search for: divbyzero

...//xen.1045712.n5.nabble.com/Alignment-check-on-domU-2-6-32-td2549903.html http://xen.1045712.n5.nabble.com/Kernel-panic-with-2-6-32-30-under-network-activity-td3423149.html Kernel messages: derefnull[15862]: segfault at 0 ip 000000000804c2eb sp 00000000ffb4dfac error 4 in derefnull[8048000+57000] divbyzero[15899] trap divide error ip:804d0be sp:ff849e9c error:0 in divbyzero[8048000+56000] derefnull[7328]: segfault at 0 ip 0000000000407701 sp 00007fff943b1c60 error 4 in derefnull[400000+77000] divbyzero[7345] trap divide error ip:408d05 sp:7fff35784750 error:0 in divbyzero[400000+76000] derefnull[3273...

...s that the language (or maybe a compiler switch) dictates that any instruction instance _should_ not trap (is undefined if it does or use NaN propagation). In this case the instructions might trap unless hardware is instructed not to (switch off FP exceptions, use a special dummy signal handler for divbyzero) before executing the instruction (or function). If the latter is implemented using MD and some optimization drops it, it might break programs that assume (due to the language/switch) that there are no traps, but propagate NaNs from illegal fp operations, because the instructions work as intended...

----- Original Message ----- > Hi Nadav, > > On 10/31/2013 08:53 PM, Nadav Rotem wrote: > > data-parallel languages which have a completely different > > semantics. In > > OpenCL/Cuda you would want to vectorize the outermost loop, and the > > language guarantees that it is safe to so. > > Yeah. This is the separate (old) discussion and not strictly

Hi Nadav, On 10/31/2013 08:53 PM, Nadav Rotem wrote: > data-parallel languages which have a completely different semantics. In > OpenCL/Cuda you would want to vectorize the outermost loop, and the > language guarantees that it is safe to so. Yeah. This is the separate (old) discussion and not strictly related to the problem at hand. Better if-conversion benefits more than OpenCL C