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digitalmars.D.bugs - [Issue 8840] New: calculating minimum of longs with following comparison compiles to wrong code when enabling the optimizer

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=8840

           Summary: calculating minimum of longs with following comparison
                    compiles to wrong code when enabling the optimizer
           Product: D
           Version: D2
          Platform: All
        OS/Version: Windows
            Status: NEW
          Keywords: wrong-code
          Severity: major
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: r.sagitario gmx.de


--- Comment #0 from Rainer Schuetze <r.sagitario gmx.de> 2012-10-17 14:16:55
PDT ---
import core.stdc.stdio;

long foo() { return 4; }

void main()
{
    long f1 = foo();    
    long f2 = foo();

    long f = (f1 < f2 ? f1 : f2);
    int len = (f == 0 ? 0 : printf("%llx\n", f));
}

compiled with "dmd -o" and running produces the output "400000004" instead of
just "4".

Here's the disassembly:
_D4test3fooFZl  comdat
        assume  CS:_D4test3fooFZl
                mov     EAX,4
                xor     EDX,EDX
                ret
_D4test3fooFZl  ends
__Dmain comdat
        assume  CS:__Dmain
L0:             sub     ESP,0Ch
                push    EBX
                push    ESI
                call    near ptr _D4test3fooFZl
                mov     8[ESP],EAX
                mov     0Ch[ESP],EDX
                call    near ptr _D4test3fooFZl
                cmp     EDX,0Ch[ESP]
                jl      L33
                jg      L25
                cmp     EAX,8[ESP]
                jbe     L33
L25:            mov     ECX,0Ch[ESP]
                mov     EBX,8[ESP]
                mov     ESI,ECX
                or      ESI,EBX
                jmp short       L39
L33:            mov     ECX,EDX
                mov     EBX,EAX
                or      ECX,EBX
L39:            je      L4B
                mov     EAX,offset FLAT:_DATA
                push    ECX
                push    EBX
                push    EAX
                call    near ptr _printf
                add     ESP,0Ch
L4B:            xor     EAX,EAX
                pop     ESI
                pop     EBX
                add     ESP,0Ch
                ret
__Dmain ends

Note that ECX is pushed in the call to printf, but it is the result of
hiword|loword in the part after L33.

dmc suffers from the same problem.

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next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=8840


Don <clugdbug yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |clugdbug yahoo.com.au
           Severity|major                       |blocker


--- Comment #1 from Don <clugdbug yahoo.com.au> 2012-10-18 01:15:40 PDT ---
Raising severity to blocker. No compiler releases should occur until this is
fixed.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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Walter Bright <bugzilla digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bugzilla digitalmars.com


--- Comment #2 from Walter Bright <bugzilla digitalmars.com> 2012-10-18
09:41:20 PDT ---
Wow. How has this one not shown its ugly face before?

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--- Comment #3 from github-bugzilla puremagic.com 2012-10-18 12:17:28 PDT ---
Commit pushed to dmd-1.x at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/551e86b022a61064d11fa43924d18222ed366d80
fix Issue 8840 - calculating minimum of longs with following comparison
compiles to wrong code when enabling the optimizer

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--- Comment #4 from github-bugzilla puremagic.com 2012-10-18 12:17:35 PDT ---
Commit pushed to master at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/fdb413235448e27dad0aab615837b051483de150
fix Issue 8840 - calculating minimum of longs with following comparison
compiles to wrong code when enabling the optimizer

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--- Comment #5 from github-bugzilla puremagic.com 2012-10-18 12:18:39 PDT ---
Commit pushed to master at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/881f9fcb740516391e1c7dd1a3e39046dd21e74a
test case for issue 8840

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prev sibling parent d-bugmail puremagic.com writes:
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Walter Bright <bugzilla digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
            Version|D2                          |D1 & D2
         Resolution|                            |FIXED
         OS/Version|Windows                     |All


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