Fix an infinite alternation in JumpThreading where two transforms would repeatedly undo each other. The solution is to perform more aggressive constant folding to make one of the edges just folded a

Fix an infinite alternation in JumpThreading where two transforms would repeatedly undo each other. The solution is to perform more aggressive constant folding to make one of the edges just folded away rather than trying to thread it.
Fixes <rdar://problem/9284786>.

Discovered with CSmith.

llvm-svn: 129538

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Remove PHINode::reserveOperandSpace(). Instead, add a parameter to
PHINode::Create() giving the (known or expected) number of operands.

llvm-svn: 128537

(Almost) always call reserveOperandSpace() on newly created PHINodes.

llvm-svn: 128535

prevent jump threading from merging blocks when their address is
taken (and used!). This prevents merging the blocks (invalidating
the block addresses) in a case like this:

#define _THIS_IP_ ({ __

prevent jump threading from merging blocks when their address is
taken (and used!). This prevents merging the blocks (invalidating
the block addresses) in a case like this:

#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })

void foo() {
printf("%p\n", _THIS_IP_);
printf("%p\n", _THIS_IP_);
printf("%p\n", _THIS_IP_);
}

which fixes PR4151.

llvm-svn: 125829

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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

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.

llvm-svn: 121966

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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

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.

llvm-svn: 121859

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simplify code and reduce indentation

llvm-svn: 121670

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.

llvm-svn: 1211

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.

llvm-svn: 121133

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Implement jump threading of 'indirectbr' by keeping track of whether we're looking for ConstantInt*s or BlockAddress*s.

llvm-svn: 121066

Refactor jump threading.
Should have no functional change other than the order of two transformations that are mutually-exclusive and the exact formatting of debug output.
Internally, it now stores t

Refactor jump threading.
Should have no functional change other than the order of two transformations that are mutually-exclusive and the exact formatting of debug output.
Internally, it now stores the ConstantInt*s as Constant*s, and actual undef values instead of nulls.

llvm-svn: 120946

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Remove trailing whitespace.

llvm-svn: 120945

Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which
must be called in the pass's constructor. This function uses static dependency

Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which
must be called in the pass's constructor. This function uses static dependency declarations to recursively initialize
the pass's dependencies.

Clients that only create passes through the createFooPass() APIs will require no changes. Clients that want to use the
CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h
before parsing commandline arguments.

I have tested this with all standard configurations of clang and llvm-gcc on Darwin. It is possible that there are problems
with the static dependencies that will only be visible with non-standard options. If you encounter any crash in pass
registration/creation, please send the testcase to me directly.

llvm-svn: 116820

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Begin adding static dependence information to passes, which will allow us to
perform initialization without static constructors AND without explicit initialization
by the client. For the moment, pas

Begin adding static dependence information to passes, which will allow us to
perform initialization without static constructors AND without explicit initialization
by the client. For the moment, passes are required to initialize both their
(potential) dependencies and any passes they preserve. I hope to be able to relax
the latter requirement in the future.

llvm-svn: 116334

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Now with fewer extraneous semicolons!

llvm-svn: 115996

Fix PR8247: JumpThreading can cause a block to become unreachable while still having predecessor, if it is part of a self-loop.
Because of this, we cannot use the Simplify* APIs, as they can assert-f

Fix PR8247: JumpThreading can cause a block to become unreachable while still having predecessor, if it is part of a self-loop.
Because of this, we cannot use the Simplify* APIs, as they can assert-fail on unreachable code. Since it's not easy to determine
if a given threading will cause a block to become unreachable, simply defer simplifying simplification to later InstCombine and/or
DCE passes.

llvm-svn: 115082

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Remove the option to disable LazyValueInfo in JumpThreading, as it is now
on by default and has received significant testing.

llvm-svn: 113852

Change lower atomic pass to use IntrinsicInst to simplify it a bit.

llvm-svn: 113114

eliminate some non-obvious casts. UndefValue isa Constant.

llvm-svn: 113113

Reapply commit 112699, speculatively reverted by echristo, since
I'm sure it is harmless. Original commit message:
If PrototypeValue is erased in the middle of using the SSAUpdator
then the SSAUpdat

Reapply commit 112699, speculatively reverted by echristo, since
I'm sure it is harmless. Original commit message:
If PrototypeValue is erased in the middle of using the SSAUpdator
then the SSAUpdator may access freed memory. Instead, simply pass
in the type and name explicitly, which is all that was used anyway.

llvm-svn: 112810

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JumpThreading keeps LazyValueInfo up to date, so we don't need to rerun it
if we schedule another LVI-using pass afterwards.

llvm-svn: 112722

Speculatively revert 112699 and 112702, they seem to be causing
self host errors on clang-x86-64.

llvm-svn: 112719

If PrototypeValue is erased in the middle of using the SSAUpdator
then the SSAUpdator may access freed memory. Instead, simply pass
in the type and name explicitly, which is all that was used anyway

If PrototypeValue is erased in the middle of using the SSAUpdator
then the SSAUpdator may access freed memory. Instead, simply pass
in the type and name explicitly, which is all that was used anyway.

llvm-svn: 112699

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More cleanups of my JumpThreading transforms, including extracting some duplicated code into a helper function.

llvm-svn: 112634

Add an RAII helper to make cleanup of the RecursionSet more fool-proof.

llvm-svn: 112628

Refactor my fix for PR5652 to terminate the predecessor lookups after the first failure.

llvm-svn: 112620