[Issue 10540] New: variable used before set for empty static arrays, with -inline -O

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=10540

           Summary: variable used before set for empty static arrays, with
                    -inline -O
           Product: D
           Version: unspecified
          Platform: All
        OS/Version: All
            Status: NEW
          Keywords: rejects-valid
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody at puremagic.com
        ReportedBy: monarchdodra at gmail.com


--- Comment #0 from monarchdodra at gmail.com 2013-07-04 02:15:47 PDT ---
Thread:
http://forum.dlang.org/thread/khdhvzfdfljbtlyfqocw@forum.dlang.org#post-khdhvzfdfljbtlyfqocw:40forum.dlang.org

When compiled with -O -inline:
--------
struct S
{
    int[0] a;

    void do_it()
    {
        foo(a);
    }
}

void foo(Args...)(Args args)
{
    //foreach(arg; args)
    //    if (arg.ptr == null)
    //        return;

    bar(args);
}

void bar(Args...)(Args args)
{
    foreach(arg; args)
        if (arg.ptr == null)
            return;
}

void main()
{}
--------
Produces:
main.d(11): Error: variable _param_0 used before set
--------

Possibly the compiler optimizes out a's initialization, since it is an empty
static array.

Code is glitchy: Not only does the bug appear only in bar (and not foo),
un-commenting the code in foo will *fix* the call in bar...

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