In `IndVarSimplify::ExpandSCEVIfNeeded`,
`SCEVExpander::findExistingExpansion` may return an `llvm::Value` that
differs in type from the SCEV it was asked to find an expansion for (but
computes the same value). In such cases, we fall back on
`expandCodeFor`; and rely on LLVM to CSE the two equivalent
expressions (different only by a no-op cast) into a single computation.
I tried a few other approaches to fixing PR24783, all of which turned
out to be more complex than this current version:
1. Move the `ExpandSCEVIfNeeded` logic into `expandCodeFor`. This got
problematic because currently we do not pass in the `Loop *` into
`expandCodeFor`. Changing the interface to do this is a more
invasive change, and really does not make much semantic sense unless
the SCEV being passed in is an add recurrence.
There is also the problem of `expandCodeFor` being used in places
other than `indvars` -- there may be performance / correctness
issues elsewhere if `expandCodeFor` is moved from always generating
IR from scratch to cache-like model.
2. Have `findExistingExpansion` only return expression with the correct
type. This would make `isHighCostExpansionHelper` and thus
`isHighCostExpansion` more conservative than necessary.
3. Insert casts on the value returned by `findExistingExpansion` if
needed using `InsertNoopCastOfTo`. This is complicated because
`InsertNoopCastOfTo` depends on internal state of its
`SCEVExpander` (specifically `Builder.GetInserPoint()`), and this
may not be set up when `ExpandSCEVIfNeeded` is called.
4. Manually insert casts on the value returned by
`findExistingExpansion` if needed using `InsertNoopCastOfTo` via
`CastInst::Create`. This is probably workable, but figuring out the
location where the cast instruction needs to be inserted has enough
edge cases (arguments, constants, invokes, LCSSA must be preserved)
makes me feel what I have right now is simplest solution.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247749 91177308-0d34-0410-b5e6-96231b3b80d8
These sections contain pointers to function that should be invoked
during startup/shutdown by __libc_csu_init and __libc_csu_fini.
Instrumenting these globals will append redzone to them, which will be
filled with zeroes. This will cause null pointer dereference at runtime.
Merge ASan regression tests for globals that should be ignored by
instrumentation pass.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247734 91177308-0d34-0410-b5e6-96231b3b80d8
The patch extends the optimization to cases where the constant's
magnitude is so small or large that the rounding of the conversion
is irrelevant. The "so small" case includes negative zero.
Differential review: http://reviews.llvm.org/D11210
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247708 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This change lets a `PlaceSafepoints` client change how wide the trip
count of a loop has to be for the loop to be considerd "counted", via
`CountedLoopTripWidth`. It also removes the boolean `SkipCounted` flag
and the `upperTripBound` constant -- we can get the old behavior of
`SkipCounted` == `false` by setting `CountedLoopTripWidth` to `13` (2 ^
13 == 8192).
Reviewers: reames
Subscribers: llvm-commits, sanjoy
Differential Revision: http://reviews.llvm.org/D12789
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247656 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: This patch replaces isKnownNonNull() with isKnownNonNullAt() when checking nullness of passing arguments at callsite. In this way it can handle cases where the argument does not have nonnull attribute but has a dominating null check from the CFG. It also adds assertions in isKnownNonNull() and isKnownNonNullFromDominatingCondition() to make sure the value checked is pointer type (as defined in LLVM document). These assertions might trip failures in things which are not covered under llvm/test, but fixes should be pretty obvious.
Reviewers: reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D12779
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247587 91177308-0d34-0410-b5e6-96231b3b80d8
This was a flawed change - it just caused the getElementType call to be
deferred until later, when we really need to remove it. Now that the IR
for GlobalAliases has been updated, the root cause is addressed that way
instead and this change is no longer needed (and in fact gets in the way
- because we want to pass the pointee type directly down further).
Follow up patches to push this through GlobalValue, bitcode format, etc,
will come along soon.
This reverts commit 236160.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247585 91177308-0d34-0410-b5e6-96231b3b80d8
GetElementPointers must have the first argument's type compared
for structural equivalence. Previously the code erroneously compared the
pointer's type, but this code was dead because all pointer types (of the
same address space) are the same. The pointee must be compared instead
(using the type stored in the GEP, not from the pointer type which will
be erased anyway).
Author: jrkoenig
Reviewers: dschuff, nlewycky, jfb
Subscribers: nlewycky, llvm-commits
Differential revision: http://reviews.llvm.org/D12820
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247570 91177308-0d34-0410-b5e6-96231b3b80d8
that could be used from a new pass manager. This one makes particular
sense as a static helper as it doesn't even need TLI.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247525 91177308-0d34-0410-b5e6-96231b3b80d8
of a method and into a re-usable static helper. We can potentially use
this function from the implementation of a new pass manager oriented
version of the pass. Also add some better documentation of exactly what
the semantic model of this routine is (it isn't trivial) and use a more
modern naming convention for it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247524 91177308-0d34-0410-b5e6-96231b3b80d8
static function rather than a method. It just needed access to
TargetLibraryInfo, and this way it can be easily reused between the
current FunctionAttrs implementation and any port for the new pass
manager.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247522 91177308-0d34-0410-b5e6-96231b3b80d8
methods. They don't need anything from the class anyways.
Also, collect the declarations into the private section of the pass.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247521 91177308-0d34-0410-b5e6-96231b3b80d8
comments, deleting duplicate comments, moving comments to consistently
live on the definition since these are all really internal routines,
etc. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247520 91177308-0d34-0410-b5e6-96231b3b80d8
Improved InstCombine support for CVTPH2PS (F16C half 2 float conversion):
<4 x float> @llvm.x86.vcvtph2ps.128(<8 x i16>) - only uses the bottom 4 i16 elements for the conversion.
Added constant folding support.
Differential Revision: http://reviews.llvm.org/D12731
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247504 91177308-0d34-0410-b5e6-96231b3b80d8
In some ways this is a very boring port to the new pass manager as there
are no interesting analyses or dependencies or other oddities.
However, this does introduce the first good example of a transformation
pass with non-trivial state porting to the new pass manager. I've tried
to carve out patterns here to replicate elsewhere, and would appreciate
comments on whether folks like these patterns:
- A common need in the new pass manager is to effectively lift the pass
class and some of its state into a public header file. Prior to this,
LLVM used anonymous namespaces to provide "module private" types and
utilities, but that doesn't scale to cases where a public header file
is needed and the new pass manager will exacerbate that. The pattern
I've adopted here is to use the namespace-cased-name of the core pass
(what would be a module if we had them) as a module-private namespace.
Then utility and other code can be declared and defined in this
namespace. At some point in the future, we could even have
(conditionally compiled) code that used modules features when
available to do the same basic thing.
- I've split the actual pass run method in two in order to expose
a private method usable by the old pass manager to wrap the new class
with a minimum of duplicated code. I actually looked at a bunch of
ways to automate or generate these, but they are all quite terrible
IMO. The fundamental need is to extract the set of analyses which need
to cross this interface boundary, and that will end up being too
unpredictable to effectively encapsulate IMO. This is also
a relatively small amount of boiler plate that will live a relatively
short time, so I'm not too worried about the fact that it is boiler
plate.
The rest of the patch is totally boring but results in a massive diff
(sorry). It just moves code around and removes or adds qualifiers to
reflect the new name and nesting structure.
Differential Revision: http://reviews.llvm.org/D12773
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247501 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: This patch replaces isKnownNonNull() with isKnownNonNullAt() when checking nullness of passing arguments at callsite. In this way it can handle cases where the argument does not have nonnull attribute but has a dominating null check from the CFG.
Reviewers: reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D12779
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247356 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: This patch replaces isKnownNonNull() with isKnownNonNullAt() when checking nullness of gc.relocate return value. In this way it can handle cases where the relocated value does not have nonnull attribute but has a dominating null check from the CFG.
Reviewers: reames
Subscribers: llvm-commits, sanjoy
Differential Revision: http://reviews.llvm.org/D12772
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247353 91177308-0d34-0410-b5e6-96231b3b80d8
This patch enables small size reductions in which the source types are smaller
than the reduction type (e.g., computing an i16 sum from the values in an i8
array). The previous behavior was to only allow small size reductions if the
source types and reduction type were the same. The change accounts for the fact
that the existing sign- and zero-extend instructions in these cases should
still be included in the cost model.
Differential Revision: http://reviews.llvm.org/D12770
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247337 91177308-0d34-0410-b5e6-96231b3b80d8
This change correctly sets the attributes on the callsites
generated in thunks. This makes sure things such as sret, sext, etc.
are correctly set, so that the call can be a proper tailcall.
Also, the transfer of attributes in the replaceDirectCallers function
appears to be unnecessary, but until this is confirmed it will remain.
Author: jrkoenig
Reviewers: dschuff, jfb
Subscribers: llvm-commits, nlewycky
Differential revision: http://reviews.llvm.org/D12581
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247313 91177308-0d34-0410-b5e6-96231b3b80d8
This is a follow up to http://reviews.llvm.org/D11995 implementing the suggestion by Hans.
If we know some of the bits of the value being switched on, we know that the maximum number of unique cases covers the unknown bits. This allows to eliminate switch defaults for large integers (i32) when most bits in the value are known.
Note that I had to make the transform contingent on not having any dead cases. This is conservatively correct with the old code, but required for the new code since we might have a dead case which varies one of the known bits. Counting that towards our number of covering cases would be bad. If we do have dead cases, we'll eliminate them first, then revisit the possibly dead default.
Differential Revision: http://reviews.llvm.org/D12497
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247309 91177308-0d34-0410-b5e6-96231b3b80d8
Except the changes that defined virtual destructors as =default, because that
ran into problems with GCC 4.7 and overriding methods that weren't noexcept.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247298 91177308-0d34-0410-b5e6-96231b3b80d8
removes cast by performing the lshr on smaller types. However, currently there
is no trunc(lshr (sext A), Cst) variant.
This patch add such optimization by transforming trunc(lshr (sext A), Cst)
to ashr A, Cst.
Differential Revision: http://reviews.llvm.org/D12520
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247271 91177308-0d34-0410-b5e6-96231b3b80d8
This can give significant improvements to alias analysis in some situations, and improves its testing coverage in all situations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247264 91177308-0d34-0410-b5e6-96231b3b80d8
GlobalsAA must by definition be preserved in function passes, but the passmanager doesn't know that. Make each pass explicitly preserve GlobalsAA.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247263 91177308-0d34-0410-b5e6-96231b3b80d8
The assertion was weaker than it should be and gave the impression we're growing the number of base defining values being considered during the fixed point interation. That's not true. The tighter form of the assert is useful documentation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247221 91177308-0d34-0410-b5e6-96231b3b80d8
Factor out common code related to naming values, fix a small style issue. More to follow in separate changes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247211 91177308-0d34-0410-b5e6-96231b3b80d8
This change is simply enhancing the existing inference algorithm to handle insertelement instructions by conservatively inserting a new instruction to propagate the vector of associated base pointers. In the process, I'm ripping out the peephole optimizations which mostly helped cover the fact this hadn't been done.
Note that most of the newly inserted nodes will be nearly immediately removed by the post insertion optimization pass introduced in 246718. Arguably, we should be trying harder to avoid the malloc traffic here, but I'd rather get the code correct, then worry about compile time.
Unlike previous extensions of the algorithm to handle more case, I discovered the existing code was causing miscompiles in some cases. In particular, we had an implicit assumption that the peephole covered *all* insert element instructions, so if we had a value directly based on a insert element the peephole didn't cover, we proceeded as if it were a base anyways. Not good. I believe we had the same issue with shufflevector which is why I adjusted the predicate for them as well.
Differential Revision: http://reviews.llvm.org/D12583
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247210 91177308-0d34-0410-b5e6-96231b3b80d8
