Summary:
An alternative is to use a worklist approach. However, that approach
would break the traversing order so that we couldn't lookup SeenExprs
efficiently. I don't see a clear winner here, so I picked the easier approach.
Along with two minor improvements:
1. preserves ScalarEvolution by forgetting instructions replaced
2. removes dead code locally avoiding the need of running DCE afterwards
Test Plan: add to slsr-add.ll a test that requires multiple iterations
Reviewers: broune, dberlin, atrick, meheff
Reviewed By: atrick
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9058
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235151 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This fixes a left-over efficiency issue in D8950.
As Andrew and Daniel suggested, we can store the candidates in a stack
and pop the top element when it does not dominate the current
instruction. This reduces the worst-case time complexity to O(n).
Test Plan: a new test in nary-add.ll that exercises this optimization.
Reviewers: broune, dberlin, meheff, atrick
Reviewed By: atrick
Subscribers: llvm-commits, sanjoy
Differential Revision: http://reviews.llvm.org/D9055
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235129 91177308-0d34-0410-b5e6-96231b3b80d8
This is very similar to D8486 / r232852 (vperm2). If we treat insertps intrinsics
as shufflevectors, we can optimize them better.
I've left all but the full zero case of the zero mask variants out of this patch.
I don't think those can be converted into a single shuffle in all cases, but I'd
be happy to be proven wrong as I was for vperm2f128.
Either way, we'd need to support whatever sequence we come up with for those cases
in the backend before converting them here.
Differential Revision: http://reviews.llvm.org/D8833
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235124 91177308-0d34-0410-b5e6-96231b3b80d8
Continuing gutting `DIDescriptor` subclasses; this edition,
`DICompileUnit` and `DIFile`. In the name of PR23080.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235055 91177308-0d34-0410-b5e6-96231b3b80d8
Remove 'inlinedAt:' from MDLocalVariable. Besides saving some memory
(variables with it seem to be single largest `Metadata` contributer to
memory usage right now in -g -flto builds), this stops optimization and
backend passes from having to change local variables.
The 'inlinedAt:' field was used by the backend in two ways:
1. To tell the backend whether and into what a variable was inlined.
2. To create a unique id for each inlined variable.
Instead, rely on the 'inlinedAt:' field of the intrinsic's `!dbg`
attachment, and change the DWARF backend to use a typedef called
`InlinedVariable` which is `std::pair<MDLocalVariable*, MDLocation*>`.
This `DebugLoc` is already passed reliably through the backend (as
verified by r234021).
This commit removes the check from r234021, but I added a new check
(that will survive) in r235048, and changed the `DIBuilder` API in
r235041 to require a `!dbg` attachment whose 'scope:` is in the same
`MDSubprogram` as the variable's.
If this breaks your out-of-tree testcases, perhaps the script I used
(mdlocalvariable-drop-inlinedat.sh) will help; I'll attach it to PR22778
in a moment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235050 91177308-0d34-0410-b5e6-96231b3b80d8
Change `DIBuilder::insertDeclare()` and `insertDbgValueIntrinsic()` to
take an `MDLocation*`/`DebugLoc` parameter which it attaches to the
created intrinsic. Assert at creation time that the `scope:` field's
subprogram matches the variable's. There's a matching `clang` commit to
use the API.
The context for this is PR22778, which is removing the `inlinedAt:`
field from `MDLocalVariable`, instead deferring to the `!dbg` location
attached to the debug info intrinsic. The best way to ensure we always
have a `!dbg` attachment is to require one at creation time. I'll be
adding verifier checks next, but this API change is the best way to
shake out frontend bugs.
Note: I added an `llvm_unreachable()` in `bindings/go` and passed in
`nullptr` for the `DebugLoc`. The `llgo` folks will eventually need to
pass a valid `DebugLoc` here.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235041 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
With this patch, SLSR may rewrite
S1: X = B + i * S
S2: Y = B + i' * S
to
S2: Y = X + (i' - i) * S
A secondary improvement: if (i' - i) is a power of 2, emit Y as X + (S << log(i' - i)). (S << log(i' -i)) is in a canonical form and thus more likely GVN'ed than (i' - i) * S.
Test Plan: slsr-add.ll
Reviewers: hfinkel, sanjoy, meheff, broune, eliben
Reviewed By: eliben
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8983
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235019 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This transformation reassociates a n-ary add so that the add can partially reuse
existing instructions. For example, this pass can simplify
void foo(int a, int b) {
bar(a + b);
bar((a + 2) + b);
}
to
void foo(int a, int b) {
int t = a + b;
bar(t);
bar(t + 2);
}
saving one add instruction.
Fixes PR22357 (https://llvm.org/bugs/show_bug.cgi?id=22357).
Test Plan: nary-add.ll
Reviewers: broune, dberlin, hfinkel, meheff, sanjoy, atrick
Reviewed By: sanjoy, atrick
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8950
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234855 91177308-0d34-0410-b5e6-96231b3b80d8
Change `DICompileUnit::replaceSubprograms()` and
`DICompileUnit::replaceGlobalVariables()` to match the `MDCompileUnit`
equivalents that they're wrapping.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234852 91177308-0d34-0410-b5e6-96231b3b80d8
Gut the `DIDescriptor` wrappers around `MDLocalScope` subclasses. Note
that `DILexicalBlock` wraps `MDLexicalBlockBase`, not `MDLexicalBlock`.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234850 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Runtime unrolling of loops needs to emit an expression to compute the
loop's runtime trip-count. Avoid runtime unrolling if this computation
will be expensive.
Depends on D8993.
Reviewers: atrick
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8994
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234846 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Move isHighCostExpansion from IndVarSimplify to SCEVExpander. This
exposed function will be used in a subsequent change.
Reviewers: bogner, atrick
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8995
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234844 91177308-0d34-0410-b5e6-96231b3b80d8
Gut all the non-pointer API from the variable wrappers, except an
implicit conversion from `DIGlobalVariable` to `DIDescriptor`. Note
that if you're updating out-of-tree code, `DIVariable` wraps
`MDLocalVariable` (`MDVariable` is a common base class shared with
`MDGlobalVariable`).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234840 91177308-0d34-0410-b5e6-96231b3b80d8
This is along the same lines as r234832, but for `DILocation`. Clean
out all accessors from `DILocation`. Any callers should be using
`MDLocation` directly (e.g., via `operator->()`).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234835 91177308-0d34-0410-b5e6-96231b3b80d8
Completely gut `DIExpression`, turning it into a simple wrapper around
`MDExpression *`. There are two bits of magic left:
- It's constructed from `const MDExpression*` but convertible to
`MDExpression*`.
- It's default-constructed to `nullptr`.
Otherwise, it should behave quite like a raw pointer. Once I've done
the same to the rest of the `DIDescriptor` subclasses, I'll come back to
delete them entirely (and update call sites as necessary to deal with
the missing magic).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234832 91177308-0d34-0410-b5e6-96231b3b80d8
Before we had real liveness, we needed to track every value that base pointer
insertion code created because these now might be live. We now just rerun
the data flow liveness algorithm (which is actually faster!) and no longer
need the associated code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234827 91177308-0d34-0410-b5e6-96231b3b80d8
As documented in PR23200 (and the FIXMEs I've added to the code here),
this logic is fairly broken: it modifies the `LLVMContext` in a way that
affects other modules and cannot be serialized to assembly/bitcode. For
now, move it over to `MDLocation::computeNewDiscriminators()` anyway.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234825 91177308-0d34-0410-b5e6-96231b3b80d8
I don't see a reason to add the `copyWithNewScope()` API over to
`MDLocation` -- it seems to be a holdover from when creating locations
required knowing details of operand layout -- so change
`AddDiscriminators` to call `MDLocation::get()` directly. Should be no
functionality change here.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234824 91177308-0d34-0410-b5e6-96231b3b80d8
The only difference between the two is a `dyn_cast<>` to
`GlobalVariable`. If optimizations have left anything behind when a
global gets replaced, then it doesn't seem like the debug info is dead.
I can't seem to find an optimization that would leave behind a
non-`GlobalVariable` without nulling the reference entirely, so I
haven't added a testcase (but I'll be deleting `getGlobal()` in a future
commit).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234792 91177308-0d34-0410-b5e6-96231b3b80d8
Use early-return style that's preferred in LLVM and updating the naming in places I touched with other changes in the last few days. Hopefully, NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234785 91177308-0d34-0410-b5e6-96231b3b80d8
We use dummy calls to adjust the liveness of values over statepoints in the midst of the insertion. If there are no values which need held live, there's no point in actually inserting the holder.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234779 91177308-0d34-0410-b5e6-96231b3b80d8
Since we're restructuring the CFG, we also need to make sure to update the analsis passes. While I'm touching the code, I dedicided to restructure it a bit. The code involved here was very confusing. This change moves the normalization to essentially being a pre-pass before the main insertion work and updates a few comments to actually say what is happening and *why*.
The restructuring should be covered by existing tests. I couldn't easily see how to create a test for the invalidation bug. Suggestions welcome.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234769 91177308-0d34-0410-b5e6-96231b3b80d8
This is related to the issues addressed in 234651. These assertions check the properties ensured by that change at the place of use. Note that a similiar property is checked in checkBasicSSA, but without the reachability constraint. Technically, the liveness would be correct to include unreachable values, but this would be problematic for actual relocation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234766 91177308-0d34-0410-b5e6-96231b3b80d8
The check in question is attempting to help find cases where we haven't relocated a pointer at a safepoint we should have. It does this by coercing the value to null at any safepoint which doesn't relocate it.
Unfortunately, this turns out to be rather expensive in terms of memory usage and time. The number of stores inserted can grow with O(number of values x number of statepoints). On at least one example I looked at, over half of peak memory usage was coming from this check.
With this change, the check is no longer enabled by default in Asserts builds. It is enabled for expensive asserts builds and has a command line option to enable it in both Asserts and non-Asserts builds.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234761 91177308-0d34-0410-b5e6-96231b3b80d8
Clean up a predicate I added in r229731, fix the relevant comment and
add a test case. The earlier version is confusing to read and was also
buggy (probably not a coincidence) till Alexey fixed it in r233881.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234701 91177308-0d34-0410-b5e6-96231b3b80d8
The patch is generated using clang-tidy misc-use-override check.
This command was used:
tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py \
-checks='-*,misc-use-override' -header-filter='llvm|clang' \
-j=32 -fix -format
http://reviews.llvm.org/D8925
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234679 91177308-0d34-0410-b5e6-96231b3b80d8
Rewrite `DILocation::atSameLineAs()` as `MDLocation::canDiscriminate()`
with a doxygen comment explaining its purpose. I've added a few FIXMEs
where I think this check is too weak; fixing that is tracked by PR23199.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234674 91177308-0d34-0410-b5e6-96231b3b80d8
When rewriting statepoints to make relocations explicit, we need to have a conservative but consistent notion of where a particular pointer is live at a particular site. The old code just used dominance, which is correct, but decidedly more conservative then it needed to be. This patch implements a simple dataflow algorithm that's run one per function (well, twice counting fixup after base pointer insertion). There's still lots of room to make this faster, but it's fast enough for all practical purposes today.
Differential Revision: http://reviews.llvm.org/D8674
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234657 91177308-0d34-0410-b5e6-96231b3b80d8
After submitting 234651, I noticed I hadn't responded to a review comment by mjacob. This patch addresses that comment and fixes a Release only build problem due to an unused variable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234653 91177308-0d34-0410-b5e6-96231b3b80d8
Two related small changes:
Various dominance based queries about liveness can get confused if we're talking about unreachable blocks. To avoid reasoning about such cases, just remove them before rewriting statepoints.
Remove single entry phis (likely left behind by LCSSA) to reduce the number of live values.
Both of these are motivated by http://reviews.llvm.org/D8674 which will be submitted shortly.
Differential Revision: http://reviews.llvm.org/D8675
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234651 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds limited support for inserting explicit relocations when there's a vector of pointers live over the statepoint. This doesn't handle the case where the vector contains a mix of base and non-base pointers; that's future work.
The current implementation just scalarizes the vector over the gc.statepoint before doing the explicit rewrite. An alternate approach would be to plumb the vector all the way though the backend lowering, but doing that appears challenging. In particular, the size of the indirect spill slot is currently assumed to be sizeof(pointer) throughout the backend.
In practice, this is enough to allow running the SLP and Loop vectorizers before RewriteStatepointsForGC.
Differential Revision: http://reviews.llvm.org/D8671
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234647 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This change moves creating calls to `llvm.uadd.with.overflow` from
InstCombine to CodeGenPrep. Combining overflow check patterns into
calls to the said intrinsic in InstCombine inhibits optimization because
it introduces an intrinsic call that not all other transforms and
analyses understand.
Depends on D8888.
Reviewers: majnemer, atrick
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8889
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234638 91177308-0d34-0410-b5e6-96231b3b80d8
WinEH currently turns invokes into calls. Long term, we will reconsider
this, but for now, make sure we remap the operands and clone the
successors of the new terminator.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234608 91177308-0d34-0410-b5e6-96231b3b80d8
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
The code uses a priority queue and a worklist, which share the same
visited set, but the visited set is only updated when inserting into
the priority queue. Instead, switch to using separate visited sets
for the priority queue and worklist.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234425 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
Summary:
This patch adds an enum `OverflowCheckFlavor` and a function
`OptimizeOverflowCheck`. This will allow InstCombine to optimize
overflow checks without directly introducing an intermediate call to the
`llvm.$op.with.overflow` instrinsics.
This specific change is a refactoring and does not intend to change
behavior.
Reviewers: majnemer, atrick
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8888
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234388 91177308-0d34-0410-b5e6-96231b3b80d8
