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Also assume wrap-around discriminants in as MIR building #111579

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May 23, 2023
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Also assume wrap-around discriminants in as MIR building #111579

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101 changes: 58 additions & 43 deletions compiler/rustc_mir_build/src/build/expr/as_rvalue.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@ use rustc_middle::mir::Place;
use rustc_middle::mir::*;
use rustc_middle::thir::*;
use rustc_middle::ty::cast::{mir_cast_kind, CastTy};
use rustc_middle::ty::layout::IntegerExt;
use rustc_middle::ty::{self, Ty, UpvarSubsts};
use rustc_span::Span;

Expand Down Expand Up @@ -225,49 +226,63 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
);
let (op,ty) = (Operand::Move(discr), discr_ty);

if let Abi::Scalar(scalar) = layout.unwrap().abi{
if let Primitive::Int(_, signed) = scalar.primitive() {
let range = scalar.valid_range(&this.tcx);
// FIXME: Handle wraparound cases too.
if range.end >= range.start {
let mut assumer = |range: u128, bin_op: BinOp| {
// We will be overwriting this val if our scalar is signed value
// because sign extension on unsigned types might cause unintended things
let mut range_val =
ConstantKind::from_bits(this.tcx, range, ty::ParamEnv::empty().and(discr_ty));
let bool_ty = this.tcx.types.bool;
if signed {
let scalar_size_extend = scalar.size(&this.tcx).sign_extend(range);
let discr_layout = this.tcx.layout_of(this.param_env.and(discr_ty));
let truncated_val = discr_layout.unwrap().size.truncate(scalar_size_extend);
range_val = ConstantKind::from_bits(
this.tcx,
truncated_val,
ty::ParamEnv::empty().and(discr_ty),
);
}
let lit_op = this.literal_operand(expr.span, range_val);
let is_bin_op = this.temp(bool_ty, expr_span);
this.cfg.push_assign(
block,
source_info,
is_bin_op,
Rvalue::BinaryOp(bin_op, Box::new(((lit_op), (Operand::Copy(discr))))),
);
this.cfg.push(
block,
Statement {
source_info,
kind: StatementKind::Intrinsic(Box::new(NonDivergingIntrinsic::Assume(
Operand::Copy(is_bin_op),
))),
},
)
};
assumer(range.end, BinOp::Ge);
assumer(range.start, BinOp::Le);
}
}
if let Abi::Scalar(scalar) = layout.unwrap().abi
&& !scalar.is_always_valid(&this.tcx)
&& let Primitive::Int(int_width, _signed) = scalar.primitive()
{
let unsigned_ty = int_width.to_ty(this.tcx, false);
let unsigned_place = this.temp(unsigned_ty, expr_span);
this.cfg.push_assign(
block,
source_info,
unsigned_place,
Rvalue::Cast(CastKind::IntToInt, Operand::Copy(discr), unsigned_ty));

let bool_ty = this.tcx.types.bool;
let range = scalar.valid_range(&this.tcx);
let merge_op =
if range.start <= range.end {
BinOp::BitAnd
} else {
BinOp::BitOr
};

let mut comparer = |range: u128, bin_op: BinOp| -> Place<'tcx> {
let range_val =
ConstantKind::from_bits(this.tcx, range, ty::ParamEnv::empty().and(unsigned_ty));
let lit_op = this.literal_operand(expr.span, range_val);
let is_bin_op = this.temp(bool_ty, expr_span);
this.cfg.push_assign(
block,
source_info,
is_bin_op,
Rvalue::BinaryOp(bin_op, Box::new((Operand::Copy(unsigned_place), lit_op))),
);
is_bin_op
};
let assert_place = if range.start == 0 {
comparer(range.end, BinOp::Le)
} else {
let start_place = comparer(range.start, BinOp::Ge);
let end_place = comparer(range.end, BinOp::Le);
let merge_place = this.temp(bool_ty, expr_span);
this.cfg.push_assign(
block,
source_info,
merge_place,
Rvalue::BinaryOp(merge_op, Box::new((Operand::Move(start_place), Operand::Move(end_place)))),
);
merge_place
};
this.cfg.push(
block,
Statement {
source_info,
kind: StatementKind::Intrinsic(Box::new(NonDivergingIntrinsic::Assume(
Operand::Move(assert_place),
))),
},
);
}

(op,ty)
Expand Down
28 changes: 28 additions & 0 deletions tests/assembly/option-nonzero-eq.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
// revisions: WIN LIN
// [WIN] only-windows
// [LIN] only-linux
// assembly-output: emit-asm
// compile-flags: --crate-type=lib -O -C llvm-args=-x86-asm-syntax=intel
// only-x86_64
// ignore-sgx
// ignore-debug

use std::cmp::Ordering;

// CHECK-lABEL: ordering_eq:
#[no_mangle]
pub fn ordering_eq(l: Option<Ordering>, r: Option<Ordering>) -> bool {
// Linux (System V): first two arguments are rdi then rsi
// Windows: first two arguments are rcx then rdx
// Both use rax for the return value.

// CHECK-NOT: mov
// CHECK-NOT: test
// CHECK-NOT: cmp

// LIN: cmp dil, sil
// WIN: cmp cl, dl
// CHECK-NEXT: sete al
// CHECK-NEXT: ret
l == r
}
12 changes: 3 additions & 9 deletions tests/codegen/option-nonzero-eq.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,9 @@ use core::cmp::Ordering;
use core::num::{NonZeroU32, NonZeroI64};
use core::ptr::NonNull;

// See also tests/assembly/option-nonzero-eq.rs, for cases with `assume`s in the
// LLVM and thus don't optimize down clearly here, but do in assembly.

// CHECK-lABEL: @non_zero_eq
#[no_mangle]
pub fn non_zero_eq(l: Option<NonZeroU32>, r: Option<NonZeroU32>) -> bool {
Expand All @@ -33,12 +36,3 @@ pub fn non_null_eq(l: Option<NonNull<u8>>, r: Option<NonNull<u8>>) -> bool {
// CHECK-NEXT: ret i1
l == r
}

// CHECK-lABEL: @ordering_eq
#[no_mangle]
pub fn ordering_eq(l: Option<Ordering>, r: Option<Ordering>) -> bool {
// CHECK: start:
// CHECK-NEXT: icmp eq i8
// CHECK-NEXT: ret i1
l == r
}
9 changes: 4 additions & 5 deletions tests/mir-opt/building/enum_cast.bar.built.after.mir
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Expand Up @@ -5,17 +5,16 @@ fn bar(_1: Bar) -> usize {
let mut _0: usize; // return place in scope 0 at $DIR/enum_cast.rs:+0:21: +0:26
let _2: Bar; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:8
let mut _3: isize; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:8
let mut _4: bool; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
let mut _4: u8; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
let mut _5: bool; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:17

bb0: {
StorageLive(_2); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:8
_2 = move _1; // scope 0 at $DIR/enum_cast.rs:+1:5: +1:8
_3 = discriminant(_2); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_4 = Ge(const 1_isize, _3); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
assume(_4); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_5 = Le(const 0_isize, _3); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
assume(_5); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_4 = _3 as u8 (IntToInt); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_5 = Le(_4, const 1_u8); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
assume(move _5); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_0 = move _3 as usize (IntToInt); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
StorageDead(_2); // scope 0 at $DIR/enum_cast.rs:+1:16: +1:17
return; // scope 0 at $DIR/enum_cast.rs:+2:2: +2:2
Expand Down
9 changes: 4 additions & 5 deletions tests/mir-opt/building/enum_cast.boo.built.after.mir
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Original file line number Diff line number Diff line change
Expand Up @@ -5,17 +5,16 @@ fn boo(_1: Boo) -> usize {
let mut _0: usize; // return place in scope 0 at $DIR/enum_cast.rs:+0:21: +0:26
let _2: Boo; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:8
let mut _3: u8; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:8
let mut _4: bool; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
let mut _4: u8; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
let mut _5: bool; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:17

bb0: {
StorageLive(_2); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:8
_2 = move _1; // scope 0 at $DIR/enum_cast.rs:+1:5: +1:8
_3 = discriminant(_2); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_4 = Ge(const 1_u8, _3); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
assume(_4); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_5 = Le(const 0_u8, _3); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
assume(_5); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_4 = _3 as u8 (IntToInt); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_5 = Le(_4, const 1_u8); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
assume(move _5); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_0 = move _3 as usize (IntToInt); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
StorageDead(_2); // scope 0 at $DIR/enum_cast.rs:+1:16: +1:17
return; // scope 0 at $DIR/enum_cast.rs:+2:2: +2:2
Expand Down
9 changes: 4 additions & 5 deletions tests/mir-opt/building/enum_cast.droppy.built.after.mir
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Expand Up @@ -6,7 +6,7 @@ fn droppy() -> () {
let _2: Droppy; // in scope 0 at $DIR/enum_cast.rs:+2:13: +2:14
let _4: Droppy; // in scope 0 at $DIR/enum_cast.rs:+5:17: +5:18
let mut _5: isize; // in scope 0 at $DIR/enum_cast.rs:+5:17: +5:18
let mut _6: bool; // in scope 0 at $DIR/enum_cast.rs:+5:17: +5:27
let mut _6: u8; // in scope 0 at $DIR/enum_cast.rs:+5:17: +5:27
let mut _7: bool; // in scope 0 at $DIR/enum_cast.rs:+5:17: +5:27
let _8: Droppy; // in scope 0 at $DIR/enum_cast.rs:+7:9: +7:10
scope 1 {
Expand All @@ -31,10 +31,9 @@ fn droppy() -> () {
StorageLive(_4); // scope 3 at $DIR/enum_cast.rs:+5:17: +5:18
_4 = move _2; // scope 3 at $DIR/enum_cast.rs:+5:17: +5:18
_5 = discriminant(_4); // scope 3 at $DIR/enum_cast.rs:+5:17: +5:27
_6 = Ge(const 2_isize, _5); // scope 3 at $DIR/enum_cast.rs:+5:17: +5:27
assume(_6); // scope 3 at $DIR/enum_cast.rs:+5:17: +5:27
_7 = Le(const 0_isize, _5); // scope 3 at $DIR/enum_cast.rs:+5:17: +5:27
assume(_7); // scope 3 at $DIR/enum_cast.rs:+5:17: +5:27
_6 = _5 as u8 (IntToInt); // scope 3 at $DIR/enum_cast.rs:+5:17: +5:27
_7 = Le(_6, const 2_u8); // scope 3 at $DIR/enum_cast.rs:+5:17: +5:27
assume(move _7); // scope 3 at $DIR/enum_cast.rs:+5:17: +5:27
_3 = move _5 as usize (IntToInt); // scope 3 at $DIR/enum_cast.rs:+5:17: +5:27
drop(_4) -> [return: bb1, unwind: bb4]; // scope 3 at $DIR/enum_cast.rs:+5:26: +5:27
}
Expand Down
22 changes: 22 additions & 0 deletions tests/mir-opt/building/enum_cast.far.built.after.mir
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@@ -0,0 +1,22 @@
// MIR for `far` after built

fn far(_1: Far) -> isize {
debug far => _1; // in scope 0 at $DIR/enum_cast.rs:+0:8: +0:11
let mut _0: isize; // return place in scope 0 at $DIR/enum_cast.rs:+0:21: +0:26
let _2: Far; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:8
let mut _3: i16; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:8
let mut _4: u16; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
let mut _5: bool; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:17

bb0: {
StorageLive(_2); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:8
_2 = move _1; // scope 0 at $DIR/enum_cast.rs:+1:5: +1:8
_3 = discriminant(_2); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_4 = _3 as u16 (IntToInt); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_5 = Le(_4, const 1_u16); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
assume(move _5); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
_0 = move _3 as isize (IntToInt); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:17
StorageDead(_2); // scope 0 at $DIR/enum_cast.rs:+1:16: +1:17
return; // scope 0 at $DIR/enum_cast.rs:+2:2: +2:2
}
}
26 changes: 26 additions & 0 deletions tests/mir-opt/building/enum_cast.offsetty.built.after.mir
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@@ -0,0 +1,26 @@
// MIR for `offsetty` after built

fn offsetty(_1: NotStartingAtZero) -> u32 {
debug x => _1; // in scope 0 at $DIR/enum_cast.rs:+0:13: +0:14
let mut _0: u32; // return place in scope 0 at $DIR/enum_cast.rs:+0:38: +0:41
let _2: NotStartingAtZero; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:6
let mut _3: isize; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:6
let mut _4: u8; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
let mut _5: bool; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
let mut _6: bool; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
let mut _7: bool; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:13

bb0: {
StorageLive(_2); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:6
_2 = move _1; // scope 0 at $DIR/enum_cast.rs:+1:5: +1:6
_3 = discriminant(_2); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
_4 = _3 as u8 (IntToInt); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
_5 = Ge(_4, const 4_u8); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
_6 = Le(_4, const 8_u8); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
_7 = BitAnd(move _5, move _6); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
assume(move _7); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
_0 = move _3 as u32 (IntToInt); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
StorageDead(_2); // scope 0 at $DIR/enum_cast.rs:+1:12: +1:13
return; // scope 0 at $DIR/enum_cast.rs:+2:2: +2:2
}
}
42 changes: 42 additions & 0 deletions tests/mir-opt/building/enum_cast.rs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
// EMIT_MIR enum_cast.foo.built.after.mir
// EMIT_MIR enum_cast.bar.built.after.mir
// EMIT_MIR enum_cast.boo.built.after.mir
// EMIT_MIR enum_cast.far.built.after.mir

enum Foo {
A
Expand All @@ -15,6 +16,11 @@ enum Boo {
A, B
}

#[repr(i16)]
enum Far {
A, B
}

fn foo(foo: Foo) -> usize {
foo as usize
}
Expand All @@ -27,6 +33,10 @@ fn boo(boo: Boo) -> usize {
boo as usize
}

fn far(far: Far) -> isize {
far as isize
}

// EMIT_MIR enum_cast.droppy.built.after.mir
enum Droppy {
A, B, C
Expand All @@ -46,5 +56,37 @@ fn droppy() {
let z = Droppy::B;
}

#[repr(i16)]
enum SignedAroundZero {
A = -2,
B = 0,
C = 2,
}

#[repr(u16)]
enum UnsignedAroundZero {
A = 65535,
B = 0,
C = 1,
}

// EMIT_MIR enum_cast.signy.built.after.mir
fn signy(x: SignedAroundZero) -> i16 {
x as i16
}

// EMIT_MIR enum_cast.unsigny.built.after.mir
fn unsigny(x: UnsignedAroundZero) -> u16 {
// FIXME: This doesn't get an around-the-end range today, sadly.
x as u16
}

enum NotStartingAtZero { A = 4, B = 6, C = 8 }

// EMIT_MIR enum_cast.offsetty.built.after.mir
fn offsetty(x: NotStartingAtZero) -> u32 {
x as u32
}

fn main() {
}
26 changes: 26 additions & 0 deletions tests/mir-opt/building/enum_cast.signy.built.after.mir
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@@ -0,0 +1,26 @@
// MIR for `signy` after built

fn signy(_1: SignedAroundZero) -> i16 {
debug x => _1; // in scope 0 at $DIR/enum_cast.rs:+0:10: +0:11
let mut _0: i16; // return place in scope 0 at $DIR/enum_cast.rs:+0:34: +0:37
let _2: SignedAroundZero; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:6
let mut _3: i16; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:6
let mut _4: u16; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
let mut _5: bool; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
let mut _6: bool; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
let mut _7: bool; // in scope 0 at $DIR/enum_cast.rs:+1:5: +1:13

bb0: {
StorageLive(_2); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:6
_2 = move _1; // scope 0 at $DIR/enum_cast.rs:+1:5: +1:6
_3 = discriminant(_2); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
_4 = _3 as u16 (IntToInt); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
_5 = Ge(_4, const 65534_u16); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
_6 = Le(_4, const 2_u16); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
_7 = BitOr(move _5, move _6); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
assume(move _7); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
_0 = move _3 as i16 (IntToInt); // scope 0 at $DIR/enum_cast.rs:+1:5: +1:13
StorageDead(_2); // scope 0 at $DIR/enum_cast.rs:+1:12: +1:13
return; // scope 0 at $DIR/enum_cast.rs:+2:2: +2:2
}
}
17 changes: 17 additions & 0 deletions tests/mir-opt/building/enum_cast.unsigny.built.after.mir
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@@ -0,0 +1,17 @@
// MIR for `unsigny` after built

fn unsigny(_1: UnsignedAroundZero) -> u16 {
debug x => _1; // in scope 0 at $DIR/enum_cast.rs:+0:12: +0:13
let mut _0: u16; // return place in scope 0 at $DIR/enum_cast.rs:+0:38: +0:41
let _2: UnsignedAroundZero; // in scope 0 at $DIR/enum_cast.rs:+2:5: +2:6
let mut _3: u16; // in scope 0 at $DIR/enum_cast.rs:+2:5: +2:6

bb0: {
StorageLive(_2); // scope 0 at $DIR/enum_cast.rs:+2:5: +2:6
_2 = move _1; // scope 0 at $DIR/enum_cast.rs:+2:5: +2:6
_3 = discriminant(_2); // scope 0 at $DIR/enum_cast.rs:+2:5: +2:13
_0 = move _3 as u16 (IntToInt); // scope 0 at $DIR/enum_cast.rs:+2:5: +2:13
StorageDead(_2); // scope 0 at $DIR/enum_cast.rs:+2:12: +2:13
return; // scope 0 at $DIR/enum_cast.rs:+3:2: +3:2
}
}