Commit Graph

4468 Commits

Author SHA1 Message Date
Chris Lattner
8e08e73f0e 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122711 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02 20:24:21 +00:00
Chris Lattner
62c50fdf69 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122704 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02 19:01:03 +00:00
Chris Lattner
81a866d615 make inSubLoop much more efficient.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122703 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02 18:53:08 +00:00
Chris Lattner
83fc584ea8 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".


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122702 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02 18:45:39 +00:00
Chris Lattner
bdce5720ad add a list of opportunities for future improvement.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122701 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02 18:32:09 +00:00
Chris Lattner
cf078f2b20 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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122685 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02 07:58:36 +00:00
Chris Lattner
6b04160dd8 remove debugging code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122683 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02 07:37:13 +00:00
Chris Lattner
4ce31fb574 add some -stats output.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122682 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02 07:36:44 +00:00
Chris Lattner
d9e079706e 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122681 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02 07:35:53 +00:00
Chris Lattner
e2c4392091 teach loop idiom recognition to form memcpy's from simple loops.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122678 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-02 03:37:56 +00:00
Chris Lattner
bafa117e8f add a validity check that was missed, fixing a crash on the
new testcase.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122662 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-01 20:12:04 +00:00
Chris Lattner
a64cbf067d improve validity check to handle constant-trip-count loops more
aggressively.  In practice, this doesn't help anything though,
see the todo.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122660 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-01 19:54:22 +00:00
Chris Lattner
30980b6815 implement the "no aliasing accesses in loop" safety check. This pass
should be correct now.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122659 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-01 19:39:01 +00:00
Chris Lattner
95ae676bc8 simplify this, isBytewiseValue handles the extra check. We still
check for "multiple of a byte" in size to make it clear that the
>> 3 below is safe.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122604 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-28 18:53:48 +00:00
Duncan Sands
7922d34b60 Silence gcc warning about an unused variable when doing a release build.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122593 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-28 09:41:15 +00:00
Chris Lattner
2e12f1ac6e fix some issues Frits noticed, add AliasAnalysis as a dependency
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122585 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-27 18:39:08 +00:00
Benjamin Kramer
a1bf4ca773 SimplifyLibCalls: Use IRBuilder to simplify code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122575 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-27 00:16:46 +00:00
Chris Lattner
9f39188def have loop-idiom nuke instructions that feed stores that get removed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122574 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-27 00:03:23 +00:00
Chris Lattner
a92ff91a96 implement enough of the memset inference algorithm to recognize and insert
memsets.  This is still missing one important validity check, but this is enough
to compile stuff like this:

void test0(std::vector<char> &X) {
  for (std::vector<char>::iterator I = X.begin(), E = X.end(); I != E; ++I)
    *I = 0;
}

void test1(std::vector<int> &X) {
  for (long i = 0, e = X.size(); i != e; ++i)
    X[i] = 0x01010101;
}

With:
 $ clang t.cpp -S -o - -O2 -emit-llvm | opt -loop-idiom | opt -O3 | llc 

to:

__Z5test0RSt6vectorIcSaIcEE:            ## @_Z5test0RSt6vectorIcSaIcEE
## BB#0:                                ## %entry
	subq	$8, %rsp
	movq	(%rdi), %rax
	movq	8(%rdi), %rsi
	cmpq	%rsi, %rax
	je	LBB0_2
## BB#1:                                ## %bb.nph
	subq	%rax, %rsi
	movq	%rax, %rdi
	callq	___bzero
LBB0_2:                                 ## %for.end
	addq	$8, %rsp
	ret
...
__Z5test1RSt6vectorIiSaIiEE:            ## @_Z5test1RSt6vectorIiSaIiEE
## BB#0:                                ## %entry
	subq	$8, %rsp
	movq	(%rdi), %rax
	movq	8(%rdi), %rdx
	subq	%rax, %rdx
	cmpq	$4, %rdx
	jb	LBB1_2
## BB#1:                                ## %for.body.preheader
	andq	$-4, %rdx
	movl	$1, %esi
	movq	%rax, %rdi
	callq	_memset
LBB1_2:                                 ## %for.end
	addq	$8, %rsp
	ret



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122573 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-26 23:42:51 +00:00
Chris Lattner
61db1f56d0 start using irbuilder to make mem intrinsics in a few passes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122572 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-26 22:57:41 +00:00
Chris Lattner
22920b5986 sketch more of this out.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122567 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-26 20:45:45 +00:00
Chris Lattner
bb89710ddd move isBytewiseValue out to ValueTracking.h/cpp
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122565 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-26 20:15:01 +00:00
Chris Lattner
e6bb649ec6 actually add the file...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122563 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-26 19:39:38 +00:00
Chris Lattner
b0db161f5b Start of a pass for recognizing memset and memcpy idioms.
No functionality yet.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122562 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-26 19:32:44 +00:00
Benjamin Kramer
3fed0d917d Simplify code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122561 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-26 15:23:45 +00:00
Benjamin Kramer
49c7e3e290 Fix a thinko pointed out by Frits van Bommel: looking through global variables in isBytewiseValue is not safe.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122550 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-24 22:23:59 +00:00
Benjamin Kramer
a112087e42 MemCpyOpt: Turn memcpys from a constant into a memset if possible.
This allows us to compile "int cst[] = {-1, -1, -1};" into
  movl  $-1, 16(%rsp)
  movq  $-1, 8(%rsp)
instead of
  movl  _cst+8(%rip), %eax
  movl  %eax, 16(%rsp)
  movq  _cst(%rip), %rax
  movq  %rax, 8(%rsp)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122548 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-24 21:17:12 +00:00
Owen Anderson
d5f8684b16 It is possible for SimplifyCFG to cause PHI nodes to become redundant too late in the optimization
pipeline to be caught by instcombine, and it's not feasible to catch them in SimplifyCFG because the
use-lists are in an inconsistent state at the point where it could know that it need to simplify them.
Instead, have CodeGenPrepare look for trivially redundant PHIs as part of its general cleanup effort.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122516 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-23 20:57:35 +00:00
Mon P Wang
e90a6333c3 Preserve the address space when generating bitcasts for MemTransferInst in ConvertToScalarInfo
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122462 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-23 01:41:32 +00:00
Jeffrey Yasskin
8e68c38735 Change all self assignments X=X to (void)X, so that we can turn on a
new gcc warning that complains on self-assignments and
self-initializations.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122458 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-23 00:58:24 +00:00
Owen Anderson
f056838956 Give GVN back the ability to perform simple conditional propagation on conditional branch values.
I still think that LVI should be handling this, but that capability is some ways off in the future,
and this matters for some significant benchmarks.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122378 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-21 23:54:34 +00:00
Owen Anderson
491e0307a8 Remove dead code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122371 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-21 22:31:24 +00:00
Benjamin Kramer
aad94aa437 GVN's Expression is not POD-like (it contains a SmallVector). Simplify code while at it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122362 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-21 21:30:19 +00:00
Chris Lattner
459f4f8c25 tidy up
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122190 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 20:24:28 +00:00
Chris Lattner
1dec0d2704 Enhance LICM to promote alias sets whose pointers themselves are stored,
which doesn't affect the memory address being promoted.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122172 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 05:57:25 +00:00
Chris Lattner
1c0af0ed25 fix PR8602, a bug in an assertion: a volatile store *of* a pointer
does not make the alias set for that pointer volatile, just stores
*to* the pointer.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122171 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 05:51:54 +00:00
Chris Lattner
a0d172f7fe revert r122164, I'm going to go with a different approach.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122168 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 04:23:03 +00:00
Chris Lattner
140f4a315b first step to fixing PR8642: don't fold away empty basic blocks
which have trapping constant exprs in them due to PHI nodes.
Eliminating them can cause the constant expr to be evalutated
on new paths if the input edges are critical.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122164 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-19 03:02:34 +00:00
Dan Gohman
c32046e6ea Revert r64460. strtol and friends cannot be marked readonly, even with
a null endptr argument, because they may write to errno.

This fixes a seflhost miscompile observed on Linux targets when TBAA
was enabled.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122014 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-17 01:09:43 +00:00
Frits van Bommel
01abcf339f Fix a bug in the loop in JumpThreading::ProcessThreadableEdges() where it could falsely produce a MultipleDestSentinel value if the first predecessor ended with an 'indirectbr'. If that happened, it caused an unnecessary FindMostPopularDest() call.
This wasn't a correctness problem, but it broke the fast path for single-predecessor blocks.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121966 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-16 12:16:00 +00:00
Dan Gohman
387f28aff4 Make memcpyopt TBAA-aware.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121944 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-16 02:51:19 +00:00
Dan Gohman
f4177aa019 Preserve TBAA tags when doing load PRE.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121921 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 23:53:55 +00:00
Dan Gohman
5034dd318a Move Value::getUnderlyingObject to be a standalone
function so that it can live in Analysis instead of
VMCore.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121885 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 20:02:24 +00:00
Frits van Bommel
26e097ca4b Teach jump threading to "look through" a select when the branch direction of a terminator depends on it.
When it sees a promising select it now tries to figure out whether the condition of the select is known in any of the predecessors and if so it maps the operands appropriately.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121859 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 09:51:20 +00:00
Owen Anderson
86e8a700f5 Fix PR8790, another instance where unreachable code can cause instruction simplification to fail,
this case involve a select that simplifies to itself.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121817 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 00:55:35 +00:00
Owen Anderson
93f83deba1 Cleanup trailing whitespace.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121816 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 00:52:44 +00:00
Chris Lattner
e991b5fdd5 simplify code and reduce indentation
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121670 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 02:38:13 +00:00
Chris Lattner
8fdca6a873 enhance memcpyopt to zap memcpy's that have the same src/dst.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121362 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-09 07:45:45 +00:00
Chris Lattner
f7f35467a9 fix PR8753, eliminating a case where we'd infinitely make a
substitution because it doesn't actually change the IR.  Patch by
Jakub Staszak!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121361 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-09 07:39:50 +00:00
Frits van Bommel
8e8cdc8fe0 Remove some dead code from the jump threading pass.
The last uses of these functions were removed in r113852 when LazyValueInfo was permanently enabled and removed the need for them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121133 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-07 13:08:07 +00:00