There are probably much larger speedups to be had by renumbering locally instead
of looping over the whole function. For now, the greedy register allocator is
25% faster.
llvm-svn: 126926
This is much faster than using a pointer to a ManagedStatic object accessed with
a function call. The greedy register allocator is 5% faster overall just from
the SlotIndex default constructor savings.
llvm-svn: 126925
The SlotIndex created by the default construction does not represent a position
in the function, and it doesn't make sense to compare it to other indexes.
llvm-svn: 126924
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
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
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
This method could probably be used by LiveIntervalAnalysis::shrinkToUses, and
now it can use extendIntervalEndTo() which coalesces ranges.
llvm-svn: 126803
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
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
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
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
