> Jiong Wang wrote: > > when generating instructions to access local variable, for example a local > array, > > if the array size very big, then we need a temp reg to keep the intermediate > index, > then use that temp reg as base reg, so that ldr is capable of indexing the > element. > > while this will cause trouble, because the introduce of temp reg break the > dependence > between the stack variable access and stack adjustment instructions which is > unsafe > when signal trampoline executed. > > this patch add barrier before stack adjustment in epilogue. > > ok for trunk?
I believe you need more barriers. Ie. for all SP modifying instructions (including ldp with writeback) except for ones that just remove the outgoing arguments. You can avoid emitting barriers if alloca is not used and there are no locals in the frame (common case). Basically without that any memory access that may alias with the locals could be scheduled incorrectly. It seems odd that the scheduler does not understand this by default. Wilco
