On Thu, Mar 31, 2011 at 12:09 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> On Thu, Mar 31, 2011 at 11:58:29AM +0200, Uros Bizjak wrote:
>> + /* Even if the stack pointer isn't the CFA register, we need to correctly
>> + describe the adjustments made to it, in particular differentiate the
>> + frame-related ones from the frame-unrelated ones. */
>> + if (size > 0)
>> + {
>> + rtx expr = gen_rtx_SEQUENCE (VOIDmode, rtvec_alloc (2));
>> + XVECEXP (expr, 0, 0)
>> + = gen_rtx_SET (VOIDmode, stack_pointer_rtx,
>> + plus_constant (stack_pointer_rtx, -size));
>> + XVECEXP (expr, 0, 1)
>> + = gen_rtx_SET (VOIDmode, stack_pointer_rtx,
>> + plus_constant (stack_pointer_rtx,
>> + PROBE_INTERVAL + dope + size));
>> + add_reg_note (last, REG_FRAME_RELATED_EXPR, expr);
>> + RTX_FRAME_RELATED_P (last) = 1;
>> +
>> + cfun->machine->fs.sp_offset += size;
>> + }
>>
>> Is there a reason why we can't just cancel (+ size and -size) in these
>> two expressions to:
>>
>> XVECEXP (expr, 0, 0)
>> = gen_rtx_SET (VOIDmode, stack_pointer_rtx,
>> plus_constant (stack_pointer_rtx,
>> PROBE_INTERVAL + dope));
>
> Yes, in RTX_FRAME_RELATED_P parallels dwarf2out only looks at
> RTX_FRAME_RELATED_P sets or the first set. See dwarf2out_frame_debug_expr
> for more details.
Jakub, thanks for explanation, I was not aware of this fact.
2011-03-30 Eric Botcazou <ebotca...@adacore.com>
PR target/48142
* config/i386/i386.c (ix86_adjust_stack_and_probe): Differentiate
frame-related from frame-unrelated adjustments to the stack pointer.
I guess that patch is OK then.
Thanks,
Uros.
