[Issue 10633] New: Win64: wrong codegen with %=

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=10633

           Summary: Win64: wrong codegen with %=
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody at puremagic.com
        ReportedBy: r.sagitario at gmx.de


--- Comment #0 from Rainer Schuetze <r.sagitario at gmx.de> 2013-07-13 09:36:33 PDT ---
This code crashes when compiled for win64:

struct TimeOfDay
{
    void roll(int value) 
    {
        value %= 60;
        auto newVal = _seconds + value;

        if(newVal < 0)
            newVal += 60;
        else if(newVal >= 60)
            newVal -= 60;

        _seconds = cast(ubyte)newVal;
    }

    ubyte _seconds;
}

void main()
{
    TimeOfDay tod = TimeOfDay(0);
    tod.roll(-1);
    assert(tod._seconds == 59);
}

generated asm for roll:

_D4test9TimeOfDay4rollMFiZv:
  0000000000000000: 55                 push        rbp
  0000000000000001: 48 8B EC           mov         rbp,rsp
  0000000000000004: 48 83 EC 18        sub         rsp,18h
  0000000000000008: 53                 push        rbx
  0000000000000009: 48 89 4D 10        mov         qword ptr [rbp+10h],rcx
  000000000000000D: 89 55 18           mov         dword ptr [rbp+18h],edx
  0000000000000010: 48 83 7D 10 00     cmp         qword ptr [rbp+10h],0
  0000000000000015: 75 1D              jne         0000000000000034
  0000000000000017: 41 B8 03 00 00 00  mov         r8d,3
  000000000000001D: 48 8D 15 00 00 00  lea         rdx,[_TMP1]
                    00
  0000000000000024: 48 8D 0D 00 00 00  lea         rcx,[_TMP3]
                    00
  000000000000002B: 48 83 EC 20        sub         rsp,20h
  000000000000002F: E8 00 00 00 00     call        _d_assert_msg
  0000000000000034: 41 B9 3C 00 00 00  mov         r9d,3Ch
  000000000000003A: 8B 45 18           mov         eax,dword ptr [rbp+18h]
  000000000000003D: 99                 cdq
  000000000000003E: 41 F7 F9           idiv        eax,r9d
  0000000000000041: 89 55 18           mov         dword ptr [rbp+18h],edx
  0000000000000044: 48 8B 5D 10        mov         rbx,qword ptr [rbp+10h]
  0000000000000048: 0F B6 03           movzx       eax,byte ptr [rbx]
  000000000000004B: 03 C2              add         eax,edx
  000000000000004D: 89 45 F8           mov         dword ptr [rbp-8],eax
  0000000000000050: 85 C0              test        eax,eax
  0000000000000052: 79 04              jns         0000000000000058
  0000000000000054: 01 CD              add         ebp,ecx
  0000000000000056: EB 08              jmp         0000000000000060
  0000000000000058: 83 7D F8 3C        cmp         dword ptr [rbp-8],3Ch
  000000000000005C: 7C 02              jl          0000000000000060
  000000000000005E: 29 CD              sub         ebp,ecx
  0000000000000060: 8A 55 F8           mov         dl,byte ptr [rbp-8]
  0000000000000063: 48 8B 4D 10        mov         rcx,qword ptr [rbp+10h]
  0000000000000067: 88 11              mov         byte ptr [rcx],dl
  0000000000000069: 5B                 pop         rbx
  000000000000006A: 48 8D 65 00        lea         rsp,[rbp]
  000000000000006E: 5D                 pop         rbp
  000000000000006F: C3                 ret

Notice that the add/sub at offsets 54/5e write to ebp, but the variable is in
[rbp-8].

Exchanging "value %= 60;" with "value = value % 60;" fixes the problem.

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