[clang][RISCV][test] Add test coverage for _Float16 ABI lowering

[asb]

Summary

I believe that by the psABI, any test case where a FPR would be used for a float, it should also be used if you replaced that float with a _Float16. This doesn't hold true for the special cases in the FP calling convention involving structs. This patch doesn't attempt to fix that, simply to add coverage.

I've also directly committed some other patches that expand our coverage for _Float16 behaviour.

clang/test/CodeGen/RISCV/riscv32-abi.c

 // be modified.
 
 // ILP32-ILP32F-ILP32D-LABEL: define dso_local fp128 @f_fp_scalar_3
 // ILP32-ILP32F-ILP32D-SAME: (fp128 noundef [[X:%.*]]) #[[ATTR0]] {
 // ILP32-ILP32F-ILP32D:  entry:
 //
 long double f_fp_scalar_3(long double x) { return x; }
 
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local half @f_fp_scalar_4
+// ILP32-ILP32F-ILP32D-SAME: (half noundef [[X:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+_Float16 f_fp_scalar_4(_Float16 x) { return x; }
+
 // Empty structs or unions are ignored.
 
 struct empty_s {};
 
 // ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_agg_empty_struct
 // ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
 // ILP32-ILP32F-ILP32D:  entry:
 //

 // ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_scalar_stack_4
 // ILP32-ILP32F-ILP32D-SAME: (double noundef [[A:%.*]], i64 noundef [[B:%.*]], double noundef [[C:%.*]], i64 noundef [[D:%.*]], i32 noundef [[E:%.*]], i64 noundef [[F:%.*]], float noundef [[G:%.*]], double noundef [[H:%.*]], fp128 noundef [[I:%.*]]) #[[ATTR0]] {
 // ILP32-ILP32F-ILP32D:  entry:
 //
 void f_scalar_stack_4(double a, int64_t b, double c, int64_t d, int e,
                       int64_t f, float g, double h, long double i) {}
 
 // ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_scalar_stack_5
-// ILP32-ILP32F-ILP32D-SAME: (i32 noundef [[A:%.*]], i64 noundef [[B:%.*]], float noundef [[C:%.*]], double noundef [[D:%.*]], fp128 noundef [[E:%.*]], i8 noundef zeroext [[F:%.*]], i8 noundef signext [[G:%.*]], i8 noundef zeroext [[H:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D-SAME: (i32 noundef [[A:%.*]], i64 noundef [[B:%.*]], float noundef [[C:%.*]], double noundef [[D:%.*]], fp128 noundef [[E:%.*]], i8 noundef zeroext [[F:%.*]], i8 noundef signext [[G:%.*]], i8 noundef zeroext [[H:%.*]], half noundef [[I:%.*]]) #[[ATTR0]] {
 // ILP32-ILP32F-ILP32D:  entry:
 //
 int f_scalar_stack_5(int32_t a, int64_t b, float c, double d, long double e,
-                     uint8_t f, int8_t g, uint8_t h) {
+                     uint8_t f, int8_t g, uint8_t h, _Float16 i) {
   return g + h;
 }
 
 // ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_scalar_stack_6
 // ILP32-ILP32F-ILP32D-SAME: (ptr noalias sret([[STRUCT_LARGE:%.*]]) align 4 [[AGG_RESULT:%.*]], float noundef [[A:%.*]], i64 noundef [[B:%.*]], double noundef [[C:%.*]], fp128 noundef [[D:%.*]], i8 noundef zeroext [[E:%.*]], i8 noundef signext [[F:%.*]], i8 noundef zeroext [[G:%.*]]) #[[ATTR0]] {
 // ILP32-ILP32F-ILP32D:  entry:
 //
 struct large f_scalar_stack_6(float a, int64_t b, double c, long double d,

 
 // ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_float_u
 // ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
 // ILP32-ILP32F-ILP32D:  entry:
 //
 union float_u f_ret_float_u(void) {
   return (union float_u){1.0};
 }
+
+// Check that fp, fp+fp, and int+fp structs are lowered correctly. These will
+// be passed in FPR, FPR+FPR, or GPR+FPR regs if sufficient registers are
+// available the widths are <= XLEN and FLEN, and should be expanded to
+// separate arguments in IR. They are passed by the same rules for returns,
+// but will be lowered to simple two-element structs if necessary (as LLVM IR
+// functions cannot return multiple values).
+// FIXME: Essentially all test cases below involving _Float16 in structs
+// aren't lowered according to the rules in the FP calling convention (i.e.
+// are incorrect for ilp32f/ilp32d).
+
+struct float16_s { _Float16 f; };
+
+// A struct containing just one floating-point real is passed as though it
+// were a standalone floating-point real.
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16_s_arg(struct float16_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_float16_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16_s f_ret_float16_s(void) {
+  return (struct float16_s){1.0};
+}
+
+// A struct containing a double and any number of zero-width bitfields is
+// passed as though it were a standalone floating-point real.
+
+struct zbf_float16_s { int : 0; _Float16 f; };
+struct zbf_float16_zbf_s { int : 0; _Float16 f; int : 0; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_zbf_float16_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_zbf_float16_s_arg(struct zbf_float16_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_zbf_float16_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct zbf_float16_s f_ret_zbf_float16_s(void) {
+  return (struct zbf_float16_s){1.0};
+}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_zbf_float16_zbf_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_zbf_float16_zbf_s_arg(struct zbf_float16_zbf_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_zbf_float16_zbf_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct zbf_float16_zbf_s f_ret_zbf_float16_zbf_s(void) {
+  return (struct zbf_float16_zbf_s){1.0};
+}
+
+// Check that structs containing two floating point values (FLEN <= width) are
+// expanded provided sufficient FPRs are available.
+
+struct double_float16_s { double f; _Float16 g; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_double_float16_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (ptr noundef [[A:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_double_float16_s_arg(struct double_float16_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_ret_double_float16_s
+// ILP32-ILP32F-ILP32D-SAME: (ptr noalias sret([[STRUCT_DOUBLE_FLOAT16_S:%.*]]) align 8 [[AGG_RESULT:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct double_float16_s f_ret_double_float16_s(void) {
+  return (struct double_float16_s){1.0, 2.0};
+}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_double_float16_s_arg_insufficient_fprs
+// ILP32-ILP32F-ILP32D-SAME: (float noundef [[A:%.*]], double noundef [[B:%.*]], double noundef [[C:%.*]], double noundef [[D:%.*]], double noundef [[E:%.*]], double noundef [[F:%.*]], double noundef [[G:%.*]], ptr noundef [[H:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_double_float16_s_arg_insufficient_fprs(float a, double b, double c, double d,
+    double e, double f, double g, struct double_float16_s h) {}
+
+// Check that structs containing int+_Float16 values are expanded, provided
+// sufficient FPRs and GPRs are available. The integer components are neither
+// sign or zero-extended.
+
+struct float16_int8_s { _Float16 f; int8_t i; };
+struct float16_uint8_s { _Float16 f; uint8_t i; };
+struct float16_int32_s { _Float16 f; int32_t i; };
+struct float16_int64_s { _Float16 f; int64_t i; };
+struct float16_int64bf_s { _Float16 f; int64_t i : 32; };
+struct float16_int8_zbf_s { _Float16 f; int8_t i; int : 0; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16_int8_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16_int8_s_arg(struct float16_int8_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_float16_int8_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16_int8_s f_ret_float16_int8_s(void) {
+  return (struct float16_int8_s){1.0, 2};
+}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16_uint8_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16_uint8_s_arg(struct float16_uint8_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_float16_uint8_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16_uint8_s f_ret_float16_uint8_s(void) {
+  return (struct float16_uint8_s){1.0, 2};
+}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16_int32_s_arg
+// ILP32-ILP32F-ILP32D-SAME: ([2 x i32] [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16_int32_s_arg(struct float16_int32_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local [2 x i32] @f_ret_float16_int32_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16_int32_s f_ret_float16_int32_s(void) {
+  return (struct float16_int32_s){1.0, 2};
+}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16_int64_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (ptr noundef [[A:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16_int64_s_arg(struct float16_int64_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_ret_float16_int64_s
+// ILP32-ILP32F-ILP32D-SAME: (ptr noalias sret([[STRUCT_FLOAT16_INT64_S:%.*]]) align 8 [[AGG_RESULT:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16_int64_s f_ret_float16_int64_s(void) {
+  return (struct float16_int64_s){1.0, 2};
+}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16_int64bf_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16_int64bf_s_arg(struct float16_int64bf_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i64 @f_ret_float16_int64bf_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16_int64bf_s f_ret_float16_int64bf_s(void) {
+  return (struct float16_int64bf_s){1.0, 2};
+}
+
+// The zero-width bitfield means the struct can't be passed according to the
+// floating point calling convention.
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16_int8_zbf_s
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16_int8_zbf_s(struct float16_int8_zbf_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_float16_int8_zbf_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16_int8_zbf_s f_ret_float16_int8_zbf_s(void) {
+  return (struct float16_int8_zbf_s){1.0, 2};
+}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16_int8_s_arg_insufficient_gprs
+// ILP32-ILP32F-ILP32D-SAME: (i32 noundef [[A:%.*]], i32 noundef [[B:%.*]], i32 noundef [[C:%.*]], i32 noundef [[D:%.*]], i32 noundef [[E:%.*]], i32 noundef [[F:%.*]], i32 noundef [[G:%.*]], i32 noundef [[H:%.*]], i32 [[I_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16_int8_s_arg_insufficient_gprs(int a, int b, int c, int d, int e,
+                                            int f, int g, int h, struct float16_int8_s i) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_struct_float16_int8_insufficient_fprs
+// ILP32-ILP32F-ILP32D-SAME: (float noundef [[A:%.*]], double noundef [[B:%.*]], double noundef [[C:%.*]], double noundef [[D:%.*]], double noundef [[E:%.*]], double noundef [[F:%.*]], double noundef [[G:%.*]], double noundef [[H:%.*]], i32 [[I_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_struct_float16_int8_insufficient_fprs(float a, double b, double c, double d,
+                                             double e, double f, double g, double h, struct float16_int8_s i) {}
+
+// Complex floating-point values or structs containing a single complex
+// floating-point value should be passed as if it were an fp+fp struct.
+
+// ILP32-LABEL: define dso_local void @f_float16complex
+// ILP32-SAME: (i32 noundef [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32:  entry:
+//
+// ILP32F-ILP32D-LABEL: define dso_local void @f_float16complex
+// ILP32F-ILP32D-SAME: (half noundef [[A_COERCE0:%.*]], half noundef [[A_COERCE1:%.*]]) #[[ATTR0]] {
+// ILP32F-ILP32D:  entry:
+//
+void f_float16complex(_Float16 __complex__ a) {}
+
+// ILP32-LABEL: define dso_local i32 @f_ret_float16complex
+// ILP32-SAME: () #[[ATTR0]] {
+// ILP32:  entry:
+//
+// ILP32F-ILP32D-LABEL: define dso_local { half, half } @f_ret_float16complex
+// ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32F-ILP32D:  entry:
+//
+_Float16 __complex__ f_ret_float16complex(void) {
+  return 1.0;
+}
+
+struct float16complex_s { _Float16 __complex__ c; };
+
+// ILP32-LABEL: define dso_local void @f_float16complex_s_arg
+// ILP32-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32:  entry:
+//
+// ILP32F-ILP32D-LABEL: define dso_local void @f_float16complex_s_arg
+// ILP32F-ILP32D-SAME: (half [[TMP0:%.*]], half [[TMP1:%.*]]) #[[ATTR0]] {
+// ILP32F-ILP32D:  entry:
+//
+void f_float16complex_s_arg(struct float16complex_s a) {}
+
+// ILP32-LABEL: define dso_local i32 @f_ret_float16complex_s
+// ILP32-SAME: () #[[ATTR0]] {
+// ILP32:  entry:
+//
+// ILP32F-ILP32D-LABEL: define dso_local { half, half } @f_ret_float16complex_s
+// ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32F-ILP32D:  entry:
+//
+struct float16complex_s f_ret_float16complex_s(void) {
+  return (struct float16complex_s){1.0};
+}
+
+// Test single or two-element structs that need flattening. e.g. those
+// containing nested structs, _Float16 in small arrays, zero-length structs etc.
+
+struct float16arr1_s { _Float16 a[1]; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16arr1_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16arr1_s_arg(struct float16arr1_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_float16arr1_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16arr1_s f_ret_float16arr1_s(void) {
+  return (struct float16arr1_s){{1.0}};
+}
+
+struct float16arr2_s { _Float16 a[2]; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16arr2_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16arr2_s_arg(struct float16arr2_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_float16arr2_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16arr2_s f_ret_float16arr2_s(void) {
+  return (struct float16arr2_s){{1.0, 2.0}};
+}
+
+struct float16arr2_tricky1_s { struct { _Float16 f[1]; } g[2]; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16arr2_tricky1_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16arr2_tricky1_s_arg(struct float16arr2_tricky1_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_float16arr2_tricky1_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16arr2_tricky1_s f_ret_float16arr2_tricky1_s(void) {
+  return (struct float16arr2_tricky1_s){{{{1.0}}, {{2.0}}}};
+}
+
+struct float16arr2_tricky2_s { struct {}; struct { _Float16 f[1]; } g[2]; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16arr2_tricky2_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16arr2_tricky2_s_arg(struct float16arr2_tricky2_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_float16arr2_tricky2_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16arr2_tricky2_s f_ret_float16arr2_tricky2_s(void) {
+  return (struct float16arr2_tricky2_s){{}, {{{1.0}}, {{2.0}}}};
+}
+
+struct float16arr2_tricky3_s { union {}; struct { _Float16 f[1]; } g[2]; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16arr2_tricky3_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16arr2_tricky3_s_arg(struct float16arr2_tricky3_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_float16arr2_tricky3_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16arr2_tricky3_s f_ret_float16arr2_tricky3_s(void) {
+  return (struct float16arr2_tricky3_s){{}, {{{1.0}}, {{2.0}}}};
+}
+
+struct float16arr2_tricky4_s { union {}; struct { struct {}; _Float16 f[1]; } g[2]; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16arr2_tricky4_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16arr2_tricky4_s_arg(struct float16arr2_tricky4_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_float16arr2_tricky4_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct float16arr2_tricky4_s f_ret_float16arr2_tricky4_s(void) {
+  return (struct float16arr2_tricky4_s){{}, {{{}, {1.0}}, {{}, {2.0}}}};
+}
+
+// Test structs that should be passed according to the normal integer calling
+// convention.
+
+struct int_float16_int_s { int a; _Float16 b; int c; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_int_float16_int_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (ptr noundef [[A:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_int_float16_int_s_arg(struct int_float16_int_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_ret_int_float16_int_s
+// ILP32-ILP32F-ILP32D-SAME: (ptr noalias sret([[STRUCT_INT_FLOAT16_INT_S:%.*]]) align 4 [[AGG_RESULT:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct int_float16_int_s f_ret_int_float16_int_s(void) {
+  return (struct int_float16_int_s){1, 2.0, 3};
+}
+
+struct int64_float16_s { int64_t a; _Float16 b; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_int64_float16_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (ptr noundef [[A:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_int64_float16_s_arg(struct int64_float16_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_ret_int64_float16_s
+// ILP32-ILP32F-ILP32D-SAME: (ptr noalias sret([[STRUCT_INT64_FLOAT16_S:%.*]]) align 8 [[AGG_RESULT:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct int64_float16_s f_ret_int64_float16_s(void) {
+  return (struct int64_float16_s){1, 2.0};
+}
+
+struct char_char_float16_s { char a; char b; _Float16 c; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_char_char_float16_s_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_char_char_float16_s_arg(struct char_char_float16_s a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_char_char_float16_s
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+struct char_char_float16_s f_ret_char_char_float16_s(void) {
+  return (struct char_char_float16_s){1, 2, 3.0};
+}
+
+// Unions are always passed according to the integer calling convention, even
+// if they can only contain a double.
+
+union float16_u { _Float16 a; };
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local void @f_float16_u_arg
+// ILP32-ILP32F-ILP32D-SAME: (i32 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+void f_float16_u_arg(union float16_u a) {}
+
+// ILP32-ILP32F-ILP32D-LABEL: define dso_local i32 @f_ret_float16_u
+// ILP32-ILP32F-ILP32D-SAME: () #[[ATTR0]] {
+// ILP32-ILP32F-ILP32D:  entry:
+//
+union float16_u f_ret_float16_u(void) {
+  return (union float16_u){1.0};
+}
+
 //// NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
 // ILP32F: {{.*}}

clang/test/CodeGen/RISCV/riscv64-abi.c

 double f_fp_scalar_2(double x) { return x; }
 
 // LP64-LP64F-LP64D-LABEL: define dso_local fp128 @f_fp_scalar_3
 // LP64-LP64F-LP64D-SAME: (fp128 noundef [[X:%.*]]) #[[ATTR0]] {
 // LP64-LP64F-LP64D:  entry:
 //
 long double f_fp_scalar_3(long double x) { return x; }
 
+// LP64-LP64F-LP64D-LABEL: define dso_local half @f_fp_scalar_4
+// LP64-LP64F-LP64D-SAME: (half noundef [[X:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+_Float16 f_fp_scalar_4(_Float16 x) { return x; }
+
 // Empty structs or unions are ignored.
 
 struct empty_s {};
 
 // LP64-LP64F-LP64D-LABEL: define dso_local void @f_agg_empty_struct
 // LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
 // LP64-LP64F-LP64D:  entry:
 //

 // LP64-LP64F-LP64D:  entry:
 //
 struct large f_scalar_stack_5(double a, __int128_t b, long double c, v32i8 d,
                               uint8_t e, int8_t f, uint8_t g) {
   return (struct large){a, e, f, g};
 }
 
 // LP64-LP64F-LP64D-LABEL: define dso_local signext i32 @f_scalar_stack_6
-// LP64-LP64F-LP64D-SAME: (i32 noundef signext [[A:%.*]], i128 noundef [[B:%.*]], float noundef [[C:%.*]], fp128 noundef [[D:%.*]], ptr noundef [[TMP0:%.*]], i8 noundef zeroext [[F:%.*]], i8 noundef signext [[G:%.*]], i8 noundef zeroext [[H:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D-SAME: (i32 noundef signext [[A:%.*]], i128 noundef [[B:%.*]], float noundef [[C:%.*]], fp128 noundef [[D:%.*]], ptr noundef [[TMP0:%.*]], i8 noundef zeroext [[F:%.*]], i8 noundef signext [[G:%.*]], i8 noundef zeroext [[H:%.*]], half noundef [[I:%.*]]) #[[ATTR0]] {
 // LP64-LP64F-LP64D:  entry:
 //
 int f_scalar_stack_6(int32_t a, __int128_t b, float c, long double d, v32i8 e,
-                     uint8_t f, int8_t g, uint8_t h) {
+                     uint8_t f, int8_t g, uint8_t h, _Float16 i) {
   return g + h;
 }
 
 // LP64-LP64F-LP64D-LABEL: define dso_local void @f_fpr_tracking
 // LP64-LP64F-LP64D-SAME: (float noundef [[A:%.*]], float noundef [[B:%.*]], float noundef [[C:%.*]], float noundef [[D:%.*]], float noundef [[E:%.*]], float noundef [[F:%.*]], float noundef [[G:%.*]], float noundef [[H:%.*]], i8 noundef zeroext [[I:%.*]]) #[[ATTR0]] {
 // LP64-LP64F-LP64D:  entry:
 //
 void f_fpr_tracking(float a, float b, float c, float d, float e, float f,

 
 // LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_double_u
 // LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
 // LP64-LP64F-LP64D:  entry:
 //
 union double_u f_ret_double_u(void) {
   return (union double_u){1.0};
 }
+
+// Check that fp, fp+fp, and int+fp structs are lowered correctly. These will
+// be passed in FPR, FPR+FPR, or GPR+FPR regs if sufficient registers are
+// available the widths are <= XLEN and FLEN, and should be expanded to
+// separate arguments in IR. They are passed by the same rules for returns,
+// but will be lowered to simple two-element structs if necessary (as LLVM IR
+// functions cannot return multiple values).
+// FIXME: Essentially all test cases below involving _Float16 in structs
+// aren't lowered according to the rules in the FP calling convention (i.e.
+// are incorrect for lp64f/lp64d).
+
+struct float16_s { _Float16 f; };
+
+// A struct containing just one floating-point real is passed as though it
+// were a standalone floating-point real.
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16_s_arg(struct float16_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16_s f_ret_float16_s(void) {
+  return (struct float16_s){1.0};
+}
+
+// A struct containing a double and any number of zero-width bitfields is
+// passed as though it were a standalone floating-point real.
+
+struct zbf_float16_s { int : 0; _Float16 f; };
+struct zbf_float16_zbf_s { int : 0; _Float16 f; int : 0; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_zbf_float16_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_zbf_float16_s_arg(struct zbf_float16_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_zbf_float16_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct zbf_float16_s f_ret_zbf_float16_s(void) {
+  return (struct zbf_float16_s){1.0};
+}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_zbf_float16_zbf_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_zbf_float16_zbf_s_arg(struct zbf_float16_zbf_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_zbf_float16_zbf_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct zbf_float16_zbf_s f_ret_zbf_float16_zbf_s(void) {
+  return (struct zbf_float16_zbf_s){1.0};
+}
+
+// Check that structs containing two floating point values (FLEN <= width) are
+// expanded provided sufficient FPRs are available.
+
+struct double_float16_s { double f; _Float16 g; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_double_float16_s_arg
+// LP64-LP64F-LP64D-SAME: ([2 x i64] [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_double_float16_s_arg(struct double_float16_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local [2 x i64] @f_ret_double_float16_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct double_float16_s f_ret_double_float16_s(void) {
+  return (struct double_float16_s){1.0, 2.0};
+}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_double_float16_s_arg_insufficient_fprs
+// LP64-LP64F-LP64D-SAME: (float noundef [[A:%.*]], double noundef [[B:%.*]], double noundef [[C:%.*]], double noundef [[D:%.*]], double noundef [[E:%.*]], double noundef [[F:%.*]], double noundef [[G:%.*]], [2 x i64] [[H_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_double_float16_s_arg_insufficient_fprs(float a, double b, double c, double d,
+    double e, double f, double g, struct double_float16_s h) {}
+
+// Check that structs containing int+_Float16 values are expanded, provided
+// sufficient FPRs and GPRs are available. The integer components are neither
+// sign or zero-extended.
+
+struct float16_int8_s { _Float16 f; int8_t i; };
+struct float16_uint8_s { _Float16 f; uint8_t i; };
+struct float16_int32_s { _Float16 f; int32_t i; };
+struct float16_int64_s { _Float16 f; int64_t i; };
+struct float16_int64bf_s { _Float16 f; int64_t i : 32; };
+struct float16_int8_zbf_s { _Float16 f; int8_t i; int : 0; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16_int8_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16_int8_s_arg(struct float16_int8_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16_int8_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16_int8_s f_ret_float16_int8_s(void) {
+  return (struct float16_int8_s){1.0, 2};
+}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16_uint8_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16_uint8_s_arg(struct float16_uint8_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16_uint8_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16_uint8_s f_ret_float16_uint8_s(void) {
+  return (struct float16_uint8_s){1.0, 2};
+}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16_int32_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16_int32_s_arg(struct float16_int32_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16_int32_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16_int32_s f_ret_float16_int32_s(void) {
+  return (struct float16_int32_s){1.0, 2};
+}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16_int64_s_arg
+// LP64-LP64F-LP64D-SAME: ([2 x i64] [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16_int64_s_arg(struct float16_int64_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local [2 x i64] @f_ret_float16_int64_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16_int64_s f_ret_float16_int64_s(void) {
+  return (struct float16_int64_s){1.0, 2};
+}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16_int64bf_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16_int64bf_s_arg(struct float16_int64bf_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16_int64bf_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16_int64bf_s f_ret_float16_int64bf_s(void) {
+  return (struct float16_int64bf_s){1.0, 2};
+}
+
+// The zero-width bitfield means the struct can't be passed according to the
+// floating point calling convention.
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16_int8_zbf_s
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16_int8_zbf_s(struct float16_int8_zbf_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16_int8_zbf_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16_int8_zbf_s f_ret_float16_int8_zbf_s(void) {
+  return (struct float16_int8_zbf_s){1.0, 2};
+}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16_int8_s_arg_insufficient_gprs
+// LP64-LP64F-LP64D-SAME: (i32 noundef signext [[A:%.*]], i32 noundef signext [[B:%.*]], i32 noundef signext [[C:%.*]], i32 noundef signext [[D:%.*]], i32 noundef signext [[E:%.*]], i32 noundef signext [[F:%.*]], i32 noundef signext [[G:%.*]], i32 noundef signext [[H:%.*]], i64 [[I_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16_int8_s_arg_insufficient_gprs(int a, int b, int c, int d, int e,
+                                            int f, int g, int h, struct float16_int8_s i) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_struct_float16_int8_insufficient_fprs
+// LP64-LP64F-LP64D-SAME: (float noundef [[A:%.*]], double noundef [[B:%.*]], double noundef [[C:%.*]], double noundef [[D:%.*]], double noundef [[E:%.*]], double noundef [[F:%.*]], double noundef [[G:%.*]], double noundef [[H:%.*]], i64 [[I_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_struct_float16_int8_insufficient_fprs(float a, double b, double c, double d,
+                                             double e, double f, double g, double h, struct float16_int8_s i) {}
+
+// Complex floating-point values or structs containing a single complex
+// floating-point value should be passed as if it were an fp+fp struct.
+
+// LP64-LABEL: define dso_local void @f_float16complex
+// LP64-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64:  entry:
+//
+// LP64F-LP64D-LABEL: define dso_local void @f_float16complex
+// LP64F-LP64D-SAME: (half noundef [[A_COERCE0:%.*]], half noundef [[A_COERCE1:%.*]]) #[[ATTR0]] {
+// LP64F-LP64D:  entry:
+//
+void f_float16complex(_Float16 __complex__ a) {}
+
+// LP64-LABEL: define dso_local i64 @f_ret_float16complex
+// LP64-SAME: () #[[ATTR0]] {
+// LP64:  entry:
+//
+// LP64F-LP64D-LABEL: define dso_local { half, half } @f_ret_float16complex
+// LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64F-LP64D:  entry:
+//
+_Float16 __complex__ f_ret_float16complex(void) {
+  return 1.0;
+}
+
+struct float16complex_s { _Float16 __complex__ c; };
+
+// LP64-LABEL: define dso_local void @f_float16complex_s_arg
+// LP64-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64:  entry:
+//
+// LP64F-LP64D-LABEL: define dso_local void @f_float16complex_s_arg
+// LP64F-LP64D-SAME: (half [[TMP0:%.*]], half [[TMP1:%.*]]) #[[ATTR0]] {
+// LP64F-LP64D:  entry:
+//
+void f_float16complex_s_arg(struct float16complex_s a) {}
+
+// LP64-LABEL: define dso_local i64 @f_ret_float16complex_s
+// LP64-SAME: () #[[ATTR0]] {
+// LP64:  entry:
+//
+// LP64F-LP64D-LABEL: define dso_local { half, half } @f_ret_float16complex_s
+// LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64F-LP64D:  entry:
+//
+struct float16complex_s f_ret_float16complex_s(void) {
+  return (struct float16complex_s){1.0};
+}
+
+// Test single or two-element structs that need flattening. e.g. those
+// containing nested structs, _Float16 in small arrays, zero-length structs etc.
+
+struct float16arr1_s { _Float16 a[1]; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16arr1_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16arr1_s_arg(struct float16arr1_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16arr1_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16arr1_s f_ret_float16arr1_s(void) {
+  return (struct float16arr1_s){{1.0}};
+}
+
+struct float16arr2_s { _Float16 a[2]; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16arr2_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16arr2_s_arg(struct float16arr2_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16arr2_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16arr2_s f_ret_float16arr2_s(void) {
+  return (struct float16arr2_s){{1.0, 2.0}};
+}
+
+struct float16arr2_tricky1_s { struct { _Float16 f[1]; } g[2]; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16arr2_tricky1_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16arr2_tricky1_s_arg(struct float16arr2_tricky1_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16arr2_tricky1_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16arr2_tricky1_s f_ret_float16arr2_tricky1_s(void) {
+  return (struct float16arr2_tricky1_s){{{{1.0}}, {{2.0}}}};
+}
+
+struct float16arr2_tricky2_s { struct {}; struct { _Float16 f[1]; } g[2]; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16arr2_tricky2_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16arr2_tricky2_s_arg(struct float16arr2_tricky2_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16arr2_tricky2_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16arr2_tricky2_s f_ret_float16arr2_tricky2_s(void) {
+  return (struct float16arr2_tricky2_s){{}, {{{1.0}}, {{2.0}}}};
+}
+
+struct float16arr2_tricky3_s { union {}; struct { _Float16 f[1]; } g[2]; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16arr2_tricky3_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16arr2_tricky3_s_arg(struct float16arr2_tricky3_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16arr2_tricky3_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16arr2_tricky3_s f_ret_float16arr2_tricky3_s(void) {
+  return (struct float16arr2_tricky3_s){{}, {{{1.0}}, {{2.0}}}};
+}
+
+struct float16arr2_tricky4_s { union {}; struct { struct {}; _Float16 f[1]; } g[2]; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16arr2_tricky4_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16arr2_tricky4_s_arg(struct float16arr2_tricky4_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16arr2_tricky4_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct float16arr2_tricky4_s f_ret_float16arr2_tricky4_s(void) {
+  return (struct float16arr2_tricky4_s){{}, {{{}, {1.0}}, {{}, {2.0}}}};
+}
+
+// Test structs that should be passed according to the normal integer calling
+// convention.
+
+struct int_float16_int_s { int a; _Float16 b; int c; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_int_float16_int_s_arg
+// LP64-LP64F-LP64D-SAME: ([2 x i64] [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_int_float16_int_s_arg(struct int_float16_int_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local [2 x i64] @f_ret_int_float16_int_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct int_float16_int_s f_ret_int_float16_int_s(void) {
+  return (struct int_float16_int_s){1, 2.0, 3};
+}
+
+struct int64_float16_s { int64_t a; _Float16 b; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_int64_float16_s_arg
+// LP64-LP64F-LP64D-SAME: ([2 x i64] [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_int64_float16_s_arg(struct int64_float16_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local [2 x i64] @f_ret_int64_float16_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct int64_float16_s f_ret_int64_float16_s(void) {
+  return (struct int64_float16_s){1, 2.0};
+}
+
+struct char_char_float16_s { char a; char b; _Float16 c; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_char_char_float16_s_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_char_char_float16_s_arg(struct char_char_float16_s a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_char_char_float16_s
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+struct char_char_float16_s f_ret_char_char_float16_s(void) {
+  return (struct char_char_float16_s){1, 2, 3.0};
+}
+
+// Unions are always passed according to the integer calling convention, even
+// if they can only contain a double.
+
+union float16_u { _Float16 a; };
+
+// LP64-LP64F-LP64D-LABEL: define dso_local void @f_float16_u_arg
+// LP64-LP64F-LP64D-SAME: (i64 [[A_COERCE:%.*]]) #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+void f_float16_u_arg(union float16_u a) {}
+
+// LP64-LP64F-LP64D-LABEL: define dso_local i64 @f_ret_float16_u
+// LP64-LP64F-LP64D-SAME: () #[[ATTR0]] {
+// LP64-LP64F-LP64D:  entry:
+//
+union float16_u f_ret_float16_u(void) {
+  return (union float16_u){1.0};
+}
+
 //// NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
 // LP64F: {{.*}}