Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 35 insertions, 0 deletions

diff --git a/src/test/codegen/mem-replace-direct-memcpy.rs b/src/test/codegen/mem-replace-direct-memcpy.rs
new file mode 100644
index 000000000..8095d309f
--- /dev/null
+++ b/src/test/codegen/mem-replace-direct-memcpy.rs
@@ -0,0 +1,35 @@
+// ignore-test
+
+// WHY IS THIS TEST BEING IGNORED:
+//
+// This test depends on characteristics of how the stdlib was compiled,
+// namely that sufficient inlining occurred to ensure that the call to
+// `std::mem::replace` boils down to just two calls of `llvm.memcpy`.
+//
+// But the MIR inlining policy is in flux as of 1.64-beta, and the intermittent
+// breakage of this test that results is causing problems for people trying to
+// do development.
+
+// This test ensures that `mem::replace::<T>` only ever calls `@llvm.memcpy`
+// with `size_of::<T>()` as the size, and never goes through any wrapper that
+// may e.g. multiply `size_of::<T>()` with a variable "count" (which is only
+// known to be `1` after inlining).
+
+// compile-flags: -C no-prepopulate-passes -Zinline-mir=no
+
+#![crate_type = "lib"]
+
+pub fn replace_byte(dst: &mut u8, src: u8) -> u8 {
+    std::mem::replace(dst, src)
+}
+
+// NOTE(eddyb) the `CHECK-NOT`s ensure that the only calls of `@llvm.memcpy` in
+// the entire output, are the two direct calls we want, from `ptr::replace`.
+
+// CHECK-NOT: call void @llvm.memcpy
+// CHECK: ; core::mem::replace
+// CHECK-NOT: call void @llvm.memcpy
+// CHECK: call void @llvm.memcpy.{{.+}}({{i8\*|ptr}} align 1 %{{.*}}, {{i8\*|ptr}} align 1 %dest, i{{.*}} 1, i1 false)
+// CHECK-NOT: call void @llvm.memcpy
+// CHECK: call void @llvm.memcpy.{{.+}}({{i8\*|ptr}} align 1 %dest, {{i8\*|ptr}} align 1 %src{{.*}}, i{{.*}} 1, i1 false)
+// CHECK-NOT: call void @llvm.memcpy