directly model in the new PM.
This also was an incredibly brittle and expensive update API that was
never fully utilized by all the passes that claimed to preserve AA, nor
could it reasonably have been extended to all of them. Any number of
places add uses of values. If we ever wanted to reliably instrument
this, we would want a callback hook much like we have with ValueHandles,
but doing this for every use addition seems *extremely* expensive in
terms of compile time.
The only user of this update mechanism is GlobalsModRef. The idea of
using this to keep it up to date doesn't really work anyways as its
analysis requires a symmetric analysis of two different memory
locations. It would be very hard to make updates be sufficiently
rigorous to *guarantee* symmetric analysis in this way, and it pretty
certainly isn't true today.
However, folks have been using GMR with this update for a long time and
seem to not be hitting the issues. The reported issue that the update
hook fixes isn't even a problem any more as other changes to
GetUnderlyingObject worked around it, and that issue stemmed from *many*
years ago. As a consequence, a prior patch provided a flag to control
the unsafe behavior of GMR, and this patch removes the update mechanism
that has questionable compile-time tradeoffs and is causing problems
with moving to the new pass manager. Note the lack of test updates --
not one test in tree actually requires this update, even for a contrived
case.
All of this was extensively discussed on the dev list, this patch will
just enact what that discussion decides on. I'm sending it for review in
part to show what I'm planning, and in part to show the *amazing* amount
of work this avoids. Every call to the AA here is something like three
to six indirect function calls, which in the non-LTO pipeline never do
any work! =[
Differential Revision: http://reviews.llvm.org/D11214
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242605 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This is a trivial code change with no functionality effect.
When LoopUnswitch determines trivial unswitch condition, it checks whether the loop header's terminator instruction is a branch instruction or switch instruction since trivial unswitch condition can only apply to these two instruction types. The current code does not fail the check directly on other instruction types, but check the nullness of LoopExitBB variable instead. The added else clause makes the check fail immediately on other instruction types and makes the code more obvious.
Reviewers: reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11239
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242345 91177308-0d34-0410-b5e6-96231b3b80d8
I am planning to add more nested classes inside RuntimePointerCheck so
all these triple-nesting would be hard to follow.
Also rename it to RuntimePointerChecking (i.e. append 'ing').
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242218 91177308-0d34-0410-b5e6-96231b3b80d8
Sometimes an incidentally created instruction can duplicate a Value used
elsewhere. It then often doesn't end up in the leader table. If it's later
removed, we attempt to remove it from the leader table and segfault.
Instead we should just ignore the removal request, which won't cause any
problems. The reverse situation, where the original instruction is replaced by
the new one (which you might think could leave the leader table empty) cannot
occur, because the incidental instruction will never be found in the first
place.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242199 91177308-0d34-0410-b5e6-96231b3b80d8
Volatile loads and stores are made visible in global state regardless of
what memory is involved. It is not correct to disregard the ordering
and synchronization scope because it is possible to synchronize with
memory operations performed by hardware.
This partially addresses PR23737.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242126 91177308-0d34-0410-b5e6-96231b3b80d8
When spotting that a loop can use ctpop, we were incorrectly replacing all uses of a value with a value derived from ctpop.
The bug here was exposed because we were replacing a use prior to the ctpop with the ctpop value and so we have a use before def, i.e., we changed
%tobool.5 = icmp ne i32 %num, 0
store i1 %tobool.5, i1* %ptr
br i1 %tobool.5, label %for.body.lr.ph, label %for.end
to
store i1 %1, i1* %ptr
%0 = call i32 @llvm.ctpop.i32(i32 %num)
%1 = icmp ne i32 %0, 0
br i1 %1, label %for.body.lr.ph, label %for.end
Even if we inserted the ctpop so that it dominates the store here, that would still be incorrect. The store doesn’t want the result of ctpop.
The fix is very simple, and involves replacing only the branch condition with the ctpop instead of all uses.
Reviewed by Hal Finkel.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242068 91177308-0d34-0410-b5e6-96231b3b80d8
Enable runtime unrolling for loops with unroll count metadata ("#pragma unroll N")
and a runtime trip count. Also, do not unroll loops with unroll full metadata if the
loop has a runtime loop count. Previously, such loops would be unrolled with a
very large threshold (pragma-unroll-threshold) if runtime unrolled happened to be
enabled resulting in a very large (and likely unwise) unroll factor.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242047 91177308-0d34-0410-b5e6-96231b3b80d8
Passes should never modify it, just use the const version. While there
reduce copying in LoopInterchange. No functional change intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242041 91177308-0d34-0410-b5e6-96231b3b80d8
There is no suitable basic block to sink instructions in loops without
exits. The only way an instruction in a loop without exits can be used
is as an incoming value to a PHI. In such cases, the incoming block for
the corresponding value is unreachable.
This fixes PR24013.
Differential Revision: http://reviews.llvm.org/D10903
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241987 91177308-0d34-0410-b5e6-96231b3b80d8
No in-tree alias analysis used this facility, and it was not called in
any particularly rigorous way, so it seems unlikely to be correct.
Note that one of the only stateful AA implementations in-tree,
GlobalsModRef is completely broken currently (and any AA passes like it
are equally broken) because Module AA passes are not effectively
invalidated when a function pass that fails to update the AA stack runs.
Ultimately, it doesn't seem like we know how we want to build stateful
AA, and until then trying to support and maintain correctness for an
untested API is essentially impossible. To that end, I'm planning to rip
out all of the update API. It can return if and when we need it and know
how to build it on top of the new pass manager and as part of *tested*
stateful AA implementations in the tree.
Differential Revision: http://reviews.llvm.org/D10889
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241975 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The class will obviously need improvement down the road. For one, there
is no reason that addPHINodes would have to be exposed like that. I
will make this and other improvements in follow-up patches.
The main goal is to be able to share this functionality. The
LoopLoadElimination pass I am working on needs it too. Later we can
move other clients as well (LV and Ashutosh's LICMVer).
Reviewers: hfinkel, ashutosh.nema
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10577
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241932 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This makes them available to the LoopVersioning class as that is moved
to its own module in the next patch.
Reviewers: ashutosh.nema, hfinkel
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10576
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241931 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This introduces new instructions neccessary to implement MSVC-compatible
exception handling support. Most of the middle-end and none of the
back-end haven't been audited or updated to take them into account.
Reviewers: rnk, JosephTremoulet, reames, nlewycky, rjmccall
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11041
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241888 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
In RewriteLoopExitValues, before expanding out an SCEV expression using
SCEVExpander, try to see if an existing LLVM IR expression already
computes the value we're interested in. If so use that existing
expression.
Apart from reducing IndVars' reliance on the rest of the compilation
pipeline, this also prevents IndVars from concluding some expressions as
"high cost" when they're not. For instance,
`InductiveRangeCheckElimination` often emits code of the following form:
```
len = umin(len_A, len_B)
loop:
...
if (i++ < len)
goto loop
outside_loop:
use(i)
```
`SCEVExpander` refuses to rewrite the use of `i` in `outside_loop`,
since it thinks the value of `i` on loop exit, `len`, is a high cost
expansion since it contains an `umax` in it. With this change,
`IndVars` can see that it can re-use `len` instead of creating a new
expression to compute `umin(len_A, len_B)`.
I considered putting this cleverness in `SCEVExpander`, but I was
worried that it may then have a deterimental effect on other passes
that use it. So I decided it was better to just do this in the one
place where it seems like an obviously good idea, with the intent of
generalizing later if needed.
Reviewers: atrick, reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10782
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241838 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Initially, these intrinsics seemed like part of a family of "frame"
related intrinsics, but now I think that's more confusing than helpful.
Initially, the LangRef specified that this would create a new kind of
allocation that would be allocated at a fixed offset from the frame
pointer (EBP/RBP). We ended up dropping that design, and leaving the
stack frame layout alone.
These intrinsics are really about sharing local stack allocations, not
frame pointers. I intend to go further and add an `llvm.localaddress()`
intrinsic that returns whatever register (EBP, ESI, ESP, RBX) is being
used to address locals, which should not be confused with the frame
pointer.
Naming suggestions at this point are welcome, I'm happy to re-run sed.
Reviewers: majnemer, nicholas
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11011
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241633 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r241602. We had a latent bug in SCCP where we would
make a basic block empty and then proceed to ask questions about it's
terminator.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241616 91177308-0d34-0410-b5e6-96231b3b80d8
Surprisingly, this is a correctness issue: the mmx type exists for
calling convention purposes, LLVM doesn't have a zero representation for
them.
This partially fixes PR23999.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241142 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
nsw are flaky and can often be removed by optimizations. This patch enhances
nsw by leveraging @llvm.assume in the IR. Specifically, NaryReassociate now
understands that
assume(a + b >= 0) && assume(a >= 0) ==> a +nsw b
As a result, it can split more sext(a + b) into sext(a) + sext(b) for CSE.
Test Plan: nary-gep.ll
Reviewers: broune, meheff
Subscribers: jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D10822
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241139 91177308-0d34-0410-b5e6-96231b3b80d8
This change extends the detection of base pointers for vector constructs to handle arbitrary phi and select nodes. The existing non-vector code already handles those, so this is basically just extending the vector special case to be less special cased. It still isn't generalized vector handling since we can't handle arbitrary vector instructions (e.g. shufflevectors), but it's a lot closer.
The general structure of the change is as follows:
* Extend the base defining value relation over a subset of vector instructions and vector typed phi & select instructions.
* Move scalarization from before base pointer rewriting to after base pointer rewriting. The extension of the BDV relation is sufficient to find vector base phis for vector inputs.
* Preserve the existing special case logic for when the base of a vector element is locally obvious. This general idea could be extended to the scalar case as well.
Differential Revision: http://reviews.llvm.org/D10461#inline-84275
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240850 91177308-0d34-0410-b5e6-96231b3b80d8
r240214 fixed some UB in IndVarSimplify, and it needed a temporary
`WeakVH` to do it. Add `simplify_type<const WeakVH>` so that this
temporary isn't necessary.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240599 91177308-0d34-0410-b5e6-96231b3b80d8
We performed a simple, but incomplete, intersection when it came time to
CSE instructions. It didn't handle, for example, the 'exact' flag.
This fixes PR23922.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240595 91177308-0d34-0410-b5e6-96231b3b80d8
Reassociate mutated existing instructions in order to form negations
which would create additional reassociate opportunities.
This fixes PR23926.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240593 91177308-0d34-0410-b5e6-96231b3b80d8
Change 1: Unswitching on trivial conditions should always happen regardless of the computed unswitching cost, as really the cost is zero. While there is code to make that happen, the logic that checks the unswitching cost against a threshold was moved to an earlier point (revision 147935) than the point where trivial unswitching is detected, so trivial unswitching is currently blocked by the cost threshold. This change fixes that.
Change 2: Before revision 147935 (from 2012-01-11), the threshold parameter was a per-loop threshold. So an unswitching happened only if the cost of the unswitching was less than the threshold. In an indirect way (and I believe unintentionally), the logic for this since then has been that the threshold is an over-all budget across all loops for all loop unswitching done by a given LoopUnswitch loop pass object. So if an unswitching with cost 100 happens in one function, that in effect reduces the threshold from 100 to 0 for the loops even in another function. This persists for the lifetime of that loop pass object. This makes no difference for most small examples but it is important for large examples. This revision fixes that.
Change 3: The cost is currently calculated as std::min(NumInstructions, 5 * NumBlocks). So a loop with 2 blocks and a million instructions will have an unswitching cost of 10. I changed this to just NumInstructions, as it were before revision 147935, though I'm open to e.g. instead replacing std::min with std::max.
I've tried to make the change minimally invasive while staying with what I think was the original intent of the code.
Submitted on behalf of broune@.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240438 91177308-0d34-0410-b5e6-96231b3b80d8
This patch copies the metadata of the unswitched branch to the newly
crreated branch in loop unswitch pass.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240378 91177308-0d34-0410-b5e6-96231b3b80d8
As with the previous patch, the goal is to turn the class into a general
loop-versioning class. This patch removes any references to loop
distribution.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240352 91177308-0d34-0410-b5e6-96231b3b80d8
Calling operator* on a WeakVH whose Value is null hits undefined
behaviour, since we bind the value to a reference. Instead, go through
`operator Value*` so that we work with the pointer itself.
Found by ubsan.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240214 91177308-0d34-0410-b5e6-96231b3b80d8
The patch is generated using this command:
tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
-checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
llvm/lib/
Thanks to Eugene Kosov for the original patch!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240137 91177308-0d34-0410-b5e6-96231b3b80d8
This is now living in MemoryLocation, which is what it pertains to. It
is also an enum there rather than a static data member which is left
never defined.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239886 91177308-0d34-0410-b5e6-96231b3b80d8
that it is its own entity in the form of MemoryLocation, and update all
the callers.
This is an entirely mechanical change. References to "Location" within
AA subclases become "MemoryLocation", and elsewhere
"AliasAnalysis::Location" becomes "MemoryLocation". Hope that helps
out-of-tree folks update.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239885 91177308-0d34-0410-b5e6-96231b3b80d8
A reduction is a special kind of recurrence. In the loop vectorizer we currently
identify basic reductions. Future patches will extend this to identifying basic
recurrences.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239835 91177308-0d34-0410-b5e6-96231b3b80d8
This change is hopefully NFC. The only tricky part is that I changed the context instruction being used to the branch rather than the comparison. I believe both to be correct, but the branch is strictly more powerful. With the moved code, using the branch instruction is required for the basic block comparison test to return the same result. The previous code was able to directly access both the branch and the comparison where the revised code is not.
Differential Revision: http://reviews.llvm.org/D9652
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239797 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Scalarizer has two data structures that hold information about changes
to the function, Gathered and Scattered. These are cleared in finish()
at the end of runOnFunction() if finish() detects any changes to the
function.
However, finish() was checking for changes by only checking if
Gathered was non-empty. The function visitStore() only modifies
Scattered without touching Gathered. As a result, Scattered could have
ended up having stale data if Scalarizer only scalarized store
instructions. Since the data in Scattered is used during the execution
of the pass, this introduced dangling pointer errors.
The fix is to check whether both Scattered and Gathered are empty
before deciding what to do in finish().
Reviewers: srhines
Reviewed By: srhines
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10422
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239644 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
A side effect of this change is that it IRBuilder now automatically
created debug info locations for new instructions, which is the
same as debug location of insertion point. This is fine for the
functions in questions (GetStoreValueForLoad and
GetMemInstValueForLoad), as they are used in two situations:
* GVN::processLoad, which tries to eliminate a load. In this case
new instructions would have the same debug location as the load they
eventually replace;
* MaterializeAdjustedValue, which adds new instructions to the end
of the basic blocks, which could later be used to replace the load
definition. In this case we don't yet know the way the load would
be eventually replaced (either by assembling the precomputed values
via PHI, or by using them directly), so just using the basic block
strategy seems to be reasonable. There is also a special case
in the code that *would* adjust the location of the last
instruction replacing the load definition to the location of the
load.
Test Plan: regression test suite
Reviewers: echristo, dberlin, dblaikie
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10405
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239585 91177308-0d34-0410-b5e6-96231b3b80d8
