When only a single value has been seen, new PHIDefs are never needed.

llvm-svn: 126911

We need to wait until we meet a PHIDef in its defining block before resurrecting
PHIKills in the predecessors.

This should unbreak the llvm-gcc-build-x86_64-darwin10-x-mingw32-x-armeabi bot.

llvm-svn: 126905

David Greene changed CannotYetSelect() to print the full DAG including multiple
copies of operands reached through different paths in the DAG.  Unfortunately
this blows up exponentially in some cases.  The depth limit of 100 is way too
high to prevent this -- I'm seeing a message string of 150MB with a depth of
only 40 in one particularly bad case, even though the DAG has less than 200
nodes.  Part of the problem is that the printing code is following chain
operands, so if you fail to select an operation with a chain, the printer will
follow all the chained operations back to the entry node.

llvm-svn: 126899

No functional change.

llvm-svn: 126898

Values that map to a single new value in a new interval after splitting don't
need new PHIDefs, and if the parent value was never rematerialized the live
range will be the same.

llvm-svn: 126894

llvm-svn: 126893

Radar 9056407.

llvm-svn: 126864

llvm-svn: 126829

Extract the updateSSA() method from the too long extendRange().

LiveOutCache can be shared among all the new intervals since there is at most
one of the new ranges live out from each basic block.

llvm-svn: 126818

llvm-svn: 126815

llvm-svn: 126811

Simplify the signature - The return value and ParentVNI are no longer needed.

llvm-svn: 126809

llvm-svn: 126806

llvm-svn: 126805

This method could probably be used by LiveIntervalAnalysis::shrinkToUses, and
now it can use extendIntervalEndTo() which coalesces ranges.

llvm-svn: 126803

llvm-svn: 126801

The value map is currently not used, all values are 'complex mapped' and
LiveIntervalMap::mapValue is used to dig them out.

This is the first step in a series changes leading to the removal of
LiveIntervalMap. Its data structures can be shared among all the live intervals
created by a split, so it is wasteful to create a copy for each.

llvm-svn: 126800

Local live range splitting is better driven by interference. This code was just
guessing.

llvm-svn: 126799

This is a waste of time since we already know how to evict all interferences
which is a better approach anyway.

llvm-svn: 126798

llvm-svn: 126794

This effectively disables the 'turbo' functionality of the greedy register
allocator where all new live ranges created by splitting would be reconsidered
as if they were originals.

There are two reasons for doing this, 1. It guarantees that the algorithm
terminates. Early versions were prone to infinite looping in certain corner
cases. 2. It is a 2x speedup. We can skip a lot of unnecessary interference
checks that won't lead to good splitting anyway.

The problem is that region splitting only gets one shot, so it should probably
be changed to target multiple physical registers at once.

Local live range splitting is still 'turbo' enabled. It only accounts for a
small fraction of compile time, so it is probably not necessary to do anything
about that.

llvm-svn: 126781

in alphabetical order.

llvm-svn: 126745

llvm-svn: 126733

llvm-svn: 126731

llvm-svn: 126684

llvm-svn: 126683

llvm-svn: 126671

patch to the front-end.  Radar 7662569.

llvm-svn: 126655

llvm-svn: 126574

llvm-svn: 126565

This follows the interface of getNodeAttributes.

llvm-svn: 126562

Add some DAGCombines for (adde 0, 0, glue), which are useful to optimize legalized code for large integer arithmetic.

1. Inform users of ADDEs with two 0 operands that it never sets carry
2. Fold other ADDs or ADDCs into the ADDE if possible

It would be neat if we could do the same thing for SETCC+ADD eventually, but we can't do that in target independent code.

llvm-svn: 126557

llvm-svn: 126526

llvm-svn: 126518

llvm-svn: 126488

llvm-svn: 126471

is possible to do better if the high bit is set in either KnownZero/KnownOne, but
in practice NumSignBits is always 1 when we are zero extending because nothing
is known about that register.

llvm-svn: 126465

actually larger.

llvm-svn: 126464

llvm-svn: 126463

New live ranges are assigned in long -> short order, but live ranges that have
been evicted at least once are deferred and assigned in short -> long order.

Also disable splitting and spilling for live ranges seen for the first time.

The intention is to create a realistic interference pattern from the heavy live
ranges before starting splitting and spilling around it.

llvm-svn: 126451