Am 14.01.2019 um 15:01 schrieb J. Gareth Moreton: > Martok mentioned doing some checks differently in the bug report in question, > such as 6 comparisons being faster than a jump table. Are there any others > worth mentioning? Not neccessarily faster, but in that code definitely smaller. Is there a way to directly estimate how large the generated code might be, maybe something like "numlabels*constant"?
For the "faster" question, the cache line occupation matters more than instruction throughput. If your jumptable gets large enough to force a full data cache line flush, you could have done a lot of instructions in the time the CPU waits for the data. And I haven't found reliable information how the Spectre-related microcode updates changed that, given that both cmp/jmp and jmp[indirect] used to be heavily optimized, but were both affected. -- Regards, Martok _______________________________________________ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
