[Issue 2356] New: array literal as non static initializer generates horribly inefficient code.

http://d.puremagic.com/issues/show_bug.cgi?id=2356

           Summary: array literal as non static initializer generates
                    horribly inefficient code.
           Product: D
           Version: unspecified
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Keywords: wrong-code
          Severity: major
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla@digitalmars.com
        ReportedBy: tomas@famolsen.dk


this simple test:

void main()
{
    int[3] x = [1,2,3];
}

should just initialize x with the values 1,2,3

what happens in reality is not as nice as this output of obj2asm shows:

_Dmain:
                push    EBP
                mov     EBP,ESP
                sub     ESP,0Ch
                push    EBX
                lea     EAX,-0Ch[EBP]
                push    EAX
                push    3
                push    3
                push    2
                push    1
                push    3
                mov     ECX,offset FLAT:_D11TypeInfo_Ai6__initZ@SYM32
                push    ECX
                call    near ptr _d_arrayliteralT@PC32
                add     ESP,014h
                mov     EDX,EAX
                mov     EBX,3
                push    EDX
                push    EBX
                push    4
                call    near ptr _d_arraycopy@PC32
                xor     EAX,EAX
                add     ESP,014h
                pop     EBX
                leave
                ret


I'm marking it wrong-code, even though the code does compile and link, it's just wrong ... I'm using 1.034 but I'd guess it's an older bug, so I'm not marking a specific version.


--

http://d.puremagic.com/issues/show_bug.cgi?id=2356 tomas@famolsen.dk changed: What |Removed |Added ---------------------------------------------------------------------------- Version|unspecified |1.034 ------- Comment #1 from tomas@famolsen.dk 2008-09-15 08:52 ------- I think this issue might have been introduced in DMD 1.034, as I've hit several issues in LLVMDC, that used to work, due to some initializers suddenly being ArrayLiterals instead of ArrayInitializers. Marking version 1.034. --

http://d.puremagic.com/issues/show_bug.cgi?id=2356 clugdbug@yahoo.com.au changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords|wrong-code |performance ------- Comment #2 from clugdbug@yahoo.com.au 2009-04-08 08:01 ------- This is a performance issue, not wrong-code. --

http://d.puremagic.com/issues/show_bug.cgi?id=2356 bearophile_hugs@eml.cc changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |bearophile_hugs@eml.cc --- Comment #3 from bearophile_hugs@eml.cc 2010-07-19 23:18:32 PDT --- *** Issue 4488 has been marked as a duplicate of this issue. *** -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=2356 Kenji Hara <k.hara.pg@gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |patch --- Comment #4 from Kenji Hara <k.hara.pg@gmail.com> 2011-09-09 09:35:07 PDT --- https://github.com/D-Programming-Language/dmd/pull/375 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=2356 --- Comment #5 from Kenji Hara <k.hara.pg@gmail.com> 2011-09-09 09:36:49 PDT --- After applying my patch, the sample code generates like follows: (output of ddbg in 64-bit Windows 7) c:\d\test.d:1 void main() 00402010: c80c0000 enter 0xc, 0x0 c:\d\test.d:3 int[3] x = [1,2,3]; 00402014: c745f401000000 mov dword [ebp-0xc], 0x1 0040201b: c745f802000000 mov dword [ebp-0x8], 0x2 00402022: c745fc03000000 mov dword [ebp-0x4], 0x3 00402029: 31c0 xor eax, eax test.obj 0040202b: c9 leave 0040202c: c3 ret -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=2356 dawg@dawgfoto.de changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |dawg@dawgfoto.de --- Comment #6 from dawg@dawgfoto.de 2011-10-07 19:09:44 PDT --- This is also a huge issue when assigning .init to a static array. ubyte[1024] v; v = typeof(v).init; This will generate a dynamically allocated [0, 0, 0 ... ] Arrayliteral for the rhs expression before calling _d_arraycopy. Even worse the allocated ArrayLiteral is initialized using 1024 comma expressions. Using -O the compiler will subsequently almost starve from O(N^2) behavior during comsub eliminations. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=2356 yebblies <yebblies@gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |rsinfu@gmail.com --- Comment #7 from yebblies <yebblies@gmail.com> 2012-02-02 14:27:49 EST --- *** Issue 4298 has been marked as a duplicate of this issue. *** -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=2356 yebblies <yebblies@gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |sean@invisibleduck.org --- Comment #8 from yebblies <yebblies@gmail.com> 2012-02-02 15:34:11 EST --- *** Issue 4881 has been marked as a duplicate of this issue. *** -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------

http://d.puremagic.com/issues/show_bug.cgi?id=2356 yebblies <yebblies@gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jarrett.billingsley@gmail.c | |om --- Comment #9 from yebblies <yebblies@gmail.com> 2012-02-02 20:49:34 EST --- *** Issue 2237 has been marked as a duplicate of this issue. *** -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------

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