[llvm-bugs] [Bug 47557] New: Trying to remove memory access that still has uses
via llvm-bugs
llvm-bugs at lists.llvm.org
Wed Sep 16 19:39:54 PDT 2020
https://bugs.llvm.org/show_bug.cgi?id=47557
Bug ID: 47557
Summary: Trying to remove memory access that still has uses
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 23973
--> https://bugs.llvm.org/attachment.cgi?id=23973&action=edit
small.bc
$clang -v
clang version 12.0.0 (https://github.com/llvm/llvm-project.git
65f6810d3a4b0ef1fdaad49e808459fbd133bb20)
Target: x86_64-unknown-linux-gnu
Thread model: posix
$clang -O3 -c -emit-llvm -femit-all-decls -mllvm -disable-llvm-optzns small.c
$opt -simplifycfg -instcombine -early-cse-memssa -loop-unroll -loop-unswitch
-loop-reduce -loop-simplifycfg small.bc -o small-opt.bc
opt:
/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/llvm/lib/Analysis/MemorySSA.cpp:1832:
void llvm::MemorySSA::removeFromLookups(llvm::MemoryAccess*): Assertion
`MA->use_empty() && "Trying to remove memory access that still has uses"'
failed.
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash
backtrace.
Stack dump:
0. Program arguments:
/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt
-simplifycfg -instcombine -early-cse-memssa -loop-unroll -loop-unswitch
-loop-reduce -loop-simplifycfg 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 'Simplify loop CFG' on basic block '%for.cond'
#0 0x000055e6e068c99c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x2b9999c)
#1 0x000055e6e068a714 llvm::sys::RunSignalHandlers()
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x2b97714)
#2 0x000055e6e068a863 SignalHandler(int)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x2b97863)
#3 0x00007fc8d302e8a0 __restore_rt
(/lib/x86_64-linux-gnu/libpthread.so.0+0x128a0)
#4 0x00007fc8d1ce0f47 raise
/build/glibc-2ORdQG/glibc-2.27/sysdeps/unix/sysv/linux/raise.c:51:0
#5 0x00007fc8d1ce28b1 abort /build/glibc-2ORdQG/glibc-2.27/stdlib/abort.c:81:0
#6 0x00007fc8d1cd242a __assert_fail_base
/build/glibc-2ORdQG/glibc-2.27/assert/assert.c:89:0
#7 0x00007fc8d1cd24a2 (/lib/x86_64-linux-gnu/libc.so.6+0x304a2)
#8 0x000055e6df769715
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x1c76715)
#9 0x000055e6df77fd77
llvm::MemorySSAUpdater::removeBlocks(llvm::SmallSetVector<llvm::BasicBlock*,
8u> const&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x1c8cd77)
#10 0x000055e6e0464661 (anonymous
namespace)::ConstantTerminatorFoldingImpl::deleteDeadLoopBlocks()
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x2971661)
#11 0x000055e6e046685a constantFoldTerminators(llvm::Loop&,
llvm::DominatorTree&, llvm::LoopInfo&, llvm::ScalarEvolution&,
llvm::MemorySSAUpdater*, bool&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x297385a)
#12 0x000055e6e0467f47 (anonymous
namespace)::LoopSimplifyCFGLegacyPass::runOnLoop(llvm::Loop*,
llvm::LPPassManager&) (.part.254)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x2974f47)
#13 0x000055e6df742ae3 llvm::LPPassManager::runOnFunction(llvm::Function&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x1c4fae3)
#14 0x000055e6dfecdcc8 llvm::FPPassManager::runOnFunction(llvm::Function&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x23dacc8)
#15 0x000055e6dfece7c9 llvm::FPPassManager::runOnModule(llvm::Module&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x23db7c9)
#16 0x000055e6dfecd546 llvm::legacy::PassManagerImpl::run(llvm::Module&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x23da546)
#17 0x000055e6de3554c9 main
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x8624c9)
#18 0x00007fc8d1cc3b97 __libc_start_main
/build/glibc-2ORdQG/glibc-2.27/csu/libc-start.c:344:0
#19 0x000055e6de4047ca _start
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x9117ca)
Aborted (core dumped)
I also use bugpoint to reduce the testcase. The reduced optimization sequence
is "-loop-unswitch -loop-reduce -loop-simplifycfg".
$opt bugpoint-reduced-simplified.bc -loop-unswitch -loop-reduce
-loop-simplifycfg
opt:
/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/llvm/lib/Analysis/MemorySSA.cpp:1832:
void llvm::MemorySSA::removeFromLookups(llvm::MemoryAccess*): Assertion
`MA->use_empty() && "Trying to remove memory access that still has uses"'
failed.
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash
backtrace.
Stack dump:
0. Program arguments:
/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt
bugpoint-reduced-simplified.bc -loop-unswitch -loop-reduce -loop-simplifycfg
1. Running pass 'Function Pass Manager' on module
'bugpoint-reduced-simplified.bc'.
2. Running pass 'Loop Pass Manager' on function '@e'
3. Running pass 'Simplify loop CFG' on basic block '%for.cond'
#0 0x00005569bb76799c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x2b9999c)
#1 0x00005569bb765714 llvm::sys::RunSignalHandlers()
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x2b97714)
#2 0x00005569bb765863 SignalHandler(int)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x2b97863)
#3 0x00007f3a5f4d28a0 __restore_rt
(/lib/x86_64-linux-gnu/libpthread.so.0+0x128a0)
#4 0x00007f3a5e184f47 raise
/build/glibc-2ORdQG/glibc-2.27/sysdeps/unix/sysv/linux/raise.c:51:0
#5 0x00007f3a5e1868b1 abort /build/glibc-2ORdQG/glibc-2.27/stdlib/abort.c:81:0
#6 0x00007f3a5e17642a __assert_fail_base
/build/glibc-2ORdQG/glibc-2.27/assert/assert.c:89:0
#7 0x00007f3a5e1764a2 (/lib/x86_64-linux-gnu/libc.so.6+0x304a2)
#8 0x00005569ba844715
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x1c76715)
#9 0x00005569ba85ad77
llvm::MemorySSAUpdater::removeBlocks(llvm::SmallSetVector<llvm::BasicBlock*,
8u> const&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x1c8cd77)
#10 0x00005569bb53f661 (anonymous
namespace)::ConstantTerminatorFoldingImpl::deleteDeadLoopBlocks()
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x2971661)
#11 0x00005569bb54185a constantFoldTerminators(llvm::Loop&,
llvm::DominatorTree&, llvm::LoopInfo&, llvm::ScalarEvolution&,
llvm::MemorySSAUpdater*, bool&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x297385a)
#12 0x00005569bb542f47 (anonymous
namespace)::LoopSimplifyCFGLegacyPass::runOnLoop(llvm::Loop*,
llvm::LPPassManager&) (.part.254)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x2974f47)
#13 0x00005569ba81dae3 llvm::LPPassManager::runOnFunction(llvm::Function&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x1c4fae3)
#14 0x00005569bafa8cc8 llvm::FPPassManager::runOnFunction(llvm::Function&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x23dacc8)
#15 0x00005569bafa97c9 llvm::FPPassManager::runOnModule(llvm::Module&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x23db7c9)
#16 0x00005569bafa8546 llvm::legacy::PassManagerImpl::run(llvm::Module&)
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x23da546)
#17 0x00005569b94304c9 main
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x8624c9)
#18 0x00007f3a5e167b97 __libc_start_main
/build/glibc-2ORdQG/glibc-2.27/csu/libc-start.c:344:0
#19 0x00005569b94df7ca _start
(/home/jack-zhou/Documents/llvm/llvm_truck/llvm-project/build/bin/opt+0x9117ca)
Aborted (core dumped)
---small.c-------
int a, b;
int c[];
long d;
void e() {
f:
d = 0;
for (;; d++) {
int g = 0;
for (; g <= 1; g++) {
a = 0;
for (; a;)
c[d] = 0;
if (b)
goto f;
}
}
}
void main() {}
--
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