[Bug c++/88362] New: attribute aligned silently ignored on C++ references

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88362

            Bug ID: 88362
           Summary: attribute aligned silently ignored on C++ references
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: msebor at gcc dot gnu.org
  Target Milestone: ---

GCC honors the aligned attribute in just two of the three definitions below: it
silently ignores it for the reference.  Clang aligns all three objects on the
same 64-byte boundary.

$ cat t.C && gcc -O2 -S -Wall -fdump-tree-optimized=/dev/stdout t.C
__attribute__ ((aligned (64))) int i = 123;   // 64-byte aligned int
__attribute__ ((aligned (64))) int *p = &i;   // 64-byte aligned pointer
__attribute__ ((aligned (64))) int &r = i;    // 4-byte aligned reference

int fi (void) { return alignof (i); }
int fp (void) { return alignof (p); }
int fr (void) { return alignof (r); }




;; Function fi (_Z2fiv, funcdef_no=0, decl_uid=2301, cgraph_uid=1,
symbol_order=3)

fi ()
{
  <bb 2> [local count: 1073741824]:
  return 64;

}



;; Function fp (_Z2fpv, funcdef_no=4, decl_uid=2303, cgraph_uid=2,
symbol_order=4)

fp ()
{
  <bb 2> [local count: 1073741824]:
  return 64;

}



;; Function fr (_Z2frv, funcdef_no=2, decl_uid=2305, cgraph_uid=3,
symbol_order=5)

fr ()
{
  <bb 2> [local count: 1073741824]:
  return 4;

}