Wilco Dijkstra wrote:
> Richard Earnshaw wrote:
> On 10/11/16 17:19, Wilco Dijkstra wrote:
> Long conditional sequences are slow on modern cores - the value 6 for
> max_insns_skipped is a few decades out of date as it was meant for ARM2!
> Even with -Os the performance loss for larger values is not worth the
> small codesize gain (there are many better options to reduce codesize
> that actually improve performance at the same time). So using the same
> code generation heuristics for ARM and Thumb-2 is a good idea.
A simple codesize comparison on CSiBE shows using 4 rather than 6 for
max_insns_skipped is just 0.07% larger on ARM with -Os. So it's not
obvious that increasing max_insns_skipped in -Os is a useful codesize
optimization...
Wilco
