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      <base href="http://bugzilla.gdcproject.org/" />
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Nested struct that has non-padded array does not initialize fields correctly when compiled with optimizations"
   href="http://bugzilla.gdcproject.org/show_bug.cgi?id=187">187</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Nested struct that has non-padded array does not initialize fields correctly when compiled with optimizations
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>GDC
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>4.9.x
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>x86_64
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>Normal
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>gdc
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>ibuclaw@gdcproject.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>liran@weka.io
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Reproducible on commit b022dd4cac195d85e9c3a6a37f2501a07ade455a from April 7th
on the 4.9 branch.

Consider the following code:
---------------
module test;
import std.stdio;

align(1) struct Unpadded {
    align(1) {
        uint unpaddedA;
        ushort unpaddedB;
    }
}

struct StructWithUnpaddedArray {
    Unpadded[3] unpaddedArray;
    // If initializer differs than ubyte.init then it does get inititalized
    // Naturally, the "= ubyte.init" part is not required for the bug to
reproduce
    ubyte wontInitialize = ubyte.init;
}

struct OuterStruct {
    StructWithUnpaddedArray interesting;
}


void prepareStack()
{
    byte[255] stackGarbage;
    foreach(i, ref b; stackGarbage) {
        b  = cast(byte)(-i);
    }
}

void main()
{
    prepareStack();
    auto a = OuterStruct(StructWithUnpaddedArray());
    writefln("Value is %s . wontInitialize is %s ", a,
a.interesting.wontInitialize);
}
-------------------------------
When compiled with optimization, the wontInitialize field ends up being 194,
instead of 0 as by the D spec.

This is the minimal code that I was able to get that reproduces.

example output:
bash-4.3# /opt/gdc/bin/gdc -ggdb -O -ogtest test.d && ./gtest
Value is OuterStruct(StructWithUnpaddedArray([Unpadded(0, 0), Unpadded(0, 0),
Unpadded(0, 0)], 194)) . wontInitialize is 194</pre>
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