Unsafe precondition violated in the x86_64 SIMD implementation of str.contains #104726
Description
PR #103779 added a x86_64 SIMD-based implementation of str.contains(&needle) to optimize searching into strings when the needle is at most 32 bytes long. Unfortunately, that implementation doesn't seem to be sound.
When compiling the standard library with debug assertions on, running UI tests excluding src/test/ui/process/no-stdio.rs results in compiletest itself panicking before executing any test due to a debug_assert in libcore:
thread 'main' panicked at 'unsafe precondition(s) violated: slice::get_unchecked requires that the range is within the slice', library/core/src/panicking.rs:89:58
stack backtrace:
0: rust_begin_unwind
at .../library/std/src/panicking.rs:575:5
1: core::panicking::panic_str_nounwind
at .../library/core/src/panicking.rs:92:14
2: <core::ops::range::Range<usize> as core::slice::index::SliceIndex<[T]>>::get_unchecked::runtime
3: core::str::pattern::simd_contains::{{closure}}
at .../library/core/src/str/pattern.rs:1787:27
4: core::str::pattern::simd_contains
at .../library/core/src/str/pattern.rs:1846:19
5: <&str as core::str::pattern::Pattern>::is_contained_in
at .../library/core/src/str/pattern.rs:965:43
6: core::str::<impl str>::contains
at .../library/core/src/str/mod.rs:1057:9
7: test::filter_tests::{{closure}}
at .../library/test/src/lib.rs:464:22
8: test::filter_tests::{{closure}}::{{closure}}
at .../library/test/src/lib.rs:475:59
9: <core::slice::iter::Iter<T> as core::iter::traits::iterator::Iterator>::any
at .../library/core/src/slice/iter/macros.rs:242:24
10: test::filter_tests::{{closure}}
at .../library/test/src/lib.rs:475:33
11: alloc::vec::Vec<T,A>::retain::{{closure}}
at .../library/alloc/src/vec/mod.rs:1561:32
12: alloc::vec::Vec<T,A>::retain_mut::process_loop
at .../library/alloc/src/vec/mod.rs:1641:21
13: alloc::vec::Vec<T,A>::retain_mut
at .../library/alloc/src/vec/mod.rs:1670:9
14: alloc::vec::Vec<T,A>::retain
at .../library/alloc/src/vec/mod.rs:1561:9
15: test::filter_tests
at .../library/test/src/lib.rs:475:9
16: test::run_tests
at .../library/test/src/lib.rs:297:17
17: test::console::run_tests_console
at /rustc/47395e0061d50df550cbd8b46dd46c132ea0c95a/library/test/src/console.rs:293:5
18: compiletest::run_tests
at /rustc/47395e0061d50df550cbd8b46dd46c132ea0c95a/src/tools/compiletest/src/main.rs:406:15
19: compiletest::main
at /rustc/47395e0061d50df550cbd8b46dd46c132ea0c95a/src/tools/compiletest/src/main.rs:57:5
20: <fn() as core::ops::function::FnOnce<()>>::call_once
at /rustc/47395e0061d50df550cbd8b46dd46c132ea0c95a/library/core/src/ops/function.rs:422:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread panicked while panicking. aborting.
To reproduce the issue, use the following configuration file:
profile = "compiler"
changelog-seen = 2
[rust]
debug-assertions-std = true...and run:
./x test --stage 1 src/test/ui --exclude src/test/ui/process/no-stdio.rs