https://issues.dlang.org/show_bug.cgi?id=19320

Eduard Staniloiu <edi33416@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |edi33416@gmail.com

--- Comment #1 from Eduard Staniloiu <edi33416@gmail.com> ---
Attempting to provide more context to this

Running `make -f posix.mak std/array.test`
will run
```
../dmd/generated/linux/release/64/dmd -od$T  -conf= -I../druntime/import  -w
-de -dip25 -m64 -fPIC -transition=complex -O -release -dip1000 -main -unittest
generated/linux/release/64/libphobos2.a -defaultlib= -debuglib= -L-ldl -cov
-run std/array.d
```

Where $T should expand to a path similar to `/tmp/.dmd-run-test.XXXXXX`

If you remove the `-cov` flag, the tests will build without any problem.

This issue is related with the Code coverage instrumentation

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https://issues.dlang.org/show_bug.cgi?id=19320

Seb <greeenify@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |greeenify@gmail.com
            Summary|Unittest error: Variable    |-cov and -O yield variable
                   |used before set in          |used before set
                   |std/array.d                 |

--- Comment #2 from Seb <greeenify@gmail.com> ---
Reduced with

$ dustmite --no-redirect . "~/dlang/bin/dmddev -O -cov -unittest -main array.d 2>&1 | grep 'variable theArray used before set'"


Resulting in:

$ dmd -O -cov array.d

```
auto staticArray(U, T)(T)
{
    U[] theArray = void;
    return theArray;
}


void main()
{
    staticArray!(int, int)(3);
}
```

Making it clear that this bug is a result of -O and -cov.

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https://issues.dlang.org/show_bug.cgi?id=19320

berni44 <bugzilla@d-ecke.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bugzilla@d-ecke.de
          Component|phobos                      |dmd

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https://issues.dlang.org/show_bug.cgi?id=19320

Luís Ferreira <lsferreira169@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |lsferreira169@gmail.com

--- Comment #3 from Luís Ferreira <lsferreira169@gmail.com> ---
By adding a asm block with a `nop` instruction to the affected scope, the compiler optimizer will give up searching:

asm { nop; }

--

https://issues.dlang.org/show_bug.cgi?id=19320

--- Comment #4 from Dlang Bot <dlang-bot@dlang.rocks> ---
@ljmf00 created dlang/phobos pull request #8204 "std.array: workaround for Issue 19320" mentioning this issue:

- std.array: workaround for Issue 19320

  By adding a asm block with a `nop` instruction to the affected scope,
  the compiler optimizer will give up searching.

https://github.com/dlang/phobos/pull/8204

--

https://issues.dlang.org/show_bug.cgi?id=19320

Dlang Bot <dlang-bot@dlang.rocks> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |pull

--- Comment #5 from Dlang Bot <dlang-bot@dlang.rocks> ---
@RazvanN7 created dlang/dmd pull request #13015 "Fix Issue 19320 - -cov and -O yield variable used before set" fixing this issue:

- Fix Issue 19320 - -cov and -O yield variable used before set

https://github.com/dlang/dmd/pull/13015

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https://issues.dlang.org/show_bug.cgi?id=19320

RazvanN <razvan.nitu1305@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |razvan.nitu1305@gmail.com

--- Comment #6 from RazvanN <razvan.nitu1305@gmail.com> ---
Simplified:

int[] staticArray(int)
{
    int[] theArray = void;
    return theArray;
}


void main()
{
    staticArray(3);
}

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https://issues.dlang.org/show_bug.cgi?id=19320

Dlang Bot <dlang-bot@dlang.rocks> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #7 from Dlang Bot <dlang-bot@dlang.rocks> ---
dlang/dmd pull request #13015 "Fix Issue 19320 - -cov and -O yield variable used before set" was merged into master:

- df0c19ec799a77b6b59bebd92ec0ed6c48870dd0 by RazvanN7:
  Fix Issue 19320 - -cov and -O yield variable used before set

https://github.com/dlang/dmd/pull/13015

--