1. If part of a register is re-defined, an implicit kill and an implicit def are added to denote read / mod / write. However, this should only be necessary if the register is actually read later. This is a performance issue.
2. If a sub-register is being defined, and it doesn't have a previous use, do not add a implicit kill to the last use of a super-register:
= EAX, AX<imp-use,kill>
...
AX =
In this case, EAX is live but AX is killed, this is wrong and will cause the coalescer to do bad things.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48521 91177308-0d34-0410-b5e6-96231b3b80d8
- Eliminate the static "print" method for operands, moving it
into MachineOperand::print.
- Change various set* methods for register flags to take a bool
for the value to set it to. Remove unset* methods.
- Group methods more logically by operand flavor in MachineOperand.h
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45461 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44198 91177308-0d34-0410-b5e6-96231b3b80d8
Due to darwin gcc bug, one version of darwin linker coalesces
static const int, which defauts PassID based pass identification.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36652 91177308-0d34-0410-b5e6-96231b3b80d8
- A register def / use now implicitly affects sub-register liveness but does
not affect liveness information of super-registers.
- Def of a larger register (if followed by a use later) is treated as
read/mod/write of a smaller register.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36434 91177308-0d34-0410-b5e6-96231b3b80d8
Revert patches that caused the problem. Evan, please investigate and reapply
when you've discovered the problem.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34399 91177308-0d34-0410-b5e6-96231b3b80d8
in a successor block for every block...resulting in some O(N^k) algorithm
which wasn't very good for performance. Calculating this information up
front and keeping it in a map made it much faster.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30697 91177308-0d34-0410-b5e6-96231b3b80d8
binary search to test for membership. This speeds up LLC a bit more on KC++,
e.g. on itanium from 16.6974s to 14.8272s, PPC from 11.4926s to 10.7089s and
X86 from 10.8128s to 9.7943s, with no difference in generated code (like all
of the RA patches).
With these changes, isel is the slowest pass for PPC/X86, but linscan+live
intervals is still > 50% of the compile time for itanium. More work could
be done, but this is the last for now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22993 91177308-0d34-0410-b5e6-96231b3b80d8
rearrange some of the accessors to be more efficient.
This makes it much more efficient to iterate over all of the things with the
same value. This speeds up liveintervals analysis from 8.63s to 3.79s with
a release build of llc on kc++ with -march=ia64. This also speeds up live
var from 1.66s -> 0.87s as well, reducing total llc time from 20.1s->15.2s.
This also speeds up other targets slightly, e.g. llc time on X86 from 16.84
-> 16.45s, and PPC from 17.64->17.03s.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22990 91177308-0d34-0410-b5e6-96231b3b80d8
