[llvm-dev] Optimizer issues on Windows

[David Majnemer via llvm-dev]

On Sat, Sep 12, 2015 at 10:35 AM, Sebastian Blessing <sebastian at causality.io
> wrote:

> … Also, it doesn’t appear that you are running on windows…
>

That is irrelevant for your example because it specifies a target triple:
$ head -n3 try.ll
; ModuleID = 'try'
target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-windows-msvc"

As to whether or not it fixed the bug:
$ ~/llvm/src/utils/git-svn/git-svnrevert r247435
$ ninja -C ~/llvm/Debug+Asserts llc
[3/3] Linking CXX executable bin/llc
$ ~/llvm/Debug+Asserts/bin/llc try.ll
LLVM ERROR: Starting a function before ending the previous one!

So yes, it seems like r247435 has fixed the bug you are running into.
To answer your other question, r247435 was committed after we branched for
3.7.0



>
> From: David Majnemer
> Date: Saturday 12 September 2015 18:31
> To: Sebastian Blessing
> Cc: Reid Kleckner, "llvm-dev at lists.llvm.org"
>
> Subject: Re: [llvm-dev] Optimizer issues on Windows
>
> $ ~/llvm/Debug+Asserts/bin/llc try.ll
> $ echo $?
> 0
>
> On Sat, Sep 12, 2015 at 6:39 AM, Sebastian Blessing via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> This got me into thinking. Indeed the problem is related to Windows
>> exceptions, so I am not sure whether the bug reported
>> <https://llvm.org/bugs/show_bug.cgi?id=24374> is actually fixed.
>>
>> Compiling Pony code (helloworld) that includes no exceptions does work
>> fine (with optimizations). As soon as exceptions on windows come into play,
>> writing the object file dies with the mentioned error in MCStreamer.cpp.
>>
>> Here <http://releases.ponylang.org/winexcept/> are two minimal IR
>> examples (helloworld.ll works, try.ll doesn’t - both verify with llc). The
>> relevant method is *@Main_create*. Can anyone of you guys confirm the
>> issue with llvm 3.7.0–final, or whether said bug has actually been fixed?
>>
>> From: Reid Kleckner
>> Date: Friday 11 September 2015 17:07
>> To: Sebastian Blessing
>> Cc: "llvm-dev at lists.llvm.org"
>> Subject: Re: [llvm-dev] Optimizer issues on Windows
>>
>> The bug https://llvm.org/bugs/show_bug.cgi?id=24374 has to do with
>> exceptions on Windows, so it is unrelated unless you are using them.
>>
>> On Fri, Sep 11, 2015 at 4:37 AM, Sebastian Blessing via llvm-dev <
>> llvm-dev at lists.llvm.org> wrote:
>>
>>> Dear Community,
>>>
>>> The ponyc <https://github.com/CausalityLtd/ponyc/tree/llvm37> (llvm37
>>> branch) project is facing an issue on Windows:
>>>
>>> When optimizations are turned on (llvm 3.7.0-final and more specifically
>>> <https://github.com/CausalityLtd/ponyc/blob/llvm37/src/libponyc/codegen/genopt.cc>,
>>> opt-level 3,  BBVectorize, LoopVectorize, SLPVectorize, RerollLoops,
>>> LoadCombine + a custom heap to stack pass) writing an object file aborts
>>> (on Windows only) with the following fatal error:
>>>
>>> “Starting a function before ending the previous one!” at
>>> MCStreamer.cpp:407 during LLVMTargetMachineEmitToFile. Verifying the IR
>>> with llc raises no errors.
>>>
>>> What exact problem is being detected here and how can we get more
>>> details on the location in the IR that is causing the problem?
>>>
>>> Turning off optimizations successfully writes the object file. This only
>>> occurs on Windows, writing object files works fine on Linux and OS X.
>>>
>>> Is this a know issue with LLVM 3.7.0-final and how can this be fixed? Is
>>> a patch required?
>>>
>>> This might be related to https://llvm.org/bugs/show_bug.cgi?id=24374.
>>>
>>> Kind regards
>>> Sebastian
>>>
>>>
>>>
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>
>>>
>>
>> _______________________________________________
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>>
>
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