Commit Graph

4455 Commits

Author SHA1 Message Date
NAKAMURA Takumi
4bf4c738e8 llvm/test/Transforms/InstCombine/sdiv-1.ll: FileCheck-ize.
"not grep '-715827882'" performed as below...bad...

Usage: grep [OPTION]... PATTERN [FILE]...
Try `grep --help' for more information.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168430 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-21 14:46:18 +00:00
Chandler Carruth
07df765e65 PR14055: Implement support for sub-vector operations in SROA.
Now if we can transform an alloca into a single vector value, but it has
subvector, non-element accesses, we form the appropriate shufflevectors
to allow SROA to proceed. This fixes PR14055 which pointed out a very
common pattern that SROA couldn't handle -- mixed vec3 and vec4
operations on a single alloca.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168418 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-21 08:16:30 +00:00
Chandler Carruth
176792990e Fix PR14132 and handle OOB loads speculated throuh PHI nodes.
The issue is that we may end up with newly OOB loads when speculating
a load into the predecessors of a PHI node, and this confuses the new
integer splitting logic in some cases, triggering an assertion failure.
In fact, the branch in question must be dead code as it loads from
a too-narrow alloca. Add code to handle this gracefully and leave the
requisite FIXMEs for both optimizing more aggressively and doing more to
aid sanitizing invalid code which triggers these patterns.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168361 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-20 10:02:19 +00:00
Chandler Carruth
f5837aacd4 Rework the rewriting of loads and stores for vector and integer allocas
to properly handle the combinations of these with split integer loads
and stores. This essentially replaces Evan's r168227 by refactoring the
code in a different way, and trynig to mirror that refactoring in both
the load and store sides of the rewriting.

Generally speaking there was some really problematic duplicated code
here that led to poorly founded assumptions and then subtle bugs. Now
much of the code actually flows through and follows a more consistent
style and logical path. There is still a tiny bit of duplication on the
store side of things, but it is much less bad.

This also changes the logic to never re-use a load or store instruction
as that was simply too error prone in practice.

I've added a few tests (one a reduction of the one in Evan's original
patch, which happened to be the same as the report in PR14349). I'm
going to look at adding a few more tests for things I found and fixed in
passing (such as the volatile tests in the vectorizable predicate).

This patch has survived bootstrap, and modulo one bugfix survived
Duncan's test suite, but let me know if anything else explodes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168346 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-20 01:12:50 +00:00
Duncan Sands
b8e1111fbf Fix PR14060, an infinite loop in reassociate. The problem was that one of the
operands of the expression being written was wrongly thought to be reusable as
an inner node of the expression resulting in it turning up as both an inner node
*and* a leaf, creating a cycle in the def-use graph.  This would have caused the
verifier to blow up if things had gotten that far, however it managed to provoke
an infinite loop first.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168291 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-18 19:27:01 +00:00
Nick Lewycky
294c965146 Don't try to calculate the alignment of an unsigned type. Fixes PR14371!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168280 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-18 05:39:39 +00:00
Nadav Rotem
9a6823516f LoopVectorizer: Add initial support for pointer induction variables (for example: *dst++ = *src++).
At the moment we still require to have an integer induction variable (for example: i++).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168231 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-17 00:27:03 +00:00
Evan Cheng
fd22019ec3 Teach SROA rewriteVectorizedStoreInst to handle cases when the loaded value is narrower than the stored value. rdar://12713675
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168227 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-17 00:05:06 +00:00
Duncan Sands
aceb03eb58 InstructionSimplify should be able to simplify A+B==B+A to 'true'
but wasn't due to the same logic bug that caused PR14361.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168186 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-16 19:41:26 +00:00
Duncan Sands
afe4539f8e Fix PR14361: wrong simplification of A+B==B+A. You may think that the old logic
replaced by this patch is equivalent to the new logic, but you'd be wrong, and
that's exactly where the bug was.  There's a similar bug in instsimplify which
manifests itself as instsimplify failing to simplify this, rather than doing it
wrong, see next commit.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168181 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-16 18:55:49 +00:00
Hans Wennborg
fbeb956876 Constant::IsThreadDependent(): Use dyn_cast<Constant> instead of cast
It turns out that the operands of a Constant are not always themselves
Constant. For example, one of the operands of BlockAddress is
BasicBlock, which is not a Constant.

This should fix the dragonegg-x86_64-linux-gcc-4.6-test build which
broke in r168037.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168147 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-16 10:33:25 +00:00
Hans Wennborg
1839858983 Make GlobalOpt be conservative with TLS variables (PR14309)
For global variables that get the same value stored into them
everywhere, GlobalOpt will replace them with a constant. The problem is
that a thread-local GlobalVariable looks like one value (the address of
the TLS var), but is different between threads.

This patch introduces Constant::isThreadDependent() which returns true
for thread-local variables and constants which depend on them (e.g. a GEP
into a thread-local array), and teaches GlobalOpt not to track such
values.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168037 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-15 11:40:00 +00:00
Duncan Sands
7ecfcc1639 Fix a crash observed by Shuxin Yang. The issue here is that LinearizeExprTree,
the utility for extracting a chain of operations from the IR, thought that it
might as well combine any constants it came across (rather than just returning
them along with everything else).  On the other hand, the factorization code
would like to see the individual constants (this is quite reasonable: it is
much easier to pull a factor of 3 out of 2*3 than it is to pull it out of 6;
you may think 6/3 isn't so hard, but due to overflow it's not as easy to undo
multiplications of constants as it may at first appear).  This patch therefore
makes LinearizeExprTree stupider: it now leaves optimizing to the optimization
part of reassociate, and sticks to just analysing the IR.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168035 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-15 09:58:38 +00:00
Jakub Staszak
de7c8530c8 Remove DOS line endings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167968 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-14 20:18:34 +00:00
Duncan Sands
707276d415 Fix the instcombine GEP index widening transform to work correctly for vector
getelementptrs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167829 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-13 13:01:00 +00:00
Duncan Sands
2333e29be4 Relax the restrictions on vector of pointer types, and vector getelementptr.
Previously in a vector of pointers, the pointer couldn't be any pointer type,
it had to be a pointer to an integer or floating point type.  This is a hassle
for dragonegg because the GCC vectorizer happily produces vectors of pointers
where the pointer is a pointer to a struct or whatever.  Vector getelementptr
was restricted to just one index, but now that vectors of pointers can have
any pointer type it is more natural to allow arbitrary vector getelementptrs.
There is however the issue of struct GEPs, where if each lane chose different
struct fields then from that point on each lane will be working down into
unrelated types.  This seems like too much pain for too little gain, so when
you have a vector struct index all the elements are required to be the same.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167828 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-13 12:59:33 +00:00
Alexey Samsonov
009c4d86c1 Figure out <size> argument of llvm.lifetime intrinsics at the moment they are created (during function inlining)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167821 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-13 07:15:32 +00:00
Meador Inge
2920a71663 instcombine: Migrate math library call simplifications
This patch migrates the math library call simplifications from the
simplify-libcalls pass into the instcombine library call simplifier.

I have typically migrated just one simplifier at a time, but the math
simplifiers are interdependent because:

   1. CosOpt, PowOpt, and Exp2Opt all depend on UnaryDoubleFPOpt.
   2. CosOpt, PowOpt, Exp2Opt, and UnaryDoubleFPOpt all depend on
      the option -enable-double-float-shrink.

These two factors made migrating each of these simplifiers individually
more of a pain than it would be worth.  So, I migrated them all together.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167815 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-13 04:16:17 +00:00
Hal Finkel
4387b8c959 BBVectorize: Don't vectorize vector-manipulation chains
Don't choose a vectorization plan containing only shuffles and
vector inserts/extracts. Due to inperfections in the cost model,
these can lead to infinite recusion.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167811 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-13 03:12:40 +00:00
Shuxin Yang
4df2826166 revert r167740
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167787 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-13 00:08:49 +00:00
Hal Finkel
b2b2469a91 BBVectorize: Only some insert element operand pairs are free.
This fixes another infinite recursion case when using target costs.
We can only replace insert element input chains that are pure (end
with inserting into an undef).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167784 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-12 23:55:36 +00:00
Hal Finkel
86c88c938a BBVectorize: Use a more sophisticated check for input cost
The old checking code, which assumed that input shuffles and insert-elements
could always be folded (and thus were free) is too simple.
This can only happen in special circumstances.
Using the simple check caused infinite recursion.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167750 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-12 21:21:02 +00:00
Hal Finkel
5094257518 BBVectorize: Check the types of compare instructions
The pass would previously assert when trying to compute the cost of
compare instructions with illegal vector types (like struct pointers).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167743 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-12 19:41:38 +00:00
Shuxin Yang
0a46bf13a3 This change is to fix rdar://12571717 which is about assertion in Reassociate pass.
The assertion is trigged when the Reassociater tries to transform expression
     ... + 2 * n * 3 + 2 * m + ...
  into:
     ... + 2 * (n*3 + m).

In the process of the transformation, a helper routine folds the constant 2*3 into 6,
confusing optimizer which is trying the to eliminate the common factor 2, and cannot
find 2 any more. 

Review is pending. But I'd like commit first in order to help those who are waiting 
for this fix. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167740 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-12 19:34:11 +00:00
Hal Finkel
8b9796f4f8 BBVectorize: Check the input types of shuffles for legality
This fixes a bug where shuffles were being fused such that the
resulting input types were not legal on the target. This would
occur only when both inputs and dependencies were also foldable
operations (such as other shuffles) and there were other connected
pairs in the same block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167731 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-12 14:50:59 +00:00
Meador Inge
30d8f0e977 Normalize memcmp constant folding results.
The library call simplifier folds memcmp calls with all constant arguments
to a constant.  For example:

  memcmp("foo", "foo", 3) ->  0
  memcmp("hel", "foo", 3) ->  1
  memcmp("foo", "hel", 3) -> -1

The folding is implemented in terms of the system memcmp that LLVM gets
linked with.  It currently just blindly uses the value returned from
the system memcmp as the folded constant.

This patch normalizes the values returned from the system memcmp to
(-1, 0, 1) so that we get consistent results across multiple platforms.
The test cases were adjusted accordingly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167726 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-12 14:00:45 +00:00
Meador Inge
0c4cbc33dd Remove hard-coded constant in Transforms/InstCombine/memcmp-1.ll
Transforms/InstCombine/memcmp-1.ll has a test case that looks like:

  @foo = constant [4 x i8] c"foo\00"
  @hel = constant [4 x i8] c"hel\00"

  ...

  %mem1 = getelementptr [4 x i8]* @hel, i32 0, i32 0
  %mem2 = getelementptr [4 x i8]* @foo, i32 0, i32 0
  %ret = call i32 @memcmp(i8* %mem1, i8* %mem2, i32 3)
  ret i32 %ret
  ; CHECK: ret i32 2

The folded return value (2 above) is computed using the system memcmp
that the compiler is linked with.  This can return different values on
different systems.  The test was originally written on an OS X 10.7.5
x86-64 box and passed.  However, it failed on one of the x86-64 FreeBSD
buildbots because the system memcpy on that machine returned a different
value (1 instead of 2).

I fixed the test by checking the folding constants with regexes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167691 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-11 07:10:25 +00:00
Meador Inge
26ebe398f2 instcombine: Migrate memset optimizations
This patch migrates the memset optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167689 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-11 06:49:03 +00:00
Meador Inge
d7cb600514 instcombine: Migrate memmove optimizations
This patch migrates the memmove optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167687 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-11 06:22:40 +00:00
Meador Inge
11b04b40f2 instcombine: Migrate memcpy optimizations
This patch migrates the memcpy optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167686 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-11 05:54:34 +00:00
Meador Inge
bb51ec8b62 instcombine: Migrate memcmp optimizations
This patch migrates the memcmp optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167683 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-11 05:11:20 +00:00
Meador Inge
6e1591a5d5 instcombine: Migrate strstr optimizations
This patch migrates the strstr optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167682 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-11 03:51:48 +00:00
Meador Inge
5464ee7eaa instcombine: Migrate strcspn optimizations
This patch migrates the strcspn optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167675 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-10 15:16:48 +00:00
Meador Inge
e29c88064f instcombine: Query target library information to gate libcall simplifications
Several of the simplifiers migrated from the simplify-libcalls pass to
the instcombine pass were not correctly checking the target library
information to gate the simplifications.  This patch ensures that the
check is made.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167660 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-10 03:11:10 +00:00
Nadav Rotem
b1bf1eeede Add support for memory runtime check. When we can, we calculate array bounds.
If the arrays are found to be disjoint then we run the vectorized version of
the loop. If they are not, we run the scalar code.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167608 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-09 07:09:44 +00:00
NAKAMURA Takumi
562b1d883f llvm/ConstantFolding.cpp: Make ReadDataFromGlobal() and FoldReinterpretLoadFromConstPtr() Big-endian-aware.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167595 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-08 20:34:25 +00:00
Meador Inge
7629de3326 instcombine: Migrate strspn optimizations
This patch migrates the strspn optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167568 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-08 01:33:50 +00:00
Hans Wennborg
b0319962cf Only do switch-to-lookup table transformation when TargetTransformInfo
is available.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167552 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-07 21:35:12 +00:00
Hans Wennborg
ab1b6c83ad Fix bad test IR in switch_to_lookup_table.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167543 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-07 18:38:24 +00:00
Nadav Rotem
b042868c01 Cost Model: add tables for some avx type-conversion hacks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167480 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-06 19:33:53 +00:00
Nadav Rotem
2d1528b358 Code Model: Improve the accuracy of the zext/sext/trunc vector cost estimation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167412 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-05 22:20:53 +00:00
Nadav Rotem
e623702c22 Implement the cost of abnormal x86 instruction lowering as a table.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167395 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-05 19:32:46 +00:00
Duncan Sands
c5b969a019 Generalize the transform that boosts GEP indices to the size of a pointer to
also do it for vectors of pointers.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167354 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-03 11:44:17 +00:00
Chandler Carruth
52df6c2eec Add a testcase to loop-idiom to cover PR14241 when we start handling
strided loops again.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167287 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-02 08:40:24 +00:00
Chandler Carruth
a864748284 Revert the switch of loop-idiom to use the new dependence analysis.
The new analysis is not yet ready for prime time. It has a *critical*
flawed assumption, and some troubling shortages of testing. Until it's
been hammered into better shape, let's stick with the working code. This
should be easy to revert itself when the analysis is ready.

Fixes PR14241, a miscompile of any memcpy-able loop which uses a pointer
as the induction mechanism. If you have been seeing miscompiles in this
revision range, you really want to test with this backed out. The
results of this miscompile are a bit subtle as they can lead to
downstream passes concluding things are impossible which are in fact
possible.

Thanks to David Blaikie for the majority of the reduction of this
miscompile. I'll be checking in the test case in a non-revert commit.

Revesions reverted here:

r167045: LoopIdiom: Fix a serious missed optimization: we only turned
         top-level loops into memmove.
r166877: LoopIdiom: Add checks to avoid turning memmove into an infinite
         loop.
r166875: LoopIdiom: Recognize memmove loops.
r166874: LoopIdiom: Replace custom dependence analysis with
         DependenceAnalysis.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167286 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-02 08:33:25 +00:00
Hal Finkel
4ac300dfac BBVectorize: Commit the rest of the test-case change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167257 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-01 21:57:27 +00:00
Hal Finkel
78fd353d5e BBVectorize: Use target costs for incoming and outgoing values instead of the depth heuristic.
When target cost information is available, compute explicit costs of inserting and
extracting values from vectors. At this point, all costs are estimated using the
target information, and the chain-depth heuristic is not needed. As a result, it is now, by
default, disabled when using target costs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167256 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-01 21:50:12 +00:00
Chandler Carruth
9cb285d510 Add a test case for PR14233.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167224 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-01 10:26:36 +00:00
Chandler Carruth
ece6c6bb63 Revert the series of commits starting with r166578 which introduced the
getIntPtrType support for multiple address spaces via a pointer type,
and also introduced a crasher bug in the constant folder reported in
PR14233.

These commits also contained several problems that should really be
addressed before they are re-committed. I have avoided reverting various
cleanups to the DataLayout APIs that are reasonable to have moving
forward in order to reduce the amount of churn, and minimize the number
of commits that were reverted. I've also manually updated merge
conflicts and manually arranged for the getIntPtrType function to stay
in DataLayout and to be defined in a plausible way after this revert.

Thanks to Duncan for working through this exact strategy with me, and
Nick Lewycky for tracking down the really annoying crasher this
triggered. (Test case to follow in its own commit.)

After discussing with Duncan extensively, and based on a note from
Micah, I'm going to continue to back out some more of the more
problematic patches in this series in order to ensure we go into the
LLVM 3.2 branch with a reasonable story here. I'll send a note to
llvmdev explaining what's going on and why.

Summary of reverted revisions:

r166634: Fix a compiler warning with an unused variable.
r166607: Add some cleanup to the DataLayout changes requested by
         Chandler.
r166596: Revert "Back out r166591, not sure why this made it through
         since I cancelled the command. Bleh, sorry about this!
r166591: Delete a directory that wasn't supposed to be checked in yet.
r166578: Add in support for getIntPtrType to get the pointer type based
         on the address space.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167221 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-01 08:07:29 +00:00
Nadav Rotem
e57b2cbce6 LoopVectorize: Preserve NSW, NUW and IsExact flags.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167174 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-31 21:40:39 +00:00