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scottmcmscottmcm
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Add mir::BinOp::Cmp 
1 parent 7b56ce0 commit 1ed478b

32 files changed

+460
-221
lines changed

‎compiler/rustc_codegen_cranelift/src/codegen_i128.rs

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -68,7 +68,7 @@ pub(crate) fn maybe_codegen<'tcx>(
6868
Some(CValue::by_val(ret_val, lhs.layout()))
6969
}
7070
}
71-
BinOp::Lt | BinOp::Le | BinOp::Eq | BinOp::Ge | BinOp::Gt | BinOp::Ne => None,
71+
BinOp::Lt | BinOp::Le | BinOp::Eq | BinOp::Ge | BinOp::Gt | BinOp::Ne | BinOp::Cmp => None,
7272
BinOp::Shl | BinOp::ShlUnchecked | BinOp::Shr | BinOp::ShrUnchecked => None,
7373
}
7474
}
@@ -134,6 +134,7 @@ pub(crate) fn maybe_codegen_checked<'tcx>(
134134
BinOp::AddUnchecked | BinOp::SubUnchecked | BinOp::MulUnchecked => unreachable!(),
135135
BinOp::Offset => unreachable!("offset should only be used on pointers, not 128bit ints"),
136136
BinOp::Div | BinOp::Rem => unreachable!(),
137+
BinOp::Cmp => unreachable!(),
137138
BinOp::Lt | BinOp::Le | BinOp::Eq | BinOp::Ge | BinOp::Gt | BinOp::Ne => unreachable!(),
138139
BinOp::Shl | BinOp::ShlUnchecked | BinOp::Shr | BinOp::ShrUnchecked => unreachable!(),
139140
}

‎compiler/rustc_codegen_cranelift/src/num.rs

Lines changed: 23 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -40,13 +40,34 @@ pub(crate) fn bin_op_to_intcc(bin_op: BinOp, signed: bool) -> Option<IntCC> {
4040
})
4141
}
4242

43+
fn codegen_three_way_compare<'tcx>(
44+
fx: &mut FunctionCx<'_, '_, 'tcx>,
45+
signed: bool,
46+
lhs: Value,
47+
rhs: Value,
48+
) -> CValue<'tcx> {
49+
let gt_cc = crate::num::bin_op_to_intcc(BinOp::Gt, signed).unwrap();
50+
let lt_cc = crate::num::bin_op_to_intcc(BinOp::Lt, signed).unwrap();
51+
let gt = fx.bcx.ins().icmp(gt_cc, lhs, rhs);
52+
let lt = fx.bcx.ins().icmp(lt_cc, lhs, rhs);
53+
// Cranelift no longer has a single-bit type, so the comparison results
54+
// are already `I8`s, which we can subtract to get the -1/0/+1 we want.
55+
// See <https://github.com/bytecodealliance/wasmtime/pull/5031>.
56+
let val = fx.bcx.ins().isub(gt, lt);
57+
CValue::by_val(val, fx.layout_of(fx.tcx.types.i8))
58+
}
59+
4360
fn codegen_compare_bin_op<'tcx>(
4461
fx: &mut FunctionCx<'_, '_, 'tcx>,
4562
bin_op: BinOp,
4663
signed: bool,
4764
lhs: Value,
4865
rhs: Value,
4966
) -> CValue<'tcx> {
67+
if bin_op == BinOp::Cmp {
68+
return codegen_three_way_compare(fx, signed, lhs, rhs);
69+
}
70+
5071
let intcc = crate::num::bin_op_to_intcc(bin_op, signed).unwrap();
5172
let val = fx.bcx.ins().icmp(intcc, lhs, rhs);
5273
CValue::by_val(val, fx.layout_of(fx.tcx.types.bool))
@@ -59,7 +80,7 @@ pub(crate) fn codegen_binop<'tcx>(
5980
in_rhs: CValue<'tcx>,
6081
) -> CValue<'tcx> {
6182
match bin_op {
62-
BinOp::Eq | BinOp::Lt | BinOp::Le | BinOp::Ne | BinOp::Ge | BinOp::Gt => {
83+
BinOp::Eq | BinOp::Lt | BinOp::Le | BinOp::Ne | BinOp::Ge | BinOp::Gt | BinOp::Cmp => {
6384
match in_lhs.layout().ty.kind() {
6485
ty::Bool | ty::Uint(_) | ty::Int(_) | ty::Char => {
6586
let signed = type_sign(in_lhs.layout().ty);
@@ -160,7 +181,7 @@ pub(crate) fn codegen_int_binop<'tcx>(
160181
}
161182
BinOp::Offset => unreachable!("Offset is not an integer operation"),
162183
// Compare binops handles by `codegen_binop`.
163-
BinOp::Eq | BinOp::Ne | BinOp::Lt | BinOp::Le | BinOp::Gt | BinOp::Ge => {
184+
BinOp::Eq | BinOp::Ne | BinOp::Lt | BinOp::Le | BinOp::Gt | BinOp::Ge | BinOp::Cmp => {
164185
unreachable!("{:?}({:?}, {:?})", bin_op, in_lhs.layout().ty, in_rhs.layout().ty);
165186
}
166187
};

‎compiler/rustc_codegen_gcc/src/common.rs

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -104,6 +104,10 @@ impl<'gcc, 'tcx> ConstMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
104104
self.const_int(self.type_i32(), i as i64)
105105
}
106106

107+
fn const_i8(&self, i: i8) -> RValue<'gcc> {
108+
self.const_int(self.type_i8(), i as i64)
109+
}
110+
107111
fn const_u32(&self, i: u32) -> RValue<'gcc> {
108112
self.const_uint(self.type_u32(), i as u64)
109113
}

‎compiler/rustc_codegen_llvm/src/common.rs

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -158,6 +158,10 @@ impl<'ll, 'tcx> ConstMethods<'tcx> for CodegenCx<'ll, 'tcx> {
158158
self.const_int(self.type_i32(), i as i64)
159159
}
160160

161+
fn const_i8(&self, i: i8) -> &'ll Value {
162+
self.const_int(self.type_i8(), i as i64)
163+
}
164+
161165
fn const_u32(&self, i: u32) -> &'ll Value {
162166
self.const_uint(self.type_i32(), i as u64)
163167
}

‎compiler/rustc_codegen_ssa/src/mir/rvalue.rs

Lines changed: 22 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -7,6 +7,7 @@ use crate::common::{self, IntPredicate};
77
use crate::traits::*;
88
use crate::MemFlags;
99

10+
use rustc_hir as hir;
1011
use rustc_middle::mir;
1112
use rustc_middle::mir::Operand;
1213
use rustc_middle::ty::cast::{CastTy, IntTy};
@@ -881,6 +882,27 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
881882
bx.icmp(base::bin_op_to_icmp_predicate(op.to_hir_binop(), is_signed), lhs, rhs)
882883
}
883884
}
885+
mir::BinOp::Cmp => {
886+
use std::cmp::Ordering;
887+
debug_assert!(!is_float);
888+
// FIXME: To avoid this PR changing behaviour, the operations used
889+
// here are those from <https://github.com/rust-lang/rust/pull/63767>,
890+
// as tested by `tests/codegen/integer-cmp.rs`.
891+
// Something in future might want to pick different ones. For example,
892+
// maybe the ones from Clang's `<=>` operator in C++20 (see
893+
// <https://github.com/llvm/llvm-project/issues/60012>) or once we
894+
// update to new LLVM, something to take advantage of the new folds in
895+
// <https://github.com/llvm/llvm-project/issues/59666>.
896+
let pred = |op| base::bin_op_to_icmp_predicate(op, is_signed);
897+
let is_lt = bx.icmp(pred(hir::BinOpKind::Lt), lhs, rhs);
898+
let is_ne = bx.icmp(pred(hir::BinOpKind::Ne), lhs, rhs);
899+
let ge = bx.select(
900+
is_ne,
901+
bx.cx().const_i8(Ordering::Greater as i8),
902+
bx.cx().const_i8(Ordering::Equal as i8),
903+
);
904+
bx.select(is_lt, bx.cx().const_i8(Ordering::Less as i8), ge)
905+
}
884906
}
885907
}
886908

‎compiler/rustc_codegen_ssa/src/traits/consts.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -19,6 +19,7 @@ pub trait ConstMethods<'tcx>: BackendTypes {
1919
fn const_bool(&self, val: bool) -> Self::Value;
2020
fn const_i16(&self, i: i16) -> Self::Value;
2121
fn const_i32(&self, i: i32) -> Self::Value;
22+
fn const_i8(&self, i: i8) -> Self::Value;
2223
fn const_u32(&self, i: u32) -> Self::Value;
2324
fn const_u64(&self, i: u64) -> Self::Value;
2425
fn const_u128(&self, i: u128) -> Self::Value;

‎compiler/rustc_const_eval/src/interpret/operand.rs

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -224,6 +224,13 @@ impl<'tcx, Prov: Provenance> ImmTy<'tcx, Prov> {
224224
Self::from_scalar(Scalar::from_bool(b), layout)
225225
}
226226

227+
#[inline]
228+
pub fn from_ordering(c: std::cmp::Ordering, tcx: TyCtxt<'tcx>) -> Self {
229+
let ty = tcx.ty_ordering_enum(None);
230+
let layout = tcx.layout_of(ty::ParamEnv::reveal_all().and(ty)).unwrap();
231+
Self::from_scalar(Scalar::from_i8(c as i8), layout)
232+
}
233+
227234
#[inline]
228235
pub fn to_const_int(self) -> ConstInt {
229236
assert!(self.layout.ty.is_integral());

‎compiler/rustc_const_eval/src/interpret/operator.rs

Lines changed: 18 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -61,6 +61,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
6161
}
6262

6363
impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
64+
fn three_way_compare<T: Ord>(&self, lhs: T, rhs: T) -> (ImmTy<'tcx, M::Provenance>, bool) {
65+
let res = Ord::cmp(&lhs, &rhs);
66+
return (ImmTy::from_ordering(res, *self.tcx), false);
67+
}
68+
6469
fn binary_char_op(
6570
&self,
6671
bin_op: mir::BinOp,
@@ -69,6 +74,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
6974
) -> (ImmTy<'tcx, M::Provenance>, bool) {
7075
use rustc_middle::mir::BinOp::*;
7176

77+
if bin_op == Cmp {
78+
return self.three_way_compare(l, r);
79+
}
80+
7281
let res = match bin_op {
7382
Eq => l == r,
7483
Ne => l != r,
@@ -231,6 +240,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
231240
let r = self.sign_extend(r, right_layout) as i128;
232241
return Ok((ImmTy::from_bool(op(&l, &r), *self.tcx), false));
233242
}
243+
if bin_op == Cmp {
244+
let l = self.sign_extend(l, left_layout) as i128;
245+
let r = self.sign_extend(r, right_layout) as i128;
246+
return Ok(self.three_way_compare(l, r));
247+
}
234248
let op: Option<fn(i128, i128) -> (i128, bool)> = match bin_op {
235249
Div if r == 0 => throw_ub!(DivisionByZero),
236250
Rem if r == 0 => throw_ub!(RemainderByZero),
@@ -270,6 +284,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
270284
}
271285
}
272286

287+
if bin_op == Cmp {
288+
return Ok(self.three_way_compare(l, r));
289+
}
290+
273291
let val = match bin_op {
274292
Eq => ImmTy::from_bool(l == r, *self.tcx),
275293
Ne => ImmTy::from_bool(l != r, *self.tcx),

‎compiler/rustc_const_eval/src/transform/promote_consts.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -573,6 +573,7 @@ impl<'tcx> Validator<'_, 'tcx> {
573573
| BinOp::Lt
574574
| BinOp::Ge
575575
| BinOp::Gt
576+
| BinOp::Cmp
576577
| BinOp::Offset
577578
| BinOp::Add
578579
| BinOp::AddUnchecked

‎compiler/rustc_const_eval/src/transform/validate.rs

Lines changed: 9 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -932,6 +932,15 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
932932
)
933933
}
934934
}
935+
Cmp => {
936+
for x in [a, b] {
937+
check_kinds!(
938+
x,
939+
"Cannot three-way compare non-integer type {:?}",
940+
ty::Char | ty::Uint(..) | ty::Int(..)
941+
)
942+
}
943+
}
935944
AddUnchecked | SubUnchecked | MulUnchecked | Shl | ShlUnchecked | Shr
936945
| ShrUnchecked => {
937946
for x in [a, b] {

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