[LLVMdev] Impressive performance result for LLVM: complex arithmetic

[David Greene]

On Friday 27 February 2009 12:12, Daniel Berlin wrote:
> On gcc's side, this is a simple missed opt on the part of builtin lowering.
> As a result, the gcc code ends up with a call to muldc3 (complex = 2x2
> multiply double) and the llvm code doesn't.
> GCC should be fixed in a second, and with that, there is no
> appreciable performance difference between the two.

FYI, gcc 4.3.3 gets the same performance with -O3.  I reproduced Jon's gcc 
results on 4.3.3 with -O0.

                                              -Dave