We have to be careful when splitting the landing pad block, because the
landingpad instruction is required to remain as the first non-PHI of an invoke's
unwind edge. To retain this, we split the block into two blocks, moving the
predecessors within the loop to one block and the remaining predecessors to the
other. The landingpad instruction is cloned into the new blocks.

llvm-svn: 138015

SplitLandingPadPredecessors is similar to SplitBlockPredecessors in that it
splits the current block and attaches a set of predecessors to the new basic
block. However, it differs from SplitBlockPredecessors in that it's specifically
designed to handle landing pad blocks.

Two new basic blocks are created: one that is has the vector of predecessors as
its predecessors and one that has the remaining predecessors as its
predecessors. Those two new blocks then receive a cloned copy of the landingpad
instruction from the original block. The landingpad instructions are joined in a
PHI, etc. Like SplitBlockPredecessors, it updates the LLVM IR, AliasAnalysis,
DominatorTree, DominanceFrontier, LoopInfo, and LCCSA analyses.

llvm-svn: 138014

llvm-svn: 138008

llvm-svn: 137985

aren't from an indirect branch need to be dominated by the loop header.

llvm-svn: 137981

function.

llvm-svn: 137979

llvm-svn: 137978

of debug info.

llvm-svn: 137972

llvm-svn: 137959

functionality change.

llvm-svn: 137926

Dramatically speedup codegen prepare by a) avoiding use of dominator tree and b) doing a separate pass over dbg.value instructions.

llvm-svn: 137908

llvm-svn: 137890

llvm-svn: 137888

PRE needs the landing pads to have their critical edges split. Doing this for a
landing pad is non-trivial. Abandon the attempt to perform PRE when we come
across a landing pad. (Reviewed by Owen!)

llvm-svn: 137876

llvm-svn: 137872

One way to exit the loop is through an unwind edge. However, that may involve
splitting the critical edge of the landing pad, which is non-trivial. Prevent
the transformation from rewriting the landing pad exit loop block.

llvm-svn: 137871

so requires more care than this generic algorithm should handle.

llvm-svn: 137866

instruction should be marked as potentially reading and/or writing memory.

llvm-svn: 137863

Silly mistake from r137777; restore significant isStructTy() checks.  While here, be a bit more defensive
with unknown instructions.

Fixes PR10687.

llvm-svn: 137836

making random bad assumptions about instructions which are not explicitly listed.  

Includes fix for rdar://9956541, a version of "undef ^ undef should return
0 because it's easier than arguing with users".

llvm-svn: 137777

Minor bug in SCCP found by inspection.  (I don't think it's possible to hit this with a normal pass pipeline, but fixing for completeness.)

llvm-svn: 137755

check for a LandingPadInst.

llvm-svn: 137745

llvm-svn: 137743

Add a mechanism for optimisation plugins to register passes that all front ends can use without needing to be aware of the plugin (or the plugin be aware of the front end).

Before 3.0, I'd like to add a mechanism for automatically loading a set of plugins from a config file.  API suggestions welcome...

llvm-svn: 137717

llvm-svn: 137712

llvm-svn: 137702

to be wrong (or at least somewhat suspect).  Leave a FIXME for Bill.

llvm-svn: 137694

llvm-svn: 137693

This commit includes a mention of the landingpad instruction, but it's not
changing the behavior around it.  I think the current behavior is correct,
though.  Bill, can you double-check that?

llvm-svn: 137691

llvm-svn: 137690

llvm-svn: 137679

llvm-svn: 137672

llvm-svn: 137667

llvm-svn: 137664

write to memory.) Marking it as such makes some checks for immobility go away.

llvm-svn: 137655

llvm-svn: 137654

llvm-svn: 137648

llvm-svn: 137642

llvm-svn: 137629

llvm-svn: 137627