Re: new sign/zero extension elimination pass

[Tom de Vries <Tom_deVries@mentor.com>]

On 11/07/12 12:30, Tom de Vries wrote:
> On 13/11/10 10:50, Eric Botcazou wrote:
>>> I profiled the pass on spec2000:
>>>
>>>                     -mabi=32     -mabi=64
>>> ee-pass (usr time):     0.70         1.16
>>> total   (usr time):   919.30       879.26
>>> ee-pass        (%):     0.08         0.13
>>>
>>> The pass takes 0.13% or less of the total usr runtime.
>>
>> For how many hits?  What are the numbers with --param ee-max-propagate=0?
>>
>>> Is it necessary to improve the runtime of this pass?
>>
>> I've already given my opinion about the implementation.  The other passes in 
>> the compiler try hard not to rescan everything when a single bit changes; as 
>> currently written, yours doesn't.
>>
> 
> Eric,
> 
> I've done the following:
> - refactored the pass such that it now scans at most twice over all
>   instructions.
> - updated the patch to be applicable to current trunk
> - updated the motivating example to a more applicable one (as discussed in
>   this thread), and added that one as test-case.
> - added a part in the header comment illustrating the working of the pass
>   on the motivating example.
> 
> bootstrapped and reg-tested on x86_64 and i686.
> 
> build and reg-tested on mips, mips64, and arm.
> 
> OK for trunk?
> 

Eric,

does the new patch meet your concerns related to rescanning?

If so, OK for trunk?

Thanks,
- Tom


> Thanks,
> - Tom
> 
> 2012-07-10  Tom de Vries  <tom@codesourcery.com>
> 
> 	* ee.c: New file.
> 	* tree-pass.h (pass_ee): Declare.
> 	* opts.c ( default_options_table): Set flag_ee at -O2.
> 	* timevar.def (TV_EE): New timevar.
> 	* common.opt (fextension-elimination): New option.
> 	* Makefile.in (ee.o): New rule.
> 	* passes.c (pass_ee): Add it.
> 
> 	* gcc.dg/extend-1.c: New test.
> 	* gcc.dg/extend-2.c: Same.
> 	* gcc.dg/extend-2-64.c: Same.
> 	* gcc.dg/extend-3.c: Same.
> 	* gcc.dg/extend-4.c: Same.
> 	* gcc.dg/extend-5.c: Same.
> 	* gcc.target/mips/octeon-bbit-2.c: Make test more robust.
>