Evan Cheng a70ecc2f51 The coalescer does not coalesce a virtual register to a physical register if any of the physical register's sub-register live intervals overlaps with the virtual register. This is overly conservative. It prevents a extract_subreg from being coalesced away: ... v1024 = EDI // not killed = = EDI One possible solution is for the coalescer to examine the sub-register live intervals in the same manner as the physical register. Another possibility is to examine defs and uses (when needed) of sub-registers. Both solutions are too expensive. For now, look for "short virtual intervals" and scan instructions to look for conflict instead. This is a small win on x86-64. e.g. It shaves 403.gcc by ~80 instructions. llvm-svn: 61847		2009-01-07 02:08:57 +00:00
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llvm	The coalescer does not coalesce a virtual register to a physical register if any of the physical register's sub-register live intervals overlaps with the virtual register. This is overly conservative. It prevents a extract_subreg from being coalesced away:	2009-01-07 02:08:57 +00:00
llvm-c	Add dyn_cast_or_null bindings for some additional classes missed in r61252.	2008-12-19 18:51:17 +00:00