[PPL-devel] Fwd: ppl 0.11.2 vs llvm

[Jack Howarth]

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. 
  Is --disable-fpmath our only option here? I ask because only a small subset of testcases
are failing and, from the response of the llvm/clang developers, it doesn't apear that
-frounding-math support will be implemented in llvm/clang anytime soon.
               Jack

>
>> ps Will --disable-fpmath introduce any problems for using the
>> resulting ppl build with graphite in FSF gcc or cloog-ppl?
>
> Not that I know: neither GCC nor any cloog-ppl used any floating-point
> based approximation.  And if they do you will have an error as soon as
> you try compiling them.  So, no, I do not foresee any problems.
> 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
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