removeDeadNodes is called, only call it at the end of the pass being run.
This saves 1.3 seconds running DSA on 177.mesa (5.3->4.0s), which is
pretty big.  This is only possible because of the automatic garbage
collection done on forwarding nodes.

llvm-svn: 11178

llvm-svn: 11177

llvm-svn: 11176

DSGraphs while they are forwarding.  When the last reference to the forwarding
node is dropped, the forwarding node is autodeleted.  This should simplify
removeTriviallyDead nodes, and is only (efficiently) possible because we are
using an ilist of dsnodes now.

llvm-svn: 11175

G == 0

llvm-svn: 11174

llvm-svn: 11173

llvm-svn: 11171

Rename stats from dsnode -> dsa
Add a new stat

llvm-svn: 11167

llvm-svn: 11166

llvm-svn: 11157

complete rewrite of load-vn will make it a bit faster.  This changes speeds up
the gcse pass (which uses load-vn) from 25.45s to 0.42s on the testcase in
PR209.

I've also verified that this gives the exact same results as the old one.

llvm-svn: 11132

which causes big reindentation.  While I'm at it, I fix the fixme by removing
some dead code.

llvm-svn: 11131

llvm-svn: 11130

llvm-svn: 11128

llvm-svn: 11126

fixes the crash in 176.gcc.

llvm-svn: 11033

llvm-svn: 11027

llvm-svn: 11024

llvm-svn: 11022

llvm-svn: 11021

llvm-svn: 11015

llvm-svn: 11006

llvm-svn: 11005

llvm-svn: 11001

llvm-svn: 11000

moving it to the start of removeDeadNodes.  This speeds up DSA by 2s on perlbmk
from 41s

llvm-svn: 10999

map.  This saves 5s in the TD pass, from 22->17s on perlbmk

llvm-svn: 10998

the globals directly.  This doesn't save any substantial time, however, because the
globals graph only contains globals!

llvm-svn: 10997

function to find the globals, iterate over all of the globals directly.  This
speeds the function up from 14s to 6.3s on perlbmk, reducing DSA time from
53->46s.

llvm-svn: 10996

timers by default

llvm-svn: 10993

This reduces the number of nodes allocated, then immediately merged and DNE'd
from 2193852 to 1298049.  unfortunately this only speeds DSA up by ~1.5s (of
53s), because it's spending most of its time waddling through the scalar map :(

llvm-svn: 10992

Also, use RC::merge when possible, reducing the number of nodes allocated, then immediately merged away from 2985444 to 2193852 on perlbmk.

llvm-svn: 10991

You gotta love spurious

llvm-svn: 10990

llvm-svn: 10989

  it to be off.  If it looks like it's completely unnecessary after testing, I
  will remove it completely (which is the hope).
* Callers of the DSNode "copy ctor" can not choose to not copy links.
* Make node collapsing not create a garbage node in some cases, avoiding a
  memory allocation, and a subsequent DNE.
* When merging types, allow two functions of different types to be merged
  without collapsing.
* Use DSNodeHandle::isNull more often instead of DSNodeHandle::getNode() == 0,
  as it is much more efficient.
*** Implement the new, more efficient reachability cloner class
    In addition to only cloning nodes that are reachable from interesting
    roots, this also fixes the huge inefficiency we had where we cloned lots
    of nodes, only to merge them away immediately after they were cloned.
    Now we only actually allocate a node if there isn't one to merge it into.
* Eliminate the now-obsolete cloneReachable* and clonePartiallyInto methods
* Rewrite updateFromGlobalsGraph to use the reachability cloner
* Rewrite mergeInGraph to use the reachability cloner
* Disable the scalar map scanning code in removeTriviallyDeadNodes.  In large
  SCC's, this is extremely expensive.  We need a better data structure for the
  scalar map, because we really want to scan the unique node handles, not ALL
  of the scalars.
* Remove the incorrect SANER_CODE_FOR_CHECKING_IF_ALL_REFERRERS_ARE_FROM_SCALARMAP code.
* Move the code for eliminating integer nodes from the trivially dead
  eliminator to the dead node eliminator.
* removeDeadNodes no longer uses removeTriviallyDeadNodes, as it contains a
  superset of the node removal power.
* Only futz around with the globals graph in removeDeadNodes if it is modified

llvm-svn: 10987

efficient in the case where a function calls into the same graph multiple times
(ie, it either contains multiple calls to the same function, or multiple calls
to functions in the same SCC graph)

llvm-svn: 10986

llvm-svn: 10985

llvm-svn: 10984

Initial support for implementing clonePartiallyInto in terms of cloneReachableSubgraph, though this support is currently disabled.

llvm-svn: 10970

map was only used to implement a marginal GlobalsGraph optimization, and it
actually slows the analysis down (due to the overhead of keeping it), so just
eliminate it entirely.

llvm-svn: 10955