CallSite roughly behaves as a common base CallInst and InvokeInst. Bring
the behavior closer to that model by making upcasts explicit. Downcasts
remain implicit and work as before.
Following dyn_cast as a mental model checking whether a Value *V isa
CallSite now looks like this:
if (auto CS = CallSite(V)) // think dyn_cast
instead of:
if (CallSite CS = V)
This is an extra token but I think it is slightly clearer. Making the
ctor explicit has the advantage of not accidentally creating nullptr
CallSites, e.g. when you pass a Value * to a function taking a CallSite
argument.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234601 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Some optimizations such as jump threading and loop unswitching can negatively
affect performance when applied to divergent branches. The divergence analysis
added in this patch conservatively estimates which branches in a GPU program
can diverge. This information can then help LLVM to run certain optimizations
selectively.
Test Plan: test/Analysis/DivergenceAnalysis/NVPTX/diverge.ll
Reviewers: resistor, hfinkel, eliben, meheff, jholewinski
Subscribers: broune, bjarke.roune, madhur13490, tstellarAMD, dberlin, echristo, jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D8576
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234567 91177308-0d34-0410-b5e6-96231b3b80d8
(Re-apply r234361 with a fix and a testcase for PR23157)
Both run-time pointer checking and the dependence analysis are capable
of dealing with uniform addresses. I.e. it's really just an orthogonal
property of the loop that the analysis computes.
Run-time pointer checking will only try to reason about SCEVAddRec
pointers or else gives up. If the uniform pointer turns out the be a
SCEVAddRec in an outer loop, the run-time checks generated will be
correct (start and end bounds would be equal).
In case of the dependence analysis, we work again with SCEVs. When
compared against a loop-dependent address of the same underlying object,
the difference of the two SCEVs won't be constant. This will result in
returning an Unknown dependence for the pair.
When compared against another uniform access, the difference would be
constant and we should return the right type of dependence
(forward/backward/etc).
The changes also adds support to query this property of the loop and
modify the vectorizer to use this.
Patch by Ashutosh Nema!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234424 91177308-0d34-0410-b5e6-96231b3b80d8
Both run-time pointer checking and the dependence analysis are capable
of dealing with uniform addresses. I.e. it's really just an orthogonal
property of the loop that the analysis computes.
Run-time pointer checking will only try to reason about SCEVAddRec
pointers or else gives up. If the uniform pointer turns out the be a
SCEVAddRec in an outer loop, the run-time checks generated will be
correct (start and end bounds would be equal).
In case of the dependence analysis, we work again with SCEVs. When
compared against a loop-dependent address of the same underlying object,
the difference of the two SCEVs won't be constant. This will result in
returning an Unknown dependence for the pair.
When compared against another uniform access, the difference would be
constant and we should return the right type of dependence
(forward/backward/etc).
The changes also adds support to query this property of the loop and
modify the vectorizer to use this.
Patch by Ashutosh Nema!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234361 91177308-0d34-0410-b5e6-96231b3b80d8
The plan here is to push the API changes out from the common components
(like Constant::getGetElementPtr and IRBuilder::CreateGEP related
functions) and just update callers to either pass the type if it's
obvious, or pass null.
Do this with LoadInst as well and anything else that comes up, then to
start porting specific uses to not pass null anymore - this may require
some refactoring in each case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234042 91177308-0d34-0410-b5e6-96231b3b80d8
Require the pointee type to be passed explicitly and assert that it is
correct. For now it's possible to pass nullptr here (and I've done so in
a few places in this patch) but eventually that will be disallowed once
all clients have been updated or removed. It'll be a long road to get
all the way there... but if you have the cahnce to update your callers
to pass the type explicitly without depending on a pointer's element
type, that would be a good thing to do soon and a necessary thing to do
eventually.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233938 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This change teaches ScalarEvolution::isLoopBackedgeGuardedByCond to look
at edges within the loop body that dominate the latch. We don't do an
exhaustive search for all possible edges, but only a quick walk up the
dom tree.
This re-lands r233447. r233447 was reverted because it caused massive
compile-time regressions. This change has a fix for the same issue.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233829 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This is part 1 of fixes to address the problems described in
https://llvm.org/bugs/show_bug.cgi?id=22719.
The restriction to limit loop scales to 4,096 does not really prevent
overflows anymore, as the underlying algorithm has changed and does
not seem to suffer from this problem.
Additionally, artificially restricting loop scales to such a low number
skews frequency information, making loops of equal hotness appear to
have very different hotness properties.
The only loops that are artificially restricted to a scale of 4096 are
infinite loops (those loops with an exit mass of 0). This prevents
infinite loops from skewing the frequencies of other regions in the CFG.
At the end of propagation, frequencies are scaled to values that take no
more than 64 bits to represent. When the range of frequencies to be
represented fits within 61 bits, it pushes up the scaling factor to a
minimum of 8 to better distinguish small frequency values. Otherwise,
small frequency values are all saturated down at 1.
Tested on x86_64.
Reviewers: dexonsmith
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8718
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233826 91177308-0d34-0410-b5e6-96231b3b80d8
Generate tables in the .xdata section representing what actions to take
when an exception is thrown. This currently fills in state for
cleanups, catch handlers are still unfinished.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233636 91177308-0d34-0410-b5e6-96231b3b80d8
This pushes the use of PointerType::getElementType up into several
callers - I'll essentially just have to keep pushing that up the stack
until I can eliminate every call to it...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233604 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This change teaches ScalarEvolution::isLoopBackedgeGuardedByCond to look
at edges within the loop body that dominate the latch. We don't do an
exhaustive search for all possible edges, but only a quick walk up the
dom tree.
Reviewers: atrick, hfinkel
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8627
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233447 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
With the introduction of MarkPendingLoopPredicates in r157092, I don't
think the bailout is needed anymore.
Reviewers: atrick, nicholas
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8624
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233296 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
`ComputeNumSignBits` returns incorrect results for `srem` instructions.
This change fixes the issue and adds a test case.
Reviewers: nadav, nicholas, atrick
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8600
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233225 91177308-0d34-0410-b5e6-96231b3b80d8
To complement getSplat. This is more general than the binary
decomposition method as it also handles non-pow2 splat sizes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233195 91177308-0d34-0410-b5e6-96231b3b80d8
A load from an invariant location is assumed to not alias any otherwise potentially aliasing stores. Our implementation only applied this rule to store instructions themselves whereas they it should apply for any memory accessing instruction. This results in both FRE and PRE becoming more effective at eliminating invariant loads.
Note that as a follow on change I will likely move this into AliasAnalysis itself. That's where the TBAA constant flag is handled and the semantics are essentially the same. I'd like to separate the semantic change from the refactoring and thus have extended the hack that's already in MemoryDependenceAnalysis for this change.
Differential Revision: http://reviews.llvm.org/D8591
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233140 91177308-0d34-0410-b5e6-96231b3b80d8
The changes to InstCombine (& SCEV) do seem a bit silly - it doesn't make
anything obviously better to have the caller access the pointers element
type (the thing I'm trying to remove) than the GEP itself, but it's a
helpful migration step. This will allow me to more obviously lock down
GEP (& Load, etc) API usage, then fix all the code that accesses pointer
element types except the places that need to be removed (most of the
InstCombines) anyway - at which point I'll need to just remove all that
code because it won't be meaningful anymore (there will be no pointer
types, so no bitcasts to combine)
SCEV looks like it'll need some restructuring - we'll have to do a bit
more work for GEP canonicalization, since it'll depend on how it's used
if we can even manage to canonicalize it to a non-ugly GEP. I guess we
can do some fun stuff like voting (do 2 out of 3 load from the GEP with
a certain type that gives a pretty GEP? Does every typed use of the GEP
use either a specific type or a generic type (i8*, etc)?)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233131 91177308-0d34-0410-b5e6-96231b3b80d8
Currently this is only used to tweak the backend's memcpy inlining
heuristics, testing that isn't very helpful. A real test case will
follow in the next commit, where this behavior would cause a real
miscompilation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232895 91177308-0d34-0410-b5e6-96231b3b80d8
r216771 introduced a change to MemoryDependenceAnalysis that allowed it
to reason about acquire/release operations. However, this change does
not ensure that the acquire/release operations pair. Unfortunately,
this leads to miscompiles as we won't see an acquire load as properly
memory effecting. This largely reverts r216771.
This fixes PR22708.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232889 91177308-0d34-0410-b5e6-96231b3b80d8
When estimating SROA savings, we want to see if an address is derived
off an alloca in the caller. For store instructions, operand 1 is the
address operand, but the current code uses operand 0. Use
getPointerOperand for loads and stores to fix this.
Patch by Easwaran Raman.
http://reviews.llvm.org/D8425
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232827 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This change teaches isImpliedCond to infer things like "X sgt 0" => "X -
1 sgt -1". The `ConstantRange` class has the logic to do the heavy
lifting, this change simply gets ScalarEvolution to exploit that when
reasonable.
Depends on D8345
Reviewers: atrick
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8346
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232576 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This change splits `makeICmpRegion` into `makeAllowedICmpRegion` and
`makeSatisfyingICmpRegion` with slightly different contracts. The first
one is useful for determining what values some expression //may// take,
given that a certain `icmp` evaluates to true. The second one is useful
for determining what values are guaranteed to //satisfy// a given
`icmp`.
Reviewers: nlewycky
Reviewed By: nlewycky
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8345
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232575 91177308-0d34-0410-b5e6-96231b3b80d8
Given that the stated purpose of `CheckFailed()` is to provide a nice
spot for a breakpoint, it'd be nice not to have to use a regex to break
on it. Recover the ability to simply use `b CheckFailed` by
specializing the message-only version, and by changing the variadic
version to call into the message-only version.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232268 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
ScalarEvolutionExpander assumes that the header block of a loop is a
legal place to have a use for a phi node. This is true only for phis
that are either in the header or dominate the header block, but it is
not true for phi nodes that are strictly internal to the loop body.
This change teaches ScalarEvolutionExpander to place uses of PHI nodes
in the basic block the PHI nodes belong to. This is always legal, and
`hoistIVInc` ensures that the said position dominates `IsomorphicInc`.
Reviewers: atrick
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8311
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232189 91177308-0d34-0410-b5e6-96231b3b80d8
There's a missed optimization opportunity where we could look at the full chain of computation and take the intersection of the flags instead of only looking one instruction deep.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232134 91177308-0d34-0410-b5e6-96231b3b80d8
Instead, run both EH preparation passes, and have them both ignore
functions with unrecognized EH personalities. Pass delegation involved
some hacky code for creating an AnalysisResolver that we don't need now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231995 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds limited support in ValueTracking for inferring known bits of a value from conditional expressions which must be true to reach the instruction we're trying to optimize. At this time, the feature is off by default. Once landed, I'm hoping for feedback from others on both profitability and compile time impact.
Forms of conditional value propagation have been tried in LLVM before and have failed due to compile time problems. In an attempt to side step that, this patch only considers conditions where the edge leaving the branch dominates the context instruction. It does not attempt full dataflow. Even with that restriction, it handles many interesting cases:
* Early exits from functions
* Early exits from loops (for context instructions in the loop and after the check)
* Conditions which control entry into loops, including multi-version loops (such as those produced during vectorization, IRCE, loop unswitch, etc..)
Possible applications include optimizing using information provided by constructs such as: preconditions, assumptions, null checks, & range checks.
This patch implements two approaches to the problem that need further benchmarking. Approach 1 is to directly walk the dominator tree looking for interesting conditions. Approach 2 is to inspect other uses of the value being queried for interesting comparisons. From initial benchmarking, it appears that Approach 2 is faster than Approach 1, but this needs to be further validated.
Differential Revision: http://reviews.llvm.org/D7708
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231879 91177308-0d34-0410-b5e6-96231b3b80d8
The debug message was pretty confusing here. It only reported the
situation with memchecks without the result of the dependence analysis.
Now it prints whether the loop is safe from the POV of the dependence
analysis and if yes, whether we need memchecks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231854 91177308-0d34-0410-b5e6-96231b3b80d8
