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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - compile-time explosion with assumes at -O1 to -Os"
href="https://bugs.llvm.org/show_bug.cgi?id=49205">49205</a>
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<th>Summary</th>
<td>compile-time explosion with assumes at -O1 to -Os
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<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
</td>
</tr>
<tr>
<th>Reporter</th>
<td>haoxintu@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
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<pre>Hi, all.
This code, s.c, is a valid program but makes Clang hung on at compile time at
-O1 to -Os.
$cat s.c
int a;
void b() {
int *c = &a;
int *d = &a;
int **e = &d;
for (*c = 7; c <= 2; *c += 1) {
int **f = d;
*c = 0;
**e /= f ? (c ? 10 : **f) % (*c &= 6) : 0;
}
*d = (*d -= *c & **e != 4) && (4 != a) - **e & d == c;
int g = &d;
g++;
}
$time clang -c -w -O0 s.c
real 0m0.021s
user 0m0.011s
sys 0m0.010s
$clang -c -w -O1 test.cc
//endless compiling (the same as -O2,-O3, and -Os options)
$clang -v
clang version 13.0.0 (<a href="https://github.com/llvm/llvm-project">https://github.com/llvm/llvm-project</a>
22f00f61dd5483a9fdaed3b7592d392c23b3646a)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir:
/home/haoxin/haoxin-data/dut-research/compilers/llvm-project/build-20210216/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Candidate multilib: .;@m64
Selected multilib: .;@m64
This problem only occurs in clang-trunk and clang-11.0.0 or clang-11.0.1, while
other released versions from clang-10 downwards perform well in this case.
Thanks.
Haoxin</pre>
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