On Tue, Jan 17, 2017 at 12:04 PM, Andrew Senkevich
<andrew.n.senkev...@gmail.com> wrote:
> 2017-01-17 1:55 GMT+03:00 Jakub Jelinek <ja...@redhat.com>:
>> On Tue, Jan 17, 2017 at 01:30:11AM +0300, Andrew Senkevich wrote:
>>> here is one more part of intrinsics for k-mask registers shifts:
>>
>> The software developer manuals describe KSHIFT{L,R}* like:
>> KSHIFTLW
>> COUNT <- imm8[7:0]
>> DEST[MAX_KL-1:0] <- 0
>> IF COUNT <=15
>> THEN DEST[15:0] <- SRC1[15:0] << COUNT;
>> FI;
>>
>> What is the behavior when src1 == dest, like:
>> kshiftld $3, %k3, %k3
>> ? Is it just a bug in the SDM and will it actually do the expected thing
>> (set %k3 to %k3 << 3 and clear just the upper bits), or do we need
>> an early-clobber on the destination to make sure GCC never emits these
>> insns with the same register as both input and output?
>
> Indeed, it should be different registers, how to do it?
"=&k" as operand 0 constraint.
Uros.
