LLVM segfault from custom MIR program

[cbeuw]

#![feature(custom_mir, core_intrinsics)]
extern crate core;
use core::intrinsics::mir::*;

#[no_mangle]
#[custom_mir(dialect = "runtime", phase = "initial")]
pub fn fn11(
    mut _2: [i8; 7],
    mut _13: usize,
    mut _14: *mut (
        *mut u64,
        ((i64,), u8),
        [i64; 5],
        [i64; 5],
        *mut [bool; 1],
        [usize; 5],
    ),
) {
    mir! {
    let _23: Adt63;
    let _72: i16;
    let _93: ((*mut u64, ((i64,), u8), [i64; 5], [i64; 5], *mut [bool; 1], [usize; 5]), [bool; 8], u128, *mut [bool; 1]);
    let _118: Adt65;
    {
    Goto(bb1)
    }
    bb1 = {
    match (*_14).1.0.0 {
    42 => bb9,
    _ => bb111
    }
    }
    bb9 = {
    match (*_14).1.0.0 {
    2 => bb11,
    42 => bb16,
    _ => bb111
    }
    }
    bb11 = {
    (*_14).5[_13] = (-65452179397411209626475467761145739571_i128) as usize;
    match (*_14).1.0.0 {
    42 => bb9,
    _ => bb111
    }
    }
    bb16 = {
    _23.fld5 = core::ptr::addr_of_mut!(_23.fld0);
    match _23.fld4 {
    17412 => bb25,
    _ => bb11
    }
    }
    bb25 = {
    match _23.fld4 {
    17412 => bb31,
    _ => bb30
    }
    }
    bb30 = {
    match (*_14).1.0.0 {
    0 => bb1,
    _ => bb111
    }
    }
    bb31 = {
    match _23.fld4 {
    17412 => bb39,
    _ => bb111
    }
    }
    bb39 = {
    match _23.fld4 {
    17412 => bb42,
    _ => bb111
    }
    }
    bb42 = {
    _72 = _23.fld4;
    match _72 {
    0 => bb39,
    17412 => bb76,
    _ => bb30
    }
    }
    bb76 = {
    _14 = core::ptr::addr_of_mut!(_93.0);
    _118.fld2 = core::ptr::addr_of_mut!(_118.fld1);
    match _23.fld4 {
    0 => bb11,
    2 => bb30,
    _ => bb111
    }
    }
    bb111 = {
    Return()
    }

    }
}

pub fn main() {}
#[derive(Copy, Clone)]
pub struct Adt63 {
    fld0: i128,
    fld4: i16,
    fld5: *mut i128,
}
pub struct Adt65 {
    fld1: usize,
    fld2: *mut usize,
}

$ rustc -Copt-level=2 repro.rs 
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-9d2b497b46d0ef1c.so(+0x320a623)[0x7fc76060a623]
/lib64/libc.so.6(+0x3db70)[0x7fc75d0cfb70]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm23ObjectSizeOffsetVisitor7computeEPNS_5ValueE+0x1f)[0x7fc759da829f]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm23ObjectSizeOffsetVisitor12visitPHINodeERNS_7PHINodeE+0x4d)[0x7fc759da7f59]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm23ObjectSizeOffsetVisitor7computeEPNS_5ValueE+0x2142)[0x7fc759daa3c2]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm23ObjectSizeOffsetVisitor12visitPHINodeERNS_7PHINodeE+0xf6)[0x7fc759da8002]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm23ObjectSizeOffsetVisitor7computeEPNS_5ValueE+0x2142)[0x7fc759daa3c2]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm23ObjectSizeOffsetVisitor12visitPHINodeERNS_7PHINodeE+0xf6)[0x7fc759da8002]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm23ObjectSizeOffsetVisitor7computeEPNS_5ValueE+0x2142)[0x7fc759daa3c2]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm23ObjectSizeOffsetVisitor12visitPHINodeERNS_7PHINodeE+0x4d)[0x7fc759da7f59]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm23ObjectSizeOffsetVisitor7computeEPNS_5ValueE+0x2142)[0x7fc759daa3c2]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm13getObjectSizeEPKNS_5ValueERmRKNS_10DataLayoutEPKNS_17TargetLibraryInfoENS_14ObjectSizeOptsE+0x3e)[0x7fc759da817e]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm13BasicAAResult5aliasERKNS_14MemoryLocationES3_RNS_11AAQueryInfoEPKNS_11InstructionE+0x3468)[0x7fc759a650ae]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm9AAResults13getModRefInfoEPKNS_11InstructionERKSt8optionalINS_14MemoryLocationEERNS_11AAQueryInfoE+0x2ebd)[0x7fc759a41555]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(+0x5a3e34c)[0x7fc759a3e34c]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm25findAvailablePtrLoadStoreERKNS_14MemoryLocationEPNS_4TypeEbPNS_10BasicBlockERNS_14ilist_iteratorINS_12ilist_detail12node_optionsINS_11InstructionELb0ELb0EvEELb0ELb0EEEjPNS_9AAResultsEPbPj+0x5cc)[0x7fc759e43260]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm17JumpThreadingPass30simplifyPartiallyRedundantLoadEPNS_8LoadInstE+0x163)[0x7fc759e41aa3]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm17JumpThreadingPass7runImplERNS_8FunctionEPNS_17TargetLibraryInfoEPNS_19TargetTransformInfoEPNS_13LazyValueInfoEPNS_9AAResultsEPNS_14DomTreeUpdaterEbSt10unique_ptrINS_18BlockFrequencyInfoESt14default_deleteISE_EESD_INS_21BranchProbabilityInfoESF_ISI_EE+0xbb6)[0x7fc759cf57b6]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm17JumpThreadingPass3runERNS_8FunctionERNS_15AnalysisManagerIS1_JEEE+0x186)[0x7fc759cf4198]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(+0x5cf400d)[0x7fc759cf400d]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm11PassManagerINS_8FunctionENS_15AnalysisManagerIS1_JEEEJEE3runERS1_RS3_+0xf7a)[0x7fc759f3dc3a]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm26CGSCCToFunctionPassAdaptor3runERNS_13LazyCallGraph3SCCERNS_15AnalysisManagerIS2_JRS1_EEES5_RNS_17CGSCCUpdateResultE+0x3a5)[0x7fc759f413c3]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(+0x5f41019)[0x7fc759f41019]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm11PassManagerINS_13LazyCallGraph3SCCENS_15AnalysisManagerIS2_JRS1_EEEJS4_RNS_17CGSCCUpdateResultEEE3runERS2_RS5_S4_S7_+0x582)[0x7fc75a00fdd4]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm21DevirtSCCRepeatedPass3runERNS_13LazyCallGraph3SCCERNS_15AnalysisManagerIS2_JRS1_EEES5_RNS_17CGSCCUpdateResultE+0x188)[0x7fc75a00eb8e]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm33ModuleToPostOrderCGSCCPassAdaptor3runERNS_6ModuleERNS_15AnalysisManagerIS1_JEEE+0xb88)[0x7fc759e10a08]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(+0x5e0fe6d)[0x7fc759e0fe6d]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm11PassManagerINS_6ModuleENS_15AnalysisManagerIS1_JEEEJEE3runERS1_RS3_+0xcf)[0x7fc759f42113]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm24ModuleInlinerWrapperPass3runERNS_6ModuleERNS_15AnalysisManagerIS1_JEEE+0x1ab)[0x7fc759f3aaeb]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(+0x5f3a92d)[0x7fc759f3a92d]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libLLVM-16-rust-1.72.0-nightly.so(_ZN4llvm11PassManagerINS_6ModuleENS_15AnalysisManagerIS1_JEEEJEE3runERS1_RS3_+0xcf)[0x7fc759f42113]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-9d2b497b46d0ef1c.so(+0x293a289)[0x7fc75fd3a289]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-9d2b497b46d0ef1c.so(+0x2936e7e)[0x7fc75fd36e7e]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-9d2b497b46d0ef1c.so(+0x2936934)[0x7fc75fd36934]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-9d2b497b46d0ef1c.so(+0x26f7f28)[0x7fc75faf7f28]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-9d2b497b46d0ef1c.so(+0x26f5d89)[0x7fc75faf5d89]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-9d2b497b46d0ef1c.so(+0x2704d76)[0x7fc75fb04d76]
/home/andy/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/libstd-c1ef87628285f700.so(rust_metadata_std_546c48fd97b1d9d5+0x105695)[0x7fc75d375695]
/lib64/libc.so.6(+0x8c907)[0x7fc75d11e907]
/lib64/libc.so.6(+0x112870)[0x7fc75d1a4870]
Segmentation fault (core dumped)

Does not trigger any debug assertion failures in LLVM when compiled with them enabled.

I couldn't get a standalone .ll reproducer as -Cno-prepopulate-passes makes the bug go away.

Not related to target-illegal vectors as nightly-2023-05-25 still segfaults.

As the backtrace suggests, the segfault is likely from JumpThreadingPass. -opt-bisect-limit prevents the segfault if this is not run.

cc @nikic

[nikic]

This looks like the same issue as llvm/llvm-project#63013.

[cbeuw]

Ah yes indeed. I thought the fix was in Rust's LLVM branch, but it isn't. I'll keep my local rustc patched.