------- Comment #30 from hjl dot tools at gmail dot com 2009-02-22 19:28
-------
(In reply to comment #29)
> I mean aligned(64).
> I guess something like this then?
> Index: config/i386/i386.c
> ===================================================================
> --- config/i386/i386.c (revision 144373)
> +++ config/i386/i386.c (working copy)
> @@ -19351,6 +19351,12 @@ unsigned int
> ix86_local_alignment (tree type, enum machine_mode mode,
> unsigned int align)
> {
> + /* We don't want to align DImode to 64bit for compilation with
> + -mpreferred-stack-boundary=2 to not enforce dynamic stack alignment
> + prologue. */
> + if (mode == DImode && !TARGET_64BIT && ix86_preferred_stack_boundary < 64)
> + align = 32;
> +
It will always align DI to 4 byte in 32bit mode. Did you mean to
replace it with the code below?
> /* If TYPE is NULL, we are allocating a stack slot for caller-save
> register in MODE. We will return the largest alignment of XF
> and DF. */
> @@ -19360,6 +19366,12 @@ ix86_local_alignment (tree type, enum ma
> align = GET_MODE_ALIGNMENT (DFmode);
> return align;
> }
> + if (!TARGET_64BIT
> + && align == 64
> + && ix86_preferred_stack_boundary < 64
> + && (mode == DImode || (type && TYPE_MODE (type) == DImode))
> + && (!type || !TYPE_USER_ALIGN (type)))
> + align = 32;
>
TYPE_USER_ALIGN isn't set on DImode due to canonical type:
Breakpoint 5, ix86_local_alignment (type=0x7ffff7ed2900, mode=VOIDmode,
align=256) at /export/gnu/src/gcc-work/gcc/gcc/config/i386/i386.c:19433
19433 if (!type)
(gdb) call debug_tree (type)
<integer_type 0x7ffff7ed2900 long long unsigned int sizes-gimplified public
unsigned DI
size <integer_cst 0x7ffff7ec1c30 type <integer_type 0x7ffff7ed20c0
bit_size_type> constant 64>
unit size <integer_cst 0x7ffff7ec1c60 type <integer_type 0x7ffff7ed2000
unsigned int> constant 8>
align 64 symtab 0 alias set -1 canonical type 0x7ffff7ed2900 precision 64
min <integer_cst 0x7ffff7ec1c90 0> max <integer_cst 0x7ffff7ec1c00
18446744073709551615>
pointer_to_this <pointer_type 0x7ffff7ee8780>>
(gdb)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39137
