On Friday, 31 May 2013 at 15:02:00 UTC, bearophile wrote:
Thanks to Kenji the latest dmd 2.063 solves part of this
problem:
http://d.puremagic.com/issues/show_bug.cgi?id=2356
Maybe this improvement is not yet in LDC/GDC.
Regarding static array initialization from literals, yes, that
change isn't in 2.062.
However, what pains me a bit is that LDC does even manage to
remove the dynamic array allocation after the fact:
---
__D9raytracer4Vec36__ctorMFxfZS9raytracer4Vec3:
movss DWORD PTR [RSP - 12], XMM0
movss DWORD PTR [RSP - 8], XMM0
movss DWORD PTR [RSP - 4], XMM0
mov EAX, DWORD PTR [RSP - 4]
mov DWORD PTR [RDI + 8], EAX
mov RAX, QWORD PTR [RSP - 12]
mov QWORD PTR [RDI], RAX
mov RAX, RDI
ret
---
It just happens too late in the optimizer pipeline for the
temporary memcpy to go away. Re-running the IR through the LLVM
optimizer then produces this:
---
__D9raytracer4Vec36__ctorMFxfZS9raytracer4Vec3:
movss DWORD PTR [RDI], XMM0
movss DWORD PTR [RDI + 4], XMM0
movss DWORD PTR [RDI + 8], XMM0
mov RAX, RDI
ret
---
— David
