On 17/12/15 17:24, James Greenhalgh wrote:
> On Thu, Dec 17, 2015 at 03:36:40PM +0000, Kyrill Tkachov wrote:
>> 2015-12-17  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
>>
>>      PR rtl-optimization/68796
>>      * config/aarch64/aarch64.md (*and<mode>3nr_compare0_zextract):
>>      New pattern.
>>      * config/aarch64/aarch64.c (aarch64_select_cc_mode): Handle
>>      ZERO_EXTRACT comparison with zero.
>>      (aarch64_mask_from_zextract_ops): New function.
>>      * config/aarch64/aarch64-protos.h (aarch64_mask_from_zextract_ops):
>>      New prototype.
>>
>> 2015-12-17  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
>>
>>      PR rtl-optimization/68796
>>      * gcc.target/aarch64/tst_3.c: New test.
>>      * gcc.target/aarch64/tst_4.c: Likewise.
> Two comments.
>
>> diff --git a/gcc/config/aarch64/aarch64-protos.h b/gcc/config/aarch64/aarch64-protos.h
>> index 87d6eb1358845527d7068550925949802a7e48e2..febca98d38d5f09c97b0f79adc55bb29eca217b9 100644
>> --- a/gcc/config/aarch64/aarch64-protos.h
>> +++ b/gcc/config/aarch64/aarch64-protos.h
>> @@ -330,6 +330,7 @@ int aarch64_uxt_size (int, HOST_WIDE_INT);
>>   int aarch64_vec_fpconst_pow_of_2 (rtx);
>>   rtx aarch64_final_eh_return_addr (void);
>>   rtx aarch64_legitimize_reload_address (rtx *, machine_mode, int, int, int);
>> +rtx aarch64_mask_from_zextract_ops (rtx, rtx);
>>   const char *aarch64_output_move_struct (rtx *operands);
>>   rtx aarch64_return_addr (int, rtx);
>>   rtx aarch64_simd_gen_const_vector_dup (machine_mode, int);
>> diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
>> index cb8955d5d6c909e8179bb1ab8203eb165f55e4b6..58a9fc68f391162ed9847d7fb79d70d3ee9919f5 100644
>> --- a/gcc/config/aarch64/aarch64.c
>> +++ b/gcc/config/aarch64/aarch64.c
>> @@ -4147,7 +4147,9 @@ aarch64_select_cc_mode (RTX_CODE code, rtx x, rtx y)
>>         && y == const0_rtx
>>         && (code == EQ || code == NE || code == LT || code == GE)
>>         && (GET_CODE (x) == PLUS || GET_CODE (x) == MINUS || GET_CODE (x) == AND
>> -	  || GET_CODE (x) == NEG))
>> +	  || GET_CODE (x) == NEG
>> +	  || (GET_CODE (x) == ZERO_EXTRACT && CONST_INT_P (XEXP (x, 1))
>> +	      && CONST_INT_P (XEXP (x, 2)))))
>>       return CC_NZmode;
>>   
>>     /* A compare with a shifted operand.  Because of canonicalization,
>> @@ -10757,6 +10759,21 @@ aarch64_simd_imm_zero_p (rtx x, machine_mode mode)
>>     return x == CONST0_RTX (mode);
>>   }
>>   
>> +
>> +/* Return the bitmask CONST_INT to select the bits required by a zero extract
>> +   operation of width WIDTH at bit position POS.  */
>> +
>> +rtx
>> +aarch64_mask_from_zextract_ops (rtx width, rtx pos)
>> +{
> It is up to you, but would this not more naturally be:
>
>    unsigned HOST_WIDE_INT
>    aarch64_mask_from_zextract_ops (rtx width, rtx pos)
>
> Given how it gets used elsewhere?
>
>> +  gcc_assert (CONST_INT_P (width));
>> +  gcc_assert (CONST_INT_P (pos));
>> +
>> +  unsigned HOST_WIDE_INT mask
>> +    = ((unsigned HOST_WIDE_INT)1 << UINTVAL (width)) - 1;
> Space between (unsigned HOST_WIDE_INT) and 1.
>
>> +  return GEN_INT (mask << UINTVAL (pos));
>> +}
>> +
>>   bool
>>   aarch64_simd_imm_scalar_p (rtx x, machine_mode mode ATTRIBUTE_UNUSED)
>>   {
> Otherwise, this is OK.

Thanks, I've chosen to keep the return type of aarch64_mask_from_zextract_ops as rtx
and fixed the whitespace. I'm committing this version to trunk.

Thanks,
Kyrill


> Thanks,
> James
>