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[LoopVectorize] Assertion `isPowerOf2_32(End.getKnownMinValue()) && "Expected End to be a power of 2"' failed. #134696

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ewlu opened this issue Apr 7, 2025 · 0 comments
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[LoopVectorize] Assertion `isPowerOf2_32(End.getKnownMinValue()) && "Expected End to be a power of 2"' failed. #134696

ewlu opened this issue Apr 7, 2025 · 0 comments
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crash Prefer [crash-on-valid] or [crash-on-invalid] generated by fuzzer vectorizers

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@ewlu
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ewlu commented Apr 7, 2025

Testcase:

target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
target triple = "riscv64-unknown-linux-gnu"

@a = external global [0 x [12 x i16]]

define void @b(i64 %0) #0 {
entry:
  br label %for.cond3.preheader

for.cond3.preheader:                              ; preds = %for.cond3.preheader, %entry
  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.cond3.preheader ]
  %arrayidx9 = getelementptr [0 x [12 x i16]], ptr @a, i64 0, i64 0, i64 %indvars.iv
  %1 = load i16, ptr %arrayidx9, align 2
  %arrayidx9.2 = getelementptr [0 x [12 x i16]], ptr @a, i64 0, i64 8, i64 %indvars.iv
  store i16 0, ptr %arrayidx9.2, align 2
  %indvars.iv.next = add nsw i64 %indvars.iv, 3
  %cmp = icmp ult i64 %indvars.iv, %0
  br i1 %cmp, label %for.cond3.preheader, label %for.cond.cleanup.loopexit

for.cond.cleanup.loopexit:                        ; preds = %for.cond3.preheader
  ret void
}

attributes #0 = { "target-features"="+v" }

Commands/backtrace

$ /scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt reduced.ll --passes=loop-vectorize
WARNING: You're attempting to print out a bitcode file.
This is inadvisable as it may cause display problems. If
you REALLY want to taste LLVM bitcode first-hand, you
can force output with the `-f' option.

opt: /scratch/ewlu/daily-upstream-build/llvm/llvm/lib/Transforms/Vectorize/VPlanHelpers.h:87: llvm::VFRange::VFRange(const llvm::ElementCount&, const llvm::ElementCount&): Assertion `isPowerOf2_32(End.getKnownMinValue()) && "Expected End to be a power of 2"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: /scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt reduced.ll --passes=loop-vectorize
1.      Running pass "function(loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>)" on module "reduced.ll"
2.      Running pass "loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>" on function "b"
 #0 0x00005c0c5d95b1a2 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x349c1a2)
 #1 0x00005c0c5d95820f llvm::sys::RunSignalHandlers() (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x349920f)
 #2 0x00005c0c5d958354 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #3 0x0000774312045330 (/lib/x86_64-linux-gnu/libc.so.6+0x45330)
 #4 0x000077431209eb2c __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 #5 0x000077431209eb2c __pthread_kill_internal ./nptl/pthread_kill.c:78:10
 #6 0x000077431209eb2c pthread_kill ./nptl/pthread_kill.c:89:10
 #7 0x000077431204527e raise ./signal/../sysdeps/posix/raise.c:27:6
 #8 0x00007743120288ff abort ./stdlib/abort.c:81:7
 #9 0x000077431202881b _nl_load_domain ./intl/loadmsgcat.c:1177:9
#10 0x000077431203b517 (/lib/x86_64-linux-gnu/libc.so.6+0x3b517)
#11 0x00005c0c5c7b1baf llvm::LoopVectorizationPlanner::buildVPlansWithVPRecipes(llvm::ElementCount, llvm::ElementCount) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x22f2baf)
#12 0x00005c0c5c7b210d llvm::LoopVectorizationPlanner::plan(llvm::ElementCount, unsigned int) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x22f310d)
#13 0x00005c0c5c7b4105 llvm::LoopVectorizePass::processLoop(llvm::Loop*) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x22f5105)
#14 0x00005c0c5c7b7511 llvm::LoopVectorizePass::runImpl(llvm::Function&) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x22f8511)
#15 0x00005c0c5c7b7ad7 llvm::LoopVectorizePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x22f8ad7)
#16 0x00005c0c5b484b75 llvm::detail::PassModel<llvm::Function, llvm::LoopVectorizePass, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0xfc5b75)
#17 0x00005c0c5d74633a llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x328733a)
#18 0x00005c0c5b4872b5 llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0xfc82b5)
#19 0x00005c0c5d744c14 llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x3285c14)
#20 0x00005c0c5b483265 llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0xfc4265)
#21 0x00005c0c5d74522d llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x328622d)
#22 0x00005c0c5ac19391 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) (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x75a391)
#23 0x00005c0c5ac0aeac optMain (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x74beac)
#24 0x000077431202a1ca __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#25 0x000077431202a28b call_init ./csu/../csu/libc-start.c:128:20
#26 0x000077431202a28b __libc_start_main ./csu/../csu/libc-start.c:347:5
#27 0x00005c0c5ac014f5 _start (/scratch/ewlu/daily-upstream-build/build-gcv/build-llvm-linux/bin/opt+0x7424f5)
Aborted (core dumped)

godbolt: https://godbolt.org/z/rKd5sx7xW

Found via fuzzer (C program before reduction)
@EugeneZelenko EugeneZelenko added vectorizers crash Prefer [crash-on-valid] or [crash-on-invalid] generated by fuzzer and removed new issue labels Apr 7, 2025
@fhahn fhahn closed this as completed in 995fd47 Apr 12, 2025
@fhahn fhahn mentioned this issue Apr 12, 2025
Merged
llvm-sync bot pushed a commit to arm/arm-toolchain that referenced this issue Apr 12, 2025
@fhahn @github-actions
Automerge: [LAA] Make sure MaxVF for Store-Load forward safe dep dist…
f6bf895 
…ances is pow2.

MaxVF computed in couldPreventStoreLoadFowrard may not be a power of 2,
as CommonStride may not be a power-of-2.

This can cause crashes after 78777a2. Use bit_floor to make sure it is
a suitable power-of-2.

Fixes llvm/llvm-project#134696.
var-const pushed a commit to ldionne/llvm-project that referenced this issue Apr 17, 2025
@fhahn @var-const
[LAA] Make sure MaxVF for Store-Load forward safe dep distances is pow2.
d4aa108 
MaxVF computed in couldPreventStoreLoadFowrard may not be a power of 2,
as CommonStride may not be a power-of-2.

This can cause crashes after 78777a2. Use bit_floor to make sure it is
a suitable power-of-2.

Fixes llvm#134696.
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