Commit Graph

7478 Commits

Author SHA1 Message Date
Owen Anderson
e39cb57b09 Complete the NumberTable --> LeaderTable rename.
llvm-svn: 122828
2011-01-04 19:29:46 +00:00
Owen Anderson
d7d06d3aaf Fix typo in a comment.
llvm-svn: 122827
2011-01-04 19:25:18 +00:00
Owen Anderson
51489b3b28 Prune #include's.
llvm-svn: 122826
2011-01-04 19:24:57 +00:00
Owen Anderson
c7c3bc63f7 Clarify terminology, settling on referring to what was the "number table" as the "leader table", and
rename methods to make it much more clear what they're doing.

llvm-svn: 122823
2011-01-04 19:13:25 +00:00
Owen Anderson
83546f2fe0 When removing a value from GVN's leaders list, don't drop the Next pointer in a corner case.
llvm-svn: 122822
2011-01-04 19:10:54 +00:00
Dale Johannesen
a71d2cc88d Improve the accuracy of the inlining heuristic looking for the
case where a static caller is itself inlined everywhere else, and
thus may go away if it doesn't get too big due to inlining other
things into it.  If there are references to the caller other than
calls, it will not be removed; account for this.
This results in same-day completion of the case in PR8853.

llvm-svn: 122821
2011-01-04 19:01:54 +00:00
Owen Anderson
41a1550ef5 Branch instructions don't produce values, so there's no need to generate a value number for them. This
avoids adding them to the various value numbering tables, resulting in a minor (~3%) speedup for GVN
on 40.gcc.

llvm-svn: 122819
2011-01-04 18:54:18 +00:00
Owen Anderson
22c53e277a Remove commented out code.
llvm-svn: 122817
2011-01-04 18:22:08 +00:00
Cameron Zwarich
b2a41e9388 Switch to the new style of asterisk placement.
llvm-svn: 122815
2011-01-04 18:19:19 +00:00
Chris Lattner
8643810ede Teach loop-idiom to turn a loop containing a memset into a larger memset
when safe.

The testcase is basically this nested loop:
void foo(char *X) {
  for (int i = 0; i != 100; ++i) 
    for (int j = 0; j != 100; ++j)
      X[j+i*100] = 0;
}

which gets turned into a single memset now.  clang -O3 doesn't optimize
this yet though due to a phase ordering issue I haven't analyzed yet.

llvm-svn: 122806
2011-01-04 07:46:33 +00:00
Chris Lattner
a62b01dc37 restructure this a bit. Initialize the WeakVH with "I", the
instruction *after* the store.  The store will always be deleted
if the transformation kicks in, so we'd do an N^2 scan of every
loop block.  Whoops.

llvm-svn: 122805
2011-01-04 07:27:30 +00:00
Cameron Zwarich
f4e13699e7 Avoid finding loop back edges when we are not splitting critical edges in
CodeGenPrepare (which is the default behavior).

llvm-svn: 122801
2011-01-04 04:43:31 +00:00
Cameron Zwarich
e924969380 Address most of Duncan's review comments. Also, make LoopInstSimplify a simple
FunctionPass. It probably doesn't have a reason to be a LoopPass, as it will
probably drop the simple fixed point and either use RPO iteration or Duncan's
approach in instsimplify of only revisiting instructions that have changed.

The next step is to preserve LoopSimplify. This looks like it won't be too hard,
although the pass manager doesn't actually seem to respect when non-loop passes
claim to preserve LCSSA or LoopSimplify. This will have to be fixed.

llvm-svn: 122791
2011-01-04 00:12:46 +00:00
Chris Lattner
0ba473c218 use the very-handy getTruncateOrZeroExtend helper function, and
stop setting NSW: signed overflow is possible.  Thanks to Dan
for pointing these out.

llvm-svn: 122790
2011-01-04 00:06:55 +00:00
Owen Anderson
0839d3930a Fix comment.
llvm-svn: 122788
2011-01-03 23:51:56 +00:00
Owen Anderson
d62d37225a Use the new addEscapingValue callback to update GlobalsModRef when GVN adds PHIs of GEPs. For the moment,
have GlobalsModRef handle this conservatively by simply removing the value from its maps.

llvm-svn: 122787
2011-01-03 23:51:43 +00:00
Chris Lattner
bde6ec1db6 Duncan deftly points out that readnone functions aren't
invalidated by stores, so they can be handled as 'simple'
operations.

llvm-svn: 122785
2011-01-03 23:38:13 +00:00
Owen Anderson
3a33d0cc4a Simplify GVN's value expression structure, allowing the elimination of a lot of
almost-but-not-quite-identical code.  No intended functionality change.

llvm-svn: 122760
2011-01-03 19:00:11 +00:00
Chris Lattner
16ca19ffc5 stength reduce my previous patch a bit. The only instructions
that are allowed to have metadata operands are intrinsic calls,
and the only ones that take metadata currently return void.
Just reject all void instructions, which should not be value
numbered anyway.  To future proof things, add an assert to the
getHashValue impl for calls to check that metadata operands 
aren't present.

llvm-svn: 122759
2011-01-03 18:43:03 +00:00
Chris Lattner
142f1cd251 fix PR8895: metadata operands don't have a strong use of their
nested values, so they can change and drop to null, which can
change the hash and cause havok.

It turns out that it isn't a good idea to value number stuff
with metadata operands anyway, so... don't.

llvm-svn: 122758
2011-01-03 18:28:15 +00:00
Duncan Sands
697de77339 Speed up instsimplify by about 10-15% by not bothering to retry
InstructionSimplify on instructions that didn't change since the
last time round the loop.

llvm-svn: 122745
2011-01-03 10:50:04 +00:00
Cameron Zwarich
43cecb1200 Switch a worklist in CodeGenPrepare to SmallVector and increase the inline
capacity on the Visited SmallPtrSet. On 403.gcc, this is about a 4.5% speedup of
CodeGenPrepare time (which itself is 10% of time spent in the backend).

This is progress towards PR8889.

llvm-svn: 122741
2011-01-03 06:33:01 +00:00
Chris Lattner
9e5e9ed79a earlycse can do trivial with-a-block dead store
elimination as well.  This deletes 60 stores in 176.gcc
that largely come from bitfield code.

llvm-svn: 122736
2011-01-03 04:17:24 +00:00
Chris Lattner
4b9a525742 switch the load table to use a recycling bump pointer allocator,
speeding earlycse up by 6%.

llvm-svn: 122733
2011-01-03 03:53:50 +00:00
Chris Lattner
e0e32a9ef0 now that loads are in their own table, we can implement
store->load forwarding.  This allows EarlyCSE to zap 600 more
loads from 176.gcc.

llvm-svn: 122732
2011-01-03 03:46:34 +00:00
Chris Lattner
92bb0f9f9d split loads and calls into separate tables. Loads are now just indexed
by their pointer instead of using MemoryValue to wrap it.

llvm-svn: 122731
2011-01-03 03:41:27 +00:00
Chris Lattner
4cb365414f various cleanups, no functionality change.
llvm-svn: 122729
2011-01-03 03:28:23 +00:00
Chris Lattner
b9a8efc960 Teach EarlyCSE to do trivial CSE of loads and read-only calls.
On 176.gcc, this catches 13090 loads and calls, and increases the
number of simple instructions CSE'd from 29658 to 36208.

llvm-svn: 122727
2011-01-03 03:18:43 +00:00
Chris Lattner
79d83067ee rename InstValue to SimpleValue, add some comments.
llvm-svn: 122725
2011-01-03 02:20:48 +00:00
Michael J. Spencer
edb5bcdde5 CMake: Add missing source file.
llvm-svn: 122724
2011-01-03 02:13:05 +00:00
Chris Lattner
d815f69b30 Allocate nodes for the scoped hash table from a recyling bump pointer
allocator.  This speeds up early cse by about 20%

llvm-svn: 122723
2011-01-03 01:42:46 +00:00
Chris Lattner
02a9776b64 reduce redundancy in the hashing code and other misc cleanups.
llvm-svn: 122720
2011-01-03 01:10:08 +00:00
Cameron Zwarich
cab9a0abab Add a new loop-instsimplify pass, with the intention of replacing the instance
of instcombine that is currently in the middle of the loop pass pipeline. This
commit only checks in the pass; it will hopefully be enabled by default later.

llvm-svn: 122719
2011-01-03 00:25:16 +00:00
Chris Lattner
0844c76f9a fix some pastos
llvm-svn: 122718
2011-01-02 23:29:58 +00:00
Chris Lattner
8fac5db251 add DEBUG and -stats output to earlycse.
Teach it to CSE the rest of the non-side-effecting instructions.

llvm-svn: 122716
2011-01-02 23:19:45 +00:00
Chris Lattner
18ae5436b1 Enhance earlycse to do CSE of casts, instsimplify and die.
Add a testcase.

llvm-svn: 122715
2011-01-02 23:04:14 +00:00
Chris Lattner
bf0aa927cc split dom frontier handling stuff out to its own DominanceFrontier header,
so that Dominators.h is *just* domtree.  Also prune #includes a bit.

llvm-svn: 122714
2011-01-02 22:09:33 +00:00
Chris Lattner
704541bb23 sketch out a new early cse pass. No functionality yet.
llvm-svn: 122713
2011-01-02 21:47:05 +00:00
Chris Lattner
9c69406f2b fix a miscompilation of tramp3d-v4: when forming a memcpy, we have to make
sure that the loop we're promoting into a memcpy doesn't mutate the input
of the memcpy.  Before we were just checking that the dest of the memcpy
wasn't mod/ref'd by the loop.

llvm-svn: 122712
2011-01-02 21:14:18 +00:00
Chris Lattner
5702a43c09 If a loop iterates exactly once (has backedge count = 0) then don't
mess with it.  We'd rather peel/unroll it than convert all of its 
stores into memsets.

llvm-svn: 122711
2011-01-02 20:24:21 +00:00
Nick Lewycky
5361b84184 Also remove functions that use complex constant expressions in terms of
another function.

llvm-svn: 122705
2011-01-02 19:16:44 +00:00
Chris Lattner
8455b6e45e enhance loop idiom recognition to scan *all* unconditionally executed
blocks in a loop, instead of just the header block.  This makes it more
aggressive, able to handle Duncan's Ada examples.

llvm-svn: 122704
2011-01-02 19:01:03 +00:00
Chris Lattner
0cdc6f62a5 make inSubLoop much more efficient.
llvm-svn: 122703
2011-01-02 18:53:08 +00:00
Chris Lattner
27497ece96 rip out isExitBlockDominatedByBlockInLoop, calling DomTree::dominates instead.
isExitBlockDominatedByBlockInLoop is a relic of the days when domtree was 
*just* a tree and didn't have DFS numbers.  Checking DFS numbers is faster
and easier than "limiting the search of the tree".

llvm-svn: 122702
2011-01-02 18:45:39 +00:00
Chris Lattner
0469e01c02 add a list of opportunities for future improvement.
llvm-svn: 122701
2011-01-02 18:32:09 +00:00
Duncan Sands
64f1c0dcda Fix PR8702 by not having LoopSimplify claim to preserve LCSSA form. As described
in the PR, the pass could break LCSSA form when inserting preheaders.  It probably
would be easy enough to fix this, but since currently we always go into LCSSA form
after running this pass, doing so is not urgent.

llvm-svn: 122695
2011-01-02 13:38:21 +00:00
Chris Lattner
ddf58010bd Allow loop-idiom to run on multiple BB loops, but still only scan the loop
header for now for memset/memcpy opportunities.  It turns out that loop-rotate
is successfully rotating loops, but *DOESN'T MERGE THE BLOCKS*, turning "for 
loops" into 2 basic block loops that loop-idiom was ignoring.

With this fix, we form many *many* more memcpy and memsets than before, including
on the "history" loops in the viterbi benchmark, which look like this:

        for (j=0; j<MAX_history; ++j) {
          history_new[i][j+1] = history[2*i][j];
        }

Transforming these loops into memcpy's speeds up the viterbi benchmark from
11.98s to 3.55s on my machine.  Woo.

llvm-svn: 122685
2011-01-02 07:58:36 +00:00
Chris Lattner
5b5a043d82 remove debugging code.
llvm-svn: 122683
2011-01-02 07:37:13 +00:00
Chris Lattner
12f91befce add some -stats output.
llvm-svn: 122682
2011-01-02 07:36:44 +00:00
Chris Lattner
679572e584 improve loop rotation to use CodeMetrics to analyze the
size of a loop header instead of its own code size estimator.
This allows it to handle bitcasts etc more precisely.

llvm-svn: 122681
2011-01-02 07:35:53 +00:00