On Thursday, 18 February 2016 at 11:41:26 UTC, Kai Nacke wrote:
LLVM has about 2.5 million code lines. I am anything than sure if it is easy to improve compilation speed.
I think you are a tad too pessimistic here. First, don't forget that there are some big LLVM customers for which low compile times are important too (remember all the buzz from when Clang first hit the scene?).
Second, when was the last time you focussed on optimizing LDC -O0 compiler performance? There is currently a lot of low-hanging fruit, and then there are still the more involved options (such as making sure we use FastISel as much as possible).
It might not end up quite as fast as DMD is right now. But imagine that Walter would have invested all the time he spent e.g. on implementing DWARF EH into optimizing the LDC frontend/glue layer/backend pass structure instead. Who knows, we might have an LDC-based compiler today that is faster than the DMD we currently have.
— David
