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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - missed interprocedural propagation opportunity"
href="https://bugs.llvm.org/show_bug.cgi?id=33253">33253</a>
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<th>Summary</th>
<td>missed interprocedural propagation opportunity
</td>
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Scalar Optimizations
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>davide@freebsd.org
</td>
</tr>
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<th>CC</th>
<td>dberlin@dberlin.org, efriedma@codeaurora.org, filcab@gmail.com, llvm-bugs@lists.llvm.org, llvm-dev@redking.me.uk, simon.f.whittaker@gmail.com
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<p>
<div>
<pre>In the following testcase:
__attribute__((noinline))
static int f(int x)
{
if (x > 300)
return 1;
else
return 2;
}
int main(void)
{
int a = f(1);
int b = f(47);
int c = f(219);
return a + b + c;
}
we should be able to propagate the fact that x in f is never greater than 300,
so the predicate in f can be removed, as the function is not visible outside of
the TU.
This is a simplified testcase, but the optimization can be more important at
LTO time.
I don't think the "paper algorithm" that we have in SCCP is able to handle this
case.</pre>
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</p>
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