On Tue, May 3, 2016 at 1:55 PM, Andy Lutomirski wrote:
> On Tue, May 3, 2016 at 10:45 AM, Brian Gerst wrote:
>> On Mon, May 2, 2016 at 10:56 AM, Denys Vlasenko wrote:
>>> Use of a temporary R8 register here seems to be unnecessary.
On Tue, May 3, 2016 at 1:55 PM, Andy Lutomirski wrote:
> On Tue, May 3, 2016 at 10:45 AM, Brian Gerst wrote:
>> On Mon, May 2, 2016 at 10:56 AM, Denys Vlasenko wrote:
>>> Use of a temporary R8 register here seems to be unnecessary.
>>>
>>> "push %r8" is a two-byte insn (it needs REX prefix to
On Tue, May 3, 2016 at 10:45 AM, Brian Gerst wrote:
> On Mon, May 2, 2016 at 10:56 AM, Denys Vlasenko wrote:
>> Use of a temporary R8 register here seems to be unnecessary.
>>
>> "push %r8" is a two-byte insn (it needs REX prefix to specify R8),
>> "push
On Tue, May 3, 2016 at 10:45 AM, Brian Gerst wrote:
> On Mon, May 2, 2016 at 10:56 AM, Denys Vlasenko wrote:
>> Use of a temporary R8 register here seems to be unnecessary.
>>
>> "push %r8" is a two-byte insn (it needs REX prefix to specify R8),
>> "push $0" is two-byte too. It seems just using
On Mon, May 2, 2016 at 10:56 AM, Denys Vlasenko wrote:
> Use of a temporary R8 register here seems to be unnecessary.
>
> "push %r8" is a two-byte insn (it needs REX prefix to specify R8),
> "push $0" is two-byte too. It seems just using the latter would be
> no worse.
>
>
On Mon, May 2, 2016 at 10:56 AM, Denys Vlasenko wrote:
> Use of a temporary R8 register here seems to be unnecessary.
>
> "push %r8" is a two-byte insn (it needs REX prefix to specify R8),
> "push $0" is two-byte too. It seems just using the latter would be
> no worse.
>
> Thus, code had an
On Mon, May 2, 2016 at 7:56 AM, Denys Vlasenko wrote:
> Use of a temporary R8 register here seems to be unnecessary.
>
> "push %r8" is a two-byte insn (it needs REX prefix to specify R8),
> "push $0" is two-byte too. It seems just using the latter would be
> no worse.
>
>
On Mon, May 2, 2016 at 7:56 AM, Denys Vlasenko wrote:
> Use of a temporary R8 register here seems to be unnecessary.
>
> "push %r8" is a two-byte insn (it needs REX prefix to specify R8),
> "push $0" is two-byte too. It seems just using the latter would be
> no worse.
>
> Thus, code had an
Use of a temporary R8 register here seems to be unnecessary.
"push %r8" is a two-byte insn (it needs REX prefix to specify R8),
"push $0" is two-byte too. It seems just using the latter would be
no worse.
Thus, code had an unnecessary "xorq %r8,%r8" insn.
It probably costs nothing in execution
Use of a temporary R8 register here seems to be unnecessary.
"push %r8" is a two-byte insn (it needs REX prefix to specify R8),
"push $0" is two-byte too. It seems just using the latter would be
no worse.
Thus, code had an unnecessary "xorq %r8,%r8" insn.
It probably costs nothing in execution
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