From: Uros Bizjak <ubizjak@gmail.com>
To: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Cc: Jeff Law <law@redhat.com>,
"Nesterovskiy, Alexander" <alexander.nesterovskiy@intel.com>
Subject: Re: [patch, i386] false dependencies fix
Date: Thu, 28 Jun 2018 07:16:00 -0000 [thread overview]
Message-ID: <CAFULd4bazoZpD27WwsQ5_tkZ=P0E7o_goNqjAqo+9Mx5+yKSZA@mail.gmail.com> (raw)
Hello!
>> --- i386.md (revision 259756)
>> +++ i386.md (working copy)
>> @@ -3547,7 +3547,7 @@
>> {
>> case MODE_DF:
>> if (TARGET_AVX && REG_P (operands[0]) && REG_P (operands[1]))
>> - return "vmovsd\t{%1, %0, %0|%0, %0, %1}";
>> + return "%vmovsd\t{%d1, %0|%0, %d1}";
>> return "%vmovsd\t{%1, %0|%0, %1}";
>>
>> case MODE_V4SF:
>> @@ -3748,7 +3748,7 @@
>> {
>> case MODE_SF:
>> if (TARGET_AVX && REG_P (operands[0]) && REG_P (operands[1]))
>> - return "vmovss\t{%1, %0, %0|%0, %0, %1}";
>> + return "%vmovss\t{%d1, %0|%0, %d1}";
>> return "%vmovss\t{%1, %0|%0, %1}";
> So what I'm confused about is in the original output template operand 0
> is duplicated. In the new template operand 1 is duplicated.
>
> Presumably what you're trying to accomplish is avoiding a false read on
> operand 0 (the destination)? Can you please confirm?
> Knowing that should also help me evaluate the changes to recp and rsqrt
> since they're being changed to the same style encoding when operating
> strictly on registers.
Please don't change "v" -> "%v" for TARGET_AVX templates. We know that
in this case, all insn mnemonics are prefixed with "v".
Uros.
next reply other threads:[~2018-06-28 7:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-28 7:16 Uros Bizjak [this message]
2018-06-28 13:56 ` Jeff Law
2018-06-29 0:04 ` Jeff Law
-- strict thread matches above, loose matches on Subject: below --
2018-05-03 9:01 Uros Bizjak
2018-05-02 9:55 Nesterovskiy, Alexander
2018-06-28 4:29 ` Jeff Law
2018-06-28 8:57 ` Nesterovskiy, Alexander
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