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AlignmentEnum should just be repr(usize) now #144667

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Merged
merged 1 commit into from
Aug 4, 2025
+22 −37
Merged

AlignmentEnum should just be repr(usize) now #144667

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8 changes: 5 additions & 3 deletions library/core/src/ptr/alignment.rs
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Original file line number Diff line number Diff line change
@@ -1,3 +1,5 @@
#![allow(clippy::enum_clike_unportable_variant)]

use crate::num::NonZero;
use crate::ub_checks::assert_unsafe_precondition;
use crate::{cmp, fmt, hash, mem, num};
Expand Down Expand Up @@ -241,7 +243,7 @@ impl const Default for Alignment {

#[cfg(target_pointer_width = "16")]
#[derive(Copy, Clone, PartialEq, Eq)]
#[repr(u16)]
#[repr(usize)]
enum AlignmentEnum {
_Align1Shl0 = 1 << 0,
_Align1Shl1 = 1 << 1,
Expand All @@ -263,7 +265,7 @@ enum AlignmentEnum {

#[cfg(target_pointer_width = "32")]
#[derive(Copy, Clone, PartialEq, Eq)]
#[repr(u32)]
#[repr(usize)]
enum AlignmentEnum {
_Align1Shl0 = 1 << 0,
_Align1Shl1 = 1 << 1,
Expand Down Expand Up @@ -301,7 +303,7 @@ enum AlignmentEnum {

#[cfg(target_pointer_width = "64")]
#[derive(Copy, Clone, PartialEq, Eq)]
#[repr(u64)]
#[repr(usize)]
enum AlignmentEnum {
_Align1Shl0 = 1 << 0,
_Align1Shl1 = 1 << 1,
Expand Down
12 changes: 4 additions & 8 deletions ...-opt/pre-codegen/drop_boxed_slice.generic_in_place.PreCodegen.after.32bit.panic-abort.mir
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ fn generic_in_place(_1: *mut Box<[T]>) -> () {
let _2: std::ptr::NonNull<[T]>;
let mut _3: *mut [T];
let mut _4: *const [T];
let _12: ();
let _11: ();
scope 3 {
let _8: std::ptr::alignment::AlignmentEnum;
scope 4 {
Expand All @@ -31,12 +31,11 @@ fn generic_in_place(_1: *mut Box<[T]>) -> () {
scope 20 (inlined NonNull::<u8>::as_ptr) {
}
scope 21 (inlined std::alloc::dealloc) {
let mut _11: usize;
let mut _10: usize;
scope 22 (inlined Layout::size) {
}
scope 23 (inlined Layout::align) {
scope 24 (inlined std::ptr::Alignment::as_usize) {
let mut _10: u32;
}
}
}
Expand Down Expand Up @@ -87,16 +86,13 @@ fn generic_in_place(_1: *mut Box<[T]>) -> () {
bb2: {
StorageLive(_9);
_9 = copy _3 as *mut u8 (PtrToPtr);
StorageLive(_11);
StorageLive(_10);
_10 = discriminant(_8);
_11 = move _10 as usize (IntToInt);
StorageDead(_10);
_12 = alloc::alloc::__rust_dealloc(move _9, move _5, move _11) -> [return: bb3, unwind unreachable];
_11 = alloc::alloc::__rust_dealloc(move _9, move _5, move _10) -> [return: bb3, unwind unreachable];
}

bb3: {
StorageDead(_11);
StorageDead(_10);
StorageDead(_9);
goto -> bb4;
}
Expand Down
12 changes: 4 additions & 8 deletions ...opt/pre-codegen/drop_boxed_slice.generic_in_place.PreCodegen.after.32bit.panic-unwind.mir
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ fn generic_in_place(_1: *mut Box<[T]>) -> () {
let _2: std::ptr::NonNull<[T]>;
let mut _3: *mut [T];
let mut _4: *const [T];
let _12: ();
let _11: ();
scope 3 {
let _8: std::ptr::alignment::AlignmentEnum;
scope 4 {
Expand All @@ -31,12 +31,11 @@ fn generic_in_place(_1: *mut Box<[T]>) -> () {
scope 20 (inlined NonNull::<u8>::as_ptr) {
}
scope 21 (inlined std::alloc::dealloc) {
let mut _11: usize;
let mut _10: usize;
scope 22 (inlined Layout::size) {
}
scope 23 (inlined Layout::align) {
scope 24 (inlined std::ptr::Alignment::as_usize) {
let mut _10: u32;
}
}
}
Expand Down Expand Up @@ -87,16 +86,13 @@ fn generic_in_place(_1: *mut Box<[T]>) -> () {
bb2: {
StorageLive(_9);
_9 = copy _3 as *mut u8 (PtrToPtr);
StorageLive(_11);
StorageLive(_10);
_10 = discriminant(_8);
_11 = move _10 as usize (IntToInt);
StorageDead(_10);
_12 = alloc::alloc::__rust_dealloc(move _9, move _5, move _11) -> [return: bb3, unwind unreachable];
_11 = alloc::alloc::__rust_dealloc(move _9, move _5, move _10) -> [return: bb3, unwind unreachable];
}

bb3: {
StorageDead(_11);
StorageDead(_10);
StorageDead(_9);
goto -> bb4;
}
Expand Down
12 changes: 4 additions & 8 deletions ...-opt/pre-codegen/drop_boxed_slice.generic_in_place.PreCodegen.after.64bit.panic-abort.mir
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ fn generic_in_place(_1: *mut Box<[T]>) -> () {
let _2: std::ptr::NonNull<[T]>;
let mut _3: *mut [T];
let mut _4: *const [T];
let _12: ();
let _11: ();
scope 3 {
let _8: std::ptr::alignment::AlignmentEnum;
scope 4 {
Expand All @@ -31,12 +31,11 @@ fn generic_in_place(_1: *mut Box<[T]>) -> () {
scope 20 (inlined NonNull::<u8>::as_ptr) {
}
scope 21 (inlined std::alloc::dealloc) {
let mut _11: usize;
let mut _10: usize;
scope 22 (inlined Layout::size) {
}
scope 23 (inlined Layout::align) {
scope 24 (inlined std::ptr::Alignment::as_usize) {
let mut _10: u64;
}
}
}
Expand Down Expand Up @@ -87,16 +86,13 @@ fn generic_in_place(_1: *mut Box<[T]>) -> () {
bb2: {
StorageLive(_9);
_9 = copy _3 as *mut u8 (PtrToPtr);
StorageLive(_11);
StorageLive(_10);
_10 = discriminant(_8);
_11 = move _10 as usize (IntToInt);
StorageDead(_10);
_12 = alloc::alloc::__rust_dealloc(move _9, move _5, move _11) -> [return: bb3, unwind unreachable];
_11 = alloc::alloc::__rust_dealloc(move _9, move _5, move _10) -> [return: bb3, unwind unreachable];
}

bb3: {
StorageDead(_11);
StorageDead(_10);
StorageDead(_9);
goto -> bb4;
}
Expand Down
12 changes: 4 additions & 8 deletions ...opt/pre-codegen/drop_boxed_slice.generic_in_place.PreCodegen.after.64bit.panic-unwind.mir
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ fn generic_in_place(_1: *mut Box<[T]>) -> () {
let _2: std::ptr::NonNull<[T]>;
let mut _3: *mut [T];
let mut _4: *const [T];
let _12: ();
let _11: ();
scope 3 {
let _8: std::ptr::alignment::AlignmentEnum;
scope 4 {
Expand All @@ -31,12 +31,11 @@ fn generic_in_place(_1: *mut Box<[T]>) -> () {
scope 20 (inlined NonNull::<u8>::as_ptr) {
}
scope 21 (inlined std::alloc::dealloc) {
let mut _11: usize;
let mut _10: usize;
scope 22 (inlined Layout::size) {
}
scope 23 (inlined Layout::align) {
scope 24 (inlined std::ptr::Alignment::as_usize) {
let mut _10: u64;
}
}
}
Expand Down Expand Up @@ -87,16 +86,13 @@ fn generic_in_place(_1: *mut Box<[T]>) -> () {
bb2: {
StorageLive(_9);
_9 = copy _3 as *mut u8 (PtrToPtr);
StorageLive(_11);
StorageLive(_10);
_10 = discriminant(_8);
_11 = move _10 as usize (IntToInt);
StorageDead(_10);
_12 = alloc::alloc::__rust_dealloc(move _9, move _5, move _11) -> [return: bb3, unwind unreachable];
_11 = alloc::alloc::__rust_dealloc(move _9, move _5, move _10) -> [return: bb3, unwind unreachable];
Comment on lines 90 to +91
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This way the discriminant just gives usize, rather than u64, so the no-op cast (and extra local) isn't needed any more.

}

bb3: {
StorageDead(_11);
StorageDead(_10);
StorageDead(_9);
goto -> bb4;
}
Expand Down
3 changes: 1 addition & 2 deletions tests/mir-opt/pre-codegen/drop_boxed_slice.rs
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Expand Up @@ -13,7 +13,6 @@ pub unsafe fn generic_in_place<T: Copy>(ptr: *mut Box<[T]>) {
// CHECK: [[B:_.+]] = copy [[ALIGN]] as std::ptr::Alignment (Transmute);
// CHECK: [[C:_.+]] = move ([[B]].0: std::ptr::alignment::AlignmentEnum);
// CHECK: [[D:_.+]] = discriminant([[C]]);
// CHECK: [[E:_.+]] = move [[D]] as usize (IntToInt);
// CHECK: = alloc::alloc::__rust_dealloc({{.+}}, move [[SIZE]], move [[E]]) ->
// CHECK: = alloc::alloc::__rust_dealloc({{.+}}, move [[SIZE]], move [[D]]) ->
std::ptr::drop_in_place(ptr)
}
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