| // 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 |
| // ignore-debug: the debug assertions get in the way |
| |
| #![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 direct calls we want, from `ptr::replace`. |
| |
| // CHECK-NOT: call void @llvm.memcpy |
| |
| // For a small type, we expect one each of `load`/`store`/`memcpy` instead |
| // CHECK-LABEL: define internal noundef i8 @{{.+}}mem{{.+}}replace |
| // CHECK-NOT: alloca |
| // CHECK: alloca i8 |
| // CHECK-NOT: alloca |
| // CHECK-NOT: call void @llvm.memcpy |
| // CHECK: load i8 |
| // CHECK-NOT: call void @llvm.memcpy |
| // CHECK: store i8 |
| // CHECK-NOT: call void @llvm.memcpy |
| // CHECK: call void @llvm.memcpy.{{.+}}({{i8\*|ptr}} align 1 %{{.*}}, {{i8\*|ptr}} align 1 %{{.*}}, i{{.*}} 1, i1 false) |
| // CHECK-NOT: call void @llvm.memcpy |
| |
| // CHECK-NOT: call void @llvm.memcpy |
