* Claudiu Zissulescu <claz...@gmail.com> [2019-03-25 11:56:49 +0100]:
> Hi,
>
> When not optimizing for size, we can restore first blink, hence the return
> instruction will be executed faster.
>
> OK to apply?
> Claudiu
>
> gcc/
> xxxx-xx-xx Claudiu Zissulescu <claz...@synopsys.com>
>
> * config/arc/arc.c (GMASK_LEN): Define.
> (arc_restore_callee_saves): Restore first blink when
> !optimize_size.
This looks fine.
Thanks,
Andrew
> ---
> gcc/config/arc/arc.c | 37 +++++++++++++++++++++++++++++++++++--
> 1 file changed, 35 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/config/arc/arc.c b/gcc/config/arc/arc.c
> index de2c8d5df9c..9a6920a709f 100644
> --- a/gcc/config/arc/arc.c
> +++ b/gcc/config/arc/arc.c
> @@ -2545,6 +2545,9 @@ struct GTY (()) arc_frame_info
> bool save_return_addr;
> };
>
> +/* GMASK bit length -1. */
> +#define GMASK_LEN 31
> +
> /* Defining data structures for per-function information. */
>
> typedef struct GTY (()) machine_function
> @@ -3087,6 +3090,8 @@ arc_restore_callee_saves (unsigned int gmask,
> {
> rtx reg;
> int frame_deallocated = 0;
> + HOST_WIDE_INT offs = cfun->machine->frame_info.reg_size;
> + bool early_blink_restore;
>
> /* Emit mov fp,sp. */
> if (arc_frame_pointer_needed () && offset)
> @@ -3112,9 +3117,21 @@ arc_restore_callee_saves (unsigned int gmask,
> offset = 0;
> }
>
> + /* When we do not optimize for size, restore first blink. */
> + early_blink_restore = restore_blink && !optimize_size && offs;
> + if (early_blink_restore)
> + {
> + rtx addr = plus_constant (Pmode, stack_pointer_rtx, offs);
> + reg = gen_rtx_REG (Pmode, RETURN_ADDR_REGNUM);
> + rtx insn = frame_move_inc (reg, gen_frame_mem (Pmode, addr),
> + stack_pointer_rtx, NULL_RTX);
> + add_reg_note (insn, REG_CFA_RESTORE, reg);
> + restore_blink = false;
> + }
> +
> /* N.B. FRAME_POINTER_MASK and RETURN_ADDR_MASK are cleared in gmask. */
> if (gmask)
> - for (int i = 0; i <= 31; i++)
> + for (int i = 0; i <= GMASK_LEN; i++)
> {
> machine_mode restore_mode = SImode;
>
> @@ -3127,7 +3144,23 @@ arc_restore_callee_saves (unsigned int gmask,
> continue;
>
> reg = gen_rtx_REG (restore_mode, i);
> - frame_deallocated += frame_restore_reg (reg, 0);
> + offs = 0;
> + switch (restore_mode)
> + {
> + case E_DImode:
> + if ((GMASK_LEN - __builtin_clz (gmask)) == (i + 1)
> + && early_blink_restore)
> + offs = 4;
> + break;
> + case E_SImode:
> + if ((GMASK_LEN - __builtin_clz (gmask)) == i
> + && early_blink_restore)
> + offs = 4;
> + break;
> + default:
> + offs = 0;
> + }
> + frame_deallocated += frame_restore_reg (reg, offs);
> offset = 0;
>
> if (restore_mode == DImode)
> --
> 2.20.1
>
