Il 06/08/2011 14:14, Jack Howarth ha scritto:
Roberto, 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 from http://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. Jack
Hello Jack.
I have downloaded the binaries above on my (Ubuntu) system and I managed to reproduce the first failure.
This is test08() in tests/Box/affineimage1.cc, compiled with -DBOX_INSTANCE=ld_r_oc (that is, using long doubles).
If you run the test as follows:
$ PPL_NOISY_TESTS=1 ./affineimage1
you will get some debugging output.
The relevant bits regarding test08() are the following: ======================================================================= === test08 === *** box *** A in [0, 1], B in [-1, 2] Containment does not hold: computed result is A in (-3689348814741910323/4611686018427387904, 3228180212899171533/2305843009213693952), B in [-1, 2] known result is A in [-4/5, 7/5], B in [-1, 2] Individual dimensions where containment does not hold (Variable: computed-result known-result): A: (-3689348814741910323/4611686018427387904, 3228180212899171533/2305843009213693952) [-4/5, 7/5] *** box.affine_image(A, -2*A - 3*B + 1, -5) *** A in (-0.79999999999999999995663191310057982263970188796520233154296875, 1.4000000000000000000867361737988403547205962240695953369140625), B in [-1, 2] =======================================================================
The relevant part here is the computed lower bound for space dimension named "A" (the first one), which should be lower than -0.8 (known result is -4/5) in order to be on the safe side: the computed value -0.79999...) was instead obtained by rounding towards the unsafe side, leading to the failure.
If compiled using gcc, the output is as follows: ======================================================================= === test08 === *** box *** A in [0, 1], B in [-1, 2] *** box.affine_image(A, -2*A - 3*B + 1, -5) *** A in (-0.8000000000000000000108420217248550443400745280086994171142578125, 1.4000000000000000000867361737988403547205962240695953369140625), B in [-1, 2] =======================================================================
So, my hypothesis seems to be correct: the cause is the missing support for -frounding-math in llvm/clang.
I will soon check some of the other failing tests and will report if I see anything new with respect to what said above.
Cheers, Enea.