The powi intrinsic requires special handling because it always takes a single
integer power regardless of the result type. As a result, we can vectorize
only if the powers are equal. Fixes PR12364.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153797 91177308-0d34-0410-b5e6-96231b3b80d8
CodeGenPrepare sinks compare instructions down to their uses to prevent
live flags and predicate registers across basic blocks.
PRE of a compare instruction prevents that, forcing the i1 compare
result into a general purpose register. That is usually more expensive
than the redundant compare PRE was trying to eliminate in the first
place.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153657 91177308-0d34-0410-b5e6-96231b3b80d8
Original commit message for r153521 (aka r153423):
Use the new range metadata in computeMaskedBits and add a new optimization to
instruction simplify that lets us remove an and when loding a boolean value.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153587 91177308-0d34-0410-b5e6-96231b3b80d8
blocks in the function cloner. This removes the last case of trivially
dead code that I've been seeing in the wild getting inlined, analyzed,
re-inlined, optimized, only to be deleted. Nukes a FIXME from the
cleanup tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153572 91177308-0d34-0410-b5e6-96231b3b80d8
undefined behavior, which Rafael was kind enough to fix.
Original commit message for r153423:
Use the new range metadata in computeMaskedBits and add a new optimization to
instruction simplify that lets us remove an and when loding a boolean value.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153521 91177308-0d34-0410-b5e6-96231b3b80d8
Original commit message:
Use the new range metadata in computeMaskedBits and add a new optimization to
instruction simplify that lets us remove an and when loading a boolean value.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153452 91177308-0d34-0410-b5e6-96231b3b80d8
constant-offsets of a common base using the generic GEP-walking logic
I added for computing pointer differences in the same situation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153419 91177308-0d34-0410-b5e6-96231b3b80d8
inbounds GEPs. This isn't really necessary for simplifying pointer
differences, but I'm planning to re-use the same code to simplify
pointer comparisons where it is necessary. Since real code almost
exclusively uses inbounds GEPs, it doesn't seem worth it to support the
extra complexity of turning it on and off. If anyone would like that
back, feel free to shout. Note that instcombine will still catch any of
these patterns.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153418 91177308-0d34-0410-b5e6-96231b3b80d8
aggressively. There are lots of dire warnings about this being expensive
that seem to predate switching to the TrackingVH-based value remapper
that is automatically updated on RAUW. This makes it easy to not just
prune single-entry PHIs, but to fully simplify PHIs, and to recursively
simplify the newly inlined code to propagate PHINode simplifications.
This introduces a bit of a thorny problem though. We may end up
simplifying a branch condition to a constant when we fold PHINodes, and
we would like to nuke any dead blocks resulting from this so that time
isn't wasted continually analyzing them, but this isn't easy. Deleting
basic blocks *after* they are fully cloned and mapped into the new
function currently requires manually updating the value map. The last
piece of the simplification-during-inlining puzzle will require either
switching to WeakVH mappings or some other piece of refactoring. I've
left a FIXME in the testcase about this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153410 91177308-0d34-0410-b5e6-96231b3b80d8
* Removed test/lib/llvm.exp - it is no longer needed
* Deleted the dg.exp reading code from test/lit.cfg. There are no dg.exp files
left in the test suite so this code is no longer required. test/lit.cfg is
now much shorter and clearer
* Removed a lot of duplicate code in lit.local.cfg files that need access to
the root configuration, by adding a "root" attribute to the TestingConfig
object. This attribute is dynamically computed to provide the same
information as was previously provided by the custom getRoot functions.
* Documented the config.root attribute in docs/CommandGuide/lit.pod
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153408 91177308-0d34-0410-b5e6-96231b3b80d8
to instead rely on much more generic and powerful instruction
simplification in the function cloner (and thus inliner).
This teaches the pruning function cloner to use instsimplify rather than
just the constant folder to fold values during cloning. This can
simplify a large number of things that constant folding alone cannot
begin to touch. For example, it will realize that 'or' and 'and'
instructions with certain constant operands actually become constants
regardless of what their other operand is. It also can thread back
through the caller to perform simplifications that are only possible by
looking up a few levels. In particular, GEPs and pointer testing tend to
fold much more heavily with this change.
This should (in some cases) have a positive impact on compile times with
optimizations on because the inliner itself will simply avoid cloning
a great deal of code. It already attempted to prune proven-dead code,
but now it will be use the stronger simplifications to prove more code
dead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153403 91177308-0d34-0410-b5e6-96231b3b80d8
regressed seriously here, we are no longer removing allocas during
inline cleanup. This appears to be because of lifetime markers "using"
them. =/ I'll look into this shortly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153394 91177308-0d34-0410-b5e6-96231b3b80d8
same basic block, and it's not safe to insert code in the successor
blocks if the edges are critical edges. Splitting those edges is
possible, but undesirable, especially on the unwind side. Instead,
make the bottom-up code motion to consider invokes to be part of
their successor blocks, rather than part of their parent blocks, so
that it doesn't push code past them and onto the edges. This fixes
PR12307.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153343 91177308-0d34-0410-b5e6-96231b3b80d8
Do not call SplitBlockPredecessors on a loop preheader when one of the
predecessors is an indirectbr. Otherwise, you will hit this assert:
!isa<IndirectBrInst>(Preds[i]->getTerminator()) && "Cannot split an edge from an IndirectBrInst"
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153134 91177308-0d34-0410-b5e6-96231b3b80d8
instead of skipping the current loop.
My prior fix was incomplete because of an overzealous compile-time optimization:
Better fix for: <rdar://problem/11049788> Segmentation fault: 11 in LoopStrengthReduce
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153131 91177308-0d34-0410-b5e6-96231b3b80d8
overflow checking multiply intrinsic as well.
Add a test for this, updating the test from grep to FileCheck.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153028 91177308-0d34-0410-b5e6-96231b3b80d8
alignment. If that's the case, then we want to make sure that we don't increase
the alignment of the store instruction. Because if we increase it to be "more
aligned" than the pointer, code-gen may use instructions which require a greater
alignment than the pointer guarantees.
<rdar://problem/11043589>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152907 91177308-0d34-0410-b5e6-96231b3b80d8
It was added in 2007 as the first cut at supporting no-inline
attributes, but we didn't have function attributes of any form at the
time. However, it was added without any mention in the LangRef or other
documentation.
Later on, in 2008, Devang added function notes for 'inline=never' and
then turned them into proper function attributes. From that point
onward, as far as I can tell, the world moved on, and no one has touched
'llvm.noinline' in any meaningful way since.
It's time has now come. We have had better mechanisms for doing this for
a long time, all the frontends I'm aware of use them, and this is just
holding back progress. Given that it was never a documented feature of
the IR, I've provided no auto-upgrade support. If people know of real,
in-the-wild bitcode that relies on this, yell at me and I'll add it, but
I *seriously* doubt anyone cares.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152904 91177308-0d34-0410-b5e6-96231b3b80d8
Only record IVUsers that are dominated by simplified loop
headers. Otherwise SCEVExpander will crash while looking for a
preheader.
I previously tried to work around this in LSR itself, but that was
insufficient. This way, LSR can continue to run if some uses are not
in simple loops, as long as we don't attempt to analyze those users.
Fixes <rdar://problem/11049788> Segmentation fault: 11 in LoopStrengthReduce
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152892 91177308-0d34-0410-b5e6-96231b3b80d8
correlated pairs of pointer arguments at the callsite. This is designed
to recognize the common C++ idiom of begin/end pointer pairs when the
end pointer is a constant offset from the begin pointer. With the
C-based idiom of a pointer and size, the inline cost saw the constant
size calculation, and this provides the same level of information for
begin/end pairs.
In order to propagate this information we have to search for candidate
operations on a pair of pointer function arguments (or derived from
them) which would be simplified if the pointers had a known constant
offset. Then the callsite analysis looks for such pointer pairs in the
argument list, and applies the appropriate bonus.
This helps LLVM detect that half of bounds-checked STL algorithms
(such as hash_combine_range, and some hybrid sort implementations)
disappear when inlined with a constant size input. However, it's not
a complete fix due the inaccuracy of our cost metric for constants in
general. I'm looking into that next.
Benchmarks showed no significant code size change, and very minor
performance changes. However, specific code such as hashing is showing
significantly cleaner inlining decisions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152752 91177308-0d34-0410-b5e6-96231b3b80d8
candidate set for subsequent inlining, try to simplify the arguments to
the inner call site now that inlining has been performed.
The goal here is to propagate and fold constants through deeply nested
call chains. Without doing this, we loose the inliner bonus that should
be applied because the arguments don't match the exact pattern the cost
estimator uses.
Reviewed on IRC by Benjamin Kramer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152556 91177308-0d34-0410-b5e6-96231b3b80d8
Typically instcombine has handled this, but pointer differences show up
in several contexts where we would like to get constant folding, and
cannot afford to run instcombine. Specifically, I'm working on improving
the constant folding of arguments used in inline cost analysis with
instsimplify.
Doing this in instsimplify implies some algorithm changes. We have to
handle multiple layers of all-constant GEPs because instsimplify cannot
fold them into a single GEP the way instcombine can. Also, we're only
interested in all-constant GEPs. The result is that this doesn't really
replace the instcombine logic, it's just complimentary and focused on
constant folding.
Reviewed on IRC by Benjamin Kramer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152555 91177308-0d34-0410-b5e6-96231b3b80d8
The 'CmpInst::isFalseWhenEqual' function returns 'false' for values other than
simply equality. For instance, it returns 'false' for <= or >=. This isn't the
correct behavior for this transformation, which is checking for strict equality
and non-equality. It was causing the gcc.c-torture/execute/frame-address.c test
to fail because it would completely (and incorrectly) optimize a whole function
into a 'ret i32 0'.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152497 91177308-0d34-0410-b5e6-96231b3b80d8
traversal, consider nodes for which the only successors are backedges
which the traversal is ignoring to be exit nodes. This fixes a problem
where the bottom-up traversal was failing to visit split blocks along
split loop backedges. This fixes rdar://10989035.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152421 91177308-0d34-0410-b5e6-96231b3b80d8
negative switch cases if the branch condition is known to be positive.
Inspired by a recent improvement to GCC's VRP.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152405 91177308-0d34-0410-b5e6-96231b3b80d8
introduced. Specifically, there are cost reductions for all
constant-operand icmp instructions against an alloca, regardless of
whether the alloca will in fact be elligible for SROA. That means we
don't want to abort the icmp reduction computation when we abort the
SROA reduction computation. That in turn frees us from the need to keep
a separate worklist and defer the ICmp calculations.
Use this new-found freedom and some judicious function boundaries to
factor the innards of computing the cost factor of any given instruction
out of the loop over the instructions and into static helper functions.
This greatly simplifies the code, and hopefully makes it more clear what
is happening here.
Reviewed by Eric Christopher. There is some concern that we'd like to
ensure this doesn't get out of hand, and I plan to benchmark the effects
of this change over the next few days along with some further fixes to
the inline cost.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152368 91177308-0d34-0410-b5e6-96231b3b80d8
equalities into phi node operands for which the equality is known to
hold in the incoming basic block. That's because replaceAllDominatedUsesWith
wasn't handling phi nodes correctly in general (that this didn't give wrong
results was just luck: the specific way GVN uses replaceAllDominatedUsesWith
precluded wrong changes to phi nodes).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152006 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151919 91177308-0d34-0410-b5e6-96231b3b80d8
%cmp (eg: A==B) we already replace %cmp with "true" under the true edge, and
with "false" under the false edge. This change enhances this to replace the
negated compare (A!=B) with "false" under the true edge and "true" under the
false edge. Reported to improve perlbench results by 1%.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151517 91177308-0d34-0410-b5e6-96231b3b80d8
verifier does. This correctly handles invoke.
Thanks to Duncan, Andrew and Chris for the comments.
Thanks to Joerg for the early testing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151469 91177308-0d34-0410-b5e6-96231b3b80d8
by using llvm::isIdentifiedObject. Also teach it to handle GEPs that have
the same base pointer and constant operands. Fixes PR11238!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151449 91177308-0d34-0410-b5e6-96231b3b80d8
the dominance once the dominates method is fixed and why we can use the builder's
insertion point.
Fixes pr12048.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151125 91177308-0d34-0410-b5e6-96231b3b80d8
they'll be simple enough to simulate, and to reduce the chance we'll encounter
equal but different simple pointer constants.
This removes the symptoms from PR11352 but is not a full fix. A proper fix would
either require a guarantee that two constant objects we simulate are folded
when equal, or a different way of handling equal pointers (ie., trying a
constantexpr icmp on them to see whether we know they're equal or non-equal or
unsure).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151093 91177308-0d34-0410-b5e6-96231b3b80d8
This transformation is not safe in some pathological cases (signed icmp of pointers should be an
extremely rare thing, but it's valid IR!). Add an explanatory comment.
Kudos to Duncan for pointing out this edge case (and not giving up explaining it until I finally got it).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151055 91177308-0d34-0410-b5e6-96231b3b80d8
- Ignore pointer casts.
- Also expand GEPs that aren't constantexprs when they have one use or only constant indices.
- We now compile "&foo[i] - &foo[j]" into "i - j".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150961 91177308-0d34-0410-b5e6-96231b3b80d8
the cast. If we do, we can end up with
inst1
--------------- < Insertion point
dbg inst
new inst
instead of the desired
inst1
new inst
--------------- < Insertion point
dbg inst
Another option would be for InsertNoopCastOfTo (or its callers) to move the
insertion point and we would end up with
inst1
dbg inst
new inst
--------------- < Insertion point
but that complicates the callers. This fixes PR12018 (and firefox's build).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150884 91177308-0d34-0410-b5e6-96231b3b80d8
metadata may still unwind, but only in ways that the ARC
optimizer doesn't need to consider. This permits more
aggressive optimization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150829 91177308-0d34-0410-b5e6-96231b3b80d8
useful to represent a variable that is const in the source but can't be constant
in the IR because of a non-trivial constructor. If globalopt evaluates the
constructor, and there was an invariant.start with no matching invariant.end
possible, it will mark the global constant afterwards.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150794 91177308-0d34-0410-b5e6-96231b3b80d8
This folds a simple loop tail into a loop latch. It covers the common (in fortran) case of postincrement loops. It's a "free" way to expose this type of loop to downstream loop optimizations that bail out on non-canonical loops (getLoopLatch is a heavily used check).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150439 91177308-0d34-0410-b5e6-96231b3b80d8
This allows BBVectorize to check the "unknown instruction" list in the
alias sets. This is important to prevent instruction fusing from reordering
function calls. Resolves PR11920.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150250 91177308-0d34-0410-b5e6-96231b3b80d8
is that patterns no longer match for vectors of booleans, because you only get
ConstantDataVector when the vector element type is i8, i16, etc, not when it is
i1). Original commit message:
Remove some dead code and tidy things up now that vectors use ConstantDataVector
instead of always using ConstantVector.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150246 91177308-0d34-0410-b5e6-96231b3b80d8
GlobalOpt runs early in the pipeline (before inlining) and complex class
hierarchies often introduce bitcasts or GEPs which weren't optimized away.
Teach it to ignore side-effect free instructions instead of depending on
other passes to remove them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150174 91177308-0d34-0410-b5e6-96231b3b80d8
* Most of the transforms come through intact by having each transformed load or
store copy the ordering and synchronization scope of the original.
* The transform that turns a global only accessed in main() into an alloca
(since main is non-recursive) with a store of the initial value uses an
unordered store, since it's guaranteed to be the first thing to happen in main.
(Threads may have started before main (!) but they can't have the address of a
function local before the point in the entry block we insert our code.)
* The heap-SRoA transforms are disabled in the face of atomic operations. This
can probably be improved; it seems odd to have atomic accesses to an alloca
that doesn't have its address taken.
AnalyzeGlobal keeps track of the strongest ordering found in any use of the
global. This is more information than we need right now, but it's cheap to
compute and likely to be useful.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149847 91177308-0d34-0410-b5e6-96231b3b80d8
logic by half: isOnlyReachableViaThisEdge was trying to be clever and
handle the case of a branch to a basic block which is contained in a
loop. This costs a domtree lookup and is completely useless due to
GVN's position in the pass pipeline: all loops have preheaders at this
point, which means it is enough for isOnlyReachableViaThisEdge to check
that Dst has only one predecessor. (I checked this theoretical argument
by running over the entire nightly testsuite, and indeed it is so!).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149838 91177308-0d34-0410-b5e6-96231b3b80d8
By default, boost the chain depth contribution of loads and stores. This will allow a load/store pair to vectorize even when it would not otherwise be long enough to satisfy the chain depth requirement.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149761 91177308-0d34-0410-b5e6-96231b3b80d8
PHI nodes which were matched, rather than climbing up the
original PHI node's operands to rediscover PHI nodes for
recording, since the PHI nodes found that are not
necessarily part of the matched set.
This fixes rdar://10589171.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149654 91177308-0d34-0410-b5e6-96231b3b80d8
This is the initial checkin of the basic-block autovectorization pass along with some supporting vectorization infrastructure.
Special thanks to everyone who helped review this code over the last several months (especially Tobias Grosser).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149468 91177308-0d34-0410-b5e6-96231b3b80d8
Changing arguments from being passed as fixed to varargs is unsafe, as
the ABI may require they be handled differently (stack vs. register, for
example).
Remove two tests which rely on the bitcast being folded into the direct
call, which is exactly the transformation that's unsafe.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149457 91177308-0d34-0410-b5e6-96231b3b80d8
Unfortunately I also had to disable constant-pool-sharing.ll the code it tests has been
updated to use the IL logic.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149148 91177308-0d34-0410-b5e6-96231b3b80d8
savings from a pointer argument becoming an alloca. Sometimes callees will even
compare a pointer to null and then branch to an otherwise unreachable block!
Detect these cases and compute the number of saved instructions, instead of
bailing out and reporting no savings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148941 91177308-0d34-0410-b5e6-96231b3b80d8
returns false in the event the computation feeding into the pointer is
unreachable, which maybe ought to be true -- but this is at least consistent
with undef->isDereferenceablePointer().) Fixes PR11825!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148671 91177308-0d34-0410-b5e6-96231b3b80d8
can't handle. Also don't produce non-zero results for things which won't be
transformed by SROA at all just because we saw the loads/stores before we saw
the use of the address.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148536 91177308-0d34-0410-b5e6-96231b3b80d8
LSR has gradually been improved to more aggressively reuse existing code, particularly existing phi cycles. This exposed problems with the SCEVExpander's sloppy treatment of its insertion point. I applied some rigor to the insertion point problem that will hopefully avoid an endless bug cycle in this area. Changes:
- Always used properlyDominates to check safe code hoisting.
- The insertion point provided to SCEV is now considered a lower bound. This is usually a block terminator or the use itself. Under no cirumstance may SCEVExpander insert below this point.
- LSR is reponsible for finding a "canonical" insertion point across expansion of different expressions.
- Robust logic to determine whether IV increments are in "expanded" form and/or can be safely hoisted above some insertion point.
Fixes PR11783: SCEVExpander assert.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148535 91177308-0d34-0410-b5e6-96231b3b80d8
It's becoming clear that LoopSimplify needs to unconditionally create loop preheaders. But that is a bigger fix. For now, continuing to hack LSR.
Fixes rdar://10701050 "Cannot split an edge from an IndirectBrInst" assert.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148288 91177308-0d34-0410-b5e6-96231b3b80d8
the optimizer doesn't eliminate objc_retainBlock calls which are needed
for their side effect of copying blocks onto the heap.
This implements rdar://10361249.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148076 91177308-0d34-0410-b5e6-96231b3b80d8
1. Size heuristics changed. Now we calculate number of unswitching
branches only once per loop.
2. Some checks was moved from UnswitchIfProfitable to
processCurrentLoop, since it is not changed during processCurrentLoop
iteration. It allows decide to skip some loops at an early stage.
Extended statistics:
- Added total number of instructions analyzed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147935 91177308-0d34-0410-b5e6-96231b3b80d8
with other symbols.
An object in the __cfstring section is suppoed to be filled with CFString
objects, which have a pointer to ___CFConstantStringClassReference followed by a
pointer to a __cstring. If we allow the object in the __cstring section to be
merged with another global, then it could end up in any section. Because the
linker is going to remove these symbols in the final executable, we shouldn't
bother to merge them.
<rdar://problem/10564621>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147899 91177308-0d34-0410-b5e6-96231b3b80d8
These heuristics are sufficient for enabling IV chains by
default. Performance analysis has been done for i386, x86_64, and
thumbv7. The optimization is rarely important, but can significantly
speed up certain cases by eliminating spill code within the
loop. Unrolled loops are prime candidates for IV chains. In many
cases, the final code could still be improved with more target
specific optimization following LSR. The goal of this feature is for
LSR to make the best choice of induction variables.
Instruction selection may not completely take advantage of this
feature yet. As a result, there could be cases of slight code size
increase.
Code size can be worse on x86 because it doesn't support postincrement
addressing. In fact, when chains are formed, you may see redundant
address plus stride addition in the addressing mode. GenerateIVChains
tries to compensate for the common cases.
On ARM, code size increase can be mitigated by using postincrement
addressing, but downstream codegen currently misses some opportunities.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147826 91177308-0d34-0410-b5e6-96231b3b80d8
After collecting chains, check if any should be materialized. If so,
hide the chained IV users from the LSR solver. LSR will only solve for
the head of the chain. GenerateIVChains will then materialize the
chained IV users by computing the IV relative to its previous value in
the chain.
In theory, chained IV users could be exposed to LSR's solver. This
would be considerably complicated to implement and I'm not aware of a
case where we need it. In practice it's more important to
intelligently prune the search space of nontrivial loops before
running the solver, otherwise the solver is often forced to prune the
most optimal solutions. Hiding the chained users does this well, so
that LSR is more likely to find the best IV for the chain as a whole.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147801 91177308-0d34-0410-b5e6-96231b3b80d8
We still save an instruction when just the "and" part is replaced.
Also change the code to match comments more closely.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147753 91177308-0d34-0410-b5e6-96231b3b80d8
LoopSimplify may not run on some outer loops, e.g. because of indirect
branches. SCEVExpander simply cannot handle outer loops with no preheaders.
Fixes rdar://10655343 SCEVExpander segfault.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147718 91177308-0d34-0410-b5e6-96231b3b80d8
present in the bottom of the CFG triangle, as the transformation isn't
ever valuable if the branch can't be eliminated.
Also, unify some heuristics between SimplifyCFG's multiple
if-converters, for consistency.
This fixes rdar://10627242.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147630 91177308-0d34-0410-b5e6-96231b3b80d8
code can incorrectly move the load across a store. This never
happens in practice today, but only because the current
heuristics accidentally preclude it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147623 91177308-0d34-0410-b5e6-96231b3b80d8
captured. This allows the tracker to look at the specific use, which may be
especially interesting for function calls.
Use this to fix 'nocapture' deduction in FunctionAttrs. The existing one does
not iterate until a fixpoint and does not guarantee that it produces the same
result regardless of iteration order. The new implementation builds up a graph
of how arguments are passed from function to function, and uses a bottom-up walk
on the argument-SCCs to assign nocapture. This gets us nocapture more often, and
does so rather efficiently and independent of iteration order.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147327 91177308-0d34-0410-b5e6-96231b3b80d8
This was intended to undo the sub canonicalization in cases where it's not profitable, but it also
finds some cases on it's own.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147256 91177308-0d34-0410-b5e6-96231b3b80d8
unsigned foo(unsigned x) { return 31 - __builtin_clz(x); }
now compiles into a single "bsrl" instruction on x86.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147255 91177308-0d34-0410-b5e6-96231b3b80d8
This has the obvious advantage of being commutable and is always a win on x86 because
const - x wastes a register there. On less weird architectures this may lead to
a regression because other arithmetic doesn't fuse with it anymore. I'll address that
problem in a followup.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147254 91177308-0d34-0410-b5e6-96231b3b80d8
time regressions. In general, it is beneficial to compile-time.
Original commit message:
Fix for bug #11429: Wrong behaviour for switches. Small improvement for code
size heuristics.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147175 91177308-0d34-0410-b5e6-96231b3b80d8
performance regressions (both execution-time and compile-time) on our
nightly testers.
Original commit message:
Fix for bug #11429: Wrong behaviour for switches. Small improvement for code
size heuristics.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147131 91177308-0d34-0410-b5e6-96231b3b80d8
For example,
if (a == b) {
if (a > b) // this is false
Fixes some of the issues on <rdar://problem/10554090>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146822 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146610 91177308-0d34-0410-b5e6-96231b3b80d8
I followed three heuristics for deciding whether to set 'true' or
'false':
- Everything target independent got 'true' as that is the expected
common output of the GCC builtins.
- If the target arch only has one way of implementing this operation,
set the flag in the way that exercises the most of codegen. For most
architectures this is also the likely path from a GCC builtin, with
'true' being set. It will (eventually) require lowering away that
difference, and then lowering to the architecture's operation.
- Otherwise, set the flag differently dependending on which target
operation should be tested.
Let me know if anyone has any issue with this pattern or would like
specific tests of another form. This should allow the x86 codegen to
just iteratively improve as I teach the backend how to differentiate
between the two forms, and everything else should remain exactly the
same.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146370 91177308-0d34-0410-b5e6-96231b3b80d8
Patch by Brendon Cahoon!
This extends the existing LoopUnroll and LoopUnrollPass. Brendon
measured no regressions in the llvm test suite with -unroll-runtime
enabled. This implementation works by using the existing loop
unrolling code to unroll the loop by a power-of-two (default 8). It
generates an if-then-else sequence of code prior to the loop to
execute the extra iterations before entering the unrolled loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146245 91177308-0d34-0410-b5e6-96231b3b80d8
It's always good to prune early, but formulae that are unsatisfactory
in their own right need to be removed before running any other pruning
heuristics. We easily avoid generating such formulae, but we need them
as an intermediate basis for forming other good formulae.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145906 91177308-0d34-0410-b5e6-96231b3b80d8
don't do this now, but add a test case to prevent this from happening in the
future.
Additional test for rdar://9892684
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145879 91177308-0d34-0410-b5e6-96231b3b80d8
where this would be bad as the backend shouldn't have a problem inlining small
memcpys.
rdar://10510150
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145865 91177308-0d34-0410-b5e6-96231b3b80d8
weak variable are compiled by different compilers, such as GCC and LLVM, while
LLVM may increase the alignment to the preferred alignment there is no reason to
think that GCC will use anything more than the ABI alignment. Since it is the
GCC version that might end up in the final program (as the linkage is weak), it
is wrong to increase the alignment of loads from the global up to the preferred
alignment as the alignment might only be the ABI alignment.
Increasing alignment up to the ABI alignment might be OK, but I'm not totally
convinced that it is. It seems better to just leave the alignment of weak
globals alone.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145413 91177308-0d34-0410-b5e6-96231b3b80d8
trampoline forms. Both of these were correct in LLVM 3.0, and we don't
need to support LLVM 2.9 and earlier in mainline.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145174 91177308-0d34-0410-b5e6-96231b3b80d8
I think this is the last of autoupgrade that can be removed in 3.1.
Can the atomic upgrade stuff also go?
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145169 91177308-0d34-0410-b5e6-96231b3b80d8
and positive: positive, because it could be directly computed to be positive;
negative, because the nsw flags means it is either negative or undefined (the
multiplication always overflowed).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145104 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144970 91177308-0d34-0410-b5e6-96231b3b80d8
The right way to check for a binary operation is
cast<BinaryOperator>. The original check: cast<Instruction> &&
numOperands() == 2 would match phi "instructions", leading to an
infinite loop in extreme corner case: a useless phi with operands
[self, constant] that prior optimization passes failed to remove,
being used in the loop by another useless phi, in turn being used by an
lshr or udiv.
Fixes PR11350: runaway iteration assertion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144935 91177308-0d34-0410-b5e6-96231b3b80d8
and stores capture) to permit the caller to see each capture point and decide
whether to continue looking.
Use this inside memdep to do an analysis that basicaa won't do. This lets us
solve another devirtualization case, fixing PR8908!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144580 91177308-0d34-0410-b5e6-96231b3b80d8
lead to it trying to re-mark a value marked as a constant with a different value. It also appears to trigger very rarely.
Fixes PR11357.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144352 91177308-0d34-0410-b5e6-96231b3b80d8
Currently checks alignment and killing stores on a power of 2 boundary as this is likely
to trim the size of the earlier store without breaking large vector stores into scalar ones.
Fixes <rdar://problem/10140300>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144239 91177308-0d34-0410-b5e6-96231b3b80d8
