Auto merge of #122256 - Nadrieril:rollup-rc232xh, r=Nadrieril

Rollup of 8 pull requests

Successful merges:

 - #99153 (Add Read Impl for &Stdin)
 - #114655 (Make `impl<Fd: AsFd>` impl take `?Sized`)
 - #120504 (Vec::try_with_capacity)
 - #121280 (Implement MaybeUninit::fill{,_with,_from})
 - #121403 (impl From<TryReserveError> for io::Error)
 - #121526 (on the fly type casting for `build.rustc` and `build.cargo`)
 - #121584 (bump itertools to 0.12)
 - #121711 (Implement junction_point)

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 35 insertions, 0 deletions

diff --git a/tests/codegen/vec-with-capacity.rs b/tests/codegen/vec-with-capacity.rs
new file mode 100644
index 00000000000..47051f2eef8
--- /dev/null
+++ b/tests/codegen/vec-with-capacity.rs
@@ -0,0 +1,35 @@
+//@ compile-flags: -O
+//@ ignore-debug
+// (with debug assertions turned on, `assert_unchecked` generates a real assertion)
+
+#![crate_type = "lib"]
+#![feature(try_with_capacity)]
+
+// CHECK-LABEL: @with_capacity_does_not_grow1
+#[no_mangle]
+pub fn with_capacity_does_not_grow1() -> Vec<u32> {
+    let v = Vec::with_capacity(1234);
+    // CHECK: call {{.*}}__rust_alloc(
+    // CHECK-NOT: call {{.*}}__rust_realloc
+    // CHECK-NOT: call {{.*}}capacity_overflow
+    // CHECK-NOT: call {{.*}}finish_grow
+    // CHECK-NOT: call {{.*}}reserve
+    // CHECK-NOT: memcpy
+    // CHECK-NOT: memset
+    v
+}
+
+// CHECK-LABEL: @try_with_capacity_does_not_grow2
+#[no_mangle]
+pub fn try_with_capacity_does_not_grow2() -> Option<Vec<Vec<u8>>> {
+    let v = Vec::try_with_capacity(1234).ok()?;
+    // CHECK: call {{.*}}__rust_alloc(
+    // CHECK-NOT: call {{.*}}__rust_realloc
+    // CHECK-NOT: call {{.*}}capacity_overflow
+    // CHECK-NOT: call {{.*}}finish_grow
+    // CHECK-NOT: call {{.*}}handle_alloc_error
+    // CHECK-NOT: call {{.*}}reserve
+    // CHECK-NOT: memcpy
+    // CHECK-NOT: memset
+    Some(v)
+}