[llvm-dev] BuildMI crashes on a certain probability on the exact same test

[Xiaochu Liu via llvm-dev]

Thanks, Tim! I pulled the latest code from llvm master and it seems to
be working now... I will try your suggestion after it crashes again.

On Sun, Nov 22, 2015 at 2:57 PM, Tim Northover <t.p.northover at gmail.com> wrote:
> On 22 November 2015 at 14:42, Xiaochu Liu via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
>> 14 clang                    0x000000010e1bcb4d llvm::DebugLoc::DebugLoc(llvm::DebugLoc const&) + 29
>>
>> And the most strange thing is that this error does not happen
>> everytime for the same test (it happens under certain probability) ?!
>> Can anyone please show me some hints on how to debug this problem?
>
> My best guess is that I == MBB.end(), in which case there is no
> MachineInstr behind it and I->getDebugLoc() is accessing random memory
> that may or may not resemble a MachineInstr. Try asserting it's valid
> just before the BuildMI, or just stepping through in a debugger.
>
> Cheers.
>
> Tim.