in so far as it compiles and, in theory, works, but does not take advantage of recent advancements. For instance, it could be improved by using
MachineRegisterInfo::use_iterator.
llvm-svn: 54924
and knowledge of PseudoSourceValues. This unfortunately isn't sufficient to allow
constants to be rematerialized in PIC mode -- the extra indirection is a
complication.
llvm-svn: 54000
the function due to empty index slots. This is suitable for use in backend heuristics that need to reason about the density
of an interval.
llvm-svn: 52652
PR1877.
A3 = op A2 B0<kill>
...
B1 = A3 <- this copy
...
= op A3 <- more uses
==>
B2 = op B0 A2<kill>
...
B1 = B2 <- now an identify copy
...
= op B2 <- more uses
This speeds up FreeBench/neural by 29%, Olden/bh by 12%, oopack_v1p8 by 53%.
llvm-svn: 47046
that "machine" classes are used to represent the current state of
the code being compiled. Given this expanded name, we can start
moving other stuff into it. For now, move the UsedPhysRegs and
LiveIn/LoveOuts vectors from MachineFunction into it.
Update all the clients to match.
This also reduces some needless #includes, such as MachineModuleInfo
from MachineFunction.
llvm-svn: 45467
This allows an important optimization to be re-enabled.
- If all uses / defs of a split interval can be folded, give the interval a
low spill weight so it would not be picked in case spilling is needed (avoid
pushing other intervals in the same BB to be spilled).
llvm-svn: 44601
in the middle of a split basic block, create a new live interval starting at
the def. This avoid artifically extending the live interval over a number of
cycles where it is dead. e.g.
bb1:
= vr1204 (use / kill) <= new interval starts and ends here.
...
...
vr1204 = (new def) <= start a new interval here.
= vr1204 (use)
llvm-svn: 44436
When a live interval is being spilled, rather than creating short, non-spillable
intervals for every def / use, split the interval at BB boundaries. That is, for
every BB where the live interval is defined or used, create a new interval that
covers all the defs and uses in the BB.
This is designed to eliminate one common problem: multiple reloads of the same
value in a single basic block. Note, it does *not* decrease the number of spills
since no copies are inserted so the split intervals are *connected* through
spill and reloads (or rematerialization). The newly created intervals can be
spilled again, in that case, since it does not span multiple basic blocks, it's
spilled in the usual manner. However, it can reuse the same stack slot as the
previously split interval.
This is currently controlled by -split-intervals-at-bb.
llvm-svn: 44198