[Bug target/37216] [cygming] Invalid alignment for SSE store to .comm data generated with -O3

[dannysmith at users dot sourceforge dot net]

------- Comment #27 from dannysmith at users dot sourceforge dot net  
2008-10-01 10:22 -------
(In reply to comment #13)
> Created an attachment (id=16425)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16425&action=view) [edit]
> Revised patch with correct section switching
> 
That patch causes other problems
This test case:

/* t1.c */
int  i[0];
int k;

void testi (void)
{
  i[0] = 0;
}

void testk (void)
{
  k = 0;
}


int main (void)
{
  return 0;
} 

now fails with 
t1.c:(.text+0x5): undefined reference to `_i' 

The assembler code is
        .file   "t1.c"
        .text
        .p2align 4,,15
.globl _testi
        .def    _testi; .scl    2;      .type   32;     .endef
_testi:
        pushl   %ebp
        movl    %esp, %ebp
        movl    $0, _i
        popl    %ebp
        ret
        .p2align 4,,15
.globl _testk
        .def    _testk; .scl    2;      .type   32;     .endef
_testk:
        pushl   %ebp
        movl    %esp, %ebp
        movl    $0, _k
        popl    %ebp
        ret
        .def    ___main;        .scl    2;      .type   32;     .endef
        .p2align 4,,15
.globl _main
        .def    _main;  .scl    2;      .type   32;     .endef
_main:
        pushl   %ebp
        movl    %esp, %ebp
        andl    $-16, %esp
        call    ___main
        xorl    %eax, %eax
        movl    %ebp, %esp
        popl    %ebp
        ret
        .bss
        .balign 4
        .comm   _i, 0 <<<<< size of i[0]
        .balign 4
        .comm   _k, 4


I suspect we need to add this bit, or similar, back in
-  rounded = size ? size : 1;
-  rounded += (BIGGEST_ALIGNMENT / BITS_PER_UNIT) - 1;
-  rounded = (rounded / (BIGGEST_ALIGNMENT / BITS_PER_UNIT)
-            * (BIGGEST_ALIGNMENT / BITS_PER_UNIT));

and output rounded rather than size.

Testing now.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37216