Commit Graph

76 Commits

Author SHA1 Message Date
Nuno Lopes ac59380dfd allow LazyValueInfo::getEdgeValue() to reason about multiple edges from the same switch instruction by doing union of ranges (which may still be conservative, but it's more aggressive than before)
llvm-svn: 157071
2012-05-18 21:02:10 +00:00
Nuno Lopes 097e37da0e minor simplification in the call to ConstantRange constructor
llvm-svn: 157024
2012-05-17 23:04:08 +00:00
Stepan Dyatkovskiy 97b02fc1b3 llvm::SwitchInst
Renamed methods caseBegin, caseEnd and caseDefault with case_begin, case_end, and case_default.
Added some notes relative to case iterators.

llvm-svn: 152532
2012-03-11 06:09:17 +00:00
Stepan Dyatkovskiy 5b648afb4d Taken into account Duncan's comments for r149481 dated by 2nd Feb 2012:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20120130/136146.html

Implemented CaseIterator and it solves almost all described issues: we don't need to mix operand/case/successor indexing anymore. Base iterator class is implemented as a template since it may be initialized either from "const SwitchInst*" or from "SwitchInst*".

ConstCaseIt is just a read-only iterator.
CaseIt is read-write iterator; it allows to change case successor and case value.

Usage of iterator allows totally remove resolveXXXX methods. All indexing convertions done automatically inside the iterator's getters.

Main way of iterator usage looks like this:
SwitchInst *SI = ... // intialize it somehow

for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd(); i != e; ++i) {
  BasicBlock *BB = i.getCaseSuccessor();
  ConstantInt *V = i.getCaseValue();
  // Do something.
}

If you want to convert case number to TerminatorInst successor index, just use getSuccessorIndex iterator's method.
If you want initialize iterator from TerminatorInst successor index, use CaseIt::fromSuccessorIndex(...) method.

There are also related changes in llvm-clients: klee and clang.

llvm-svn: 152297
2012-03-08 07:06:20 +00:00
Benjamin Kramer d9d80b1dde LVI: Recognize the form instcombine canonicalizes range checks into when forming constant ranges.
This could probably be made a lot smarter, but this is a common case and doesn't require LVI to scan a lot
of code. With this change CVP can optimize away the "shift == 0" case in Hashing.h that only gets hit when
"shift" is in a range not containing 0.

llvm-svn: 151919
2012-03-02 15:34:43 +00:00
Stepan Dyatkovskiy 513aaa5691 SwitchInst refactoring.
The purpose of refactoring is to hide operand roles from SwitchInst user (programmer). If you want to play with operands directly, probably you will need lower level methods than SwitchInst ones (TerminatorInst or may be User). After this patch we can reorganize SwitchInst operands and successors as we want.

What was done:

1. Changed semantics of index inside the getCaseValue method:
getCaseValue(0) means "get first case", not a condition. Use getCondition() if you want to resolve the condition. I propose don't mix SwitchInst case indexing with low level indexing (TI successors indexing, User's operands indexing), since it may be dangerous.
2. By the same reason findCaseValue(ConstantInt*) returns actual number of case value. 0 means first case, not default. If there is no case with given value, ErrorIndex will returned.
3. Added getCaseSuccessor method. I propose to avoid usage of TerminatorInst::getSuccessor if you want to resolve case successor BB. Use getCaseSuccessor instead, since internal SwitchInst organization of operands/successors is hidden and may be changed in any moment.
4. Added resolveSuccessorIndex and resolveCaseIndex. The main purpose of these methods is to see how case successors are really mapped in TerminatorInst.
4.1 "resolveSuccessorIndex" was created if you need to level down from SwitchInst to TerminatorInst. It returns TerminatorInst's successor index for given case successor.
4.2 "resolveCaseIndex" converts low level successors index to case index that curresponds to the given successor.

Note: There are also related compatability fix patches for dragonegg, klee, llvm-gcc-4.0, llvm-gcc-4.2, safecode, clang.
llvm-svn: 149481
2012-02-01 07:49:51 +00:00
Bill Wendling 75afc7afe8 Remove dead code.
llvm-svn: 148384
2012-01-18 10:10:28 +00:00
Bill Wendling 58c7569854 A DenseMap of a std::map isn't a very good idea because the "grow()" method will
need to make a deep copy of each of the std::maps. Use a std::map of the
std::map instead. This improves the compile time of sqlite3 by ~2%.

llvm-svn: 148003
2012-01-12 01:41:03 +00:00
Bill Wendling 4ec081a4d2 Revert r147978. A DenseMap's iterators may become invalidated here.
llvm-svn: 147980
2012-01-11 23:43:34 +00:00
Bill Wendling f0275df9e3 Use a DenseMap.
This appears to improve sqlite3's compile time by ~2%.

llvm-svn: 147978
2012-01-11 22:57:32 +00:00
Benjamin Kramer bbf3c60786 Clear the new cache.
llvm-svn: 145771
2011-12-03 15:19:55 +00:00
Benjamin Kramer 3664708378 Add a "seen blocks" cache to LVI to avoid a linear scan over the whole cache just to remove no blocks from the maps.
-15% on ARMDisassembler.cpp (Release build).  It's not that great to add another
layer of caching to the caching-heavy LVI but I don't see a better way.

llvm-svn: 145770
2011-12-03 15:16:45 +00:00
Chad Rosier 43a33066b4 Fix a few more places where TargetData/TargetLibraryInfo is not being passed.
Add FIXMEs to places that are non-trivial to fix.

llvm-svn: 145661
2011-12-02 01:26:24 +00:00
Chris Lattner 229907cd11 land David Blaikie's patch to de-constify Type, with a few tweaks.
llvm-svn: 135375
2011-07-18 04:54:35 +00:00
Eli Friedman 7a5fc693f9 llvm.memcpy.* has two distinct associated address spaces; the source address space, and the destination address space. Fix up the interface on MemIntrinsic and MemTransferInst to make this clear, and fix InstructionDereferencesPointer in LazyValueInfo.cpp to use the interface properly.
llvm-svn: 132356
2011-05-31 20:40:16 +00:00
Jay Foad 1a180156b6 Remove unused STL header includes.
llvm-svn: 130068
2011-04-23 19:53:52 +00:00
Chandler Carruth 2b1ba48f8d Mark some functions as used which are used within debug-only code. This
silences Clang's -Wunused-function when building in release mode.

llvm-svn: 129709
2011-04-18 18:49:44 +00:00
Nick Lewycky 367f98f000 Teach LazyValueInfo that allocas aren't NULL. Over all of llvm-test, this saves
half a million non-local queries, each of which would otherwise have triggered a
linear scan over a basic block.

Also fix a fixme for memory intrinsics which dereference pointers. With this,
we prove that a pointer is non-null because it was dereferenced by an intrinsic
112 times in llvm-test.

llvm-svn: 123533
2011-01-15 09:16:12 +00:00
Owen Anderson 6f060afbbd Reorder, rename, and document some members to make this easier to follow.
llvm-svn: 122929
2011-01-05 23:26:22 +00:00
Owen Anderson e86dacf449 When computing the value on an edge, in certain cases LVI would fail to compute the value range
in the predecessor block, leading to an incorrect conclusion for the edge value.  Found by inspection.

llvm-svn: 122908
2011-01-05 21:37:18 +00:00
Owen Anderson 118ac80c81 Re-convert several of LazyValueInfo's internal maps to Dense{Map|Set}, and fix the issue in
hasBlockValue() that was causing iterator invalidations.  Many thanks to Dimitry Andric for
tracking down those invalidations!

llvm-svn: 122906
2011-01-05 21:15:29 +00:00
Owen Anderson c6beda80ff Speculatively revert the use of DenseMap in LazyValueInfo, which may be causing Linux self-host failures.
llvm-svn: 122291
2010-12-20 23:53:19 +00:00
Owen Anderson 9be3ec6264 Attempt to appease the DragonEgg buildbots.
llvm-svn: 122288
2010-12-20 23:23:18 +00:00
Owen Anderson 813a2c45a8 Convert one of LVI's primary maps to a DenseMap, now that we know are more assured of iterator stability.
llvm-svn: 122273
2010-12-20 21:30:54 +00:00
Owen Anderson d83f98a51e More LVI cleanups, including trying to simplify the process of maintaining the OverDefinedCache.
llvm-svn: 122256
2010-12-20 19:33:41 +00:00
Owen Anderson 64c2c5798a Reuse the reference into the LVI cache throughout the solver subsystem. This is much easier to
verify as being safe thanks its recent de-recursivization.

llvm-svn: 122254
2010-12-20 18:18:16 +00:00
Nick Lewycky 55a700b0cf Make LazyValueInfo non-recursive.
llvm-svn: 122120
2010-12-18 01:00:40 +00:00
Dan Gohman a4fcd2418d Move Value::getUnderlyingObject to be a standalone
function so that it can live in Analysis instead of
VMCore.

llvm-svn: 121885
2010-12-15 20:02:24 +00:00
Nick Lewycky 11678bd299 Clean up some of LVI:
* mergeIn now uses constant folding for constants that are provably not-equal.
 * sink some sanity checks from the get*() methods into the mark*() methods, to ensure that we never have a constant/notconstant ConstantInt
 * some textual cleanups, whitespace changes, removing "else" after return, that sort of thing.

llvm-svn: 121877
2010-12-15 18:57:18 +00:00
Owen Anderson c7ed4dc932 Take the first step towards making LVI non-recursive: get rid of the LVIQuery abstraction.
llvm-svn: 121357
2010-12-09 06:14:58 +00:00
Owen Anderson df7a4f2515 Now with fewer extraneous semicolons!
llvm-svn: 115996
2010-10-07 22:25:06 +00:00
Owen Anderson 140296f5c0 It is possible, under specific circumstances involving ptrtoint ConstantExpr's, for LVI to end up trying to merge
a Constant into a ConstantRange.  Handle this conservatively for now, rather than asserting.  The testcase is
more complex that I would like, but the manifestation of the problem is sensitive to iteration orders and the state of the
LVI cache, and I have not been able to reproduce it with manually constructed or simplified cases.

Fixes PR8162.

llvm-svn: 114103
2010-09-16 18:28:33 +00:00
Owen Anderson a74fa15f32 Clean up some of the PassRegistry implementation, and pImpl-ize it to reduce #include clutter
and exposing internal details.

llvm-svn: 113252
2010-09-07 19:16:25 +00:00
Nick Lewycky ad48e01eef Add completely hokey binary-and and binary-or operations to ConstantRange and
teach LazyValueInfo to use them.

llvm-svn: 113196
2010-09-07 05:39:02 +00:00
Chris Lattner 65b48b5dfc zap dead code.
llvm-svn: 113073
2010-09-04 18:12:00 +00:00
Owen Anderson c725462245 Add support for simplifying a load from a computed value to a load from a global when it
is provable that they're equivalent.  This fixes PR4855.

llvm-svn: 112994
2010-09-03 19:08:37 +00:00
Owen Anderson 2912df072d Remove incorrect and poorly tested code for trying to reason about values on default edges of
switches.  Just return the conservatively correct answer.

llvm-svn: 112876
2010-09-02 22:16:52 +00:00
Owen Anderson a8c896b704 Fix a bug in LazyValueInfo that CorrelatedValuePropagation exposed: In the LVI lattice, undef and the full set ConstantRange should not
be treated as equivalent.

llvm-svn: 112843
2010-09-02 18:23:58 +00:00
Owen Anderson 9517943d11 It is possible to try to merge a not-constant with a constantrage, when dealing with ptrtoint ConstantExpr's.
Unfortunately, the only testcase I have for this is huge and doesn't reduce well because the error is
sensitive to iteration-order issues, since the problem only occurs when merging values in a particular order.

llvm-svn: 112489
2010-08-30 17:03:45 +00:00
Owen Anderson 38f6b7fe3b Improve the precision of getConstant().
llvm-svn: 112323
2010-08-27 23:29:38 +00:00
Owen Anderson 6ebbd92380 Use LVI to eliminate conditional branches where we've tested a related condition previously. Update tests for this change.
This fixes PR5652.

llvm-svn: 112270
2010-08-27 17:12:29 +00:00
Owen Anderson 4afea9e3c6 In the default address space, any GEP off of null results in a trap value if you try to load it. Thus,
any load in the default address space that completes implies that the base value that it GEP'd from
was not null.

llvm-svn: 112015
2010-08-25 01:16:47 +00:00
Owen Anderson a10000006e NULL loads are only invalid in the default address space.
llvm-svn: 111972
2010-08-24 22:00:55 +00:00
Owen Anderson b695c83de9 Add support for inferring values for the default cases of switches.
llvm-svn: 111971
2010-08-24 21:59:42 +00:00
Owen Anderson da34de1599 Add support for inferring that a load from a pointer implies that it is not null.
llvm-svn: 111959
2010-08-24 20:47:29 +00:00
Owen Anderson c62f704576 Don't assume that all constants with integer types are ConstantInts.
llvm-svn: 111906
2010-08-24 07:55:44 +00:00
Owen Anderson 80d19f0905 Use ConstantRange to propagate information through value definitions.
llvm-svn: 111425
2010-08-18 21:11:37 +00:00
Owen Anderson 208636fa33 Inform LazyValueInfo whenever a block is deleted, to avoid dangling pointer issues.
llvm-svn: 111382
2010-08-18 18:39:01 +00:00
Owen Anderson fa7d44687f Fix another iterator invalidation that caused a *really* nasty miscompilation in 403.gcc.
llvm-svn: 111210
2010-08-16 23:42:33 +00:00
Owen Anderson 7b974a45db Fix a subtle use-after-free issue.
llvm-svn: 110863
2010-08-11 22:36:04 +00:00