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Re: GCC beaten by ICC in stupid trig test!
- From: Roger Sayle <roger at eyesopen dot com>
- To: Bradley Lucier <lucier at math dot purdue dot edu>, Toon Moene <toon at moene dot indiv dot nluug dot nl>, Scott Robert Ladd <coyote at coyotegulch dot com>
- Cc: gcc at gcc dot gnu dot org, <gcc-patches at gcc dot gnu dot org>
- Date: Wed, 24 Mar 2004 14:00:08 -0700 (MST)
- Subject: Re: GCC beaten by ICC in stupid trig test!
May I remind everyone that the subject title "GCC beaten by ICC in
stupid trig test!" refers to a posting by Scott Robert Ladd in which
Intel's icc compiler generates floating point code 64x faster than
gcc 3.3.3 (http://gcc.gnu.org/ml/gcc/2004-03/msg00634.html).
Would anyone like to hazard a guess at how many floating point additions
Intel icc v7 generates for the following function? Even with icc's
default arguments, i.e. "icc foo.c"?
int foo(double a, double b, double c)
{
return (a+b)+c == a+(b+c);
}
It might surprise some people that even with -funsafe-math-optimizations
and/or -ffast-math GCC can't generate code with that performance/accuracy
trade-off!
Roger
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