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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:18:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:18:58 +0000 |
commit | a4b7ed7a42c716ab9f05e351f003d589124fd55d (patch) | |
tree | b620cd3f223850b28716e474e80c58059dca5dd4 /tests/codegen/iter-repeat-n-trivial-drop.rs | |
parent | Adding upstream version 1.67.1+dfsg1. (diff) | |
download | rustc-a4b7ed7a42c716ab9f05e351f003d589124fd55d.tar.xz rustc-a4b7ed7a42c716ab9f05e351f003d589124fd55d.zip |
Adding upstream version 1.68.2+dfsg1.upstream/1.68.2+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tests/codegen/iter-repeat-n-trivial-drop.rs')
-rw-r--r-- | tests/codegen/iter-repeat-n-trivial-drop.rs | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/tests/codegen/iter-repeat-n-trivial-drop.rs b/tests/codegen/iter-repeat-n-trivial-drop.rs new file mode 100644 index 000000000..24059f190 --- /dev/null +++ b/tests/codegen/iter-repeat-n-trivial-drop.rs @@ -0,0 +1,56 @@ +// compile-flags: -O +// only-x86_64 +// ignore-debug: the debug assertions get in the way + +#![crate_type = "lib"] +#![feature(iter_repeat_n)] + +#[derive(Clone)] +pub struct NotCopy(u16); + +impl Drop for NotCopy { + fn drop(&mut self) {} +} + +// For a type where `Drop::drop` doesn't do anything observable and a clone is the +// same as a move, make sure that the extra case for the last item disappears. + +#[no_mangle] +// CHECK-LABEL: @iter_repeat_n_next +pub fn iter_repeat_n_next(it: &mut std::iter::RepeatN<NotCopy>) -> Option<NotCopy> { + // CHECK-NEXT: start: + // CHECK-NOT: br + // CHECK: %[[COUNT:.+]] = load i64 + // CHECK-NEXT: %[[COUNT_ZERO:.+]] = icmp eq i64 %[[COUNT]], 0 + // CHECK-NEXT: br i1 %[[COUNT_ZERO]], label %[[EMPTY:.+]], label %[[NOT_EMPTY:.+]] + + // CHECK: [[NOT_EMPTY]]: + // CHECK-NEXT: %[[DEC:.+]] = add i64 %[[COUNT]], -1 + // CHECK-NEXT: store i64 %[[DEC]] + // CHECK-NOT: br + // CHECK: %[[VAL:.+]] = load i16 + // CHECK-NEXT: br label %[[EMPTY]] + + // CHECK: [[EMPTY]]: + // CHECK-NOT: br + // CHECK: phi i16 [ undef, %start ], [ %[[VAL]], %[[NOT_EMPTY]] ] + // CHECK-NOT: br + // CHECK: ret + + it.next() +} + +// And as a result, using the iterator can optimize without special cases for +// the last iteration, like `memset`ing all the items in one call. + +#[no_mangle] +// CHECK-LABEL: @vec_extend_via_iter_repeat_n +pub fn vec_extend_via_iter_repeat_n() -> Vec<u8> { + // CHECK: %[[ADDR:.+]] = tail call noundef dereferenceable_or_null(1234) ptr @__rust_alloc(i64 noundef 1234, i64 noundef 1) + // CHECK: tail call void @llvm.memset.p0.i64(ptr noundef nonnull align 1 dereferenceable(1234) %[[ADDR]], i8 42, i64 1234, + + let n = 1234_usize; + let mut v = Vec::with_capacity(n); + v.extend(std::iter::repeat_n(42_u8, n)); + v +} |