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Re: Optimal compile flags for ultra2 & power2
- To: Stephen Hocking-Senior Programmer PGS Tensor Perth <shocking at prth dot pgs dot com>
- Subject: Re: Optimal compile flags for ultra2 & power2
- From: David Edelsohn <dje at watson dot ibm dot com>
- Date: Tue, 22 Sep 1998 10:57:32 -0400
- Cc: egcs at cygnus dot com
>>>>> Stephen Hocking-Senior Programmer PGS Tensor Perth writes:
Stephen> I was wondering what flags people use for best FP performance on these -
Stephen> b) IBM Power2.
-mcpu=rios2 -ffast-math -lrs2
Make sure that -ffast-math is safe for your application -- it is a general
GCC optimization. /usr/lib/librs2.a is an additional math library
provided by IBM that substitutes the hardware fsqrt instruction for the
library sqrt call and all places that it is used.
David