[PATCH] D13378: [SCEV] Recognize simple br-phi patterns

[Sanjoy Das via llvm-commits]

sanjoy added a comment.

Diego Novillo via llvm-commits wrote:

> dnovillo added a subscriber: dnovillo.

>  dnovillo added a comment.

> 

> Sanjoy,

> 

> This commit is causing an internal compiler error with the following code:

> 

> int x0, x1, x2;

>  double *x3;

>  int fsolv() {

> 

>   int x4, x5 = x4 = 0;

>   for (; x4<  x2; ++x4) {

>     x0 = 0;

>     for (; x0<  x4; ++x0)

>       x1 = x3[x5++];

>   }

>   return 0;

> 

> }

> 

> Is this something you recognize?  If not, do you mind if I revert your

>  commit while you work on the test case?


It is plausible that this is the same issue as in http://reviews.llvm.org/D13460.  If it is possible, can you please try 
http://reviews.llvm.org/D13460 and see if it fixes the ICE?  If not or if trying out a new patch will be too much work, reverting this is okay.

Thanks!

- Sanjoy



> Thanks.  Diego.

> 

> $ clang -c -O2 a.c

>  clang-3.8:

>  /usr/local/google/home/dnovillo/llvm/llvm/lib/Analysis/LazyValueInfo.cpp:632:

>  bool (anonymous namespace)::LazyValueInfoCache

>  ::solveBlockValueNonLocal((anonymous namespace)::LVILatticeVal&,

>  llvm::Value *, llvm::BasicBlock *): Assertion `isa<Argument>(Val)&&

>  "Unknown live-in to the entry block"' failed.

>  0  libLLVMSupport.so.3.8       0x00007f484d2fafde

>  llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 46

>  1  libLLVMSupport.so.3.8       0x00007f484d2fc119

>  2  libLLVMSupport.so.3.8       0x00007f484d2fab53

>  llvm::sys::RunSignalHandlers() + 131

>  3  libLLVMSupport.so.3.8       0x00007f484d2fc35b

>  4  libc.so.6                   0x00007f484a447d40

>  5  libc.so.6                   0x00007f484a447cc9 gsignal + 57

>  6  libc.so.6                   0x00007f484a44b0d8 abort + 328

>  7  libc.so.6                   0x00007f484a440b86

>  8  libc.so.6                   0x00007f484a440c32

>  9  libLLVMAnalysis.so.3.8      0x00007f48504ba546

>  10 libLLVMAnalysis.so.3.8      0x00007f48504b9dd6

>  11 libLLVMAnalysis.so.3.8      0x00007f48504b97b2

>  12 libLLVMAnalysis.so.3.8      0x00007f48504b776e

>  13 libLLVMAnalysis.so.3.8      0x00007f48504b7541

>  llvm::LazyValueInfo::getConstantOnEdge(llvm::Value*, llvm::BasicBlock*,

> llvm::BasicBl

>  ock*, llvm::Instruction*) + 129

>  14 libLLVMScalarOpts.so.3.8    0x00007f484d60a6ea

>  15 libLLVMScalarOpts.so.3.8    0x00007f484d60a317

>  16 libLLVMCore.so.3.8          0x00007f484f4281ff

>  llvm::FPPassManager::runOnFunction(llvm::Function&) + 399

>  17 libLLVMAnalysis.so.3.8      0x00007f48503f1611

>  18 libLLVMAnalysis.so.3.8      0x00007f48503f107d

>  19 libLLVMAnalysis.so.3.8      0x00007f48503f0928

>  20 libLLVMCore.so.3.8          0x00007f484f428caa

>  21 libLLVMCore.so.3.8          0x00007f484f4287d6

>  llvm::legacy::PassManagerImpl::run(llvm::Module&) + 342

>  22 libLLVMCore.so.3.8          0x00007f484f4291c1

>  llvm::legacy::PassManager::run(llvm::Module&) + 33

>  23 libclangCodeGen.so.3.8      0x00007f484bbb6dd5

>  24 libclangCodeGen.so.3.8      0x00007f484bbb6502

>  clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::CodeGenOptions

>  const&, clang::TargetOptions const&, clang::LangOptions const&,

>  llvm::StringRef, llvm::Module*, clang::BackendAction,

>  llvm::raw_pwrite_stream*) + 162

>  25 libclangCodeGen.so.3.8      0x00007f484be89a39

>  26 libclangParse.so.3.8        0x00007f48463905b1

>  clang::ParseAST(clang::Sema&, bool, bool) + 817

>  27 libclangFrontend.so.3.8     0x00007f484b402d10

>  clang::ASTFrontendAction::ExecuteAction() + 320

>  28 libclangCodeGen.so.3.8      0x00007f484be875f4

>  clang::CodeGenAction::ExecuteAction() + 2100

>  29 libclangFrontend.so.3.8     0x00007f484b4027f0

>  clang::FrontendAction::Execute() + 112

>  30 libclangFrontend.so.3.8     0x00007f484b39f402

>  clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 978

>  31 libclangFrontendTool.so.3.8 0x00007f484affa764

>  clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 1172

>  32 clang-3.8                   0x0000000000423f08

>  cc1_main(llvm::ArrayRef<char const*>, char const*, void*) + 920

>  33 clang-3.8                   0x0000000000417839

>  34 clang-3.8                   0x0000000000416715 main + 2277

>  35 libc.so.6                   0x00007f484a432ec5 __libc_start_main + 245

>  36 clang-3.8                   0x0000000000415ce4

>  Stack dump:

> 

> 1.<eof>  parser at end of file

> 

> 2. Per-module optimization passes

> 3. Running pass 'CallGraph Pass Manager' on module 'a.c'.

> 4. Running pass 'Value Propagation' on function '@fsolv'

> 

> Repository:

> 

>   rL LLVM

> 

> http://reviews.llvm.org/D13378

> 

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> 

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Repository:
  rL LLVM

http://reviews.llvm.org/D13378