[llvm-bugs] [Bug 42946] New: gvn-hoist crashes: Assertion `MSSA->dominates(NewDef, FirstDef) && "Should have dominated the new access"' failed.

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=42946

            Bug ID: 42946
           Summary: gvn-hoist crashes: Assertion `MSSA->dominates(NewDef,
                    FirstDef) && "Should have dominated the new access"'
                    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 22364
  --> https://bugs.llvm.org/attachment.cgi?id=22364&action=edit
.bc file of the source code

$clang -v
clang version 10.0.0 (trunk 368431)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/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 -deadargelim -reg2mem -instcombine -gvn-hoist small.bc -o small-opt.bc
opt:
/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/lib/Analysis/MemorySSAUpdater.cpp:429:
void llvm::MemorySSAUpdater::fixupDefs(const
llvm::SmallVectorImpl<llvm::WeakVH>&): Assertion `MSSA->dominates(NewDef,
FirstDef) && "Should have dominated the new access"' failed.
Stack dump:
0.      Program arguments:
/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt -deadargelim
-reg2mem -instcombine -gvn-hoist small.bc -o small-opt.bc 
1.      Running pass 'Function Pass Manager' on module 'small.bc'.
2.      Running pass 'Early GVN Hoisting of Expressions' on function '@d'
 #0 0x0000556d1c55274a llvm::sys::PrintStackTrace(llvm::raw_ostream&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x26ef74a)
 #1 0x0000556d1c550424 llvm::sys::RunSignalHandlers()
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x26ed424)
 #2 0x0000556d1c550562 SignalHandler(int)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x26ed562)
 #3 0x00007f0ae577d890 __restore_rt
(/lib/x86_64-linux-gnu/libpthread.so.0+0x12890)
 #4 0x00007f0ae442fe97 raise
/build/glibc-OTsEL5/glibc-2.27/signal/../sysdeps/unix/sysv/linux/raise.c:51:0
 #5 0x00007f0ae4431801 abort /build/glibc-OTsEL5/glibc-2.27/stdlib/abort.c:81:0
 #6 0x00007f0ae442139a __assert_fail_base
/build/glibc-OTsEL5/glibc-2.27/assert/assert.c:89:0
 #7 0x00007f0ae4421412 (/lib/x86_64-linux-gnu/libc.so.6+0x30412)
 #8 0x0000556d1b8aa6f0
llvm::MemorySSAUpdater::fixupDefs(llvm::SmallVectorImpl<llvm::WeakVH> const&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x1a476f0)
 #9 0x0000556d1b8aa967 llvm::MemorySSAUpdater::insertDef(llvm::MemoryDef*,
bool)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x1a47967)
#10 0x0000556d1b8ab58f void
llvm::MemorySSAUpdater::moveTo<llvm::MemorySSA::InsertionPlace>(llvm::MemoryUseOrDef*,
llvm::BasicBlock*, llvm::MemorySSA::InsertionPlace)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x1a4858f)
#11 0x0000556d1c2c922c
llvm::GVNHoist::hoist(llvm::SmallVector<std::pair<llvm::BasicBlock*,
llvm::SmallVector<llvm::Instruction*, 4u> >, 4u>&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x246622c)
#12 0x0000556d1c2d13a9 llvm::GVNHoist::hoistExpressions(llvm::Function&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x246e3a9)
#13 0x0000556d1c2d1932 llvm::GVNHoist::run(llvm::Function&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x246e932)
#14 0x0000556d1c2d1e2a llvm::GVNHoistLegacyPass::runOnFunction(llvm::Function&)
(.part.598)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x246ee2a)
#15 0x0000556d1bec4159 llvm::FPPassManager::runOnFunction(llvm::Function&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x2061159)
#16 0x0000556d1bec4251 llvm::FPPassManager::runOnModule(llvm::Module&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x2061251)
#17 0x0000556d1bec33b1 llvm::legacy::PassManagerImpl::run(llvm::Module&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x20603b1)
#18 0x0000556d1a6cf285 main
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x86c285)
#19 0x00007f0ae4412b97 __libc_start_main
/build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:344:0
#20 0x0000556d1a75603a _start
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build5/bin/opt+0x8f303a)
Aborted (core dumped)

---------------------------------------------------------------
char a;
short b;
char(c)();
static long d() {
  {
    int e;
    if (c())
      for (; 1; e){
        if (b){
          return 1;
        }
        else{
          return a;
        }
      }
  }
  return a;
}

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