2012/1/13 Georg-Johann Lay <a...@gjlay.de>:
> Denis Chertykov wrote:
>
>> Committed
>>
>> Denis
>
>
> Consider code prom PR51374
>
> void __vector_18 (void)
> {
> extern char slot;
> unsigned char status = (*(volatile unsigned char*) 0x2B);
> unsigned char data = (*(volatile unsigned char*) 0x2C);
>
> if (status & 0x10)
> slot = 0;
> }
>
> the code with -Os -S -dp sets up a frame pointer which is not needed and
> should
> not be there:
>
> __vector_18:
> push r28 ; 28 pushqi1/1 [length = 1]
> push r29 ; 29 pushqi1/1 [length = 1]
> in r28,__SP_L__ ; 30 *movhi/8 [length = 2]
> in r29,__SP_H__
> /* prologue: function */
> /* frame size = 0 */
> /* stack size = 2 */
> .L__stack_usage = 2
> in r24,0xc ; 8 movqi_insn/4 [length = 1]
> sbis 0xb,4 ; 11 *sbix_branch [length = 2]
> rjmp .L1
> sts slot,__zero_reg__ ; 13 movqi_insn/3 [length = 2]
> .L1:
> /* epilogue start */
> pop r29 ; 33 popqi [length = 1]
> pop r28 ; 34 popqi [length = 1]
> ret ; 35 return_from_epilogue [length = 1]
>
> This happens even for empty function.
Oops.
Something wrong happened, probably I committed a wrong untested patch.
It must be reverted.
Denis.
