At Sat, 9 Jun 2007 04:25:55 +0200, Tommy Nordgren wrote: > Are there any way, when using the GNU Compiler Collection, to make > the compiler optimize expressions where the same function call > occurs more than once. (Same function, same parameters) GCC does > this for standard C functions such as cos and sin, when passed -O3 > or -Os -fgcse I'm interested in this, because most special functions > computed by GSL are probably more expensive to compute than the > basic transcendental functions, and in general you can get many > common subexpressions when generating C code from symbol math > programs.
__attribute__ ((pure), see "Function attributes" in the GCC manual for details. -- Brian Gough
