[llvm-bugs] [Bug 43325] New: loop-unswitch crashes: Assertion `NewInst && "All instructions that are in SrcBB must be in VMap."' failed.

Mon Sep 16 05:05:15 PDT 2019

https://bugs.llvm.org/show_bug.cgi?id=43325

            Bug ID: 43325
           Summary: loop-unswitch crashes: Assertion `NewInst && "All
                    instructions that are in SrcBB must be in VMap."'
                    failed.
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Scalar Optimizations
          Assignee: unassignedbugs at nondot.org
          Reporter: cszide at 163.com
                CC: llvm-bugs at lists.llvm.org

Created attachment 22506
  --> https://bugs.llvm.org/attachment.cgi?id=22506&action=edit
.bc file of the source code

$clang -v
clang version 10.0.0 (trunk 371952)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.4.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64

$clang -O3 -c -emit-llvm -femit-all-decls -mllvm -disable-llvm-optzns small.c

$opt -mem2reg -simplifycfg -loop-simplifycfg -loop-unswitch small.bc -o
small-opt.bc
opt:
/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/lib/Transforms/Scalar/LoopUnswitch.cpp:380:
void {anonymous}::LUAnalysisCache::cloneData(const llvm::Loop*, const
llvm::Loop*, const ValueToValueMapTy&): Assertion `NewInst && "All instructions
that are in SrcBB must be in VMap."' failed.
Stack dump:
0.      Program arguments:
/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt -mem2reg
-simplifycfg -loop-simplifycfg -loop-unswitch small.bc -o small-opt.bc 
1.      Running pass 'Function Pass Manager' on module 'small.bc'.
2.      Running pass 'Loop Pass Manager' on function '@e'
3.      Running pass 'Unswitch loops' on basic block '%for.cond.us'
 #0 0x000055ed5b1b127a llvm::sys::PrintStackTrace(llvm::raw_ostream&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x277727a)
 #1 0x000055ed5b1aef54 llvm::sys::RunSignalHandlers()
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x2774f54)
 #2 0x000055ed5b1af092 SignalHandler(int)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x2775092)
 #3 0x00007f6629376890 __restore_rt
(/lib/x86_64-linux-gnu/libpthread.so.0+0x12890)
 #4 0x00007f6628028e97 raise
/build/glibc-OTsEL5/glibc-2.27/signal/../sysdeps/unix/sysv/linux/raise.c:51:0
 #5 0x00007f662802a801 abort /build/glibc-OTsEL5/glibc-2.27/stdlib/abort.c:81:0
 #6 0x00007f662801a39a __assert_fail_base
/build/glibc-OTsEL5/glibc-2.27/assert/assert.c:89:0
 #7 0x00007f662801a412 (/lib/x86_64-linux-gnu/libc.so.6+0x30412)
 #8 0x000055ed5affe6d5 (anonymous
namespace)::LUAnalysisCache::cloneData(llvm::Loop const*, llvm::Loop const*,
llvm::ValueMap<llvm::Value const*, llvm::WeakTrackingVH,
llvm::ValueMapConfig<llvm::Value const*, llvm::sys::SmartMutex<false> > >
const&) (.isra.503)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x25c46d5)
 #9 0x000055ed5afff9e9 (anonymous
namespace)::LoopUnswitch::UnswitchNontrivialCondition(llvm::Value*,
llvm::Constant*, llvm::Loop*, llvm::Instruction*)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x25c59e9)
#10 0x000055ed5b000c60 (anonymous
namespace)::LoopUnswitch::UnswitchIfProfitable(llvm::Value*, llvm::Constant*,
llvm::Instruction*)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x25c6c60)
#11 0x000055ed5b001e71 (anonymous
namespace)::LoopUnswitch::processCurrentLoop()
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x25c7e71)
#12 0x000055ed5b002947 (anonymous
namespace)::LoopUnswitch::runOnLoop(llvm::Loop*, llvm::LPPassManager&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x25c8947)
#13 0x000055ed5a48442b llvm::LPPassManager::runOnFunction(llvm::Function&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x1a4a42b)
#14 0x000055ed5aaf0de9 llvm::FPPassManager::runOnFunction(llvm::Function&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x20b6de9)
#15 0x000055ed5aaf0ee1 llvm::FPPassManager::runOnModule(llvm::Module&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x20b6ee1)
#16 0x000055ed5aaf0041 llvm::legacy::PassManagerImpl::run(llvm::Module&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x20b6041)
#17 0x000055ed592c974f main
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x88f74f)
#18 0x00007f662800bb97 __libc_start_main
/build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:344:0
#19 0x000055ed5934154a _start
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x90754a)
Aborted (core dumped)

By using bugpoint, the optimization sequences can be reduced to
"-loop-simplifycfg -loop-unswitch"

$opt bugpoint-reduced-simplified.bc -loop-simplifycfg -loop-unswitch
opt:
/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/lib/Transforms/Scalar/LoopUnswitch.cpp:380:
void {anonymous}::LUAnalysisCache::cloneData(const llvm::Loop*, const
llvm::Loop*, const ValueToValueMapTy&): Assertion `NewInst && "All instructions
that are in SrcBB must be in VMap."' failed.
Stack dump:
0.      Program arguments:
/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt
bugpoint-reduced-simplified.bc -loop-simplifycfg -loop-unswitch 
1.      Running pass 'Function Pass Manager' on module
'bugpoint-reduced-simplified.bc'.
2.      Running pass 'Loop Pass Manager' on function '@e'
3.      Running pass 'Unswitch loops' on basic block '%for.cond.us'
 #0 0x000055898fb9927a llvm::sys::PrintStackTrace(llvm::raw_ostream&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x277727a)
 #1 0x000055898fb96f54 llvm::sys::RunSignalHandlers()
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x2774f54)
 #2 0x000055898fb97092 SignalHandler(int)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x2775092)
 #3 0x00007f73f9df1890 __restore_rt
(/lib/x86_64-linux-gnu/libpthread.so.0+0x12890)
 #4 0x00007f73f8aa3e97 raise
/build/glibc-OTsEL5/glibc-2.27/signal/../sysdeps/unix/sysv/linux/raise.c:51:0
 #5 0x00007f73f8aa5801 abort /build/glibc-OTsEL5/glibc-2.27/stdlib/abort.c:81:0
 #6 0x00007f73f8a9539a __assert_fail_base
/build/glibc-OTsEL5/glibc-2.27/assert/assert.c:89:0
 #7 0x00007f73f8a95412 (/lib/x86_64-linux-gnu/libc.so.6+0x30412)
 #8 0x000055898f9e66d5 (anonymous
namespace)::LUAnalysisCache::cloneData(llvm::Loop const*, llvm::Loop const*,
llvm::ValueMap<llvm::Value const*, llvm::WeakTrackingVH,
llvm::ValueMapConfig<llvm::Value const*, llvm::sys::SmartMutex<false> > >
const&) (.isra.503)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x25c46d5)
 #9 0x000055898f9e79e9 (anonymous
namespace)::LoopUnswitch::UnswitchNontrivialCondition(llvm::Value*,
llvm::Constant*, llvm::Loop*, llvm::Instruction*)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x25c59e9)
#10 0x000055898f9e8c60 (anonymous
namespace)::LoopUnswitch::UnswitchIfProfitable(llvm::Value*, llvm::Constant*,
llvm::Instruction*)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x25c6c60)
#11 0x000055898f9e9e71 (anonymous
namespace)::LoopUnswitch::processCurrentLoop()
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x25c7e71)
#12 0x000055898f9ea947 (anonymous
namespace)::LoopUnswitch::runOnLoop(llvm::Loop*, llvm::LPPassManager&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x25c8947)
#13 0x000055898ee6c42b llvm::LPPassManager::runOnFunction(llvm::Function&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x1a4a42b)
#14 0x000055898f4d8de9 llvm::FPPassManager::runOnFunction(llvm::Function&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x20b6de9)
#15 0x000055898f4d8ee1 llvm::FPPassManager::runOnModule(llvm::Module&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x20b6ee1)
#16 0x000055898f4d8041 llvm::legacy::PassManagerImpl::run(llvm::Module&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x20b6041)
#17 0x000055898dcb174f main
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x88f74f)
#18 0x00007f73f8a86b97 __libc_start_main
/build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:344:0
#19 0x000055898dd2954a _start
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build9/bin/opt+0x90754a)
Aborted (core dumped)

---------------------------------
int a, b, c, d;
int *e(int f) {
  if (d)
  g:
    for (;;) {
      short h;
      if (f)
        goto g;
      {
        int i;
        for (; 4;)
          return &b;
        if (c)
          continue;
      }
    }
  return &a;
}

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