Thanks for the information, what we were doing was to call update_life_info_in_dirty_blocks, but for some reason this wasn't sufficient to mark a register dead (REG_DEAD note) when the register was defined in a predecessor block and dies in the dirty block; we had to call update_life_info for all the blocks to mark that register as dead. Is there cases that we know about that such case could happen? is this means a bug in update_life_info
I am not sure I have enough info to answer this.
If you are moving instructions from one block to another, then you may need a full life pass, which means not using UPDATE_LIFE_LOCAL. With UPDATE_LIFE_LOCAL, we assume that the info on which registers are live at the end of each block is still correct, and we just update info within blocks, i.e. making sure REG_DEAD notes within a block are in the right place, as this might have changed. But if you need changes to global_live_at_{start,end} then you need to rerun a full life pass without UPDATE_LIFE_LOCAL to recompute this info.
Otherwise, I am not sure what the problem might be. You might try spending a little time figuring out how update_life_info works.
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Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com
