast:?}");
255            }
256            (OperandValue::Ref(source_place_val), abi::BackendRepr::Memory { .. }, _) => {
257                assert_eq!(source_place_val.llextra, None);
258                // The existing alignment is part of `source_place_val`,
259                // so that alignment will be used, not `cast`'s.
260                bx.load_operand(source_place_val.with_type(cast)).val
261            }
262            (
263                OperandValue::Immediate(imm),
264                abi::BackendRepr::Scalar(from_scalar),
265                abi::BackendRepr::Scalar(to_scalar),
266            ) => OperandValue::Immediate(transmute_scalar(bx, imm, from_scalar, to_scalar)),
267            (
268                OperandValue::Pair(imm_a, imm_b),
269                abi::BackendRepr::ScalarPair(in_a, in_b),
270                abi::BackendRepr::ScalarPair(out_a, out_b),
271            ) => OperandValue::Pair(
272                transmute_scalar(bx, imm_a, in_a, out_a),
273                transmute_scalar(bx, imm_b, in_b, out_b),
274            ),
275            _ => bug!("Cannot `codegen_transmute_operand` {operand:?} to {cast:?}"),
276        }
277    }
278
279    /// Cast one of the immediates from an [`OperandValue::Immediate`]
280    /// or an [`OperandValue::Pair`] to an immediate of the target type.
281    ///
282    /// Returns `None` if the cast is not possible.
283    fn cast_immediate(
284        &self,
285        bx: &mut Bx,
286        mut imm: Bx::Value,
287        from_scalar: abi::Scalar,
288        from_backend_ty: Bx::Type,
289        to_scalar: abi::Scalar,
290        to_backend_ty: Bx::Type,
291    ) -> Option<Bx::Value> {
292        use abi::Primitive::*;
293
294        // When scalars are passed by value, there's no metadata recording their
295        // valid ranges. For example, `char`s are passed as just `i32`, with no
296        // way for LLVM to know that they're 0x10FFFF at most. Thus we assume
297        // the range of the input value too, not just the output range.
298        assume_scalar_range(bx, imm, from_scalar, from_backend_ty);
299
300        imm = match (from_scalar.primitive(), to_scalar.primitive()) {
301            (Int(_, is_signed), Int(..)) => bx.intcast(imm, to_backend_ty, is_signed),
302            (Float(_), Float(_)) => {
303                let srcsz = bx.cx().float_width(from_backend_ty);
304                let dstsz = bx.cx().float_width(to_backend_ty);
305                if dstsz > srcsz {
306                    bx.fpext(imm, to_backend_ty)
307                } else if srcsz > dstsz {
308                    bx.fptrunc(imm, to_backend_ty)
309                } else {
310                    imm
311                }
312            }
313            (Int(_, is_signed), Float(_)) => {
314                if is_signed {
315                    bx.sitofp(imm, to_backend_ty)
316                } else {
317                    bx.uitofp(imm, to_backend_ty)
318                }
319            }
320            (Pointer(..), Pointer(..)) => bx.pointercast(imm, to_backend_ty),
321            (Int(_, is_signed), Pointer(..)) => {
322                let usize_imm = bx.intcast(imm, bx.cx().type_isize(), is_signed);
323                bx.inttoptr(usize_imm, to_backend_ty)
324            }
325            (Float(_), Int(_, is_signed)) => bx.cast_float_to_int(is_signed, imm, to_backend_ty),
326            _ => return None,
327        };
328        Some(imm)
329    }
330
331    pub(crate) fn codegen_rvalue_unsized(
332        &mut self,
333        bx: &mut Bx,
334        indirect_dest: PlaceRef<'tcx, Bx::Value>,
335        rvalue: &mir::Rvalue<'tcx>,
336    ) {
337        debug!(
338            "codegen_rvalue_unsized(indirect_dest.llval={:?}, rvalue={:?})",
339            indirect_dest.val.llval, rvalue
340        );
341
342        match *rvalue {
343            mir::Rvalue::Use(ref operand) => {
344                let cg_operand = self.codegen_operand(bx, operand);
345                cg_operand.val.store_unsized(bx, indirect_dest);
346            }
347
348            _ => bug!("unsized assignment other than `Rvalue::Use`"),
349        }
350    }
351
352    pub(crate) fn codegen_rvalue_operand(
353        &mut self,
354        bx: &mut Bx,
355        rvalue: &mir::Rvalue<'tcx>,
356    ) -> OperandRef<'tcx, Bx::Value> {
357        assert!(
358            self.rvalue_creates_operand(rvalue, DUMMY_SP),
359            "cannot codegen {rvalue:?} to operand",
360        );
361
362        match *rvalue {
363            mir::Rvalue::Cast(ref kind, ref source, mir_cast_ty) => {
364                let operand = self.codegen_operand(bx, source);
365                debug!("cast operand is {:?}", operand);
366                let cast = bx.cx().layout_of(self.monomorphize(mir_cast_ty));
367
368                let val = match *kind {
369                    mir::CastKind::PointerExposeProvenance => {
370                        assert!(bx.cx().is_backend_immediate(cast));
371                        let llptr = operand.immediate();
372                        let llcast_ty = bx.cx().immediate_backend_type(cast);
373                        let lladdr = bx.ptrtoint(llptr, llcast_ty);
374                        OperandValue::Immediate(lladdr)
375                    }
376                    mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, _) => {
377                        match *operand.layout.ty.kind() {
378                            ty::FnDef(def_id, args) => {
379                                let instance = ty::Instance::resolve_for_fn_ptr(
380                                    bx.tcx(),
381                                    bx.typing_env(),
382                                    def_id,
383                                    args,
384                                )
385                                .unwrap();
386                                OperandValue::Immediate(bx.get_fn_addr(instance))
387                            }
388                            _ => bug!("{} cannot be reified to a fn ptr", operand.layout.ty),
389                        }
390                    }
391                    mir::CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_), _) => {
392                        match *operand.layout.ty.kind() {
393                            ty::Closure(def_id, args) => {
394                                let instance = Instance::resolve_closure(
395                                    bx.cx().tcx(),
396                                    def_id,
397                                    args,
398                                    ty::ClosureKind::FnOnce,
399                                );
400                                OperandValue::Immediate(bx.cx().get_fn_addr(instance))
401                            }
402                            _ => bug!("{} cannot be cast to a fn ptr", operand.layout.ty),
403                        }
404                    }
405                    mir::CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer, _) => {
406                        // This is a no-op at the LLVM level.
407                        operand.val
408                    }
409                    mir::CastKind::PointerCoercion(PointerCoercion::Unsize, _) => {
410                        assert!(bx.cx().is_backend_scalar_pair(cast));
411                        let (lldata, llextra) = operand.val.pointer_parts();
412                        let (lldata, llextra) =
413                            base::unsize_ptr(bx, lldata, operand.layout.ty, cast.ty, llextra);
414                        OperandValue::Pair(lldata, llextra)
415                    }
416                    mir::CastKind::PointerCoercion(
417                        PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer, _
418                    ) => {
419                        bug!("{kind:?} is for borrowck, and should never appear in codegen");
420                    }
421                    mir::CastKind::PtrToPtr
422                        if bx.cx().is_backend_scalar_pair(operand.layout) =>
423                    {
424                        if let OperandValue::Pair(data_ptr, meta) = operand.val {
425                            if bx.cx().is_backend_scalar_pair(cast) {
426                                OperandValue::Pair(data_ptr, meta)
427                            } else {
428                                // Cast of wide-ptr to thin-ptr is an extraction of data-ptr.
429                                OperandValue::Immediate(data_ptr)
430                            }
431                        } else {
432                            bug!("unexpected non-pair operand");
433                        }
434                    }
435                    | mir::CastKind::IntToInt
436                    | mir::CastKind::FloatToInt
437                    | mir::CastKind::FloatToFloat
438                    | mir::CastKind::IntToFloat
439                    | mir::CastKind::PtrToPtr
440                    | mir::CastKind::FnPtrToPtr
441                    // Since int2ptr can have arbitrary integer types as input (so we have to do
442                    // sign extension and all that), it is currently best handled in the same code
443                    // path as the other integer-to-X casts.
444                    | mir::CastKind::PointerWithExposedProvenance => {
445                        let imm = operand.immediate();
446                        let abi::BackendRepr::Scalar(from_scalar) = operand.layout.backend_repr else {
447                            bug!("Found non-scalar for operand {operand:?}");
448                        };
449                        let from_backend_ty = bx.cx().immediate_backend_type(operand.layout);
450
451                        assert!(bx.cx().is_backend_immediate(cast));
452                        let to_backend_ty = bx.cx().immediate_backend_type(cast);
453                        if operand.layout.is_uninhabited() {
454                            let val = OperandValue::Immediate(bx.cx().const_poison(to_backend_ty));
455                            return OperandRef { val, layout: cast };
456                        }
457                        let abi::BackendRepr::Scalar(to_scalar) = cast.layout.backend_repr else {
458                            bug!("Found non-scalar for cast {cast:?}");
459                        };
460
461                        self.cast_immediate(bx, imm, from_scalar, from_backend_ty, to_scalar, to_backend_ty)
462                            .map(OperandValue::Immediate)
463                            .unwrap_or_else(|| {
464                                bug!("Unsupported cast of {operand:?} to {cast:?}");
465                            })
466                    }
467                    mir::CastKind::Transmute => {
468                        self.codegen_transmute_operand(bx, operand, cast)
469                    }
470                };
471                OperandRef { val, layout: cast }
472            }
473
474            mir::Rvalue::Ref(_, bk, place) => {
475                let mk_ref = move |tcx: TyCtxt<'tcx>, ty: Ty<'tcx>| {
476                    Ty::new_ref(tcx, tcx.lifetimes.re_erased, ty, bk.to_mutbl_lossy())
477                };
478                self.codegen_place_to_pointer(bx, place, mk_ref)
479            }
480
481            mir::Rvalue::CopyForDeref(place) => {
482                self.codegen_operand(bx, &mir::Operand::Copy(place))
483            }
484            mir::Rvalue::RawPtr(kind, place) => {
485                let mk_ptr = move |tcx: TyCtxt<'tcx>, ty: Ty<'tcx>| {
486                    Ty::new_ptr(tcx, ty, kind.to_mutbl_lossy())
487                };
488                self.codegen_place_to_pointer(bx, place, mk_ptr)
489            }
490
491            mir::Rvalue::Len(place) => {
492                let size = self.evaluate_array_len(bx, place);
493                OperandRef {
494                    val: OperandValue::Immediate(size),
495                    layout: bx.cx().layout_of(bx.tcx().types.usize),
496                }
497            }
498
499            mir::Rvalue::BinaryOp(op_with_overflow, box (ref lhs, ref rhs))
500                if let Some(op) = op_with_overflow.overflowing_to_wrapping() =>
501            {
502                let lhs = self.codegen_operand(bx, lhs);
503                let rhs = self.codegen_operand(bx, rhs);
504                let result = self.codegen_scalar_checked_binop(
505                    bx,
506                    op,
507                    lhs.immediate(),
508                    rhs.immediate(),
509                    lhs.layout.ty,
510                );
511                let val_ty = op.ty(bx.tcx(), lhs.layout.ty, rhs.layout.ty);
512                let operand_ty = Ty::new_tup(bx.tcx(), &[val_ty, bx.tcx().types.bool]);
513                OperandRef { val: result, layout: bx.cx().layout_of(operand_ty) }
514            }
515            mir::Rvalue::BinaryOp(op, box (ref lhs, ref rhs)) => {
516                let lhs = self.codegen_operand(bx, lhs);
517                let rhs = self.codegen_operand(bx, rhs);
518                let llresult = match (lhs.val, rhs.val) {
519                    (
520                        OperandValue::Pair(lhs_addr, lhs_extra),
521                        OperandValue::Pair(rhs_addr, rhs_extra),
522                    ) => self.codegen_wide_ptr_binop(
523                        bx,
524                        op,
525                        lhs_addr,
526                        lhs_extra,
527                        rhs_addr,
528                        rhs_extra,
529                        lhs.layout.ty,
530                    ),
531
532                    (OperandValue::Immediate(lhs_val), OperandValue::Immediate(rhs_val)) => self
533                        .codegen_scalar_binop(
534                            bx,
535                            op,
536                            lhs_val,
537                            rhs_val,
538                            lhs.layout.ty,
539                            rhs.layout.ty,
540                        ),
541
542                    _ => bug!(),
543                };
544                OperandRef {
545                    val: OperandValue::Immediate(llresult),
546                    layout: bx.cx().layout_of(op.ty(bx.tcx(), lhs.layout.ty, rhs.layout.ty)),
547                }
548            }
549
550            mir::Rvalue::UnaryOp(op, ref operand) => {
551                let operand = self.codegen_operand(bx, operand);
552                let is_float = operand.layout.ty.is_floating_point();
553                let (val, layout) = match op {
554                    mir::UnOp::Not => {
555                        let llval = bx.not(operand.immediate());
556                        (OperandValue::Immediate(llval), operand.layout)
557                    }
558                    mir::UnOp::Neg => {
559                        let llval = if is_float {
560                            bx.fneg(operand.immediate())
561                        } else {
562                            bx.neg(operand.immediate())
563                        };
564                        (OperandValue::Immediate(llval), operand.layout)
565                    }
566                    mir::UnOp::PtrMetadata => {
567                        assert!(operand.layout.ty.is_raw_ptr() || operand.layout.ty.is_ref(),);
568                        let (_, meta) = operand.val.pointer_parts();
569                        assert_eq!(operand.layout.fields.count() > 1, meta.is_some());
570                        if let Some(meta) = meta {
571                            (OperandValue::Immediate(meta), operand.layout.field(self.cx, 1))
572                        } else {
573                            (OperandValue::ZeroSized, bx.cx().layout_of(bx.tcx().types.unit))
574                        }
575                    }
576                };
577                assert!(
578                    val.is_expected_variant_for_type(self.cx, layout),
579                    "Made wrong variant {val:?} for type {layout:?}",
580                );
581                OperandRef { val, layout }
582            }
583
584            mir::Rvalue::Discriminant(ref place) => {
585                let discr_ty = rvalue.ty(self.mir, bx.tcx());
586                let discr_ty = self.monomorphize(discr_ty);
587                let operand = self.codegen_consume(bx, place.as_ref());
588                let discr = operand.codegen_get_discr(self, bx, discr_ty);
589                OperandRef {
590                    val: OperandValue::Immediate(discr),
591                    layout: self.cx.layout_of(discr_ty),
592                }
593            }
594
595            mir::Rvalue::NullaryOp(ref null_op, ty) => {
596                let ty = self.monomorphize(ty);
597                let layout = bx.cx().layout_of(ty);
598                let val = match null_op {
599                    mir::NullOp::SizeOf => {
600                        assert!(bx.cx().type_is_sized(ty));
601                        let val = layout.size.bytes();
602                        bx.cx().const_usize(val)
603                    }
604                    mir::NullOp::AlignOf => {
605                        assert!(bx.cx().type_is_sized(ty));
606                        let val = layout.align.abi.bytes();
607                        bx.cx().const_usize(val)
608                    }
609                    mir::NullOp::OffsetOf(fields) => {
610                        let val = bx
611                            .tcx()
612                            .offset_of_subfield(bx.typing_env(), layout, fields.iter())
613                            .bytes();
614                        bx.cx().const_usize(val)
615                    }
616                    mir::NullOp::UbChecks => {
617                        let val = bx.tcx().sess.ub_checks();
618                        bx.cx().const_bool(val)
619                    }
620                    mir::NullOp::ContractChecks => {
621                        let val = bx.tcx().sess.contract_checks();
622                        bx.cx().const_bool(val)
623                    }
624                };
625                let tcx = self.cx.tcx();
626                OperandRef {
627                    val: OperandValue::Immediate(val),
628                    layout: self.cx.layout_of(null_op.ty(tcx)),
629                }
630            }
631
632            mir::Rvalue::ThreadLocalRef(def_id) => {
633                assert!(bx.cx().tcx().is_static(def_id));
634                let layout = bx.layout_of(bx.cx().tcx().static_ptr_ty(def_id, bx.typing_env()));
635                let static_ = if !def_id.is_local() && bx.cx().tcx().needs_thread_local_shim(def_id)
636                {
637                    let instance = ty::Instance {
638                        def: ty::InstanceKind::ThreadLocalShim(def_id),
639                        args: ty::GenericArgs::empty(),
640                    };
641                    let fn_ptr = bx.get_fn_addr(instance);
642                    let fn_abi = bx.fn_abi_of_instance(instance, ty::List::empty());
643                    let fn_ty = bx.fn_decl_backend_type(fn_abi);
644                    let fn_attrs = if bx.tcx().def_kind(instance.def_id()).has_codegen_attrs() {
645                        Some(bx.tcx().codegen_fn_attrs(instance.def_id()))
646                    } else {
647                        None
648                    };
649                    bx.call(fn_ty, fn_attrs, Some(fn_abi), fn_ptr, &[], None, Some(instance))
650                } else {
651                    bx.get_static(def_id)
652                };
653                OperandRef { val: OperandValue::Immediate(static_), layout }
654            }
655            mir::Rvalue::Use(ref operand) => self.codegen_operand(bx, operand),
656            mir::Rvalue::Repeat(..) => bug!("{rvalue:?} in codegen_rvalue_operand"),
657            mir::Rvalue::Aggregate(ref kind, ref fields) => {
658                let (variant_index, active_field_index) = match **kind {
659                    mir::AggregateKind::Adt(_, variant_index, _, _, active_field_index) => {
660                        (variant_index, active_field_index)
661                    }
662                    _ => (FIRST_VARIANT, None),
663                };
664
665                let ty = rvalue.ty(self.mir, self.cx.tcx());
666                let ty = self.monomorphize(ty);
667                let layout = self.cx.layout_of(ty);
668
669                // `rvalue_creates_operand` has arranged that we only get here if
670                // we can build the aggregate immediate from the field immediates.
671                let Some(mut builder) = OperandRef::builder(layout) else {
672                    bug!("Cannot use type in operand builder: {layout:?}")
673                };
674                for (field_idx, field) in fields.iter_enumerated() {
675                    let op = self.codegen_operand(bx, field);
676                    let fi = active_field_index.unwrap_or(field_idx);
677                    builder.insert_field(bx, variant_index, fi, op);
678                }
679
680                let tag_result = codegen_tag_value(self.cx, variant_index, layout);
681                match tag_result {
682                    Err(super::place::UninhabitedVariantError) => {
683                        // Like codegen_set_discr we use a sound abort, but could
684                        // potentially `unreachable` or just return the poison for
685                        // more optimizability, if that turns out to be helpful.
686                        bx.abort();
687                        let val = OperandValue::poison(bx, layout);
688                        OperandRef { val, layout }
689                    }
690                    Ok(maybe_tag_value) => {
691                        if let Some((tag_field, tag_imm)) = maybe_tag_value {
692                            builder.insert_imm(tag_field, tag_imm);
693                        }
694                        builder.build(bx.cx())
695                    }
696                }
697            }
698            mir::Rvalue::ShallowInitBox(ref operand, content_ty) => {
699                let operand = self.codegen_operand(bx, operand);
700                let val = operand.immediate();
701
702                let content_ty = self.monomorphize(content_ty);
703                let box_layout = bx.cx().layout_of(Ty::new_box(bx.tcx(), content_ty));
704
705                OperandRef { val: OperandValue::Immediate(val), layout: box_layout }
706            }
707            mir::Rvalue::WrapUnsafeBinder(ref operand, binder_ty) => {
708                let operand = self.codegen_operand(bx, operand);
709                let binder_ty = self.monomorphize(binder_ty);
710                let layout = bx.cx().layout_of(binder_ty);
711                OperandRef { val: operand.val, layout }
712            }
713        }
714    }
715
716    fn evaluate_array_len(&mut self, bx: &mut Bx, place: mir::Place<'tcx>) -> Bx::Value {
717        // ZST are passed as operands and require special handling
718        // because codegen_place() panics if Local is operand.
719        if let Some(index) = place.as_local()
720            && let LocalRef::Operand(op) = self.locals[index]
721            && let ty::Array(_, n) = op.layout.ty.kind()
722        {
723            let n = n.try_to_target_usize(bx.tcx()).expect("expected monomorphic const in codegen");
724            return bx.cx().const_usize(n);
725        }
726        // use common size calculation for non zero-sized types
727        let cg_value = self.codegen_place(bx, place.as_ref());
728        cg_value.len(bx.cx())
729    }
730
731    /// Codegen an `Rvalue::RawPtr` or `Rvalue::Ref`
732    fn codegen_place_to_pointer(
733        &mut self,
734        bx: &mut Bx,
735        place: mir::Place<'tcx>,
736        mk_ptr_ty: impl FnOnce(TyCtxt<'tcx>, Ty<'tcx>) -> Ty<'tcx>,
737    ) -> OperandRef<'tcx, Bx::Value> {
738        let cg_place = self.codegen_place(bx, place.as_ref());
739        let val = cg_place.val.address();
740
741        let ty = cg_place.layout.ty;
742        assert!(
743            if bx.cx().tcx().type_has_metadata(ty, bx.cx().typing_env()) {
744                matches!(val, OperandValue::Pair(..))
745            } else {
746                matches!(val, OperandValue::Immediate(..))
747            },
748            "Address of place was unexpectedly {val:?} for pointee type {ty:?}",
749        );
750
751        OperandRef { val, layout: self.cx.layout_of(mk_ptr_ty(self.cx.tcx(), ty)) }
752    }
753
754    fn codegen_scalar_binop(
755        &mut self,
756        bx: &mut Bx,
757        op: mir::BinOp,
758        lhs: Bx::Value,
759        rhs: Bx::Value,
760        lhs_ty: Ty<'tcx>,
761        rhs_ty: Ty<'tcx>,
762    ) -> Bx::Value {
763        let is_float = lhs_ty.is_floating_point();
764        let is_signed = lhs_ty.is_signed();
765        match op {
766            mir::BinOp::Add => {
767                if is_float {
768                    bx.fadd(lhs, rhs)
769                } else {
770                    bx.add(lhs, rhs)
771                }
772            }
773            mir::BinOp::AddUnchecked => {
774                if is_signed {
775                    bx.unchecked_sadd(lhs, rhs)
776                } else {
777                    bx.unchecked_uadd(lhs, rhs)
778                }
779            }
780            mir::BinOp::Sub => {
781                if is_float {
782                    bx.fsub(lhs, rhs)
783                } else {
784                    bx.sub(lhs, rhs)
785                }
786            }
787            mir::BinOp::SubUnchecked => {
788                if is_signed {
789                    bx.unchecked_ssub(lhs, rhs)
790                } else {
791                    bx.unchecked_usub(lhs, rhs)
792                }
793            }
794            mir::BinOp::Mul => {
795                if is_float {
796                    bx.fmul(lhs, rhs)
797                } else {
798                    bx.mul(lhs, rhs)
799                }
800            }
801            mir::BinOp::MulUnchecked => {
802                if is_signed {
803                    bx.unchecked_smul(lhs, rhs)
804                } else {
805                    bx.unchecked_umul(lhs, rhs)
806                }
807            }
808            mir::BinOp::Div => {
809                if is_float {
810                    bx.fdiv(lhs, rhs)
811                } else if is_signed {
812                    bx.sdiv(lhs, rhs)
813                } else {
814                    bx.udiv(lhs, rhs)
815                }
816            }
817            mir::BinOp::Rem => {
818                if is_float {
819                    bx.frem(lhs, rhs)
820                } else if is_signed {
821                    bx.srem(lhs, rhs)
822                } else {
823                    bx.urem(lhs, rhs)
824                }
825            }
826            mir::BinOp::BitOr => bx.or(lhs, rhs),
827            mir::BinOp::BitAnd => bx.and(lhs, rhs),
828            mir::BinOp::BitXor => bx.xor(lhs, rhs),
829            mir::BinOp::Offset => {
830                let pointee_type = lhs_ty
831                    .builtin_deref(true)
832                    .unwrap_or_else(|| bug!("deref of non-pointer {:?}", lhs_ty));
833                let pointee_layout = bx.cx().layout_of(pointee_type);
834                if pointee_layout.is_zst() {
835                    // `Offset` works in terms of the size of pointee,
836                    // so offsetting a pointer to ZST is a noop.
837                    lhs
838                } else {
839                    let llty = bx.cx().backend_type(pointee_layout);
840                    if !rhs_ty.is_signed() {
841                        bx.inbounds_nuw_gep(llty, lhs, &[rhs])
842                    } else {
843                        bx.inbounds_gep(llty, lhs, &[rhs])
844                    }
845                }
846            }
847            mir::BinOp::Shl | mir::BinOp::ShlUnchecked => {
848                let rhs = base::build_shift_expr_rhs(bx, lhs, rhs, op == mir::BinOp::ShlUnchecked);
849                bx.shl(lhs, rhs)
850            }
851            mir::BinOp::Shr | mir::BinOp::ShrUnchecked => {
852                let rhs = base::build_shift_expr_rhs(bx, lhs, rhs, op == mir::BinOp::ShrUnchecked);
853                if is_signed { bx.ashr(lhs, rhs) } else { bx.lshr(lhs, rhs) }
854            }
855            mir::BinOp::Ne
856            | mir::BinOp::Lt
857            | mir::BinOp::Gt
858            | mir::BinOp::Eq
859            | mir::BinOp::Le
860            | mir::BinOp::Ge => {
861                if is_float {
862                    bx.fcmp(base::bin_op_to_fcmp_predicate(op), lhs, rhs)
863                } else {
864                    bx.icmp(base::bin_op_to_icmp_predicate(op, is_signed), lhs, rhs)
865                }
866            }
867            mir::BinOp::Cmp => {
868                use std::cmp::Ordering;
869                assert!(!is_float);
870                if let Some(value) = bx.three_way_compare(lhs_ty, lhs, rhs) {
871                    return value;
872                }
873                let pred = |op| base::bin_op_to_icmp_predicate(op, is_signed);
874                if bx.cx().tcx().sess.opts.optimize == OptLevel::No {
875                    // FIXME: This actually generates tighter assembly, and is a classic trick
876                    // <https://graphics.stanford.edu/~seander/bithacks.html#CopyIntegerSign>
877                    // However, as of 2023-11 it optimizes worse in things like derived
878                    // `PartialOrd`, so only use it in debug for now. Once LLVM can handle it
879                    // better (see <https://github.com/llvm/llvm-project/issues/73417>), it'll
880                    // be worth trying it in optimized builds as well.
881                    let is_gt = bx.icmp(pred(mir::BinOp::Gt), lhs, rhs);
882                    let gtext = bx.zext(is_gt, bx.type_i8());
883                    let is_lt = bx.icmp(pred(mir::BinOp::Lt), lhs, rhs);
884                    let ltext = bx.zext(is_lt, bx.type_i8());
885                    bx.unchecked_ssub(gtext, ltext)
886                } else {
887                    // These operations are those expected by `tests/codegen/integer-cmp.rs`,
888                    // from <https://github.com/rust-lang/rust/pull/63767>.
889                    let is_lt = bx.icmp(pred(mir::BinOp::Lt), lhs, rhs);
890                    let is_ne = bx.icmp(pred(mir::BinOp::Ne), lhs, rhs);
891                    let ge = bx.select(
892                        is_ne,
893                        bx.cx().const_i8(Ordering::Greater as i8),
894                        bx.cx().const_i8(Ordering::Equal as i8),
895                    );
896                    bx.select(is_lt, bx.cx().const_i8(Ordering::Less as i8), ge)
897                }
898            }
899            mir::BinOp::AddWithOverflow
900            | mir::BinOp::SubWithOverflow
901            | mir::BinOp::MulWithOverflow => {
902                bug!("{op:?} needs to return a pair, so call codegen_scalar_checked_binop instead")
903            }
904        }
905    }
906
907    fn codegen_wide_ptr_binop(
908        &mut self,
909        bx: &mut Bx,
910        op: mir::BinOp,
911        lhs_addr: Bx::Value,
912        lhs_extra: Bx::Value,
913        rhs_addr: Bx::Value,
914        rhs_extra: Bx::Value,
915        _input_ty: Ty<'tcx>,
916    ) -> Bx::Value {
917        match op {
918            mir::BinOp::Eq => {
919                let lhs = bx.icmp(IntPredicate::IntEQ, lhs_addr, rhs_addr);
920                let rhs = bx.icmp(IntPredicate::IntEQ, lhs_extra, rhs_extra);
921                bx.and(lhs, rhs)
922            }
923            mir::BinOp::Ne => {
924                let lhs = bx.icmp(IntPredicate::IntNE, lhs_addr, rhs_addr);
925                let rhs = bx.icmp(IntPredicate::IntNE, lhs_extra, rhs_extra);
926                bx.or(lhs, rhs)
927            }
928            mir::BinOp::Le | mir::BinOp::Lt | mir::BinOp::Ge | mir::BinOp::Gt => {
929                // a OP b ~ a.0 STRICT(OP) b.0 | (a.0 == b.0 && a.1 OP a.1)
930                let (op, strict_op) = match op {
931                    mir::BinOp::Lt => (IntPredicate::IntULT, IntPredicate::IntULT),
932                    mir::BinOp::Le => (IntPredicate::IntULE, IntPredicate::IntULT),
933                    mir::BinOp::Gt => (IntPredicate::IntUGT, IntPredicate::IntUGT),
934                    mir::BinOp::Ge => (IntPredicate::IntUGE, IntPredicate::IntUGT),
935                    _ => bug!(),
936                };
937                let lhs = bx.icmp(strict_op, lhs_addr, rhs_addr);
938                let and_lhs = bx.icmp(IntPredicate::IntEQ, lhs_addr, rhs_addr);
939                let and_rhs = bx.icmp(op, lhs_extra, rhs_extra);
940                let rhs = bx.and(and_lhs, and_rhs);
941                bx.or(lhs, rhs)
942            }
943            _ => {
944                bug!("unexpected wide ptr binop");
945            }
946        }
947    }
948
949    fn codegen_scalar_checked_binop(
950        &mut self,
951        bx: &mut Bx,
952        op: mir::BinOp,
953        lhs: Bx::Value,
954        rhs: Bx::Value,
955        input_ty: Ty<'tcx>,
956    ) -> OperandValue<Bx::Value> {
957        let (val, of) = match op {
958            // These are checked using intrinsics
959            mir::BinOp::Add | mir::BinOp::Sub | mir::BinOp::Mul => {
960                let oop = match op {
961                    mir::BinOp::Add => OverflowOp::Add,
962                    mir::BinOp::Sub => OverflowOp::Sub,
963                    mir::BinOp::Mul => OverflowOp::Mul,
964                    _ => unreachable!(),
965                };
966                bx.checked_binop(oop, input_ty, lhs, rhs)
967            }
968            _ => bug!("Operator `{:?}` is not a checkable operator", op),
969        };
970
971        OperandValue::Pair(val, of)
972    }
973
974    /// Returns `true` if the `rvalue` can be computed into an [`OperandRef`],
975    /// rather than needing a full `PlaceRef` for the assignment destination.
976    ///
977    /// This is used by the [`super::analyze`] code to decide which MIR locals
978    /// can stay as SSA values (as opposed to generating `alloca` slots for them).
979    /// As such, some paths here return `true` even where the specific rvalue
980    /// will not actually take the operand path because the result type is such
981    /// that it always gets an `alloca`, but where it's not worth re-checking the
982    /// layout in this code when the right thing will happen anyway.
983    pub(crate) fn rvalue_creates_operand(&self, rvalue: &mir::Rvalue<'tcx>, span: Span) -> bool {
984        match *rvalue {
985            mir::Rvalue::Cast(mir::CastKind::Transmute, ref operand, cast_ty) => {
986                let operand_ty = operand.ty(self.mir, self.cx.tcx());
987                let cast_layout = self.cx.layout_of(self.monomorphize(cast_ty));
988                let operand_layout = self.cx.layout_of(self.monomorphize(operand_ty));
989                match (operand_layout.backend_repr, cast_layout.backend_repr) {
990                    // When the output will be in memory anyway, just use its place
991                    // (instead of the operand path) unless it's the trivial ZST case.
992                    (_, abi::BackendRepr::Memory { .. }) => cast_layout.is_zst(),
993
994                    // Otherwise (for a non-memory output) if the input is memory
995                    // then we can just read the value from the place.
996                    (abi::BackendRepr::Memory { .. }, _) => true,
997
998                    // When we have scalar immediates, we can only convert things
999                    // where the sizes match, to avoid endianness questions.
1000                    (abi::BackendRepr::Scalar(a), abi::BackendRepr::Scalar(b)) =>
1001                        a.size(self.cx) == b.size(self.cx),
1002                    (abi::BackendRepr::ScalarPair(a0, a1), abi::BackendRepr::ScalarPair(b0, b1)) =>
1003                        a0.size(self.cx) == b0.size(self.cx) && a1.size(self.cx) == b1.size(self.cx),
1004
1005                    // Mixing Scalars and ScalarPairs can get quite complicated when
1006                    // padding and undef get involved, so leave that to the memory path.
1007                    (abi::BackendRepr::Scalar(_), abi::BackendRepr::ScalarPair(_, _)) |
1008                    (abi::BackendRepr::ScalarPair(_, _), abi::BackendRepr::Scalar(_)) => false,
1009
1010                    // SIMD vectors aren't worth the trouble of dealing with complex
1011                    // cases like from vectors of f32 to vectors of pointers or
1012                    // from fat pointers to vectors of u16. (See #143194 #110021 ...)
1013                    (abi::BackendRepr::SimdVector { .. }, _) | (_, abi::BackendRepr::SimdVector { .. }) => false,
1014                }
1015            }
1016            mir::Rvalue::Ref(..) |
1017            mir::Rvalue::CopyForDeref(..) |
1018            mir::Rvalue::RawPtr(..) |
1019            mir::Rvalue::Len(..) |
1020            mir::Rvalue::Cast(..) | // (*)
1021            mir::Rvalue::ShallowInitBox(..) | // (*)
1022            mir::Rvalue::BinaryOp(..) |
1023            mir::Rvalue::UnaryOp(..) |
1024            mir::Rvalue::Discriminant(..) |
1025            mir::Rvalue::NullaryOp(..) |
1026            mir::Rvalue::ThreadLocalRef(_) |
1027            mir::Rvalue::Use(..) |
1028            mir::Rvalue::WrapUnsafeBinder(..) => // (*)
1029                true,
1030            // Arrays are always aggregates, so it's not worth checking anything here.
1031            // (If it's really `[(); N]` or `[T; 0]` and we use the place path, fine.)
1032            mir::Rvalue::Repeat(..) => false,
1033            mir::Rvalue::Aggregate(..) => {
1034                    let ty = rvalue.ty(self.mir, self.cx.tcx());
1035                    let ty = self.monomorphize(ty);
1036                    let layout = self.cx.spanned_layout_of(ty, span);
1037                    OperandRef::<Bx::Value>::builder(layout).is_some()
1038                }
1039            }
1040
1041        // (*) this is only true if the type is suitable
1042    }
1043}
1044
1045/// Transmutes a single scalar value `imm` from `from_scalar` to `to_scalar`.
1046///
1047/// This is expected to be in *immediate* form, as seen in [`OperandValue::Immediate`]
1048/// or [`OperandValue::Pair`] (so `i1` for bools, not `i8`, for example).
1049///
1050/// ICEs if the passed-in `imm` is not a value of the expected type for
1051/// `from_scalar`, such as if it's a vector or a pair.
1052pub(super) fn transmute_scalar<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
1053    bx: &mut Bx,
1054    mut imm: Bx::Value,
1055    from_scalar: abi::Scalar,
1056    to_scalar: abi::Scalar,
1057) -> Bx::Value {
1058    assert_eq!(from_scalar.size(bx.cx()), to_scalar.size(bx.cx()));
1059    let imm_ty = bx.cx().val_ty(imm);
1060    assert_ne!(
1061        bx.cx().type_kind(imm_ty),
1062        TypeKind::Vector,
1063        "Vector type {imm_ty:?} not allowed in transmute_scalar {from_scalar:?} -> {to_scalar:?}"
1064    );
1065
1066    // While optimizations will remove no-op transmutes, they might still be
1067    // there in debug or things that aren't no-op in MIR because they change
1068    // the Rust type but not the underlying layout/niche.
1069    if from_scalar == to_scalar {
1070        return imm;
1071    }
1072
1073    use abi::Primitive::*;
1074    imm = bx.from_immediate(imm);
1075
1076    let from_backend_ty = bx.cx().type_from_scalar(from_scalar);
1077    debug_assert_eq!(bx.cx().val_ty(imm), from_backend_ty);
1078    let to_backend_ty = bx.cx().type_from_scalar(to_scalar);
1079
1080    // If we have a scalar, we must already know its range. Either
1081    //
1082    // 1) It's a parameter with `range` parameter metadata,
1083    // 2) It's something we `load`ed with `!range` metadata, or
1084    // 3) After a transmute we `assume`d the range (see below).
1085    //
1086    // That said, last time we tried removing this, it didn't actually help
1087    // the rustc-perf results, so might as well keep doing it
1088    // <https://github.com/rust-lang/rust/pull/135610#issuecomment-2599275182>
1089    assume_scalar_range(bx, imm, from_scalar, from_backend_ty);
1090
1091    imm = match (from_scalar.primitive(), to_scalar.primitive()) {
1092        (Int(..) | Float(_), Int(..) | Float(_)) => bx.bitcast(imm, to_backend_ty),
1093        (Pointer(..), Pointer(..)) => bx.pointercast(imm, to_backend_ty),
1094        (Int(..), Pointer(..)) => bx.ptradd(bx.const_null(bx.type_ptr()), imm),
1095        (Pointer(..), Int(..)) => {
1096            // FIXME: this exposes the provenance, which shouldn't be necessary.
1097            bx.ptrtoint(imm, to_backend_ty)
1098        }
1099        (Float(_), Pointer(..)) => {
1100            let int_imm = bx.bitcast(imm, bx.cx().type_isize());
1101            bx.ptradd(bx.const_null(bx.type_ptr()), int_imm)
1102        }
1103        (Pointer(..), Float(_)) => {
1104            // FIXME: this exposes the provenance, which shouldn't be necessary.
1105            let int_imm = bx.ptrtoint(imm, bx.cx().type_isize());
1106            bx.bitcast(int_imm, to_backend_ty)
1107        }
1108    };
1109
1110    debug_assert_eq!(bx.cx().val_ty(imm), to_backend_ty);
1111
1112    // This `assume` remains important for cases like (a conceptual)
1113    //    transmute::<u32, NonZeroU32>(x) == 0
1114    // since it's never passed to something with parameter metadata (especially
1115    // after MIR inlining) so the only way to tell the backend about the
1116    // constraint that the `transmute` introduced is to `assume` it.
1117    assume_scalar_range(bx, imm, to_scalar, to_backend_ty);
1118
1119    imm = bx.to_immediate_scalar(imm, to_scalar);
1120    imm
1121}
1122
1123fn assume_scalar_range<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
1124    bx: &mut Bx,
1125    imm: Bx::Value,
1126    scalar: abi::Scalar,
1127    backend_ty: Bx::Type,
1128) {
1129    if matches!(bx.cx().sess().opts.optimize, OptLevel::No) || scalar.is_always_valid(bx.cx()) {
1130        return;
1131    }
1132
1133    match scalar.primitive() {
1134        abi::Primitive::Int(..) => {
1135            let range = scalar.valid_range(bx.cx());
1136            bx.assume_integer_range(imm, backend_ty, range);
1137        }
1138        abi::Primitive::Pointer(abi::AddressSpace::ZERO)
1139            if !scalar.valid_range(bx.cx()).contains(0) =>
1140        {
1141            bx.assume_nonnull(imm);
1142        }
1143        abi::Primitive::Pointer(..) | abi::Primitive::Float(..) => {}
1144    }
1145}
rustc_codegen_ssa/mir/rvalue.rs

rustc_codegen_ssa/mir/
rvalue.rs
