too large limit.
The function would return immediately when finding an addrmode 3/5 instruction.
It needs to keep scanning in case there is an addrmode 6 instruction which drops
the limit to 0.
A test case is very difficult to produce because it will only fail when the
scavenger is used.
rdar://problem/7894847
llvm-svn: 103995
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.
llvm-svn: 103835
the variable actually tracks.
N.B., several back-ends are using "HasCalls" as being synonymous for something
that adjusts the stack. This isn't 100% correct and should be looked into.
llvm-svn: 103802
v1024 = REG_SEQUENCE ...
v1025 = EXTRACT_SUBREG v1024, 5
v1026 = EXTRACR_SUBREG v1024, 6
= VSTxx <addr>, v1025, v1026
The REG_SEQUENCE ensures the sources that feed into the VST instruction
are getting the right register allocation so they form a large super-
register. The extract_subreg will be coalesced away all would just work:
v1024 = REG_SEQUENCE ...
= VSTxx <addr>, v1024:5, v1024:6
The problem is if the coalescer isn't run, the extract_subreg instructions
would stick around and there is no assurance v1025 and v1026 will get the
right registers.
As a short term workaround, teach the NEON pre-allocation pass to transfer
the sub-register indices over. An alternative would be do it 2addr pass
when reg_sequence's are eliminated. But that *seems* wrong and require
updating liveness information.
Another alternative is to do this in the scheduler when the instructions are
created. But that would mean somehow the scheduler this has to be done for
correctness reason. That's yucky as well. So for now, we are leaving this
in the target specific pass.
llvm-svn: 103540
Move EmitTargetCodeForMemcpy, EmitTargetCodeForMemset, and
EmitTargetCodeForMemmove out of TargetLowering and into
SelectionDAGInfo to exercise this.
llvm-svn: 103481
Evan Cheng