rust/tests/codegen/align-struct.rs
Nikita Popov c2fd26a115 Separate immediate and in-memory ScalarPair representation
Currently, we assume that ScalarPair is always represented using
a two-element struct, both as an immediate value and when stored
in memory.

This currently works fairly well, but runs into problems with
https://github.com/rust-lang/rust/pull/116672, where a ScalarPair
involving an i128 type can no longer be represented as a two-element
struct in memory. For example, the tuple `(i32, i128)` needs to be
represented in-memory as `{ i32, [3 x i32], i128 }` to satisfy
alignment requirement. Using `{ i32, i128 }` instead will result in
the second element being stored at the wrong offset (prior to
LLVM 18).

Resolve this issue by no longer requiring that the immediate and
in-memory type for ScalarPair are the same. The in-memory type
will now look the same as for normal struct types (and will include
padding filler and similar), while the immediate type stays a
simple two-element struct type. This also means that booleans in
immediate ScalarPair are now represented as i1 rather than i8,
just like we do everywhere else.

The core change here is to llvm_type (which now treats ScalarPair
as a normal struct) and immediate_llvm_type (which returns the
two-element struct that llvm_type used to produce). The rest is
fixing things up to no longer assume these are the same. In
particular, this switches places that try to get pointers to the
ScalarPair elements to use byte-geps instead of struct-geps.
2023-12-15 17:42:05 +01:00

72 lines
1.5 KiB
Rust

// compile-flags: -C no-prepopulate-passes -Z mir-opt-level=0
//
#![crate_type = "lib"]
#[repr(align(64))]
pub struct Align64(i32);
// CHECK: %Align64 = type { i32, [15 x i32] }
pub struct Nested64 {
a: Align64,
b: i32,
c: i32,
d: i8,
}
// CHECK: %Nested64 = type { %Align64, i32, i32, i8, [55 x i8] }
pub enum Enum4 {
A(i32),
B(i32),
}
// No Aggregate type, and hence nothing in LLVM IR.
pub enum Enum64 {
A(Align64),
B(i32),
}
// CHECK: %Enum64 = type { i32, [31 x i32] }
// CHECK: %"Enum64::A" = type { [8 x i64], %Align64 }
// CHECK-LABEL: @align64
#[no_mangle]
pub fn align64(i : i32) -> Align64 {
// CHECK: %a64 = alloca %Align64, align 64
// CHECK: call void @llvm.memcpy.{{.*}}(ptr align 64 %{{.*}}, ptr align 64 %{{.*}}, i{{[0-9]+}} 64, i1 false)
let a64 = Align64(i);
a64
}
// For issue 54028: make sure that we are specifying the correct alignment for fields of aligned
// structs
// CHECK-LABEL: @align64_load
#[no_mangle]
pub fn align64_load(a: Align64) -> i32 {
// CHECK: {{%.*}} = load i32, ptr {{%.*}}, align 64
a.0
}
// CHECK-LABEL: @nested64
#[no_mangle]
pub fn nested64(a: Align64, b: i32, c: i32, d: i8) -> Nested64 {
// CHECK: %n64 = alloca %Nested64, align 64
let n64 = Nested64 { a, b, c, d };
n64
}
// CHECK-LABEL: @enum4
#[no_mangle]
pub fn enum4(a: i32) -> Enum4 {
// CHECK: %e4 = alloca %Enum4, align 4
let e4 = Enum4::A(a);
e4
}
// CHECK-LABEL: @enum64
#[no_mangle]
pub fn enum64(a: Align64) -> Enum64 {
// CHECK: %e64 = alloca %Enum64, align 64
let e64 = Enum64::A(a);
e64
}