Namespace:
> void main() {
> float[3][] arr;
> arr ~= [1, 2, 3];
> }
> ----
> It seems [1, 2, 3] is in this case erroneously a dynamic array (according to objconv). So is it also erroneously allocated on the heap?
Generally array literals allocate on the heap. Recently some of their cases have being optimized, but even more recently part of those optimizations were reverted. So I don't know what's happening in your case and why.
With DMD your code generates this (optimized build!), so it's far from well optimized:
__Dmain:
sub ESP,020h
mov EAX,offset FLAT:_D12TypeInfo_G3f6__initZ
push EBX
push ESI
push EDI
mov dword ptr 010h[ESP],0
mov dword ptr 014h[ESP],0
push 3
push EAX
call near ptr __d_arrayliteralTX
mov EBX,EAX
fld float ptr FLAT:_DATA[00h]
mov ESI,EBX
lea EDI,028h[ESP]
fstp float ptr [EBX]
fld float ptr FLAT:_DATA[04h]
fstp float ptr 4[EBX]
fld float ptr FLAT:_DATA[08h]
fstp float ptr 8[EBX]
movsd
movsd
movsd
mov EDX,offset FLAT:_D13TypeInfo_AG3f6__initZ
push 1
lea ECX,01Ch[ESP]
push ECX
push EDX
call near ptr __d_arrayappendcTX
lea ESI,034h[ESP]
mov 02Ch[ESP],EAX
mov EDI,02Ch[ESP]
lea EDI,[EDI*2][EDI]
mov 030h[ESP],EDX
mov EAX,030h[ESP]
lea EDI,-0Ch[EDI*4][EAX]
movsd
movsd
movsd
add ESP,014h
xor EAX,EAX
pop EDI
pop ESI
pop EBX
add ESP,020h
ret
With ldc2 V.0.12.1 the situation is better:
__Dmain:
pushl %ebp
movl %esp, %ebp
andl $-8, %esp
subl $24, %esp
movl $0, 16(%esp)
movl $0, 20(%esp)
leal 16(%esp), %eax
movl %eax, 4(%esp)
movl $1, 8(%esp)
movl $__D13TypeInfo_AG3f6__initZ, (%esp)
calll __d_arrayappendcTX
movl 20(%esp), %eax
movl $1065353216, (%eax)
movl $1073741824, 4(%eax)
movl $1077936128, 8(%eax)
xorl %eax, %eax
movl %ebp, %esp
popl %ebp
ret
Bye,
bearophile
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