LLVM assertion from pointer arithmetic on i686-pc-windows-gnu

[matthewjasper]

The following code, when compiled with opt level of 2 or higher results in an llvm assertion (if they're enabled) on i686-pc-windows-gnu.

#![crate_type="lib"]

pub fn check_overlap(ext: &i32) -> usize {
    let src_usize = &1 as *const _ as usize;
    let dst_usize = ext as *const _ as usize;
    let mut diff = src_usize.wrapping_sub(dst_usize);
    if src_usize > dst_usize {
        diff = diff.wrapping_neg();
    };

    diff
}

llc backtrace when compiling the --emit llvm-ir output

llc: ./src/llvm-project/llvm/include/llvm/CodeGen/MachineOperand.h:527: int64_t llvm::MachineOperand::getImm() const: Assertion `isImm() && "Wrong MachineOperand accessor"' failed.
Stack dump:
0.	Program arguments: ./build/x86_64-unknown-linux-gnu/llvm/bin/llc -O1 /media/matthew/Data1/Matthew/dev/proc-macro2/lib.ll -o - 
1.	Running pass 'Function Pass Manager' on module '/media/matthew/Data1/Matthew/dev/proc-macro2/lib.ll'.
2.	Running pass 'Two-Address instruction pass' on function '@check_overlap'
 #0 0x00007f4aaa65a2de llvm::sys::PrintStackTrace(llvm::raw_ostream&) (./build/x86_64-unknown-linux-gnu/llvm/bin/../lib/libLLVM-9-rust-1.40.0-dev-14a3b1230.so+0xa5f2de)
 #1 0x00007f4aaa6580f4 llvm::sys::RunSignalHandlers() (./build/x86_64-unknown-linux-gnu/llvm/bin/../lib/libLLVM-9-rust-1.40.0-dev-14a3b1230.so+0xa5d0f4)
 #2 0x00007f4aaa658275 SignalHandler(int) (./build/x86_64-unknown-linux-gnu/llvm/bin/../lib/libLLVM-9-rust-1.40.0-dev-14a3b1230.so+0xa5d275)
 #3 0x00007f4aa9845470 (/lib/x86_64-linux-gnu/libc.so.6+0x46470)
 #4 0x00007f4aa98453eb raise /build/glibc-4WA41p/glibc-2.30/signal/../sysdeps/unix/sysv/linux/raise.c:51:1
 #5 0x00007f4aa9824899 abort /build/glibc-4WA41p/glibc-2.30/stdlib/abort.c:81:7
 #6 0x00007f4aa9824769 get_sysdep_segment_value /build/glibc-4WA41p/glibc-2.30/intl/loadmsgcat.c:509:8
 #7 0x00007f4aa9824769 _nl_load_domain /build/glibc-4WA41p/glibc-2.30/intl/loadmsgcat.c:970:34
 #8 0x00007f4aa9836006 (/lib/x86_64-linux-gnu/libc.so.6+0x37006)
 #9 0x00007f4aaccc4c86 llvm::X86InstrInfo::convertToThreeAddress(llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::MachineBasicBlock, true, false, void>, false, false>&, llvm::MachineInstr&, llvm::LiveVariables*) const (./build/x86_64-unknown-linux-gnu/llvm/bin/../lib/libLLVM-9-rust-1.40.0-dev-14a3b1230.so+0x30c9c86)
#10 0x00007f4aaac50916 (anonymous namespace)::TwoAddressInstructionPass::convertInstTo3Addr(llvm::MachineInstrBundleIterator<llvm::MachineInstr, false>&, llvm::MachineInstrBundleIterator<llvm::MachineInstr, false>&, unsigned int, unsigned int, unsigned int) (./build/x86_64-unknown-linux-gnu/llvm/bin/../lib/libLLVM-9-rust-1.40.0-dev-14a3b1230.so+0x1055916)
#11 0x00007f4aaac527e8 (anonymous namespace)::TwoAddressInstructionPass::tryInstructionTransform(llvm::MachineInstrBundleIterator<llvm::MachineInstr, false>&, llvm::MachineInstrBundleIterator<llvm::MachineInstr, false>&, unsigned int, unsigned int, unsigned int, bool) (./build/x86_64-unknown-linux-gnu/llvm/bin/../lib/libLLVM-9-rust-1.40.0-dev-14a3b1230.so+0x10577e8)
#12 0x00007f4aaac57155 (anonymous namespace)::TwoAddressInstructionPass::runOnMachineFunction(llvm::MachineFunction&) (./build/x86_64-unknown-linux-gnu/llvm/bin/../lib/libLLVM-9-rust-1.40.0-dev-14a3b1230.so+0x105c155)
#13 0x00007f4aaaa04459 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (./build/x86_64-unknown-linux-gnu/llvm/bin/../lib/libLLVM-9-rust-1.40.0-dev-14a3b1230.so+0xe09459)
#14 0x00007f4aaa7a5688 llvm::FPPassManager::runOnFunction(llvm::Function&) (./build/x86_64-unknown-linux-gnu/llvm/bin/../lib/libLLVM-9-rust-1.40.0-dev-14a3b1230.so+0xbaa688)
#15 0x00007f4aaa7a57c1 llvm::FPPassManager::runOnModule(llvm::Module&) (./build/x86_64-unknown-linux-gnu/llvm/bin/../lib/libLLVM-9-rust-1.40.0-dev-14a3b1230.so+0xbaa7c1)
#16 0x00007f4aaa7a4a19 llvm::legacy::PassManagerImpl::run(llvm::Module&) (./build/x86_64-unknown-linux-gnu/llvm/bin/../lib/libLLVM-9-rust-1.40.0-dev-14a3b1230.so+0xba9a19)
#17 0x00005577274b31ec compileModule(char**, llvm::LLVMContext&) (./build/x86_64-unknown-linux-gnu/llvm/bin/llc+0x1e1ec)
#18 0x00005577274a4dfa main (./build/x86_64-unknown-linux-gnu/llvm/bin/llc+0xfdfa)
#19 0x00007f4aa98261e3 __libc_start_main /build/glibc-4WA41p/glibc-2.30/csu/../csu/libc-start.c:342:3
#20 0x00005577274a4f4e _start (./build/x86_64-unknown-linux-gnu/llvm/bin/llc+0xff4e)
Aborted (core dumped)

[mati865]

I don't think it's windows-gnu specific: https://bugs.llvm.org/show_bug.cgi?id=43529
I'll try to backport the fix.

[mati865]

Opened #66318 which waits for bors try (I don't have permission).