Posted by speckx 2 hours ago
Option<Walrus>Of note, as of C#9 (and maybe prior), the dotnet runtime does this automatically whenever it is deemed safe. https://devblogs.microsoft.com/dotnet/performance-improvemen...
The same technique is applied as an optimization, when deemed safe, in all current gen c compilers (gcc, llvm, etc).
I'm very confused why neither measurements nor references to when this is done automatically in most modern languages is included in the article.
For example:
var map = new HashMap<String, String>();
map.put("foo", "bar");
for (var i : items) {
if ("bar".equals(map.get("foo")) {
doStuff(i);
}
}
Speed was almost never the reason.
"the loop runs without a branch, and is a candidate for vectorization".
That's it, that's the article. This matters a lot in huge-scale / scientific computing / HPF, where if you can express something as an operation on vectors on matrices, you win big (those ops parallelize well, can be run on GPUs, clusters, what have you).