[5/9] Create sensible dummy registers

[Jeff Law]

On 05/22/2015 09:39 AM, Richard Sandiford wrote:
> Eric Botcazou <ebotcazou@adacore.com> writes:
>>> Some pieces of code create a temporary REG or MEM and only fill it
>>> in later when they're testing the cost of a particular rtx.  This patch
>>> makes sure that even the dummy REG or MEM is valid, rather than force
>>> the gen_* code to handle garbage values.
>>>
>>>
>>> gcc/
>>> 	* caller-save.c (init_caller_save): Use word_mode and
>>> 	FIRST_PSEUDO_REGISTER when creating temporary rtxes.
>>> 	* expr.c (init_expr_target): Likewise.
>>> 	* ira.c (setup_prohibited_mode_move_regs): Likewise.
>>> 	* postreload.c (reload_cse_regs_1): Likewise.
>>
>> Isn't LAST_VIRTUAL_REGISTER + 1 the canonical regno to be used in this case?
>
> Ah, yeah.  Here's patch to fix all instances of that (I hope).
>
> Bootstrapped & regression-tested on x86_64-linux-gnu.  OK to install?
>
> Thanks,
> Richard
>
>
> gcc/
> 	* caller-save.c (init_caller_save): Base temporary register numbers
> 	on LAST_VIRTUAL_REGISTER + 1 rather than FIRST_PSEUDO_REGISTER.
> 	* cfgloopanal.c (init_set_costs): Likewise.
> 	* dojump.c (prefer_and_bit_test): Likewise.
> 	* expr.c (init_expr_target): Likewise.
> 	* ira.c (setup_prohibited_mode_move_regs): Likewise.
> 	* lower-subreg.c (init_lower_subreg): Likewise.
> 	* postreload.c (reload_cse_regs_1): Likewise.
OK.
jeff