Crash in DAGCombiner, aarch64-windows-msvc, llvm-19.1.3

[abique]

Hi,

I'm getting a weird crash in llvm optimizer:

BitwigAudioEngine-ARM64-NEON.exe!std::pair<llvm::AACacheLoc,llvm::AACacheLoc>::pair<llvm::AACacheLoc,llvm::AACacheLoc,0>(llvm::AACacheLoc && _Val1, llvm::AACacheLoc && _Val2) Line 247 (c:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.41.34120\include\utility:247)
BitwigAudioEngine-ARM64-NEON.exe!std::make_pair<llvm::AACacheLoc,llvm::AACacheLoc>(llvm::AACacheLoc && _Val1, llvm::AACacheLoc && _Val2) Line 561 (c:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.41.34120\include\utility:561)
BitwigAudioEngine-ARM64-NEON.exe!llvm::DenseMapInfo<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,void>::getEmptyKey() Line 227 (c:\Users\alex\bitwig\target\dependencies\windows-arm64\include\llvm\ADT\DenseMapInfo.h:227)
BitwigAudioEngine-ARM64-NEON.exe!llvm::DenseMapBase<llvm::SmallDenseMap<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry,8,llvm::DenseMapInfo<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,void>,llvm::detail::DenseMapPair<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry>>,std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry,llvm::DenseMapInfo<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,void>,llvm::detail::DenseMapPair<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry>>::getEmptyKey() Line 499 (c:\Users\alex\bitwig\target\dependencies\windows-arm64\include\llvm\ADT\DenseMap.h:499)
BitwigAudioEngine-ARM64-NEON.exe!llvm::DenseMapBase<llvm::SmallDenseMap<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry,8,llvm::DenseMapInfo<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,void>,llvm::detail::DenseMapPair<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry>>,std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry,llvm::DenseMapInfo<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,void>,llvm::detail::DenseMapPair<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry>>::LookupBucketFor<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>>(const std::pair<llvm::AACacheLoc,llvm::AACacheLoc> & Val, const llvm::detail::DenseMapPair<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry> * & FoundBucket) Line 664 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\include\llvm\ADT\DenseMap.h:664)
BitwigAudioEngine-ARM64-NEON.exe!llvm::DenseMapBase<llvm::SmallDenseMap<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry,8,llvm::DenseMapInfo<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,void>,llvm::detail::DenseMapPair<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry>>,std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry,llvm::DenseMapInfo<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,void>,llvm::detail::DenseMapPair<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry>>::LookupBucketFor<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>>(const std::pair<llvm::AACacheLoc,llvm::AACacheLoc> & Val, llvm::detail::DenseMapPair<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry> * & FoundBucket) Line 704 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\include\llvm\ADT\DenseMap.h:704)
BitwigAudioEngine-ARM64-NEON.exe!llvm::DenseMapBase<llvm::SmallDenseMap<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry,8,llvm::DenseMapInfo<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,void>,llvm::detail::DenseMapPair<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry>>,std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry,llvm::DenseMapInfo<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,void>,llvm::detail::DenseMapPair<std::pair<llvm::AACacheLoc,llvm::AACacheLoc>,llvm::AAQueryInfo::CacheEntry>>::try_emplace<llvm::AAQueryInfo::CacheEntry>(const std::pair<llvm::AACacheLoc,llvm::AACacheLoc> & Key, llvm::AAQueryInfo::CacheEntry && <Args_0>) Line 262 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\include\llvm\ADT\DenseMap.h:262)
BitwigAudioEngine-ARM64-NEON.exe!llvm::BasicAAResult::aliasCheck(const llvm::Value * V1, llvm::LocationSize V1Size, const llvm::Value * V2, llvm::LocationSize V2Size, llvm::AAQueryInfo & AAQI, const llvm::Instruction * CtxI) Line 1690 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\lib\Analysis\BasicAliasAnalysis.cpp:1690)
BitwigAudioEngine-ARM64-NEON.exe!llvm::BasicAAResult::alias(const llvm::MemoryLocation & LocA, const llvm::MemoryLocation & LocB, llvm::AAQueryInfo & AAQI, const llvm::Instruction * CtxI) Line 900 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\lib\Analysis\BasicAliasAnalysis.cpp:900)
BitwigAudioEngine-ARM64-NEON.exe!llvm::AAResults::Model<llvm::BasicAAResult>::alias(const llvm::MemoryLocation & LocA, const llvm::MemoryLocation & LocB, llvm::AAQueryInfo & AAQI, const llvm::Instruction * CtxI) Line 777 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\include\llvm\Analysis\AliasAnalysis.h:777)
BitwigAudioEngine-ARM64-NEON.exe!llvm::AAResults::alias(const llvm::MemoryLocation & LocA, const llvm::MemoryLocation & LocB, llvm::AAQueryInfo & AAQI, const llvm::Instruction * CtxI) Line 127 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\lib\Analysis\AliasAnalysis.cpp:127)
BitwigAudioEngine-ARM64-NEON.exe!llvm::AAResults::alias(const llvm::MemoryLocation & LocA, const llvm::MemoryLocation & LocB) Line 110 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\lib\Analysis\AliasAnalysis.cpp:110)
BitwigAudioEngine-ARM64-NEON.exe!llvm::AAResults::isNoAlias(const llvm::MemoryLocation & LocA, const llvm::MemoryLocation & LocB) Line 374 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\include\llvm\Analysis\AliasAnalysis.h:374)
BitwigAudioEngine-ARM64-NEON.exe!`anonymous namespace'::DAGCombiner::mayAlias(llvm::SDNode * Op0, llvm::SDNode * Op1) Line 28395 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\lib\CodeGen\SelectionDAG\DAGCombiner.cpp:28395)
BitwigAudioEngine-ARM64-NEON.exe!`anonymous-namespace'::DAGCombiner::GatherAllAliases::__l2::<lambda_1>::operator()(llvm::SDValue & C) Line 28435 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\lib\CodeGen\SelectionDAG\DAGCombiner.cpp:28435)
BitwigAudioEngine-ARM64-NEON.exe!`anonymous namespace'::DAGCombiner::GatherAllAliases(llvm::SDNode * N, llvm::SDValue OriginalChain, llvm::SmallVectorImpl<llvm::SDValue> & Aliases) Line 28502 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\lib\CodeGen\SelectionDAG\DAGCombiner.cpp:28502)
BitwigAudioEngine-ARM64-NEON.exe!`anonymous namespace'::DAGCombiner::FindBetterChain(llvm::SDNode * N, llvm::SDValue OldChain) Line 28524 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\lib\CodeGen\SelectionDAG\DAGCombiner.cpp:28524)
BitwigAudioEngine-ARM64-NEON.exe!`anonymous namespace'::DAGCombiner::findBetterNeighborChains(llvm::StoreSDNode * St) Line 28692 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\lib\CodeGen\SelectionDAG\DAGCombiner.cpp:28692)
BitwigAudioEngine-ARM64-NEON.exe!`anonymous namespace'::DAGCombiner::visitSTORE(llvm::SDNode * N) Line 21481 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\lib\CodeGen\SelectionDAG\DAGCombiner.cpp:21481)
BitwigAudioEngine-ARM64-NEON.exe!`anonymous namespace'::DAGCombiner::visit(llvm::SDNode * N) Line 1952 (c:\j\workspace\ext-libs\src\vcpkg\buildtrees\llvm\src\org-19.1.3-a54b36719d.clean\llvm\lib\CodeGen\SelectionDAG\DAGCombiner.cpp:1952)

Exception thrown at 0x00007FF6C36EE4B8 in BitwigAudioEngine-ARM64-NEON.exe: 0xC0000005: Access violation writing location 0x0000000000000000

I've a JIT engine using LLVM-19.1.3 on Windows ARM64.

Do you have anyidea what the problem could be based upon the backtrace?

Thanks!

[abique]

Could it be that llvm::LocationSize when default constructed doesn't initialize Value?
It also seems that PunnedPointer doesn't initialize memory with the default constructor.

[abique]

[abique]

I've tried linking with a larger stack: add_link_options("/stack:32000000") and the issue still occurs, so I don't think it is a stack size issue.

[abique]

Enabling the global instruction selector seems to workaround this issue.
Unfortunately the global isel doesn't seem to be something that always works either.