Re: [AArch64 costs 14/18] Cost comparisons, flag setting operators and IF_THEN_ELSE

[Andrew Pinski]

On Thu, Mar 27, 2014 at 10:33 AM, James Greenhalgh
<james.greenha...@arm.com> wrote:
> Hi,
>
> Next, comparisons, flag setting operations and IF_THEN_ELSE.
>
> Tested on aarch64-none-elf.
>
> Ok for stage 1?

This broke building the Linux kernel.
A simple testcase:
unsigned grab_cache_page_write_begin(unsigned flags, unsigned capabilities)
{
  unsigned gfp_mask;
  unsigned gfp_notmask = 0;
  gfp_mask = flags & ((1 << 25) - 1);
  if (!(capabilities & 0x00000001))
    gfp_mask |= 0x1000000u;
  return (gfp_mask & ~gfp_notmask);
}

---- CUT ----
The problem is combine creates the following RTL:
(if_then_else:SI (reg:SI 78 [ D.2578 ])
    (const_int 0 [0])
    (const_int 16777216 [0x1000000]))

Which the code you added does not handle.  I am going to fix this but
I need to re-factor this code.  I am going to place the code for
IF_THEN_ELSE in its own function also since it is getting too large
for my taste.

Thanks,
Andrew Pinski

>
> Thanks,
> James
>
> ---
> 2014-03-27  James Greenhalgh  <james.greenha...@arm.com>
>             Philipp Tomsich  <philipp.toms...@theobroma-systems.com>
>
>         * config/aarch64/aarch64.c (aarch64_rtx_costs): Cost comparison
>         operators.