Some subregisters are only to indicate different access sizes, while not
providing any way to actually divide the register up into multiple
disjunct parts. Avoid tracking subregister liveness in these cases as it
is not beneficial.
Differential Revision: http://reviews.llvm.org/D8429
llvm-svn: 232695
Summary:
Letting them begin at the PHI instruction slightly simplifies the code
but more importantly avoids breaking the assumption that live ranges
starting at the block begin are also live at the end of the predecessor
blocks. The MachineVerifier checks that but was apparently never run in
the few instances where liveranges are calculated for machine-SSA
functions.
Reviewers: qcolombet
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D7779
llvm-svn: 230093
This function constructs the main liverange by merging all subranges if
subregister liveness tracking is available. This should be slightly
faster to compute instead of performing the liveness calculation again
for the main range. More importantly it avoids cases where the main
liverange would cover positions where no subrange was live. These cases
happened for partial definitions where the actual defined part was dead
and only the undefined parts used later.
The register coalescing requires that every part covered by the main
live range has at least one subrange live.
I also expect this function to become usefull later for places where the
subranges are modified in a way that it is hard to correctly fix the
main liverange in the machine scheduler, we can simply reconstruct it
from subranges then.
llvm-svn: 224806
This changes subrange calculation to calculate subranges sequentially
instead of in parallel. The code is easier to understand that way and
addresses the code review issues raised about LiveOutData being
hard to understand/needing more comments by removing them :)
llvm-svn: 224313
This changes subrange calculation to calculate subranges sequentially
instead of in parallel. The code is easier to understand that way and
addresses the code review issues raised about LiveOutData being
hard to understand/needing more comments by removing them :)
llvm-svn: 224272
define below all header includes in the lib/CodeGen/... tree. While the
current modules implementation doesn't check for this kind of ODR
violation yet, it is likely to grow support for it in the future. It
also removes one layer of macro pollution across all the included
headers.
Other sub-trees will follow.
llvm-svn: 206837
operator* on the by-operand iterators to return a MachineOperand& rather than
a MachineInstr&. At this point they almost behave like normal iterators!
Again, this requires making some existing loops more verbose, but should pave
the way for the big range-based for-loop cleanups in the future.
llvm-svn: 203865
The Segment struct contains a single interval; multiple instances of this struct
are used to construct a live range, but the struct is not a live range by
itself.
llvm-svn: 192392
When findReachingDefs() finds that only one value can reach the basic
block, just copy the work list of visited blocks directly into the live
interval.
Sort the block list and use a LiveRangeUpdater to make the bulk add
fast.
When multiple reaching defs are found, transfer the work list to the
updateSSA() work list as before. Also use LiveRangeUpdater in
updateLiveIns() following updateSSA().
This makes live interval analysis more than 3x faster on one huge test
case.
llvm-svn: 175685
Kill flags are difficult to maintain, and liveness queries are better
handled by live intervals.
Kill flags are reinserted after register allocation by addKillFlags().
llvm-svn: 163334
A value number is a PHI def if and only if it begins at a block
boundary. This can be derived from the def slot, a separate flag is not
necessary.
llvm-svn: 160893
Catch uses of undefined physregs that haven't been added to basic block
live-in lists. Run the verifier to pinpoint the problem.
Also run the verifier when a virtual register use is not jointly
dominated by defs.
llvm-svn: 160207
If a value is defined by a COPY, that instuction can easily and cheaply
be found by getInstructionFromIndex(VNI->def).
This reduces the size of VNInfo from 24 to 16 bytes, and improves
llc compile time by 3%.
llvm-svn: 149763
SplitKit will soon need two copies of these data structures, and the
algorithms will also be useful when LiveIntervalAnalysis becomes
independent of LiveVariables.
llvm-svn: 139572
