[Bug c/116357] New: The item's address of the array is not correct if aligned is used

["alwin.zhang at sap dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116357

            Bug ID: 116357
           Summary: The item's address of the array is not correct if
                    aligned is used
           Product: gcc
           Version: 10.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: alwin.zhang at sap dot com
  Target Milestone: ---

Created attachment 58922
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58922&action=edit
Test code to reproduce the issue.

The item's address of the array is not correct if aligned is used on the type
of array item. The debug version (without gcc optimization) doesn't have the
issue, but if we enable optimization like -O1/O2, all the items of the array
are using the same address.
Attached file is the test code to reproduce the issue. This issue could be
reproduced from gcc 7.1 to latest 14.2.

From following asm code we can see that the items of the array are using the
same address.

C code is -
------------------
u64 * l1;
u64 * l2;
void align_test(chn_t * p)
{
        l1 = (u64*)(&(p->lock[0]));
        l2 = (u64*)(&(p->lock[99]));
        printf("addr is [0]=%llu, [99]=%llu\n", l1, l2);
}
------------------

asm code is -
------------------
align_test:
        sub     rsp, 8
        mov     rsi, rdi
        mov     QWORD PTR l1[rip], rdi
        mov     QWORD PTR l2[rip], rdi
        mov     rdx, rdi
        mov     edi, OFFSET FLAT:.LC0
        mov     eax, 0
        call    printf
        add     rsp, 8
        ret
------------------

Please download the test code and compile with gcc optimization like -O2 to
check the issue.

Bug 65204 appears to be the same as this issue, but it's resolved. 

Thanks!