[PATCH][Review Requested][Compilation Time] Small Vector for Machine Operand

[Bill Wendling]

Hi Tyler,

When passing around vectors that you're not going to modify, please use an 'ArrayRef<>' instead. The numbers for the SPEC tests seemed to increase. Is that a good thing? I.e., what are those numbers measuring? Have you considered using a '.reserve()' call on the std::vectors to limit the amount of reallocating and copying it does?

-bw

P.S. If you're going to pass a SmallVector around that you plan on modifying, you should use this:

	void foo(SmallVectorImpl<SomeType> &fnord) {}

You can use the same when looping:

	for (SmallVectorImpl<SomeType>::iterator I = ...)

That way you don't have to worry about the SmallVector count.

On Feb 4, 2013, at 12:22 PM, "Nowicki, Tyler" <tyler.nowicki at intel.com> wrote:

> Could someone please review this patch.
>  
> Thanks,
>  
> Tyler
>  
> From: llvm-commits-bounces at cs.uiuc.edu [mailto:llvm-commits-bounces at cs.uiuc.edu] On Behalf Of Nowicki, Tyler
> Sent: Thursday, January 31, 2013 5:10 PM
> To: Jakub Staszak
> Cc: llvm-commits at cs.uiuc.edu; Jakub Staszak
> Subject: RE: [PATCH][Review Requested][Compilation Time] Small Vector for Machine Operand
>  
> Oops, thanks.
>  
> Here is the patch…
>  
> Tyler
>  
> From: Jakub Staszak [mailto:kubastaszak at gmail.com] 
> Sent: Thursday, January 31, 2013 5:01 PM
> To: Nowicki, Tyler
> Cc: Jakub Staszak; llvm-commits at cs.uiuc.edu
> Subject: Re: [PATCH][Review Requested][Compilation Time] Small Vector for Machine Operand
>  
> Looks like you forgot to attach the patch :)
>  
> - Kuba
>  
> On Jan 31, 2013, at 7:58 PM, "Nowicki, Tyler" <tyler.nowicki at intel.com> wrote:
>  
> 
> This patch aims to improve compile time performance by changing when the SchedulerDAG object is created and destroyed, and replacing std::vector with SmallVector. Currently, ScheduleDAG is deleted after each BB which causes frequent SUnits vector clearance, and std::vector causes frequent element copies the vector size grows. Please see attached performance data.
>  
> This patch is part of a series of compile time improvements. Although these were originally produced by our colleague Wan Xiaofei, our team consisting of preston.gurd at intel.com; sriram.murali at intel.com and myself, are assuming all responsibility for this work.
>  
> PLEASE REVIEW. Thanks!
>  
> Tyler Nowicki
> Intel
>  
> Benchmark
> Trunk
> SmallVec.SU
> 401.bzip2
> 74.21
> 72.48
> 403.gcc
> 73.88
> 71.65
> 429.mcf
> 72.80
> 71.33
> 433.milc
> 78.78
> 78.14
> 444.namd
> 94.73
> 93.45
> 445.gobmk
> 36.28
> 35.51
> 450.soplex
> 71.41
> 69.64
> 456.hmmer
> 86.80
> 84.86
> 458.sjeng
> 96.38
> 94.27
> 464.h264ref
> 87.61
> 86.36
> 470.lbm
> 68.95
> 68.09
> 471.omnetpp
> 89.07
> 86.57
> bitmnp01
> 84.06
> 81.60
> cjpegv2data6
> 59.70
> 58.84
> idctrn01
> 40.18
> 39.79
> libquake2
> 48.48
> 47.54
> libquake_portable
> 63.54
> 62.38
> libxcsoar
> 47.44
> 46.81
> linpack
> 142.14
> 141.63
> matrix01
> 24.75
> 24.40
> nbench
> 108.04
> 107.04
> tblook01
> 44.03
> 43.71
> ttsprk01
> 39.23
> 38.54
> Geomean
> 65.85
> 64.72
> 401.bzip2
> 100.00
> 102.39
> 403.gcc
> 100.00
> 103.11
> 429.mcf
> 100.00
> 102.06
> 433.milc
> 100.00
> 100.82
> 444.namd
> 100.00
> 101.37
> 445.gobmk
> 100.00
> 102.17
> 450.soplex
> 100.00
> 102.54
> 456.hmmer
> 100.00
> 102.29
> 458.sjeng
> 100.00
> 102.24
> 464.h264ref
> 100.00
> 101.45
> 470.lbm
> 100.00
> 101.26
> 471.omnetpp
> 100.00
> 102.89
> bitmnp01
> 100.00
> 103.01
> cjpegv2data6
> 100.00
> 101.46
> idctrn01
> 100.00
> 100.98
> libquake2
> 100.00
> 101.98
> libquake_portable
> 100.00
> 101.86
> libxcsoar
> 100.00
> 101.35
> linpack
> 100.00
> 100.36
> matrix01
> 100.00
> 101.43
> nbench
> 100.00
> 100.93
> tblook01
> 100.00
> 100.73
> ttsprk01
> 100.00
> 101.79
> Geomean
> 100.00
> 101.76
>  
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