[LLVMbugs] [Bug 14546] New: "Instruction does not dominate all uses" in Loop Vectorization

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=14546

             Bug #: 14546
           Summary: "Instruction does not dominate all uses" in Loop
                    Vectorization
           Product: new-bugs
           Version: trunk
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: new bugs
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: antoine.balestrat at gmail.com
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified


The following testcase makes LLVM/Clang as of r169674 crash with Loop
Vectorization enabled.

$ cat dominate.c
int a, b, c;

void f(void)
{
    while(c++)
    {
        b = 1;
        a && (b = 0);
    }
}

$ clong -O1 -w -mllvm -vectorize-loops dominate.c
Instruction does not dominate all uses!
  %. = zext i1 %tobool1 to i32
  store i32 %., i32* @b, align 4
Broken module found, compilation aborted!
0  clang           0x0000000001ad26bf
1  clang           0x0000000001ad2ba3
2  libpthread.so.0 0x00007f53ebffc910
3  libc.so.6       0x00007f53eb265ff5 gsignal + 53
4  libc.so.6       0x00007f53eb267307 abort + 327
5  clang           0x0000000001a8c4e3
6  clang           0x0000000001a8c1aa
7  clang           0x0000000001a7505c
llvm::FPPassManager::runOnFunction(llvm::Function&) + 444
8  clang           0x0000000001a7525b
llvm::FPPassManager::runOnModule(llvm::Module&) + 59
9  clang           0x0000000001a755ce
llvm::MPPassManager::runOnModule(llvm::Module&) + 494
10 clang           0x0000000001a75bd8 llvm::PassManagerImpl::run(llvm::Module&)
+ 456
11 clang           0x0000000001a75d7a llvm::PassManager::run(llvm::Module&) +
10
12 clang           0x00000000007aa0f7
clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::CodeGenOptions
const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::Module*,
clang::BackendAction, llvm::raw_ostream*) + 5991
13 clang           0x00000000007a7bda
14 clang           0x00000000008dc0d5 clang::ParseAST(clang::Sema&, bool, bool)
+ 549
15 clang           0x00000000007a6c2c clang::CodeGenAction::ExecuteAction() +
204
16 clang           0x0000000000645b8a clang::FrontendAction::Execute() + 106
17 clang           0x0000000000626f7d
clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 989
18 clang           0x000000000060cf50
clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 3936
19 clang           0x0000000000603fc6 cc1_main(char const**, char const**, char
const*, void*) + 694
20 clang           0x0000000000609016 main + 3558
21 libc.so.6       0x00007f53eb252985 __libc_start_main + 245
22 clang           0x0000000000603c4d
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
dominate.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/3.3
-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/3.3/include
-internal-externc-isystem /include -internal-externc-isystem /usr/include -O1
-w -fdebug-compilation-dir /home/merkil/bugs -ferror-limit 19 -fmessage-length
0 -mstackrealign -fobjc-runtime=gcc -fdiagnostics-show-option -mllvm
-vectorize-loops -o /tmp/dominate-ndR2Vs.o -x c dominate.c 
1.    <eof> parser at end of file
2.    Code generation
3.    Running pass 'Function Pass Manager' on module 'dominate.c'.
4.    Running pass 'Module Verifier' on function '@f'
clang: error: unable to execute command: Aborted
clang: error: clang frontend command failed due to signal (use -v to see
invocation)
clang version 3.3 (trunk 169674)
Target: x86_64-unknown-linux-gnu
Thread model: posix
clang: note: diagnostic msg: PLEASE submit a bug report to
http://llvm.org/bugs/ and include the crash backtrace, preprocessed source, and
associated run script.

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