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Re: [PATCH, x86-Atom] Enabling look-ahead scheduling feature for Atom processors


I'd like this patch (original version at the bottom) also to be
backported into 4.7.

Is it safe to backport?

On Fri, Aug 24, 2012 at 11:35 AM, Uros Bizjak <> wrote:
> On Fri, Aug 24, 2012 at 9:22 AM, Igor Zamyatin <> wrote:
>> Following change enables look ahead feature in the code scheduler for
>> Atom processors. This gives quite reasonable gain for some benchmarks
>> for mobile market.
>> Overall compile time increase for SPEC2000 is about 1%.
>> Regtested for x86_64 and also bootstrapped with "--with-arch=core2
>> --with-cpu=atom"
>> 2012-08-23  Yuri Rumyantsev  <>
>>         * config/i386/i386.c (ia32_multipass_dfa_lookahead) : Add
>>         case for Atom processor.
> OK.
> Thanks,
> Uros.

Original patch:

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 976bbb4..331e29a 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -24103,6 +24103,7 @@ ia32_multipass_dfa_lookahead (void)
     case PROCESSOR_CORE2_64:
     case PROCESSOR_COREI7_32:
     case PROCESSOR_COREI7_64:
       /* Generally, we want haifa-sched:max_issue() to look ahead as far
         as many instructions can be executed on a cycle, i.e.,
         issue_rate.  I wonder why tuning for many CPUs does not do this.  */

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