Delete some useless casts from global_allocator expansion

[dtolnay]

These casts are from when #[global_allocator] needed to translate back and forth between *mut u8 and *mut Opaque. This should have been cleaned up as part of f6ab74b.

Difference to code generated by #[global_allocator] static ALLOCATOR: Allocator = Allocator;:

 const _: () = {
     #[rustc_std_internal_symbol]
     unsafe fn __rust_alloc(arg0: usize, arg1: usize) -> *mut u8 {
         ::core::alloc::GlobalAlloc::alloc(
             &ALLOCATOR,
             ::core::alloc::Layout::from_size_align_unchecked(arg0, arg1),
-        ) as *mut u8
+        )
     }
     #[rustc_std_internal_symbol]
     unsafe fn __rust_dealloc(arg0: *mut u8, arg1: usize, arg2: usize) -> () {
         ::core::alloc::GlobalAlloc::dealloc(
             &ALLOCATOR,
-            arg0 as *mut u8,
+            arg0,
             ::core::alloc::Layout::from_size_align_unchecked(arg1, arg2),
         )
     }
     #[rustc_std_internal_symbol]
     unsafe fn __rust_realloc(
         arg0: *mut u8,
         arg1: usize,
         arg2: usize,
         arg3: usize,
     ) -> *mut u8 {
         ::core::alloc::GlobalAlloc::realloc(
             &ALLOCATOR,
-            arg0 as *mut u8,
+            arg0,
             ::core::alloc::Layout::from_size_align_unchecked(arg1, arg2),
             arg3,
-        ) as *mut u8
+        )
     }
     #[rustc_std_internal_symbol]
     unsafe fn __rust_alloc_zeroed(arg0: usize, arg1: usize) -> *mut u8 {
         ::core::alloc::GlobalAlloc::alloc_zeroed(
             &ALLOCATOR,
             ::core::alloc::Layout::from_size_align_unchecked(arg0, arg1),
-        ) as *mut u8
+        )
     }
 };

[rustbot]

r? @cjgillot

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[cjgillot]

@bors r+

[bors]

📌 Commit e57a891 has been approved by cjgillot

It is now in the queue for this repository.

[bors]

⌛ Testing commit e57a891 with merge a339ed1...

[bors]

☀️ Test successful - checks-actions
Approved by: cjgillot
Pushing a339ed1 to master...

[rust-timer]

Finished benchmarking commit (a339ed1): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-3.8%	[-3.8%, -3.8%]	1
Improvements ✅ (secondary)	-2.6%	[-3.1%, -2.1%]	2
All ❌✅ (primary)	-3.8%	[-3.8%, -3.8%]	1

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	4.5%	[3.9%, 5.2%]	6
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	4.5%	[3.9%, 5.2%]	6

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 649.941s -> 651.351s (0.22%)