[llvm] [InstCombine] Fold trunc(lshr(add(shl(X, ShAmt), C), ShrAmt)) (PR #214562)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

The following correctness issue was found by [llvm-hackme](https://github.com/dtcxzyw/llvm-hackme).

<!-- llvm-hackme-state: bug_found -->
<!-- llvm-hackme-baseline: febf50748effc5fb381ad479cf129f1ebcdc4bec -->
<!-- llvm-hackme-head-sha: 697bef34604954e97751b64f1858bae4e9ebd987 -->
<!-- llvm-hackme-patch-sha256: 891286a7537dd7b927b2bb8459cf937eb7f7ca4143d0867b4e1ce2e738e5c49f -->
<!-- llvm-hackme-kind: crash -->

This comment is generated by an automated correctness checking service designed to help identify critical correctness bugs (opt crashes or Alive2 miscompilations) and improve PR review efficiency under limited reviewer bandwidth.

The reproducer was generated by LLM.

This bug is a regression introduced by this PR. It does not reproduce on the baseline commit.

## Reproducer

**Kind**: crash

**IR Reproducer**:
```llvm
; RUN: opt -passes=instcombine<no-verify-fixpoint> -S
define i32 @f(i32 %x) {
  %v2 = shl i32 %x, 12
  %v3 = add i32 %v2, 34816
  %v16 = lshr i32 %v3, 8
  %r = and i32 %v16, 255
  ret i32 %r
}
```

**Stacktrace**:
```
Instruction does not dominate all uses!
  %2 = shl i32 %x, 4
  %1 = add i32 %2, 136
LLVM ERROR: Broken module found, compilation aborted!
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
Stack dump:
0.	Program arguments: /llvm-hackme/work/llvm-hackme/llvm-build-pr/bin/opt -S -o /dev/null /tmp/tmpprv9vrwl.ll -passes=instcombine<no-verify-fixpoint>
1.	Running pass "verify" on module "/tmp/tmpprv9vrwl.ll"
 #0 0x00007ffff7e1a092 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Support/Unix/Signals.inc:931:22
 #1 0x00007ffff7e16ccc llvm::sys::RunSignalHandlers() /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Support/Signals.cpp:108:20
 #2 0x00007ffff7e16ed5 SignalHandler(int, siginfo_t*, void*) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Support/Unix/Signals.inc:474:14
 #3 0x00007ffff7a19520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007ffff7a6d9fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x00007ffff7a19476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007ffff79ff7f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x00007ffff7c76a58 std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string() /usr/include/c++/11/bits/basic_string.h:672:19
 #8 0x00007ffff7c76a58 llvm::report_fatal_error(llvm::Twine const&, bool) (.cold) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Support/ErrorHandling.cpp:117:36
 #9 0x00007ffff7d1d6c5 (/llvm-hackme/work/llvm-hackme/llvm-build-pr/bin/../lib/libLLVMSupport.so.24.0git+0x11d6c5)
#10 0x00007fffedd3eee0 llvm::VerifierPass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/IR/Verifier.cpp:8142:79
#11 0x00007ffff7f87da6 llvm::detail::PassModel<llvm::Module, llvm::VerifierPass, llvm::AnalysisManager<llvm::Module> >::runImpl(llvm::detail::PassConcept<llvm::Module, llvm::AnalysisManager<llvm::Module> >&, llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/IR/PassManagerInternal.h:129:3
#12 0x00007fffedd01fb8 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/IR/PassManagerImpl.h:80:18
#13 0x00007ffff7f94874 llvm::SmallPtrSetImplBase::~SmallPtrSetImplBase() /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/ADT/SmallPtrSet.h:89:5
#14 0x00007ffff7f94874 llvm::SmallPtrSetImpl<llvm::AnalysisKey*>::~SmallPtrSetImpl() /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/ADT/SmallPtrSet.h:365:35
#15 0x00007ffff7f94874 llvm::SmallPtrSet<llvm::AnalysisKey*, 2u>::~SmallPtrSet() /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/ADT/SmallPtrSet.h:532:7
#16 0x00007ffff7f94874 llvm::PreservedAnalyses::~PreservedAnalyses() /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/IR/Analysis.h:112:7
#17 0x00007ffff7f94874 llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::PassPlugin>, llvm::ArrayRef<std::function<void (llvm::PassBuilder&)> >, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool, bool, bool) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/tools/opt/NewPMDriver.cpp:580:10
#18 0x00007ffff7fa18c4 optMain /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/tools/opt/optdriver.cpp:805:25
#19 0x00007ffff7a00d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#20 0x00007ffff7a00e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#21 0x0000555555555095 _start (/llvm-hackme/work/llvm-hackme/llvm-build-pr/bin/opt+0x1095)
```


**Baseline Revision**: `febf50748effc5fb381ad479cf129f1ebcdc4bec`
**PR Head SHA**: `697bef34604954e97751b64f1858bae4e9ebd987`
**Patch SHA256**: `891286a7537dd7b927b2bb8459cf937eb7f7ca4143d0867b4e1ce2e738e5c49f`


https://github.com/llvm/llvm-project/pull/214562