[PPL-devel] Fwd: ppl 0.11.2 vs llvm

[Roberto Bagnara]

On 08/07/11 17:33, Jack Howarth wrote:
> On Sun, Aug 07, 2011 at 05:23:15PM +0200, Roberto Bagnara wrote:
>> On 08/07/11 16:56, Jack Howarth wrote:
>>> On Sun, Aug 07, 2011 at 09:31:46AM +0200, Roberto Bagnara wrote:
>>>> On 08/06/11 14:14, Jack Howarth wrote:
>>>>>       I am rather baffled that you can't reproduce this problem on Linux.
>>>>> Attached is a build and make check log from x86_64 Fedora 10 using the
>>>>> ppl 0.11.2 release and the binary distribution of the clang 2.9 compilers
>>>>> fromhttp://llvm.org/releases/2.9/clang+llvm-2.9-x86_64-linux.tar.bz2.
>>>>> With CC set to clang and CXX set to clang++, I see the same failures as
>>>>> under the clang compilers from Xcode 4.1 under Lion.
>>>>
>>>> Hi Jack,
>>>>
>>>> please try configuring the PPL with --disable-fpmath on both platforms
>>>> and let us know if `make check' passes this way.
>>>
>>>      Building ppl9 with...
>>>
>>>     $ ../configure --prefix=/sw --mandir=/sw/share/man --infodir=/sw/share/info --disable-static --enable-pch --with-java=/System/Library/Frameworks/JavaVM.framework/Home CFLAGS=-g -O2 -pipe -fpch-preprocess -fPIC -fwrapv CXXFLAGS=-g -O2 -pipe -fpch-preprocess -fPIC -fwrapv CPPFLAGS=-I/System/Library/Frameworks/JavaVM.framework/Headers --enable-check=thorough --disable-fpmath -C
>>>
>>> produces no testsuite failures when using clang3.0svn from Xcode 4.1. I'll repeat this with the stock llvm-gcc-4.2
>>> system compilers from Xcode 4.1 as well.
>>
>> Great, thanks!
>
> Roberto,
>    The results for llvm-gcc-4.2 from Xcode 4.1 weren't as positive. The testcase...
>
> /bin/sh: line 1: 91482 Segmentation fault: 11  ${dir}$tst
> FAIL: simplifyusingcontext1
>
> segfaults with --disable-fpmath. I wouldn't worry too much about that as Apple is
> using a much older llvm release for llvm-gcc-4.2 than clang3.0svn in Xcode 4.1.
> Also, their usual response to llvm-gcc bugs is that it is being depreciated in
> favor of clang and to use that compiler instead.

I am pretty confident this is a compiler bug.

>    Is --disable-fpmath our only option here?

The only other option I see is to debug the compiler bug.
I guess it will not be an easy task though.
Cheers,

    Roberto

-- 
Prof. Roberto Bagnara
Applied Formal Methods Laboratory
Department of Mathematics, University of Parma, Italy
http://www.cs.unipr.it/~bagnara/
mailto:bagnara at cs.unipr.it