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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [DebugInfo@O2] SLP Vectorizer drops DebugInfo"
href="https://bugs.llvm.org/show_bug.cgi?id=46162">46162</a>
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<th>Summary</th>
<td>[DebugInfo@O2] SLP Vectorizer drops DebugInfo
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>Wolfgang_Pieb@playstation.sony.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre>/* Compile the following source with clang -g -O2. The SLP Vectorizer pass
drops location information for the local variables x1 and x2. */
typedef unsigned int U32;
typedef float F32;
extern "C" double log(float);
extern "C" double sqrt(float);
extern unsigned RandU32();
float RandF32()
{
U32 uRand = RandU32();
F32 fRand = ((F32)uRand / 4294967810.0f);
return(fRand);
}
void randGauss(float work[2])
{
float x1, x2, w;
do {
x1 = 2.f * RandF32() - 1.f;
x2 = 2.f * RandF32() - 1.f;
w = x1 * x1 + x2 * x2;
} while ( w >= 1.f );
w = sqrt( (-2.f * log( w ) ) / w );
work[0] = x1 * w;
work[1] = x2 * w;
}
/* This turns out to be a rather special case, where the same operation is
performed on 2 different local variables in a lexical block. The vectorizer
places the 2 variables in 2 different lanes of a vector register and performs
the operation on both simultaneously.
After some investigation I didn't see an obvious way to fix this. The current
compiler infrastructure seems insufficient to describe what's going on. Given
that ist's a corner case I would consider it low priority. */</pre>
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