[LLVMbugs] [Bug 13021] New: Clang in an infinite loop

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=13021

             Bug #: 13021
           Summary: Clang in an infinite loop
           Product: new-bugs
           Version: trunk
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: new bugs
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: merkil at savhon.org
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified


This testcase makes Clang as of r157903 go into what looks like an infinite
loop, which causes very high memory consumption.

$ cat file.c
unsigned char a, i;

void f1(void)
{
    for(i = 0; i < 30; i++)
        a *= a;
}

void f2(void)
{
    f1();
}

$ ulimit -t 60

$ ~/clang/build/Release+Asserts/bin/clang -O3 -w file.c
0  clang           0x0000000001bb22af
1  clang           0x0000000001bb27c4
2  libpthread.so.0 0x00007f9488e04280
3  clang           0x00000000018ba2fb
4  clang           0x00000000018b9bf3
5  clang           0x00000000018b3d7b
6  clang           0x00000000018b305b
7  clang           0x0000000001b2036b
llvm::FPPassManager::runOnFunction(llvm::Function&) + 443
8  clang           0x0000000001988225
9  clang           0x0000000001b20843
llvm::MPPassManager::runOnModule(llvm::Module&) + 419
10 clang           0x0000000001b20dc8 llvm::PassManagerImpl::run(llvm::Module&)
+ 408
11 clang           0x0000000001b20f2a llvm::PassManager::run(llvm::Module&) +
10
12 clang           0x0000000000786b20
clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::CodeGenOptions
const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::Module*,
clang::BackendAction, llvm::raw_ostream*) + 4976
13 clang           0x00000000007849ea
14 clang           0x00000000008add35 clang::ParseAST(clang::Sema&, bool, bool)
+ 389
15 clang           0x0000000000783a78 clang::CodeGenAction::ExecuteAction() +
184
16 clang           0x000000000065270d
clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 973
17 clang           0x000000000063b0ab
clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 3307
18 clang           0x000000000063038b cc1_main(char const**, char const**, char
const*, void*) + 731
19 clang           0x000000000063772a main + 3482
20 libc.so.6       0x00007f948805d4bd __libc_start_main + 253
21 clang           0x000000000062ffed
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
file.c -mrelocation-model static -fmath-errno -masm-verbose
-mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-linker-version
2.22 -momit-leaf-frame-pointer -resource-dir
/home/merkil/git/clang/build/Release+Asserts/bin/../lib/clang/3.2
-fmodule-cache-path /var/tmp/clang-module-cache -internal-isystem
/usr/local/include -internal-isystem
/home/merkil/git/clang/build/Release+Asserts/bin/../lib/clang/3.2/include
-internal-externc-isystem /include -internal-externc-isystem /usr/include -O3
-w -fdebug-compilation-dir /home/merkil/garbage/creduce/creduce -ferror-limit
19 -fmessage-length 96 -mstackrealign -fgnu-runtime -fobjc-runtime-has-arc
-fobjc-runtime-has-weak -fobjc-fragile-abi -fdiagnostics-show-option
-fcolor-diagnostics -o /tmp/file-tIT535.o -x c file.c 
1.    <eof> parser at end of file
2.    Per-module optimization passes
3.    Running pass 'CallGraph Pass Manager' on module 'file.c'.
4.    Running pass 'Reassociate expressions' on function '@f2'
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: note: diagnostic msg: Please submit a bug report to
http://llvm.org/bugs/ and include command line arguments and all diagnostic
information.
clang version 3.2 (trunk 157903)
Target: x86_64-unknown-linux-gnu
Thread model: posix
clang: note: diagnostic msg: Preprocessed source(s) and associated run
script(s) are located at:
clang: note: diagnostic msg: /tmp/file-hnsPlF.i
clang: note: diagnostic msg: /tmp/file-hnsPlF.sh

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