From: Ian Lance Taylor <iant@google.com>
To: kevin diggs <diggskevin38@gmail.com>
Cc: gcc-help@gcc.gnu.org
Subject: Re: code gen for C string literals
Date: Tue, 15 Feb 2011 23:11:00 -0000 [thread overview]
Message-ID: <mcr1v39567s.fsf@google.com> (raw)
In-Reply-To: <AANLkTim4CrAJG5r4g24ObGTowG5v8rRERpV6ppLKCEhB@mail.gmail.com> (kevin diggs's message of "Tue, 15 Feb 2011 13:42:04 -0600")
kevin diggs <diggskevin38@gmail.com> writes:
> On Tue, Feb 15, 2011 at 11:25 AM, Ian Lance Taylor <iant@google.com> wrote:
>> kevin diggs <diggskevin38@gmail.com> writes:
>>
>>
>> GIMPLE is the representation used by the middle-end.
>
> ??? what is the relationship between GIMPLE and RTL, which at my VERY
> EARLY understanding of what goes on under the hood I would have
> thought was the middle-end representation? Is RTL "the back-end
> representation" (my guess would have been asm though maybe that is the
> output)?
Yes, RTL is also a representation used by the middle-end. RTL is much
more machine specific than GIMPLE. The middle-end starts with the
conversion to GIMPLE. It runs a bunch of general optimization passes.
Then the GIMPLE is converted to RTL. Then comes a few more optimization
passes, then stuff like register allocation, instruction scheduling, and
final code generation.
>> SSA is a compiler optimization technique which heavily influences the
>> design of the intermediate representation. See
>> http://en.wikipedia.org/wiki/Static_single_assignment_form .
>>
> Is SSA new? i.e. in what gcc version did it start getting used?
SSA was introduced into gcc in version 4.0.
Ian
prev parent reply other threads:[~2011-02-15 21:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-12 20:20 kevin diggs
2011-02-14 5:10 ` Ian Lance Taylor
2011-02-14 16:43 ` kevin diggs
2011-02-14 17:47 ` Ian Lance Taylor
2011-02-15 17:25 ` kevin diggs
2011-02-15 19:42 ` Ian Lance Taylor
2011-02-15 20:03 ` kevin diggs
2011-02-15 23:11 ` Ian Lance Taylor [this message]
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