On 24/05/16 14:25, Kyrill Tkachov wrote:
> Hi all,
>
> The int_log2 function in arm.c is not really useful since we already have a
> generic function for calculating
> the log2 of HOST_WIDE_INTs. The only difference in functionality is that
> int_log2 also asserts that the result
> is no greater than 31.
>
> This patch removes int_log2 in favour of exact_log2 and adds an assert on the
> result to make sure the return
> value was as expected.
>
> Bootstrapped and tested on arm-none-linux-gnueabihf.
>
> Is this ok? Or is there something I'm missing about int_log2?
Not that I can see - this is OK.
Thanks for the patience, I'm behind on patch reviews thanks to unplanned time
off recently.
Ramana
>
> Thanks,
> Kyrill
>
> 2016-05-24 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
>
> * config/arm/arm.c (int_log2): Delete definition and prototype.
> (shift_op): Use exact_log2 instead of int_log2.
> (vfp3_const_double_for_fract_bits): Likewise.
>
> arm-1.patch
>
>
> diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> index
> 6cc0feb6f87157171c889e998e52b4e5d8683c66..3fe6eab46f3c18ace6899b5be45ad646992f43e4
> 100644
> --- a/gcc/config/arm/arm.c
> +++ b/gcc/config/arm/arm.c
> @@ -104,7 +104,6 @@ static void arm_print_operand_address (FILE *,
> machine_mode, rtx);
> static bool arm_print_operand_punct_valid_p (unsigned char code);
> static const char *fp_const_from_val (REAL_VALUE_TYPE *);
> static arm_cc get_arm_condition_code (rtx);
> -static HOST_WIDE_INT int_log2 (HOST_WIDE_INT);
> static const char *output_multi_immediate (rtx *, const char *, const char *,
> int, HOST_WIDE_INT);
> static const char *shift_op (rtx, HOST_WIDE_INT *);
> @@ -18920,7 +18919,8 @@ shift_op (rtx op, HOST_WIDE_INT *amountp)
> return NULL;
> }
>
> - *amountp = int_log2 (*amountp);
> + *amountp = exact_log2 (*amountp);
> + gcc_assert (IN_RANGE (*amountp, 0, 31));
> return ARM_LSL_NAME;
>
> default:
> @@ -18952,22 +18952,6 @@ shift_op (rtx op, HOST_WIDE_INT *amountp)
> return mnem;
> }
>
> -/* Obtain the shift from the POWER of two. */
> -
> -static HOST_WIDE_INT
> -int_log2 (HOST_WIDE_INT power)
> -{
> - HOST_WIDE_INT shift = 0;
> -
> - while ((((HOST_WIDE_INT) 1 << shift) & power) == 0)
> - {
> - gcc_assert (shift <= 31);
> - shift++;
> - }
> -
> - return shift;
> -}
> -
> /* Output a .ascii pseudo-op, keeping track of lengths. This is
> because /bin/as is horribly restrictive. The judgement about
> whether or not each character is 'printable' (and can be output as
> @@ -27691,7 +27675,11 @@ vfp3_const_double_for_fract_bits (rtx operand)
> HOST_WIDE_INT value = real_to_integer (&r0);
> value = value & 0xffffffff;
> if ((value != 0) && ( (value & (value - 1)) == 0))
> - return int_log2 (value);
> + {
> + int ret = exact_log2 (value);
> + gcc_assert (IN_RANGE (ret, 0, 31));
> + return ret;
> + }
> }
> }
> return 0;
>
