Re:C++ Pattern Matching Proposal [pdf]
by umanwizard on Friday January 03, 2020 @07:12PM
(#21951736)
For example: https://godbolt.org/z/m3xSse
Re:C++ Pattern Matching Proposal [pdf]
by huhtenberg on Saturday January 04, 2020 @05:09AM
(#21954014)
How is basic loop unrolling is "not even close" to the expected result when you explicitly ask for optimization with O3?
Re:C++ Pattern Matching Proposal [pdf]
by umanwizard on Saturday January 04, 2020 @08:58AM
(#21954916)
This isn’t basic loop unrolling; it’s replacing an entire loop with a closed form mathematical formula.
Re:C++ Pattern Matching Proposal [pdf]
by huhtenberg on Saturday January 04, 2020 @09:54AM
(#21955152)
It's a form of loop unrolling. Regardless of the term, this is still very much in the ballpark of what you'd expect when asking for optimization.
No, this actually doesn't get said a lot, however the simplicity of C compilation semantics is one of its biggest strengths.
> ... but unless you're writing C code for a microcontroller (or a PDP11), that isn't even close to being true.
Do humor us with an example of a C code that compiles into something that is "not even close" to what you'd reasonably expect.