[Issue 10642] New: Win64: wrong codegen comparing different sized integer arguments

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http://d.puremagic.com/issues/show_bug.cgi?id=10642

           Summary: Win64: wrong codegen comparing different sized integer
                    arguments
           Product: D
           Version: D2
          Platform: x86_64
        OS/Version: Windows
            Status: NEW
          Keywords: wrong-code
          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> 2013-07-14 09:55:38 PDT ---
Another faiing reduction from the phobos unittests:

import std.stdio;

void _assertEq (ubyte lhs, short rhs, string msg, string file, size_t line)
{
    immutable result = lhs == rhs;

    if(!result)
    {
        string op = "==";
        if(msg.length > 0)
            writefln(`_assertEq failed: [%s] is not [%s].`, lhs, rhs);
        else
            writefln(`_assertEq failed: [%s] is not [%s]: %s`, lhs, rhs, msg);
    }

    assert(result);
}

struct Date
{
    short year;
    ubyte month;
    ubyte day;
}

struct MonthDay
{
    ubyte month;
    short day;
}

unittest
{
    static void test(Date date, int day, MonthDay expected, size_t line =
__LINE__)
    {
        _assertEq(date.day, expected.day, "", __FILE__, line);
    }

    test(Date(1999, 1, 1), 1, MonthDay(1,1));
}

void main() {}

compile with "dmd -O -m64 test.d" produces

_assertEq failed: [208] is not [1]:
core.exception.AssertError at test(16): Assertion failure

Checking the disassembly shows that DIL is read in _assertEq, but never
initialized properly. I guess bh was meant instead:

_D4test9_assertEqFhsAyaAyamZv:
  0000000000000000: 55                 push        rbp
  0000000000000001: 48 8B EC           mov         rbp,rsp
  0000000000000004: 48 83 EC 48        sub         rsp,48h
  0000000000000008: 56                 push        rsi
  0000000000000009: 57                 push        rdi
  000000000000000A: 41 54              push        r12
  000000000000000C: 4C 89 45 20        mov         qword ptr [rbp+20h],r8
  0000000000000010: 4C 89 CE           mov         rsi,r9
  0000000000000013: 8A 7D 30           mov         bh,byte ptr [rbp+30h]
  0000000000000016: 44 0F B6 D7        movzx       r10d,dil
  000000000000001A: 44 0F BF DE        movsx       r11d,si
  000000000000001E: 45 3B D3           cmp         r10d,r11d
  0000000000000021: 41 0F 94 C4        sete        r12b
  0000000000000025: 45 0F B6 E4        movzx       r12d,r12b
  0000000000000029: 44 88 65 F0        mov         byte ptr [rbp-10h],r12b

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