Fix alignment for array indexing

We need to reduce the alignment with the used offset. If the offset
isn't known, we need to reduce with the element size to support
arbitrary offsets.

2 files changed, 80 insertions, 0 deletions

diff --git a/src/test/codegen/issue-56927.rs b/src/test/codegen/issue-56927.rs
new file mode 100644
index 00000000000..0544ff86aac
--- /dev/null
+++ b/src/test/codegen/issue-56927.rs
@@ -0,0 +1,44 @@
+// compile-flags: -C no-prepopulate-passes
+
+#![crate_type="rlib"]
+use std::usize;
+
+#[repr(align(16))]
+pub struct S {
+    arr: [u32; 4],
+}
+
+// CHECK-LABEL: @test1
+// CHECK: store i32 0, i32* %{{.+}}, align 16
+// CHECK: store i32 1, i32* %{{.+}}, align 4
+// CHECK: store i32 2, i32* %{{.+}}, align 8
+// CHECK: store i32 3, i32* %{{.+}}, align 4
+#[no_mangle]
+pub fn test1(s: &mut S) {
+    s.arr[0] = 0;
+    s.arr[1] = 1;
+    s.arr[2] = 2;
+    s.arr[3] = 3;
+}
+
+// CHECK-LABEL: @test2
+// CHECK: store i32 4, i32* %{{.+}}, align 4
+#[allow(const_err)]
+#[no_mangle]
+pub fn test2(s: &mut S) {
+    s.arr[usize::MAX / 4 + 1] = 4;
+}
+
+// CHECK-LABEL: @test3
+// CHECK: store i32 5, i32* %{{.+}}, align 4
+#[no_mangle]
+pub fn test3(s: &mut S, i: usize) {
+    s.arr[i] = 5;
+}
+
+// CHECK-LABEL: @test4
+// CHECK: store i32 6, i32* %{{.+}}, align 4
+#[no_mangle]
+pub fn test4(s: &mut S) {
+    s.arr = [6; 4];
+}
diff --git a/src/test/codegen/packed.rs b/src/test/codegen/packed.rs
index b50f5b6f16f..e60051de559 100644
--- a/src/test/codegen/packed.rs
+++ b/src/test/codegen/packed.rs
@@ -84,6 +84,42 @@ pub fn call_pkd2(f: fn() -> Array) -> BigPacked2 {
     BigPacked2 { dealign: 0, data: f() }
 }
 
+// CHECK-LABEL: @write_packed_array1
+// CHECK: store i32 0, i32* %{{.+}}, align 1
+// CHECK: store i32 1, i32* %{{.+}}, align 1
+// CHECK: store i32 2, i32* %{{.+}}, align 1
+#[no_mangle]
+pub fn write_packed_array1(p: &mut BigPacked1) {
+    p.data.0[0] = 0;
+    p.data.0[1] = 1;
+    p.data.0[2] = 2;
+}
+
+// CHECK-LABEL: @write_packed_array2
+// CHECK: store i32 0, i32* %{{.+}}, align 2
+// CHECK: store i32 1, i32* %{{.+}}, align 2
+// CHECK: store i32 2, i32* %{{.+}}, align 2
+#[no_mangle]
+pub fn write_packed_array2(p: &mut BigPacked2) {
+    p.data.0[0] = 0;
+    p.data.0[1] = 1;
+    p.data.0[2] = 2;
+}
+
+// CHECK-LABEL: @repeat_packed_array1
+// CHECK: store i32 42, i32* %{{.+}}, align 1
+#[no_mangle]
+pub fn repeat_packed_array1(p: &mut BigPacked1) {
+    p.data.0 = [42; 8];
+}
+
+// CHECK-LABEL: @repeat_packed_array2
+// CHECK: store i32 42, i32* %{{.+}}, align 2
+#[no_mangle]
+pub fn repeat_packed_array2(p: &mut BigPacked2) {
+    p.data.0 = [42; 8];
+}
+
 #[repr(packed)]
 #[derive(Copy, Clone)]
 pub struct Packed1Pair(u8, u32);