[llvm] [AMDGPU] Constant folding for wave-reduce intrinsics (PR #212755)

Sat Aug 1 03:26:55 PDT 2026

dtcxzyw wrote:

> The following correctness issue was found by [llvm-hackme](https://github.com/dtcxzyw/llvm-hackme).
> 
> 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
> target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
> target triple = "amdgcn--"
> 
> define <2 x i32> @test_wave_reduce_vector_add(<2 x i32> %x) {
>   %r = call <2 x i32> @llvm.amdgcn.wave.reduce.add.v2i32(<2 x i32> zeroinitializer, i32 0)
>   ret <2 x i32> %r
> }
> ```
> 
> **Stacktrace**:
> 
> ```
> opt: ../llvm-project-pr/llvm/lib/IR/Constants.cpp:447: llvm::Constant* llvm::Constant::getAggregateElement(unsigned int) const: Assertion `(getType()->isAggregateType() || getType()->isVectorTy()) && "Must be an aggregate/vector constant"' failed.
> 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/tmp4k1jati4.ll -passes=instcombine<no-verify-fixpoint>
> 1.	Running pass "function(instcombine<max-iterations=1;no-verify-fixpoint>)" on module "/tmp/tmp4k1jati4.ll"
> 2.	Running pass "instcombine<max-iterations=1;no-verify-fixpoint>" on function "test_wave_reduce_vector_add"
>  #0 0x00007ffff7e1a1a2 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Support/Unix/Signals.inc:928:22
>  #1 0x00007ffff7e16ddc llvm::sys::RunSignalHandlers() /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Support/Signals.cpp:108:20
>  #2 0x00007ffff7e16fe5 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 0x00007ffff79ff71b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
>  #8 0x00007ffff7a10e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
>  #9 0x00007fffedf721ef llvm::ConstantDataSequential::classof(llvm::Value const*) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/IR/Constants.h:851:52
> #10 0x00007fffedf721ef llvm::isa_impl<llvm::ConstantDataSequential, llvm::Constant, void>::doit(llvm::Constant const&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/Support/Casting.h:64:64
> #11 0x00007fffedf721ef llvm::isa_impl_cl<llvm::ConstantDataSequential, llvm::Constant const*>::doit(llvm::Constant const*) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/Support/Casting.h:110:36
> #12 0x00007fffedf721ef llvm::isa_impl_wrap<llvm::ConstantDataSequential, llvm::Constant const*, llvm::Constant const*>::doit(llvm::Constant const* const&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/Support/Casting.h:137:41
> #13 0x00007fffedf721ef llvm::isa_impl_wrap<llvm::ConstantDataSequential, llvm::Constant const* const, llvm::Constant const*>::doit(llvm::Constant const* const&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/Support/Casting.h:129:13
> #14 0x00007fffedf721ef llvm::CastIsPossible<llvm::ConstantDataSequential, llvm::Constant const*, void>::isPossible(llvm::Constant const* const&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/Support/Casting.h:257:62
> #15 0x00007fffedf721ef llvm::CastInfo<llvm::ConstantDataSequential, llvm::Constant const*, void>::doCastIfPossible(llvm::Constant const* const&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/Support/Casting.h:493:26
> #16 0x00007fffedf721ef decltype(auto) llvm::dyn_cast<llvm::ConstantDataSequential, llvm::Constant const>(llvm::Constant const*) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/Support/Casting.h:657:48
> #17 0x00007fffedf721ef llvm::Constant::getAggregateElement(unsigned int) const /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/IR/Constants.cpp:496:57
> #18 0x00007fffee7b4d9e (anonymous namespace)::ConstantFoldFixedVectorCall(llvm::StringRef, unsigned int, llvm::FixedVectorType*, llvm::ArrayRef<llvm::Constant*>, llvm::DataLayout const&, llvm::TargetLibraryInfo const*, llvm::CallBase const*) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Analysis/ConstantFolding.cpp:4493:7
> #19 0x00007fffee7b5897 llvm::ConstantFoldCall(llvm::CallBase const*, llvm::Function*, llvm::ArrayRef<llvm::Constant*>, llvm::TargetLibraryInfo const*, bool) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Analysis/ConstantFolding.cpp:4743:39
> #20 0x00007fffee7b978e llvm::ConstantFoldInstOperands(llvm::Instruction const*, llvm::ArrayRef<llvm::Constant*>, llvm::DataLayout const&, llvm::TargetLibraryInfo const*, bool) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Analysis/ConstantFolding.cpp:1327:38
> #21 0x00007fffee7b978e llvm::ConstantFoldInstruction(llvm::Instruction const*, llvm::DataLayout const&, llvm::TargetLibraryInfo const*) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Analysis/ConstantFolding.cpp:1313:34
> #22 0x00007fffef253ae1 llvm::InstCombinerImpl::prepareWorklist(llvm::Function&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp:6084:50
> #23 0x00007fffef267d9f combineInstructionsOverFunction(llvm::Function&, llvm::InstructionWorklist&, llvm::AAResults*, llvm::AssumptionCache&, llvm::TargetLibraryInfo&, llvm::TargetTransformInfo&, llvm::DominatorTree&, llvm::OptimizationRemarkEmitter&, llvm::BlockFrequencyInfo*, llvm::BranchProbabilityInfo*, llvm::ProfileSummaryInfo*, llvm::InstCombineOptions const&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp:6239:40
> #24 0x00007fffef268c0c llvm::InstCombinePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp:6301:3
> #25 0x00007ffff145f2c6 llvm::detail::PassModel<llvm::Function, llvm::InstCombinePass, llvm::AnalysisManager<llvm::Function> >::runImpl(llvm::detail::PassConcept<llvm::Function, llvm::AnalysisManager<llvm::Function> >&, llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/IR/PassManagerInternal.h:129:3
> #26 0x00007fffee101d98 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function> >::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/IR/PassManagerImpl.h:80:18
> #27 0x00007ffff145ca76 llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function> >, llvm::AnalysisManager<llvm::Function> >::runImpl(llvm::detail::PassConcept<llvm::Function, llvm::AnalysisManager<llvm::Function> >&, llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/IR/PassManagerInternal.h:129:3
> #28 0x00007fffee100b8c llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/lib/IR/PassManager.cpp:132:41
> #29 0x00007ffff1460406 llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, 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
> #30 0x00007fffee1005e8 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
> #31 0x00007ffff7f948c4 llvm::SmallPtrSetImplBase::~SmallPtrSetImplBase() /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/ADT/SmallPtrSet.h:89:5
> #32 0x00007ffff7f948c4 llvm::SmallPtrSetImpl<llvm::AnalysisKey*>::~SmallPtrSetImpl() /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/ADT/SmallPtrSet.h:365:35
> #33 0x00007ffff7f948c4 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
> #34 0x00007ffff7f948c4 llvm::PreservedAnalyses::~PreservedAnalyses() /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/include/llvm/IR/Analysis.h:112:7
> #35 0x00007ffff7f948c4 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
> #36 0x00007ffff7fa1914 optMain /llvm-hackme/work/llvm-hackme/llvm-build-pr/../llvm-project-pr/llvm/tools/opt/optdriver.cpp:805:25
> #37 0x00007ffff7a00d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
> #38 0x00007ffff7a00e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
> #39 0x0000555555555095 _start (/llvm-hackme/work/llvm-hackme/llvm-build-pr/bin/opt+0x1095)
> ```
> 
> **Baseline Revision**: `232e8b5f458479163340ae2d9c1925ccaaaa154b` **PR Head SHA**: `e1c9c452148fe4ce3f5c09182f73d7530b5cc675` **Patch SHA256**: `e3ab5422849ccd769dfb1908cab3996a44ed2bae8001f5d516d4195dd7bc3b9e`

This should be a false positive. IIRC these intrinsics only accept scalar inputs, right?

https://github.com/llvm/llvm-project/pull/212755