Assertion `hasPlanWithVF(ScalarVF) && "More than a single plan/VF w/o any plan having scalar VF"' failed.

[TatyanaDoubts]

To reproduce run the following test with -passes=loop-vectorize

; ModuleID = './reduced.ll'
source_filename = "./reduced.ll"
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-ni:1-p2:32:8:8:32-ni:2"
target triple = "x86_64-unknown-linux-gnu"

define void @wombat() gc "statepoint-example" {
bb:
  br label %bb1

bb1:                                              ; preds = %bb1, %bb
  %phi = phi i64 [ %add, %bb1 ], [ 1, %bb ]
  %phi2 = phi i32 [ %trunc, %bb1 ], [ 1, %bb ]
  %phi3 = phi i32 [ %or, %bb1 ], [ 0, %bb ]
  %or = or i32 %phi2, 0
  %add = add i64 %phi, 1
  store i32 %phi3, ptr addrspace(1) null, align 4
  %icmp = icmp ult i64 %phi, 337
  %trunc = trunc i64 %phi to i32
  br i1 %icmp, label %bb1, label %bb4

bb4:                                              ; preds = %bb1
  ret void
}

Reproducer: https://godbolt.org/z/e14eWvxMb

Stack dump:

opt: /root/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:7304: llvm::VectorizationFactor llvm::LoopVectorizationPlanner::computeBestVF(): Assertion `hasPlanWithVF(ScalarVF) && "More than a single plan/VF w/o any plan having scalar VF"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/opt -o /app/output.s -S -passes=loop-vectorize <source>
1.	Running pass "function(loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>)" on module "<source>"
2.	Running pass "loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>" on function "wombat"
 #0 0x0000000004fa4138 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x4fa4138)
 #1 0x0000000004fa18ac SignalHandler(int) Signals.cpp:0:0
 #2 0x000073e073a42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #3 0x000073e073a969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #4 0x000073e073a42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #5 0x000073e073a287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #6 0x000073e073a2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #7 0x000073e073a39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #8 0x0000000003fe5276 llvm::LoopVectorizationPlanner::computeBestVF() (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x3fe5276)
 #9 0x0000000004001214 llvm::LoopVectorizePass::processLoop(llvm::Loop*) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x4001214)
#10 0x0000000004003eb9 llvm::LoopVectorizePass::runImpl(llvm::Function&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x4003eb9)
#11 0x0000000004004543 llvm::LoopVectorizePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x4004543)
#12 0x0000000002ec85ae llvm::detail::PassModel<llvm::Function, llvm::LoopVectorizePass, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x2ec85ae)
#13 0x0000000004da08f8 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x4da08f8)
#14 0x0000000000df11be llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0xdf11be)
#15 0x0000000004d9f2fe llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x4d9f2fe)
#16 0x0000000000df0aae llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0xdf0aae)
#17 0x0000000004d9d490 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x4d9d490)
#18 0x00000000008e8002 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) (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x8e8002)
#19 0x00000000008daedc optMain (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x8daedc)
#20 0x000073e073a29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#21 0x000073e073a29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#22 0x00000000008d296e _start (/opt/compiler-explorer/clang-assertions-trunk/bin/opt+0x8d296e)
Program terminated with signal: SIGSEGV
Compiler returned: 139

[fhahn]

Very interesting issue thanks! Proposed fix #106523