{
  "bug_id": "108697",
  "issue_url": "https://github.com/llvm/llvm-project/issues/108697",
  "bug_type": "crash",
  "base_commit": "848cb21ddca5dc4d8c52e487264936be8f1bfe8d",
  "knowledge_cutoff": "2024-09-14T13:01:28Z",
  "lit_test_dir": [
    "llvm/test/Transforms/LoopVectorize"
  ],
  "hints": {
    "fix_commit": "9de327c94d0c995803b6485fb28ac4cad1e53bbe",
    "components": [
      "LoopVectorize"
    ],
    "bug_location_lineno": {
      "llvm/lib/Transforms/Vectorize/LoopVectorize.cpp": [
        [
          6551,
          6564
        ]
      ]
    },
    "bug_location_funcname": {
      "llvm/lib/Transforms/Vectorize/LoopVectorize.cpp": [
        "LoopVectorizationCostModel::getInstructionCost"
      ]
    }
  },
  "patch": "commit 9de327c94d0c995803b6485fb28ac4cad1e53bbe\nAuthor: Florian Hahn <flo@fhahn.com>\nDate:   Wed Oct 2 20:16:41 2024 +0100\n\n    [LV] Generalize predication checks from 2c8836c899 for operands.\n    \n    This fixes another case where the VPlan-based and legacy cost models\n    disagree. If any of the operands is predicated, it can't be trivially\n    hoisted and we should consider the cost for evaluating it each loop\n    iteration.\n    \n    Fixes https://github.com/llvm/llvm-project/issues/108697.\n\ndiff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp\nindex de3b981a4fe3..6e082b1c134d 100644\n--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp\n+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp\n@@ -6551,14 +6551,17 @@ LoopVectorizationCostModel::getInstructionCost(Instruction *I,\n       Op2 = cast<SCEVConstant>(PSE.getSCEV(Op2))->getValue();\n     }\n     auto Op2Info = TTI.getOperandInfo(Op2);\n-    auto IsInvariant = [this](Value *Op) {\n+    std::function<bool(Value *)> IsInvariant =\n+        [this, &IsInvariant](Value *Op) -> bool {\n       if (!Legal->isInvariant(Op))\n         return false;\n-      // Consider Op2 invariant, if it is not a predicated instruction in the\n-      // loop. In that case, it is not trivially hoistable.\n+      // Consider Op2invariant, if it or its operands aren't predicated\n+      // instruction in the loop. In that case, it is not trivially hoistable.\n       return !isa<Instruction>(Op) ||\n              !TheLoop->contains(cast<Instruction>(Op)) ||\n-             !isPredicatedInst(cast<Instruction>(Op));\n+             (!isPredicatedInst(cast<Instruction>(Op)) &&\n+              all_of(cast<Instruction>(Op)->operands(),\n+                     [&IsInvariant](Value *Op) { return IsInvariant(Op); }));\n     };\n     if (Op2Info.Kind == TargetTransformInfo::OK_AnyValue && IsInvariant(Op2))\n       Op2Info.Kind = TargetTransformInfo::OK_UniformValue;\n",
  "tests": [
    {
      "file": "llvm/test/Transforms/LoopVectorize/X86/predicated-instruction-cost.ll",
      "commands": [
        "opt -p loop-vectorize -S %s"
      ],
      "tests": [
        {
          "test_name": "predicated_urem_shl_cost",
          "test_body": "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\"\ntarget triple = \"x86_64-unknown-linux-gnu\"\n\ndefine void @predicated_urem_shl_cost(ptr %A, i32 %x, i1 %c) {\nentry:\n  br label %loop.header\n\nloop.header:                                      ; preds = %loop.latch, %entry\n  %iv = phi i32 [ 1, %entry ], [ %iv.next, %loop.latch ]\n  %gep = getelementptr inbounds i32, ptr %A, i32 %iv\n  %l = load i32, ptr %gep, align 4\n  br i1 %c, label %then, label %loop.latch\n\nthen:                                             ; preds = %loop.header\n  %rem = urem i32 2, %x\n  %shl = shl i32 %l, %rem\n  br label %loop.latch\n\nloop.latch:                                       ; preds = %then, %loop.header\n  %p = phi i32 [ 0, %loop.header ], [ %shl, %then ]\n  store i32 %p, ptr %gep, align 4\n  %iv.next = add i32 %iv, 1\n  %ec = icmp eq i32 %iv, 0\n  br i1 %ec, label %exit, label %loop.header\n\nexit:                                             ; preds = %loop.latch\n  ret void\n}\n"
        },
        {
          "test_name": "test_wide_shift_uses_predicated_invariant_instruction",
          "test_body": "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\"\ntarget triple = \"x86_64-unknown-linux-gnu\"\n\ndefine void @test_wide_shift_uses_predicated_invariant_instruction(i32 %d, i1 %c, ptr %dst) {\nentry:\n  br label %loop.header\n\nloop.header:                                      ; preds = %loop.latch, %entry\n  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]\n  br i1 %c, label %loop.latch, label %else\n\nelse:                                             ; preds = %loop.header\n  %rem = urem i32 100, %d\n  %sext = shl i32 %rem, 12\n  %shl.i = shl i32 999, %sext\n  br label %loop.latch\n\nloop.latch:                                       ; preds = %else, %loop.header\n  %p = phi i32 [ %shl.i, %else ], [ 0, %loop.header ]\n  %gep = getelementptr inbounds i32, ptr %dst, i32 %iv\n  store i32 %p, ptr %gep, align 4\n  %iv.next = add i32 %iv, 1\n  %ec = icmp eq i32 %iv.next, 100\n  br i1 %ec, label %exit, label %loop.header\n\nexit:                                             ; preds = %loop.latch\n  ret void\n}\n"
        }
      ]
    }
  ],
  "issue": {
    "title": "clang crashes on valid code at -O{2,3} on x86_64-linux-gnu: Assertion `(BestFactor.Width == LegacyVF.Width || planContainsAdditionalSimplifications(getPlanFor(BestFactor.Width), CostCtx, OrigLoop)) && \" VPlan cost model and legacy cost model disagreed\"' failed ",
    "body": "Compiler Explorer: https://godbolt.org/z/9K4a3Pr7j\r\n\r\n```\r\n[508] % clangtk -v\r\nclang version 20.0.0git (https://github.com/llvm/llvm-project.git 223e2efa5e886502a9467b7ef700ebce9b7886e8)\r\nTarget: x86_64-unknown-linux-gnu\r\nThread model: posix\r\nInstalledDir: /local/suz-local/software/local/clang-trunk/bin\r\nBuild config: +assertions\r\nFound candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/10\r\nFound candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/11\r\nFound candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/9\r\nSelected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/11\r\nCandidate multilib: .;@m64\r\nSelected multilib: .;@m64\r\n[509] % \r\n[509] % clangtk -O2 small.c\r\nclang-20: /local/suz-local/software/clangbuild/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:7390: llvm::VectorizationFactor llvm::LoopVectorizationPlanner::computeBestVF(): Assertion `(BestFactor.Width == LegacyVF.Width || planContainsAdditionalSimplifications(getPlanFor(BestFactor.Width), CostCtx, OrigLoop)) && \" VPlan cost model and legacy cost model disagreed\"' failed.\r\nPLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.\r\nStack dump:\r\n0.\tProgram arguments: /local/suz-local/software/local/clang-trunk/bin/clang-20 -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -dumpdir a- -disable-free -clear-ast-before-backend -main-file-name small.c -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fdebug-compilation-dir=/local/suz-local/software/emitesting/bugs/20240914-clangtk-m64-O3-build-061621/delta -fcoverage-compilation-dir=/local/suz-local/software/emitesting/bugs/20240914-clangtk-m64-O3-build-061621/delta -resource-dir /local/suz-local/software/local/clang-trunk/lib/clang/20 -I /usr/local/include -I /local/suz-local/software/local/include -internal-isystem /local/suz-local/software/local/clang-trunk/lib/clang/20/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/11/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -ferror-limit 19 -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fcolor-diagnostics -vectorize-loops -vectorize-slp -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/small-34578e.o -x c small.c\r\n1.\t<eof> parser at end of file\r\n2.\tOptimizer\r\n3.\tRunning pass \"function<eager-inv>(float2int,lower-constant-intrinsics,loop(loop-rotate<header-duplication;no-prepare-for-lto>,loop-deletion),loop-distribute,inject-tli-mappings,loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>,infer-alignment,loop-load-elim,instcombine<max-iterations=1;no-verify-fixpoint>,simplifycfg<bonus-inst-threshold=1;forward-switch-cond;switch-range-to-icmp;switch-to-lookup;no-keep-loops;hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,slp-vectorizer,vector-combine,instcombine<max-iterations=1;no-verify-fixpoint>,loop-unroll<O2>,transform-warning,sroa<preserve-cfg>,infer-alignment,instcombine<max-iterations=1;no-verify-fixpoint>,loop-mssa(licm<allowspeculation>),alignment-from-assumptions,loop-sink,instsimplify,div-rem-pairs,tailcallelim,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;speculate-unpredictables>)\" on module \"small.c\"\r\n4.\tRunning pass \"loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>\" on function \"main\"\r\n #0 0x000055ba1845c4ff llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x43484ff)\r\n #1 0x000055ba18459a34 SignalHandler(int) Signals.cpp:0:0\r\n #2 0x00007fbbfabd4420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)\r\n #3 0x00007fbbfa60b00b raise /build/glibc-LcI20x/glibc-2.31/signal/../sysdeps/unix/sysv/linux/raise.c:51:1\r\n #4 0x00007fbbfa5ea859 abort /build/glibc-LcI20x/glibc-2.31/stdlib/abort.c:81:7\r\n #5 0x00007fbbfa5ea729 get_sysdep_segment_value /build/glibc-LcI20x/glibc-2.31/intl/loadmsgcat.c:509:8\r\n #6 0x00007fbbfa5ea729 _nl_load_domain /build/glibc-LcI20x/glibc-2.31/intl/loadmsgcat.c:970:34\r\n #7 0x00007fbbfa5fbfd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)\r\n #8 0x000055ba19db5fcb llvm::LoopVectorizationPlanner::computeBestVF() (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5ca1fcb)\r\n #9 0x000055ba19dd169a llvm::LoopVectorizePass::processLoop(llvm::Loop*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5cbd69a)\r\n#10 0x000055ba19dd42d1 llvm::LoopVectorizePass::runImpl(llvm::Function&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5cc02d1)\r\n#11 0x000055ba19dd4943 llvm::LoopVectorizePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5cc0943)\r\n#12 0x000055ba19946a06 llvm::detail::PassModel<llvm::Function, llvm::LoopVectorizePass, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x5832a06)\r\n#13 0x000055ba17dec0d1 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x3cd80d1)\r\n#14 0x000055ba15926546 llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x1812546)\r\n#15 0x000055ba17deaa3d llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x3cd6a3d)\r\n#16 0x000055ba15925216 llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x1811216)\r\n#17 0x000055ba17dea471 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x3cd6471)\r\n#18 0x000055ba18713673 (anonymous namespace)::EmitAssemblyHelper::RunOptimizationPipeline(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>&, std::unique_ptr<llvm::ToolOutputFile, std::default_delete<llvm::ToolOutputFile>>&, clang::BackendConsumer*) BackendUtil.cpp:0:0\r\n#19 0x000055ba187167f8 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>, clang::BackendConsumer*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x46027f8)\r\n#20 0x000055ba18decf5c clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x4cd8f5c)\r\n#21 0x000055ba1ac8966c clang::ParseAST(clang::Sema&, bool, bool) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x6b7566c)\r\n#22 0x000055ba18ded378 clang::CodeGenAction::ExecuteAction() (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x4cd9378)\r\n#23 0x000055ba1908a659 clang::FrontendAction::Execute() (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x4f76659)\r\n#24 0x000055ba1900c07e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x4ef807e)\r\n#25 0x000055ba191772b6 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x50632b6)\r\n#26 0x000055ba154f2b15 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x13deb15)\r\n#27 0x000055ba154ebbba ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0\r\n#28 0x000055ba154ef58e clang_main(int, char**, llvm::ToolContext const&) (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x13db58e)\r\n#29 0x000055ba153dd43b main (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x12c943b)\r\n#30 0x00007fbbfa5ec083 __libc_start_main /build/glibc-LcI20x/glibc-2.31/csu/../csu/libc-start.c:342:3\r\n#31 0x000055ba154eb64e _start (/local/suz-local/software/local/clang-trunk/bin/clang-20+0x13d764e)\r\nclangtk: error: unable to execute command: Aborted\r\nclangtk: error: clang frontend command failed due to signal (use -v to see invocation)\r\nclang version 20.0.0git (https://github.com/llvm/llvm-project.git 223e2efa5e886502a9467b7ef700ebce9b7886e8)\r\nTarget: x86_64-unknown-linux-gnu\r\nThread model: posix\r\nInstalledDir: /local/suz-local/software/local/clang-trunk/bin\r\nBuild config: +assertions\r\nclangtk: note: diagnostic msg: \r\n********************\r\n\r\nPLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:\r\nPreprocessed source(s) and associated run script(s) are located at:\r\nclangtk: note: diagnostic msg: /tmp/small-682958.c\r\nclangtk: note: diagnostic msg: /tmp/small-682958.sh\r\nclangtk: note: diagnostic msg: \r\n\r\n********************\r\n[510] % \r\n[510] % cat small.c\r\nshort a, b, c, d;\r\nunsigned short e;\r\nint main() {\r\n  for (; d; d++) {\r\n    e = a + b;\r\n    c = b > 3 || e > b ? e : e << b;\r\n    c = c ? 2 / c : 0;\r\n    b = 1;\r\n  }\r\n  return 0;\r\n}\r\n```",
    "author": "zhendongsu",
    "labels": [
      "vectorizers",
      "crash-on-valid"
    ],
    "comments": []
  },
  "verified": true
}