On Wed, 25 Oct 2000, Andre wrote:
All results are in clock cycles on a Pentium III:
gcc version egcs-2.91.66 (ie stock RH 6.2):
gcc -O1 : 1329 clocks (asm mad_f_mul), 1529 clocks (C mad_f_mul) gcc -O2 : 1607 clocks (asm mad_f_mul), 2176 clocks (C mad_f_mul) gcc -O3 : 1608 clocks (asm mad_f_mul), 2186 clocks (C mad_f_mul)
gcc version 2.95.2 19991024:
gcc -O0 : 2946 clocks (asm mad_f_mul), 2616 clocks (C mad_f_mul) gcc -O1 : 1735 clocks (asm mad_f_mul), 1201 clocks (C mad_f_mul) gcc -O2 : 1380 clocks (asm mad_f_mul), 1567 clocks (C mad_f_mul) gcc -O3 : 1380 clocks (asm mad_f_mul), 1567 clocks (C mad_f_mul)
This is strange.
The gcc-2.95.2 results are somewhat different on a StrongARM. They are more inline with the egcs-2.91.66 results above...
Nicolas