Evan Cheng b990a2f249 Teach two-address pass to do some coalescing while eliminating REG_SEQUENCE ... instructions. e.g. %reg1026<def> = VLDMQ %reg1025<kill>, 260, pred:14, pred:%reg0 %reg1027<def> = EXTRACT_SUBREG %reg1026, 6 %reg1028<def> = EXTRACT_SUBREG %reg1026<kill>, 5 ... %reg1029<def> = REG_SEQUENCE %reg1028<kill>, 5, %reg1027<kill>, 6, %reg1028, 7, %reg1027, 8, %reg1028, 9, %reg1027, 10, %reg1030<kill>, 11, %reg1032<kill>, 12 After REG_SEQUENCE is eliminated, we are left with: %reg1026<def> = VLDMQ %reg1025<kill>, 260, pred:14, pred:%reg0 %reg1029:6<def> = EXTRACT_SUBREG %reg1026, 6 %reg1029:5<def> = EXTRACT_SUBREG %reg1026<kill>, 5 The regular coalescer will not be able to coalesce reg1026 and reg1029 because it doesn't know how to combine sub-register indices 5 and 6. Now 2-address pass will consult the target whether sub-registers 5 and 6 of reg1026 can be combined to into a larger sub-register (or combined to be reg1026 itself as is the case here). If it is possible, it will be able to replace references of reg1026 with reg1029 + the larger sub-register index. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103835 91177308-0d34-0410-b5e6-96231b3b80d8		2010-05-14 23:21:14 +00:00
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llvm	Teach two-address pass to do some coalescing while eliminating REG_SEQUENCE	2010-05-14 23:21:14 +00:00
llvm-c	add some more (void)'s to prototypes for PR6961	2010-04-29 23:27:32 +00:00