clang/test/CodeGen/mips-transparent-union.c

   1 // RUN: %clang_cc1 -triple mips64-linux-gnu -o - -emit-llvm %s | FileCheck %s
   2 //
   3 // Transparent unions are passed according to the calling convention rules of
   4 // the first member. In this case, it is as if it were a void pointer so we
   5 // do not have the inreg attribute we would normally have for unions.
   6 //
   7 // This comes up in glibc's wait() function and matters for the big-endian N32
   8 // case where pointers are promoted to i64 and a non-transparent union would be
   9 // passed in the upper 32-bits of an i64.
  10
  11 union either_pointer {
  12   void *void_ptr;
  13   int *int_ptr;
  14 } __attribute__((transparent_union));
  15
  16 extern void foo(union either_pointer p);
  17
  18 int data;
  19
  20 void bar(void) {
  21   return foo(&data);
  22 }
  23
  24 // CHECK-LABEL: define{{.*}} void @bar()
  25 // CHECK:         call void @foo(ptr %{{[0-9]+}})
  26
  27 // CHECK: declare void @foo(ptr)