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Subject: Re: [Boost-users] Static linking/GCC 4.3.2 on Linux (-fPIC missing?)
From: Ravi (lists_ravi_at_[hidden])
Date: 2009-03-09 10:52:08

On Sunday 08 March 2009 01:47:52 Vladimir Prus wrote:
> Or are there any negative effects by enabling -fPIC?
> -fPIC generates slower code. I am not aware of up-to-date data on how much
> slower.

On my numerically intensive software, -fPIC does not lead to any measurable
slowdowns. Another data point comes from ATLAS (whose sole raison d'etre is
speed in numerical computations) in its INSTALL.txt file:

NOTE: Since gcc uses one less int register when compiling with this flag, this
      could potentially impact performance of the architectural defaults,
      but we have not seen it so far.
However, note that both my library of code and ATLAS are primarily interested 
in floating point computation performance. Different conclusions may be 
reached for other types of computation load though I very much doubt it.

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