> Under what circumstances are we seeing a SEQUENCE in the x86 backend? I'm > surprised we need to handle that case. > > So your pass modifies the insn in place, which is fine. But do we actually > remove the original constant pool entry if it's no longer used? If not, does > this patch actually save anything (memory bandwidth perhaps?)
Constant pool entries are output only if actually used by asm output, so this could just work. > > Is there an existing pass over the RTL chain where this would work so that > it's > more compile-time efficient? I was also concerned about adding yet another pass and wanted to look bit more into posibility to make this a part of peephole pass. While it is true that the usual way to write it (adding extra pattern for every instruction) is a lot of work I was thinking if we can perhaps just add quite generic define_peephole which will match everything containing broadcast via predicate, call into the expander that will try to build mathcing instruction and fail otherwise. While it is still bit of a hack I think it may be less intrusive then yet another machine specific pass. Honza > > jeff >
