more robust check for multiplier in addressing mode when determining the costs

I'm working on a chip with some unusual addressing modes.
it does have [base_rage+msize*index_reg] and one can't omit base_reg like
on x86.
But when ivopts tries to calculate the costs of different addressing modes
it only checks [mult*reg] to determine allowable multipliers.
I modified multiplier_allowed_in_address_p to check both cases.

There's no actual testcase that fails it's just my back-end generated
sub-optimal code.
I tested it on my tree off 4.8.1 and it fixes the problem.
Rebuilt trunk for x86_64-linux-gnu.

Should it be included in trunk to make check more robust?

Thanks
Igor

2013-10-22  Igor Shevlyakov  <igor.shevlyakov@gmail.com>

* tree-ssa-loop-ivopts.c (multiplier_allowed_in_address_p ): Check both
  [reg+mult*reg] and [mult*reg] to determine if multiplier is allowed.

On Wed, Oct 23, 2013 at 1:42 AM, Igor Shevlyakov
<igor.shevlyakov@gmail.com> wrote:
> I'm working on a chip with some unusual addressing modes.
> it does have [base_rage+msize*index_reg] and one can't omit base_reg like
> on x86.
> But when ivopts tries to calculate the costs of different addressing modes
> it only checks [mult*reg] to determine allowable multipliers.
> I modified multiplier_allowed_in_address_p to check both cases.
>
> There's no actual testcase that fails it's just my back-end generated
> sub-optimal code.
> I tested it on my tree off 4.8.1 and it fixes the problem.
> Rebuilt trunk for x86_64-linux-gnu.
>
> Should it be included in trunk to make check more robust?

I think somebody else fixed this on trunk already.

Richard.

> Thanks
> Igor
>
> 2013-10-22  Igor Shevlyakov  <igor.shevlyakov@gmail.com>
>
> * tree-ssa-loop-ivopts.c (multiplier_allowed_in_address_p ): Check both
>   [reg+mult*reg] and [mult*reg] to determine if multiplier is allowed.
>
>
> Index: tree-ssa-loop-ivopts.c
> ===================================================================
> --- tree-ssa-loop-ivopts.c (revision 203937)
> +++ tree-ssa-loop-ivopts.c (working copy)
> @@ -3108,16 +3108,19 @@ multiplier_allowed_in_address_p (HOST_WI
>      {
>        enum machine_mode address_mode = targetm.addr_space.address_mode
> (as);
>        rtx reg1 = gen_raw_REG (address_mode, LAST_VIRTUAL_REGISTER + 1);
> -      rtx addr;
> +      rtx reg2 = gen_raw_REG (address_mode, LAST_VIRTUAL_REGISTER + 2);
> +      rtx addr, scaled;
>        HOST_WIDE_INT i;
>
>        valid_mult = sbitmap_alloc (2 * MAX_RATIO + 1);
>        bitmap_clear (valid_mult);
> -      addr = gen_rtx_fmt_ee (MULT, address_mode, reg1, NULL_RTX);
> +      scaled = gen_rtx_fmt_ee (MULT, address_mode, reg1,   NULL_RTX);
> +      addr   = gen_rtx_fmt_ee (PLUS, address_mode, scaled, reg2);
>        for (i = -MAX_RATIO; i <= MAX_RATIO; i++)
>   {
> -  XEXP (addr, 1) = gen_int_mode (i, address_mode);
> -  if (memory_address_addr_space_p (mode, addr, as))
> +  XEXP (scaled, 1) = gen_int_mode (i, address_mode);
> +  if (memory_address_addr_space_p (mode, addr, as) ||
> +      memory_address_addr_space_p (mode, scaled, as))
>      bitmap_set_bit (valid_mult, i + MAX_RATIO);
>   }

On 10/22/13 17:42, Igor Shevlyakov wrote:
> 2013-10-22  Igor Shevlyakov<igor.shevlyakov@gmail.com>
>
> * tree-ssa-loop-ivopts.c (multiplier_allowed_in_address_p ): Check both
>    [reg+mult*reg] and [mult*reg] to determine if multiplier is allowed.
Thanks.  I've re-bootstrapped & regtested on x86_64-unknown-linux-gnu 
with the trunk and installed this patch on your behalf.

Thanks,
Jeff