[cfe-users] Compiling llvm 3.4 using g++-4.7 on ARM: lib/LTO/LTOCodeGenerator.cpp:166:1: internal compiler error: in merge_if_block, at ifcvt.c

[David Blaikie]

On Thu, Jul 31, 2014 at 12:19 PM, Kim Gräsman <kim.grasman at gmail.com> wrote:
> David,
>
> Would you do the honors? I don't have commit access.

If we come up with a good solution, sure.

> It would be best, of course, if there was a way to phrase this so GCC
> doesn't die, but this pattern is everywhere so it might be futile to solve
> it only here.

Yeah, if this fires for all our switch-over-enum-without-default... I
don't think we'll fix it (& there's no point fixing 3 cases if we
leave hundreds more in-tree). So if it's just these three, that's
something & would still need comments most likely. But it'd be better
if there were a solution that didn't suppress diagnostics (oh, and
this change as-is will probably fire Clang's -Wcovered-switch-default
warning... which we'd have to suppress).

- David

>
> - Kim
>
>
> On Thu, Jul 31, 2014 at 9:03 PM, David Blaikie <dblaikie at gmail.com> wrote:
>>
>> Probably worth adding a comment to exlpain why it needs to be there.
>>
>> Also, there's a reason that coding standard is in place - because we
>> get better error (warning ) messages that way. Is there a way to
>> workaround the bug without sacrificing future warning quality?
>>
>> On Thu, Jul 31, 2014 at 11:47 AM, Kim Gräsman <kim.grasman at gmail.com>
>> wrote:
>> > Hi Cy,
>> >
>> > Unfortunately this goes against the general coding standards for LLVM:
>> >
>> > http://llvm.org/docs/CodingStandards.html#don-t-use-default-labels-in-fully-covered-switches-over-enumerations
>> >
>> > but as a local workaround it seems fine.
>> >
>> > I wonder if GCC 4.7 for ARM should be listed here:
>> > http://llvm.org/docs/GettingStarted.html#check-here
>> >
>> > - Kim
>> >
>> >
>> > On Wed, Jul 30, 2014 at 10:57 AM, Cy Anetwork <cya3636 at yahoo.com> wrote:
>> >>
>> >> Hello,
>> >>
>> >> I've managed to track down some code which causes GCC to fail with an
>> >> internal compiler error when compiling llvm/clang for ARM.  I've
>> >> included
>> >> the diff for this one file inline.. hope that's ok.
>> >>
>> >>
>> >> ==================================8<====================================
>> >> --- ../llvm/lib/LTO/LTOCodeGenerator.cpp.old    2014-07-30 08:33:30
>> >> +0000
>> >> +++ ../llvm/lib/LTO/LTOCodeGenerator.cpp        2014-07-30 08:39:03
>> >> +0000
>> >> @@ -150,6 +150,9 @@
>> >>    case LTO_DEBUG_MODEL_DWARF:
>> >>      EmitDwarfDebugInfo = true;
>> >>      return;
>> >> +
>> >> +  default:
>> >> +    return;
>> >>    }
>> >>    llvm_unreachable("Unknown debug format!");
>> >>  }
>> >> @@ -161,6 +164,8 @@
>> >>    case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
>> >>      CodeModel = model;
>> >>      return;
>> >> +  default:
>> >> +    return;
>> >>    }
>> >>    llvm_unreachable("Unknown PIC model!");
>> >>  }
>> >> @@ -293,6 +298,8 @@
>> >>    case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
>> >>      RelocModel = Reloc::DynamicNoPIC;
>> >>      break;
>> >> +  default:
>> >> +    break;
>> >>    }
>> >>
>> >>    // construct LTOModule, hand over ownership of module and target
>> >>
>> >> ==================================8<====================================
>> >>
>> >> Many thanks,
>> >>
>> >> cya.net
>> >>
>> >>
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>> >
>> >
>> >
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>
>