Take this opportunity to generalize the indirectbr bailout logic for
loop transformations. CFG transformations will never get indirectbr
right, and there's no point trying.
llvm-svn: 154386
into Analysis as a standalone function, since there's no need for
it to be in VMCore. Also, update it to use isKnownNonZero and
other goodies available in Analysis, making it more precise,
enabling more aggressive optimization.
llvm-svn: 146610
The loop tree's inclusive block lists are painful and expensive to
update. (I have no idea why they're inclusive). The design was
supposed to handle this case but the implementation missed it and my
unit tests weren't thorough enough.
Fixes PR11335: loop unroll update.
llvm-svn: 144970
ancestor loops.
I have a unit test that depends on scev-unroll, which unfortunately
isn't checked in. But I will check it in when I can.
llvm-svn: 137341
An algorithm for incrementally updating LoopInfo within a
LoopPassManager. The incremental update should be extremely cheap in
most cases and can be used in places where it's not feasible to
regenerate the entire loop forest.
- "Unloop" is a node in the loop tree whose last backedge has been removed.
- Perform reverse dataflow on the block inside Unloop to propagate the
nearest loop from the block's successors.
- For reducible CFG, each block in unloop is visited exactly
once. This is because unloop no longer has a backedge and blocks
within subloops don't change parents.
- Immediate subloops are summarized by the nearest loop reachable from
their exits or exits within nested subloops.
- At completion the unloop blocks each have a new parent loop, and
each immediate subloop has a new parent.
llvm-svn: 137276
LoopPassManager. The incremental update should be extremely cheap in
most cases and can be used in places where it's not feasible to
regenerate the entire loop forest.
- "Unloop" is a node in the loop tree whose last backedge has been removed.
- Perform reverse dataflow on the block inside Unloop to propagate the
nearest loop from the block's successors.
- For reducible CFG, each block in unloop is visited exactly
once. This is because unloop no longer has a backedge and blocks
within subloops don't change parents.
- Immediate subloops are summarized by the nearest loop reachable from
their exits or exits within nested subloops.
- At completion the unloop blocks each have a new parent loop, and
each immediate subloop has a new parent.
llvm-svn: 136844
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
Loop::hasLoopInvariantOperands method. Remove
a useless and confusing Loop::isLoopInvariant(Instruction)
method, which didn't do what you thought it did.
No functionality change.
llvm-svn: 113133
contains another loop, or an instruction. The loop form is
substantially more efficient on large loops than the typical
code it replaces.
llvm-svn: 91654
container of the blocks and do efficient lookups. This makes
isLoopSimplifyForm much faster on large loops, fixing a significant
compile-time issue in builds with assertions enabled.
llvm-svn: 84673
the PassManager code into a regular verifyAnalysis method.
Also, reorganize loop verification. Make the LoopPass infrastructure
call verifyLoop as needed instead of having LoopInfo::verifyAnalysis
check every loop in the function after each looop pass. Add a new
command-line argument, -verify-loop-info, to enable the expensive
full checking.
llvm-svn: 82952
that get created during loop unswitching, and fix SplitBlockPredecessors'
LCSSA updating code to create new PHIs instead of trying to just move
existing ones.
Also, optimize Loop::verifyLoop, since it gets called a lot. Use
searches on a sorted list of blocks instead of calling the "contains"
function, as is done in other places in the Loop class, since "contains"
does a linear search. Also, don't call verifyLoop from LoopSimplify or
LCSSA, as the PassManager is already calling verifyLoop as part of
LoopInfo's verifyAnalysis.
llvm-svn: 81221
isSafeToSpeculativelyExecute. The new method is a bit closer to what
the callers actually care about in that it rejects more things callers
don't want. It also adds more precise handling for integer
division, and unifies code for analyzing the legality of a speculative
load.
llvm-svn: 76150
works similar to isLoopInvariant, except that it will do trivial
hoisting to try to make the value loop invariant if it isn't already.
This makes it easier for transformation passes to clear trivial
instructions out of the way (the regular LICM pass doesn't run
until relatively late). This is code factored out of LoopSimplify
and other places.
llvm-svn: 75578
and related functions out of LoopBase and into Loop, since they
are specific to BasicBlock-based loops. This also allows the code
to be moved out-of-line.
llvm-svn: 75523
