diff --git a/src/test/auxiliary/rust_test_helpers.c b/src/test/auxiliary/rust_test_helpers.c
index b95b0ca1a89..22bb5498836 100644
--- a/src/test/auxiliary/rust_test_helpers.c
+++ b/src/test/auxiliary/rust_test_helpers.c
@@ -168,6 +168,18 @@ struct floats {
     double c;
 };
 
+struct char_char_double {
+    uint8_t a;
+    uint8_t b;
+    double c;
+};
+
+struct char_char_float {
+    uint8_t a;
+    uint8_t b;
+    float c;
+};
+
 struct quad
 rust_dbg_abi_1(struct quad q) {
     struct quad qq = { q.c + 1,
@@ -185,6 +197,23 @@ rust_dbg_abi_2(struct floats f) {
     return ff;
 }
 
+struct char_char_double
+rust_dbg_abi_3(struct char_char_double a) {
+    struct char_char_double ccd = { a.a + 1,
+                                    a.b - 1,
+                                    a.c + 1.0 };
+    return ccd;
+}
+
+struct char_char_float
+rust_dbg_abi_4(struct char_char_float a) {
+    struct char_char_float ccd = { a.a + 1,
+                                   a.b - 1,
+                                   a.c + 1.0 };
+    return ccd;
+}
+
+
 int
 rust_dbg_static_mut = 3;
 
diff --git a/src/test/codegen/riscv-abi/riscv64-lp64-lp64f-lp64d-abi.rs b/src/test/codegen/riscv-abi/riscv64-lp64-lp64f-lp64d-abi.rs
new file mode 100644
index 00000000000..f0f052fe5c5
--- /dev/null
+++ b/src/test/codegen/riscv-abi/riscv64-lp64-lp64f-lp64d-abi.rs
@@ -0,0 +1,181 @@
+// ignore-tidy-linelength
+// compile-flags: -C no-prepopulate-passes
+// only-riscv64
+// only-linux
+#![crate_type = "lib"]
+#![allow(improper_ctypes)]
+
+// CHECK: define void @f_void()
+#[no_mangle]
+pub extern "C" fn f_void() {}
+
+// CHECK: define zeroext i1 @f_scalar_0(i1 zeroext %a)
+#[no_mangle]
+pub extern "C" fn f_scalar_0(a: bool) -> bool {
+    a
+}
+
+// CHECK: define signext i8 @f_scalar_1(i8 signext %x)
+#[no_mangle]
+pub extern "C" fn f_scalar_1(x: i8) -> i8 {
+    x
+}
+
+// CHECK: define zeroext i8 @f_scalar_2(i8 zeroext %x)
+#[no_mangle]
+pub extern "C" fn f_scalar_2(x: u8) -> u8 {
+    x
+}
+
+// CHECK: define signext i32 @f_scalar_3(i32 signext %x)
+#[no_mangle]
+pub extern "C" fn f_scalar_3(x: i32) -> u32 {
+    x as u32
+}
+
+// CHECK: define i64 @f_scalar_4(i64 %x)
+#[no_mangle]
+pub extern "C" fn f_scalar_4(x: i64) -> i64 {
+    x
+}
+
+// CHECK: define float @f_fp_scalar_1(float)
+#[no_mangle]
+pub extern "C" fn f_fp_scalar_1(x: f32) -> f32 {
+    x
+}
+// CHECK: define double @f_fp_scalar_2(double)
+#[no_mangle]
+pub extern "C" fn f_fp_scalar_2(x: f64) -> f64 {
+    x
+}
+
+#[repr(C)]
+pub struct Empty {}
+
+// CHECK: define void @f_agg_empty_struct()
+#[no_mangle]
+pub extern "C" fn f_agg_empty_struct(e: Empty) -> Empty {
+    e
+}
+
+#[repr(C)]
+pub struct Tiny {
+    a: u16,
+    b: u16,
+    c: u16,
+    d: u16,
+}
+
+// CHECK: define void @f_agg_tiny(i64)
+#[no_mangle]
+pub extern "C" fn f_agg_tiny(mut e: Tiny) {
+    e.a += e.b;
+    e.c += e.d;
+}
+
+// CHECK: define i64 @f_agg_tiny_ret()
+#[no_mangle]
+pub extern "C" fn f_agg_tiny_ret() -> Tiny {
+    Tiny { a: 1, b: 2, c: 3, d: 4 }
+}
+
+#[repr(C)]
+pub struct Small {
+    a: i64,
+    b: *mut i64,
+}
+
+// CHECK: define void @f_agg_small([2 x i64])
+#[no_mangle]
+pub extern "C" fn f_agg_small(mut x: Small) {
+    x.a += unsafe { *x.b };
+    x.b = &mut x.a;
+}
+
+// CHECK: define [2 x i64] @f_agg_small_ret()
+#[no_mangle]
+pub extern "C" fn f_agg_small_ret() -> Small {
+    Small { a: 1, b: core::ptr::null_mut() }
+}
+
+#[repr(C)]
+pub struct SmallAligned {
+    a: i128,
+}
+
+// CHECK: define void @f_agg_small_aligned(i128)
+#[no_mangle]
+pub extern "C" fn f_agg_small_aligned(mut x: SmallAligned) {
+    x.a += x.a;
+}
+
+#[repr(C)]
+pub struct Large {
+    a: i64,
+    b: i64,
+    c: i64,
+    d: i64,
+}
+
+// CHECK: define void @f_agg_large(%Large* {{.*}}%x)
+#[no_mangle]
+pub extern "C" fn f_agg_large(mut x: Large) {
+    x.a = x.b + x.c + x.d;
+}
+
+// CHECK: define void @f_agg_large_ret(%Large* {{.*}}sret{{.*}}, i32 signext %i, i8 signext %j)
+#[no_mangle]
+pub extern "C" fn f_agg_large_ret(i: i32, j: i8) -> Large {
+    Large { a: 1, b: 2, c: 3, d: 4 }
+}
+
+// CHECK: define void @f_scalar_stack_1(i64, [2 x i64], i128, %Large* {{.*}}%d, i8 zeroext %e, i8 signext %f, i8 %g, i8 %h)
+#[no_mangle]
+pub extern "C" fn f_scalar_stack_1(
+    a: Tiny,
+    b: Small,
+    c: SmallAligned,
+    d: Large,
+    e: u8,
+    f: i8,
+    g: u8,
+    h: i8,
+) {
+}
+
+// CHECK: define void @f_scalar_stack_2(%Large* {{.*}}sret{{.*}}, i64 %a, i128, i128, i64 %d, i8 zeroext %e, i8 %f, i8 %g)
+#[no_mangle]
+pub extern "C" fn f_scalar_stack_2(
+    a: u64,
+    b: SmallAligned,
+    c: SmallAligned,
+    d: u64,
+    e: u8,
+    f: i8,
+    g: u8,
+) -> Large {
+    Large { a: a as i64, b: e as i64, c: f as i64, d: g as i64 }
+}
+
+extern "C" {
+    fn f_va_callee(_: i32, ...) -> i32;
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn f_va_caller() {
+    // CHECK: call signext i32 (i32, ...) @f_va_callee(i32 signext 1, i32 signext 2, i64 3, double {{.*}}, double {{.*}}, i64 {{.*}}, [2 x i64] {{.*}}, i128 {{.*}}, %Large* {{.*}})
+    f_va_callee(
+        1,
+        2i32,
+        3i64,
+        4.0f64,
+        5.0f64,
+        Tiny { a: 1, b: 2, c: 3, d: 4 },
+        Small { a: 10, b: core::ptr::null_mut() },
+        SmallAligned { a: 11 },
+        Large { a: 12, b: 13, c: 14, d: 15 },
+    );
+    // CHECK: call signext i32 (i32, ...) @f_va_callee(i32 signext 1, i32 signext 2, i32 signext 3, i32 signext 4, i128 {{.*}}, i32 signext 6, i32 signext 7, i32 8, i32 9)
+    f_va_callee(1, 2i32, 3i32, 4i32, SmallAligned { a: 5 }, 6i32, 7i32, 8i32, 9i32);
+}
diff --git a/src/test/codegen/riscv-abi/riscv64-lp64d-abi.rs b/src/test/codegen/riscv-abi/riscv64-lp64d-abi.rs
new file mode 100644
index 00000000000..66a3b9e4952
--- /dev/null
+++ b/src/test/codegen/riscv-abi/riscv64-lp64d-abi.rs
@@ -0,0 +1,293 @@
+// ignore-tidy-linelength
+// compile-flags: -C no-prepopulate-passes
+// only-riscv64
+// only-linux
+#![crate_type = "lib"]
+
+// CHECK: define void @f_fpr_tracking(double, double, double, double, double, double, double, double, i8 zeroext %i)
+#[no_mangle]
+pub extern "C" fn f_fpr_tracking(
+    a: f64,
+    b: f64,
+    c: f64,
+    d: f64,
+    e: f64,
+    f: f64,
+    g: f64,
+    h: f64,
+    i: u8,
+) {
+}
+
+#[repr(C)]
+pub struct Double {
+    f: f64,
+}
+
+#[repr(C)]
+pub struct DoubleDouble {
+    f: f64,
+    g: f64,
+}
+
+#[repr(C)]
+pub struct DoubleFloat {
+    f: f64,
+    g: f32,
+}
+
+// CHECK: define void @f_double_s_arg(double)
+#[no_mangle]
+pub extern "C" fn f_double_s_arg(a: Double) {}
+
+// CHECK: define double @f_ret_double_s()
+#[no_mangle]
+pub extern "C" fn f_ret_double_s() -> Double {
+    Double { f: 1. }
+}
+
+// CHECK: define void @f_double_double_s_arg({ double, double })
+#[no_mangle]
+pub extern "C" fn f_double_double_s_arg(a: DoubleDouble) {}
+
+// CHECK: define { double, double } @f_ret_double_double_s()
+#[no_mangle]
+pub extern "C" fn f_ret_double_double_s() -> DoubleDouble {
+    DoubleDouble { f: 1., g: 2. }
+}
+
+// CHECK: define void @f_double_float_s_arg({ double, float })
+#[no_mangle]
+pub extern "C" fn f_double_float_s_arg(a: DoubleFloat) {}
+
+// CHECK: define { double, float } @f_ret_double_float_s()
+#[no_mangle]
+pub extern "C" fn f_ret_double_float_s() -> DoubleFloat {
+    DoubleFloat { f: 1., g: 2. }
+}
+
+// CHECK: define void @f_double_double_s_arg_insufficient_fprs(double, double, double, double, double, double, double, [2 x i64])
+#[no_mangle]
+pub extern "C" fn f_double_double_s_arg_insufficient_fprs(
+    a: f64,
+    b: f64,
+    c: f64,
+    d: f64,
+    e: f64,
+    f: f64,
+    g: f64,
+    h: DoubleDouble,
+) {
+}
+
+#[repr(C)]
+pub struct DoubleInt8 {
+    f: f64,
+    i: i8,
+}
+
+#[repr(C)]
+pub struct DoubleUInt8 {
+    f: f64,
+    i: u8,
+}
+
+#[repr(C)]
+pub struct DoubleInt32 {
+    f: f64,
+    i: i32,
+}
+
+#[repr(C)]
+pub struct DoubleInt64 {
+    f: f64,
+    i: i64,
+}
+
+// CHECK: define void @f_double_int8_s_arg({ double, i8 })
+#[no_mangle]
+pub extern "C" fn f_double_int8_s_arg(a: DoubleInt8) {}
+
+// CHECK: define { double, i8 } @f_ret_double_int8_s()
+#[no_mangle]
+pub extern "C" fn f_ret_double_int8_s() -> DoubleInt8 {
+    DoubleInt8 { f: 1., i: 2 }
+}
+
+// CHECK: define void @f_double_int32_s_arg({ double, i32 })
+#[no_mangle]
+pub extern "C" fn f_double_int32_s_arg(a: DoubleInt32) {}
+
+// CHECK: define { double, i32 } @f_ret_double_int32_s()
+#[no_mangle]
+pub extern "C" fn f_ret_double_int32_s() -> DoubleInt32 {
+    DoubleInt32 { f: 1., i: 2 }
+}
+
+// CHECK: define void @f_double_uint8_s_arg({ double, i8 })
+#[no_mangle]
+pub extern "C" fn f_double_uint8_s_arg(a: DoubleUInt8) {}
+
+// CHECK: define { double, i8 } @f_ret_double_uint8_s()
+#[no_mangle]
+pub extern "C" fn f_ret_double_uint8_s() -> DoubleUInt8 {
+    DoubleUInt8 { f: 1., i: 2 }
+}
+
+// CHECK: define void @f_double_int64_s_arg({ double, i64 })
+#[no_mangle]
+pub extern "C" fn f_double_int64_s_arg(a: DoubleInt64) {}
+
+// CHECK: define { double, i64 } @f_ret_double_int64_s()
+#[no_mangle]
+pub extern "C" fn f_ret_double_int64_s() -> DoubleInt64 {
+    DoubleInt64 { f: 1., i: 2 }
+}
+
+// CHECK: define void @f_double_int8_s_arg_insufficient_gprs(i32 signext %a, i32 signext %b, i32 signext %c, i32 signext %d, i32 signext %e, i32 signext %f, i32 signext %g, i32 signext %h, [2 x i64])
+#[no_mangle]
+pub extern "C" fn f_double_int8_s_arg_insufficient_gprs(
+    a: i32,
+    b: i32,
+    c: i32,
+    d: i32,
+    e: i32,
+    f: i32,
+    g: i32,
+    h: i32,
+    i: DoubleInt8,
+) {
+}
+
+// CHECK: define void @f_struct_double_int8_insufficient_fprs(float, double, double, double, double, double, double, double, [2 x i64])
+#[no_mangle]
+pub extern "C" fn f_struct_double_int8_insufficient_fprs(
+    a: f32,
+    b: f64,
+    c: f64,
+    d: f64,
+    e: f64,
+    f: f64,
+    g: f64,
+    h: f64,
+    i: DoubleInt8,
+) {
+}
+
+#[repr(C)]
+pub struct DoubleArr1 {
+    a: [f64; 1],
+}
+
+// CHECK: define void @f_doublearr1_s_arg(double)
+#[no_mangle]
+pub extern "C" fn f_doublearr1_s_arg(a: DoubleArr1) {}
+
+// CHECK: define double @f_ret_doublearr1_s()
+#[no_mangle]
+pub extern "C" fn f_ret_doublearr1_s() -> DoubleArr1 {
+    DoubleArr1 { a: [1.] }
+}
+
+#[repr(C)]
+pub struct DoubleArr2 {
+    a: [f64; 2],
+}
+
+// CHECK: define void @f_doublearr2_s_arg({ double, double })
+#[no_mangle]
+pub extern "C" fn f_doublearr2_s_arg(a: DoubleArr2) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_s()
+#[no_mangle]
+pub extern "C" fn f_ret_doublearr2_s() -> DoubleArr2 {
+    DoubleArr2 { a: [1., 2.] }
+}
+
+#[repr(C)]
+pub struct Tricky1 {
+    f: [f64; 1],
+}
+
+#[repr(C)]
+pub struct DoubleArr2Tricky1 {
+    g: [Tricky1; 2],
+}
+
+// CHECK: define void @f_doublearr2_tricky1_s_arg({ double, double })
+#[no_mangle]
+pub extern "C" fn f_doublearr2_tricky1_s_arg(a: DoubleArr2Tricky1) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_tricky1_s()
+#[no_mangle]
+pub extern "C" fn f_ret_doublearr2_tricky1_s() -> DoubleArr2Tricky1 {
+    DoubleArr2Tricky1 { g: [Tricky1 { f: [1.] }, Tricky1 { f: [2.] }] }
+}
+
+#[repr(C)]
+pub struct EmptyStruct {}
+
+#[repr(C)]
+pub struct DoubleArr2Tricky2 {
+    s: EmptyStruct,
+    g: [Tricky1; 2],
+}
+
+// CHECK: define void @f_doublearr2_tricky2_s_arg({ double, double })
+#[no_mangle]
+pub extern "C" fn f_doublearr2_tricky2_s_arg(a: DoubleArr2Tricky2) {}
+
+// CHECK: define { double, double } @f_ret_doublearr2_tricky2_s()
+#[no_mangle]
+pub extern "C" fn f_ret_doublearr2_tricky2_s() -> DoubleArr2Tricky2 {
+    DoubleArr2Tricky2 { s: EmptyStruct {}, g: [Tricky1 { f: [1.] }, Tricky1 { f: [2.] }] }
+}
+
+#[repr(C)]
+pub struct IntDoubleInt {
+    a: i32,
+    b: f64,
+    c: i32,
+}
+
+// CHECK: define void @f_int_double_int_s_arg(%IntDoubleInt* {{.*}}%a)
+#[no_mangle]
+pub extern "C" fn f_int_double_int_s_arg(a: IntDoubleInt) {}
+
+// CHECK: define void @f_ret_int_double_int_s(%IntDoubleInt* {{.*}}sret
+#[no_mangle]
+pub extern "C" fn f_ret_int_double_int_s() -> IntDoubleInt {
+    IntDoubleInt { a: 1, b: 2., c: 3 }
+}
+
+#[repr(C)]
+pub struct CharCharDouble {
+    a: u8,
+    b: u8,
+    c: f64,
+}
+
+// CHECK: define void @f_char_char_double_s_arg([2 x i64])
+#[no_mangle]
+pub extern "C" fn f_char_char_double_s_arg(a: CharCharDouble) {}
+
+// CHECK: define [2 x i64] @f_ret_char_char_double_s()
+#[no_mangle]
+pub extern "C" fn f_ret_char_char_double_s() -> CharCharDouble {
+    CharCharDouble { a: 1, b: 2, c: 3. }
+}
+
+#[repr(C)]
+pub union DoubleU {
+    a: f64,
+}
+
+// CHECK: define void @f_double_u_arg(i64)
+#[no_mangle]
+pub extern "C" fn f_double_u_arg(a: DoubleU) {}
+
+// CHECK: define i64 @f_ret_double_u()
+#[no_mangle]
+pub extern "C" fn f_ret_double_u() -> DoubleU {
+    unsafe { DoubleU { a: 1. } }
+}
diff --git a/src/test/codegen/riscv-abi/riscv64-lp64f-lp64d-abi.rs b/src/test/codegen/riscv-abi/riscv64-lp64f-lp64d-abi.rs
new file mode 100644
index 00000000000..d843331f425
--- /dev/null
+++ b/src/test/codegen/riscv-abi/riscv64-lp64f-lp64d-abi.rs
@@ -0,0 +1,277 @@
+// ignore-tidy-linelength
+// compile-flags: -C no-prepopulate-passes
+// only-riscv64
+// only-linux
+#![crate_type = "lib"]
+
+// CHECK: define void @f_fpr_tracking(float, float, float, float, float, float, float, float, i8 zeroext %i)
+#[no_mangle]
+pub extern "C" fn f_fpr_tracking(
+    a: f32,
+    b: f32,
+    c: f32,
+    d: f32,
+    e: f32,
+    f: f32,
+    g: f32,
+    h: f32,
+    i: u8,
+) {
+}
+
+#[repr(C)]
+pub struct Float {
+    f: f32,
+}
+
+#[repr(C)]
+pub struct FloatFloat {
+    f: f32,
+    g: f32,
+}
+
+// CHECK: define void @f_float_s_arg(float)
+#[no_mangle]
+pub extern "C" fn f_float_s_arg(a: Float) {}
+
+// CHECK: define float @f_ret_float_s()
+#[no_mangle]
+pub extern "C" fn f_ret_float_s() -> Float {
+    Float { f: 1. }
+}
+
+// CHECK: define void @f_float_float_s_arg({ float, float })
+#[no_mangle]
+pub extern "C" fn f_float_float_s_arg(a: FloatFloat) {}
+
+// CHECK: define { float, float } @f_ret_float_float_s()
+#[no_mangle]
+pub extern "C" fn f_ret_float_float_s() -> FloatFloat {
+    FloatFloat { f: 1., g: 2. }
+}
+
+// CHECK: define void @f_float_float_s_arg_insufficient_fprs(float, float, float, float, float, float, float, i64)
+#[no_mangle]
+pub extern "C" fn f_float_float_s_arg_insufficient_fprs(
+    a: f32,
+    b: f32,
+    c: f32,
+    d: f32,
+    e: f32,
+    f: f32,
+    g: f32,
+    h: FloatFloat,
+) {
+}
+
+#[repr(C)]
+pub struct FloatInt8 {
+    f: f32,
+    i: i8,
+}
+
+#[repr(C)]
+pub struct FloatUInt8 {
+    f: f32,
+    i: u8,
+}
+
+#[repr(C)]
+pub struct FloatInt32 {
+    f: f32,
+    i: i32,
+}
+
+#[repr(C)]
+pub struct FloatInt64 {
+    f: f32,
+    i: i64,
+}
+
+// CHECK: define void @f_float_int8_s_arg({ float, i8 })
+#[no_mangle]
+pub extern "C" fn f_float_int8_s_arg(a: FloatInt8) {}
+
+// CHECK: define { float, i8 } @f_ret_float_int8_s()
+#[no_mangle]
+pub extern "C" fn f_ret_float_int8_s() -> FloatInt8 {
+    FloatInt8 { f: 1., i: 2 }
+}
+
+// CHECK: define void @f_float_int32_s_arg({ float, i32 })
+#[no_mangle]
+pub extern "C" fn f_float_int32_s_arg(a: FloatInt32) {}
+
+// CHECK: define { float, i32 } @f_ret_float_int32_s()
+#[no_mangle]
+pub extern "C" fn f_ret_float_int32_s() -> FloatInt32 {
+    FloatInt32 { f: 1., i: 2 }
+}
+
+// CHECK: define void @f_float_uint8_s_arg({ float, i8 })
+#[no_mangle]
+pub extern "C" fn f_float_uint8_s_arg(a: FloatUInt8) {}
+
+// CHECK: define { float, i8 } @f_ret_float_uint8_s()
+#[no_mangle]
+pub extern "C" fn f_ret_float_uint8_s() -> FloatUInt8 {
+    FloatUInt8 { f: 1., i: 2 }
+}
+
+// CHECK: define void @f_float_int64_s_arg({ float, i64 })
+#[no_mangle]
+pub extern "C" fn f_float_int64_s_arg(a: FloatInt64) {}
+
+// CHECK: define { float, i64 } @f_ret_float_int64_s()
+#[no_mangle]
+pub extern "C" fn f_ret_float_int64_s() -> FloatInt64 {
+    FloatInt64 { f: 1., i: 2 }
+}
+
+// CHECK: define void @f_float_int8_s_arg_insufficient_gprs(i32 signext %a, i32 signext %b, i32 signext %c, i32 signext %d, i32 signext %e, i32 signext %f, i32 signext %g, i32 signext %h, i64)
+#[no_mangle]
+pub extern "C" fn f_float_int8_s_arg_insufficient_gprs(
+    a: i32,
+    b: i32,
+    c: i32,
+    d: i32,
+    e: i32,
+    f: i32,
+    g: i32,
+    h: i32,
+    i: FloatInt8,
+) {
+}
+
+// CHECK: define void @f_struct_float_int8_insufficient_fprs(float, float, float, float, float, float, float, float, i64)
+#[no_mangle]
+pub extern "C" fn f_struct_float_int8_insufficient_fprs(
+    a: f32,
+    b: f32,
+    c: f32,
+    d: f32,
+    e: f32,
+    f: f32,
+    g: f32,
+    h: f32,
+    i: FloatInt8,
+) {
+}
+
+#[repr(C)]
+pub struct FloatArr1 {
+    a: [f32; 1],
+}
+
+// CHECK: define void @f_floatarr1_s_arg(float)
+#[no_mangle]
+pub extern "C" fn f_floatarr1_s_arg(a: FloatArr1) {}
+
+// CHECK: define float @f_ret_floatarr1_s()
+#[no_mangle]
+pub extern "C" fn f_ret_floatarr1_s() -> FloatArr1 {
+    FloatArr1 { a: [1.] }
+}
+
+#[repr(C)]
+pub struct FloatArr2 {
+    a: [f32; 2],
+}
+
+// CHECK: define void @f_floatarr2_s_arg({ float, float })
+#[no_mangle]
+pub extern "C" fn f_floatarr2_s_arg(a: FloatArr2) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_s()
+#[no_mangle]
+pub extern "C" fn f_ret_floatarr2_s() -> FloatArr2 {
+    FloatArr2 { a: [1., 2.] }
+}
+
+#[repr(C)]
+pub struct Tricky1 {
+    f: [f32; 1],
+}
+
+#[repr(C)]
+pub struct FloatArr2Tricky1 {
+    g: [Tricky1; 2],
+}
+
+// CHECK: define void @f_floatarr2_tricky1_s_arg({ float, float })
+#[no_mangle]
+pub extern "C" fn f_floatarr2_tricky1_s_arg(a: FloatArr2Tricky1) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_tricky1_s()
+#[no_mangle]
+pub extern "C" fn f_ret_floatarr2_tricky1_s() -> FloatArr2Tricky1 {
+    FloatArr2Tricky1 { g: [Tricky1 { f: [1.] }, Tricky1 { f: [2.] }] }
+}
+
+#[repr(C)]
+pub struct EmptyStruct {}
+
+#[repr(C)]
+pub struct FloatArr2Tricky2 {
+    s: EmptyStruct,
+    g: [Tricky1; 2],
+}
+
+// CHECK: define void @f_floatarr2_tricky2_s_arg({ float, float })
+#[no_mangle]
+pub extern "C" fn f_floatarr2_tricky2_s_arg(a: FloatArr2Tricky2) {}
+
+// CHECK: define { float, float } @f_ret_floatarr2_tricky2_s()
+#[no_mangle]
+pub extern "C" fn f_ret_floatarr2_tricky2_s() -> FloatArr2Tricky2 {
+    FloatArr2Tricky2 { s: EmptyStruct {}, g: [Tricky1 { f: [1.] }, Tricky1 { f: [2.] }] }
+}
+
+#[repr(C)]
+pub struct IntFloatInt {
+    a: i32,
+    b: f32,
+    c: i32,
+}
+
+// CHECK: define void @f_int_float_int_s_arg([2 x i64])
+#[no_mangle]
+pub extern "C" fn f_int_float_int_s_arg(a: IntFloatInt) {}
+
+// CHECK: define [2 x i64] @f_ret_int_float_int_s()
+#[no_mangle]
+pub extern "C" fn f_ret_int_float_int_s() -> IntFloatInt {
+    IntFloatInt { a: 1, b: 2., c: 3 }
+}
+
+#[repr(C)]
+pub struct CharCharFloat {
+    a: u8,
+    b: u8,
+    c: f32,
+}
+
+// CHECK: define void @f_char_char_float_s_arg(i64)
+#[no_mangle]
+pub extern "C" fn f_char_char_float_s_arg(a: CharCharFloat) {}
+
+// CHECK: define i64 @f_ret_char_char_float_s()
+#[no_mangle]
+pub extern "C" fn f_ret_char_char_float_s() -> CharCharFloat {
+    CharCharFloat { a: 1, b: 2, c: 3. }
+}
+
+#[repr(C)]
+pub union FloatU {
+    a: f32,
+}
+
+// CHECK: define void @f_float_u_arg(i64)
+#[no_mangle]
+pub extern "C" fn f_float_u_arg(a: FloatU) {}
+
+// CHECK: define i64 @f_ret_float_u()
+#[no_mangle]
+pub extern "C" fn f_ret_float_u() -> FloatU {
+    unsafe { FloatU { a: 1. } }
+}
diff --git a/src/test/ui/abi/struct-enums/struct-return.rs b/src/test/ui/abi/struct-enums/struct-return.rs
index 5930fc4acbb..a3e70bbdb08 100644
--- a/src/test/ui/abi/struct-enums/struct-return.rs
+++ b/src/test/ui/abi/struct-enums/struct-return.rs
@@ -10,13 +10,23 @@ pub struct Quad { a: u64, b: u64, c: u64, d: u64 }
 #[derive(Copy, Clone)]
 pub struct Floats { a: f64, b: u8, c: f64 }
 
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct CharCharDouble { a: u8, b: u8, c: f64 }
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct CharCharFloat { a: u8, b: u8, c: f32 }
+
 mod rustrt {
-    use super::{Floats, Quad};
+    use super::{Floats, Quad, CharCharDouble, CharCharFloat};
 
     #[link(name = "rust_test_helpers", kind = "static")]
     extern {
         pub fn rust_dbg_abi_1(q: Quad) -> Quad;
         pub fn rust_dbg_abi_2(f: Floats) -> Floats;
+        pub fn rust_dbg_abi_3(a: CharCharDouble) -> CharCharDouble;
+        pub fn rust_dbg_abi_4(a: CharCharFloat) -> CharCharFloat;
     }
 }
 
@@ -58,7 +68,47 @@ fn test2() {
 fn test2() {
 }
 
+#[cfg(target_pointer_width = "64")]
+fn test3() {
+    unsafe {
+        let a = CharCharDouble {
+            a: 1,
+            b: 2,
+            c: 3.,
+        };
+        let b = rustrt::rust_dbg_abi_3(a);
+        println!("a: {}", b.a);
+        println!("b: {}", b.b);
+        println!("c: {}", b.c);
+        assert_eq!(b.a, a.a + 1);
+        assert_eq!(b.b, a.b - 1);
+        assert_eq!(b.c, a.c + 1.0);
+    }
+}
+
+#[cfg(target_pointer_width = "32")]
+fn test3() {}
+
+fn test4() {
+    unsafe {
+        let a = CharCharFloat {
+            a: 1,
+            b: 2,
+            c: 3.,
+        };
+        let b = rustrt::rust_dbg_abi_4(a);
+        println!("a: {}", b.a);
+        println!("b: {}", b.b);
+        println!("c: {}", b.c);
+        assert_eq!(b.a, a.a + 1);
+        assert_eq!(b.b, a.b - 1);
+        assert_eq!(b.c, a.c + 1.0);
+    }
+}
+
 pub fn main() {
     test1();
     test2();
+    test3();
+    test4();
 }