• Namespace (9/9) Dec 02 2013 ----
• bearophile (76/84) Dec 02 2013 Generally array literals allocate on the heap. Recently some of
• Namespace (2/2) Dec 02 2013 So it would be unfortunately better to use a struct with a

"Namespace" <rswhite4 googlemail.com> writes:

----
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?

"bearophile" <bearophileHUGS lycos.com> writes:

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

"Namespace" <rswhite4 googlemail.com> writes:

So it would be unfortunately better to use a struct with a 
internal static array. :/