gnzlbg gnzlbg

Feature Name: compatible_trait
Start Date: YYYY-MM-DD
RFC PR: rust-lang/rfcs#0000
Rust Issue: rust-lang/rust#0000

Summary

This proposal introduces two traits, Compatible and TryCompatible, which allows specifying safe mem::transmute relationships and performing them in an

Add the following intrinsics to core::arch::x86_64:

/// (Module documentation)
///
/// Semantics of volatile memory operations: volatile memory operations (reads and writes)
/// must be emitted by the compiler and cannot be re-ordered across other volatile operations.
/// 
/// The result of a volatile read is frozen (`freeze` is applied to it). That is,
/// reading uninitialized memory via a volatile read never returns uninitialized memory.

	Row;A;B;C
	R1;1;0;0
	R2;0;1;0
	R3;0;0;1

	;; Emacs: 28.0.50 Tramp: 2.5.0-pre -- mode: outline; --
	;; Location: /usr/local/Cellar/emacs-plus/HEAD-962562c/share/emacs/28.0.50/lisp/net/tramp.elc Git: /
	15:52:26.791947 tramp-get-file-property (8) # file-attributes-string nil
	15:52:26.793260 tramp-get-connection-property (7) # stat undef
	15:52:26.793416 tramp-get-connection-property (7) # uname
	15:52:26.793534 tramp-get-remote-stat (5) # Finding a suitable ‘stat’ command
	15:52:26.793645 tramp-get-connection-property (7) # process-buffer nil
	15:52:26.793800 tramp-get-connection-property (7) # process-buffer nil
	15:52:26.793927 tramp-set-connection-property (7) # process-buffer nil
	15:52:26.794058 tramp-get-connection-property (7) # process-buffer nil

	nvme0n1
	nvme0n1p1 vfat FAT32 ...
	nvme0n1p2 crypto_LUKS 1 451331e2-e9a1-42d8-aff8-6dff4fd1944b
	cryptroot btrfs root fef6185f-0281-4006-80c6-bf85efe0b63d

	Consider this code:

	struct foo {};
	int id_foo(struct foo bar, int x) {
	return x;
	}
	int id(int x) {
	return x;
	}

	// WARNING: This output format is intended for human consumers only
	// and is subject to change without notice. Knock yourself out.
	fn S(_1: [f32; _]) -> S<N> {
	let mut _0: S<N>; // return place in scope 0 at /Users/gnzlbg/projects/sideprojects/rust/src/test/ui/simd/simd-generics.rs:9:1: 9:36

	bb0: {
	(_0.0: [f32; _]) = move _1; // bb0[0]: scope 0 at /Users/gnzlbg/projects/sideprojects/rust/src/test/ui/simd/simd-generics.rs:9:1: 9:36
	return; // bb0[1]: scope 0 at /Users/gnzlbg/projects/sideprojects/rust/src/test/ui/simd/simd-generics.rs:9:1: 9:36
	}
	}

	name old ns/iter new ns/iter diff ns/iter diff % speedup
	acos 3 2 -1 -33.33% x 1.50
	acosf 2 3 1 50.00% x 0.67
	acosh 114 132 18 15.79% x 0.86
	acoshf 48 52 4 8.33% x 0.92
	asin 2 4 2 100.00% x 0.50
	asinf 2 3 1 50.00% x 0.67
	atan 13 15 2 15.38% x 0.87
	atan2 23 22 -1 -4.35% x 1.05
	atan2f 11 15 4 36.36% x 0.73

	[error]: Function "erf" not `extern "C"`
	[error]: Function "erfc" not `extern "C"`
	[error]: Function "floor" not `extern "C"`
	[error]: Function "exp2f" not `extern "C"`
	[error]: Function "fmaxf" not `extern "C"`
	[error]: Function "fdimf" not `extern "C"`
	[error]: Function "fmodf" not `extern "C"`
	[error]: Function "ldexp" not `extern "C"`
	[error]: Function "modf" not `extern "C"`
	[error]: Function "modf" missing `#[inline]` and `#[no_panic]` attributes

	name old ns/iter new ns/iter diff ns/iter diff % speedup
	misc::anchored_literal_long_match 32 (12187 MB/s) 29 (13448 MB/s) -3 -9.38% x 1.10
	misc::anchored_literal_long_non_match 35 (11142 MB/s) 35 (11142 MB/s) 0 0.00% x 1.00
	misc::anchored_literal_short_match 32 (812 MB/s) 29 (896 MB/s) -3 -9.38% x 1.10
	misc::anchored_literal_short_non_match 32 (812 MB/s) 35 (742 MB/s) 3 9.38% x 0.91
	misc::easy0_1K 40 (26275 MB/s) 39 (26948 MB/s) -1 -2.50% x 1.03
	misc::easy0_1MB 62 (16912951 MB/s) 66 (15887924 MB/s) 4 6.45% x 0.94
	misc::easy0_32 40 (1475 MB/s) 43 (1372 MB/s) 3 7.50% x 0.93
	misc::easy0_32K 40 (819875 MB/s)