On Jan 19, 7:21 pm, Jonathan Bober <jwbo...@gmail.com> wrote: > Should PARI always be compiled with -fPIC? (Should I really be asking > this question to PARI developers who decided not to use PIC?) I don't > know much about this, but apparently -fPIC might cause some slowdown on > some systems. It seems that just about everything else in Sage is > compiled to be position independent, though (at least, nothing else > causes this problem).
You should probably always use -fPIC. PIC code is slower because there is a symbol lookup table which adds an extra level of indirection to function calls, however this doesn't matter much in practice (max 10%?) and should only affect 32-bit Linux on x86. My understanding is that x86-64 Linux code generated by GCC will always be -fPIC, and there is hardly any gain to be had because register pressure is greatly reduced.
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