<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [LTO] -Os and -Oz -flto results in error message from LTO code generator."
href="https://bugs.llvm.org/show_bug.cgi?id=41568">41568</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[LTO] -Os and -Oz -flto results in error message from LTO code generator.
</td>
</tr>
<tr>
<th>Product</th>
<td>tools
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>lto
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>peter.smith@linaro.org
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>clang t.c -Os -flto -o optlto -fuse-ld=lld
ld.lld: error: -plugin-opt=Os: number expected, but got 's'
clang-9: error: linker command failed with exit code 1 (use -v to see
invocation)
Anything that will compile will do for the t.c file, I used an empty main.
This is the same for -Oz. While the error is reported by LLD it is coming from
the LTO Code Generator.
This has been raised before as <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED INVALID - No --lto-Os and --lto-Oz"
href="show_bug.cgi?id=31665">https://bugs.llvm.org/show_bug.cgi?id=31665</a>
however it was closed by the raiser as invalid as the optsize and minsize
attributes are added to the functions when they were compiled.
However I think that there still could be some work to do here:
- It isn't convenient to change the optimization flags just for the link steps
in some build systems. It also isn't discoverable what the equivalent
optimization setting should be given as a replacement. I believe -O2 comes
closest.
- When using the new pass manager there are some passes that check the
PassBuilder optimisation setting using isOptimizingForSize(). I think the
impact on code-generation will be low, but this may change in the future.
At this stage I don't think that supporting -Os and -Oz need be much more than
translating to one of the other optimization levels. Of course there could be a
custom size focused -Os, -Oz LTO added later.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>