Hi, I am developing a set of unit tests, which I would also like to run through valgrind from time to time. On their own the unit tests run absolutely fine, but when I run them through valgrind I get zillions of failed tests. I tracked this down to an overloaded routine (called exp10) which returns a __float128. The prototype is:
__float128 exp10(__float128); When that routine is called with a negative argument, the return value changes when I run the code through valgrind, e.g. -20 3fbc79ca10c9242235d511e976394d7a (without valgrind) -20 3fbc79ca10c9240e12445f2000000000 (with valgrind) The -20 is the argument for exp10() and was obviously converted to __float128, and the return value is printed here in hex format. Initially I thought that the lowest 64 bits were mangled, but from this example you can see that it is a bit more (the lowest 70 bits differ). When exp10 is called with a positive argument, the return value is just fine, e.g. 9 401cdcd6500000000000000000000000 (without valgrind) 9 401cdcd6500000000000000000000000 (with valgrind) This is compiled on an amd64 platform using g++ 4.7.1 and valgrind 3.7.0 (openSUSE 12.2). I also tried openSUSE 12.3 and got the same behavior (this is g++ 4.7.2, valgrind 3.8.1). I am totally mystified by this. Especially the part where positive arguments work fine and negative do not... Is this a valgrind bug? Peter. ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60133471&iu=/4140/ostg.clktrk _______________________________________________ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
