<html>
<head>
<base href="http://llvm.org/bugs/" />
</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 --- - Infinite loop at -O2"
href="http://llvm.org/bugs/show_bug.cgi?id=16067">16067</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Infinite loop at -O2
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</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>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>antoine.balestrat@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>baldrick@free.fr, llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>LLVM/Clang 3.4 as of r182207 fails to compile the following testcase at -O2.
This reminds me of the testcase of PR13021, but since the related pass is
supposed to be disabled, I'm filling a new bug report.
$ cat inf.c
int a;
void f(void)
{
int i;
while(a)
for(i = 0; i < 32; i++)
a *= a;
}
$ ulimit -t 30
$ clong -w -O2 inf.c
0 clang 0x0000000001a384f5 llvm::sys::PrintStackTrace(_IO_FILE*) +
37
1 clang 0x0000000001a389e3
2 libpthread.so.0 0x0000003000c10910
3 libc.so.6 0x000000300048d374
4 libc.so.6 0x000000300048725d
5 clang 0x00000000018c6d5e
6 clang 0x00000000018c683f
7 clang 0x00000000018c6729
8 clang 0x00000000018b13b9
9 clang 0x00000000018a81e0
llvm::ScalarEvolution::getMulExpr(llvm::SmallVectorImpl<llvm::SCEV const*>&,
llvm::SCEV::NoWrapFlags) + 464
10 clang 0x00000000018a850f
llvm::ScalarEvolution::getMulExpr(llvm::SmallVectorImpl<llvm::SCEV const*>&,
llvm::SCEV::NoWrapFlags) + 1279
11 clang 0x00000000018b53d6
llvm::ScalarEvolution::createSCEV(llvm::Value*) + 3094
12 clang 0x00000000018b40ef
llvm::ScalarEvolution::getSCEV(llvm::Value*) + 143
13 clang 0x00000000018b4bc5
llvm::ScalarEvolution::createSCEV(llvm::Value*) + 1029
14 clang 0x00000000018b40ef
llvm::ScalarEvolution::getSCEV(llvm::Value*) + 143
15 clang 0x00000000018b4bc5
llvm::ScalarEvolution::createSCEV(llvm::Value*) + 1029
16 clang 0x00000000018b40ef
llvm::ScalarEvolution::getSCEV(llvm::Value*) + 143
17 clang 0x00000000018b4bc5
llvm::ScalarEvolution::createSCEV(llvm::Value*) + 1029
18 clang 0x00000000018b40ef
llvm::ScalarEvolution::getSCEV(llvm::Value*) + 143
19 clang 0x00000000018b4bc5
llvm::ScalarEvolution::createSCEV(llvm::Value*) + 1029
20 clang 0x00000000018b40ef
llvm::ScalarEvolution::getSCEV(llvm::Value*) + 143
21 clang 0x00000000018b4bc5
llvm::ScalarEvolution::createSCEV(llvm::Value*) + 1029
87 clang 0x00000000018b40ef
llvm::ScalarEvolution::getSCEV(llvm::Value*) + 143
88 clang 0x00000000018b4bc5
llvm::ScalarEvolution::createSCEV(llvm::Value*) + 1029
89 clang 0x00000000018b40ef
llvm::ScalarEvolution::getSCEV(llvm::Value*) + 143
90 clang 0x00000000018b4bc5
llvm::ScalarEvolution::createSCEV(llvm::Value*) + 1029
91 clang 0x00000000018b40ef
llvm::ScalarEvolution::getSCEV(llvm::Value*) + 143
92 clang 0x00000000018b4bc5
llvm::ScalarEvolution::createSCEV(llvm::Value*) + 1029
93 clang 0x00000000018b40ef
llvm::ScalarEvolution::getSCEV(llvm::Value*) + 143
94 clang 0x00000000018baac9
llvm::ScalarEvolution::ComputeExitLimitFromICmp(llvm::Loop const*,
llvm::ICmpInst*, llvm::BasicBlock*, llvm::BasicBlock*) +
345
95 clang 0x00000000018ba40f
llvm::ScalarEvolution::ComputeExitLimitFromCond(llvm::Loop const*,
llvm::Value*, llvm::BasicBlock*, llvm::BasicBlock*) +
591
96 clang 0x00000000018ba116
llvm::ScalarEvolution::ComputeExitLimit(llvm::Loop const*, llvm::BasicBlock*) +
550
97 clang 0x00000000018b935a
llvm::ScalarEvolution::ComputeBackedgeTakenCount(llvm::Loop const*) + 250
98 clang 0x00000000018b8b8d
llvm::ScalarEvolution::getBackedgeTakenInfo(llvm::Loop const*) + 269
99 clang 0x00000000018b9169
llvm::ScalarEvolution::getBackedgeTakenCount(llvm::Loop const*) + 9
100 clang 0x00000000016a7f7a
101 clang 0x0000000001863360
llvm::LPPassManager::runOnFunction(llvm::Function&) + 784
102 clang 0x00000000019e029c
llvm::FPPassManager::runOnFunction(llvm::Function&) + 364
103 clang 0x00000000017e7155
104 clang 0x00000000019e086e
llvm::MPPassManager::runOnModule(llvm::Module&) + 430
105 clang 0x00000000019e0dbb
llvm::PassManagerImpl::run(llvm::Module&) + 203
106 clang 0x00000000019e0f3a llvm::PassManager::run(llvm::Module&) +
10
107 clang 0x00000000007c67e0
clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::CodeGenOptions
const&, clang::TargetOptions const&,
clang::LangOptions const&, llvm::Module*, clang::BackendAction,
llvm::raw_ostream*) + 6016
108 clang 0x00000000007c4303
109 clang 0x00000000008f7223 clang::ParseAST(clang::Sema&, bool,
bool) + 515
110 clang 0x00000000007c3732 clang::CodeGenAction::ExecuteAction() +
530
111 clang 0x0000000000664881 clang::FrontendAction::Execute() + 113
112 clang 0x00000000006449ad
clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 957
113 clang 0x000000000062b770
clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 3760
114 clang 0x0000000000622ab7 cc1_main(char const**, char const**,
char const*, void*) + 663
115 clang 0x00000000006289f8 main + 6440
116 libc.so.6 0x0000003000424985 __libc_start_main + 245
117 clang 0x000000000062275d
Stack dump:
0. Program arguments: /home/merkil/git/clang/build/Release+Asserts/bin/clang
-cc1 -triple x86_64-unknown-linux-gnu -emit-obj -disable-free -main-file-name
inf.c -mrelocation-model static -fmath-errno -masm-verbose
-mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64
-target-linker-version
2.23.1 -momit-leaf-frame-pointer -resource-dir
/home/merkil/git/clang/build/Release+Asserts/bin/../lib/clang/3.4
-internal-isystem /usr/local/include
-internal-isystem
/home/merkil/git/clang/build/Release+Asserts/bin/../lib/clang/3.4/include
-internal-externc-isystem /include -internal-externc-isystem
/usr/include -O2 -w -fdebug-compilation-dir /home/merkil -ferror-limit 19
-fmessage-length 169 -mstackrealign -fobjc-runtime=gcc
-fobjc-default-synthesize-properties -fdiagnostics-show-option
-fcolor-diagnostics -backend-option -vectorize-loops -o /tmp/inf-APH9cF.o -x c
inf.c
1. <eof> parser at end of file
2. Per-module optimization passes
3. Running pass 'CallGraph Pass Manager' on module 'inf.c'.
4. Running pass 'Loop Pass Manager' on function '@f'
5. Running pass 'Induction Variable Simplification' on basic block
'%for.cond.preheader'
clang: error: unable to execute command: CPU time limit exceeded
clang: error: clang frontend command failed due to signal (use -v to see
invocation)
clang version 3.4 (trunk 182207)
Target: x86_64-unknown-linux-gnu
Thread model: posix
clang: note: diagnostic msg: PLEASE submit a bug report to
<a href="http://llvm.org/bugs/">http://llvm.org/bugs/</a> and include the crash backtrace, preprocessed source, and
associated run script.</pre>
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