On Mon, Oct 1, 2012 at 9:30 PM, Adam D. Ruppe <destructiona...@gmail.com> wrote: > On Monday, 1 October 2012 at 19:22:37 UTC, Philippe Sigaud wrote: >> >> Something I wanted to ask for a long time: is there any runtime speed >> penalty in using __ctfe? > > > No. What happens is when it goes to the compile the runtime code, __ctfe is > a constant false, so then the optimizer can see it is obviously dead code > and eliminate the branch entirely.
Cool.I feared it was a runtime-determined value, somehow. > $ dmd test.d -c > $ objdump --disassemble test.o > Disassembly of section .text._D4test4testFZv: > > 00000000 <_D4test4testFZv>: > 0: 55 push %ebp > 1: 8b ec mov %esp,%ebp > 3: f4 hlt > 4: 5d pop %ebp > 5: c3 ret > > > Note that there's no trace of a compare, jmp, nor the nops from the dead > ctfe branch. OK, I'm sold. Thanks!
