Summary:
It is fairly common to call SE->getConstant(Ty, 0) or
SE->getConstant(Ty, 1); this change makes such uses a little bit
briefer.
I've refactored the call sites I could find easily to use getZero /
getOne.
Reviewers: hfinkel, majnemer, reames
Subscribers: sanjoy, llvm-commits
Differential Revision: http://reviews.llvm.org/D12947
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248362 91177308-0d34-0410-b5e6-96231b3b80d8
Add two new ways of accessing the unsafe stack pointer:
* At a fixed offset from the thread TLS base. This is very similar to
StackProtector cookies, but we plan to extend it to other backends
(ARM in particular) soon. Bionic-side implementation here:
https://android-review.googlesource.com/170988.
* Via a function call, as a fallback for platforms that provide
neither a fixed TLS slot, nor a reasonable TLS implementation (i.e.
not emutls).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248357 91177308-0d34-0410-b5e6-96231b3b80d8
Apart from checking that GlobalVariable is a constant, we should check
that it's not a weak constant, in which case we can't propagate its
value.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248327 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
We should either require the DT info to be available, or check if it's
available in every place we use DT (and we already miss such check in
one place, which causes failures in some cases). As other loop passes
preserve DT and it's usually available, it makes sense to just require
it here.
There is no regression test, because the bug only shows up if pass
manager decides to clean DT info right before LoopUnswitch. If
loop-unswitch is run separately, DT is available, so bug isn't exposed.
Reviewers: chandlerc, hfinkel
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D13036
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248230 91177308-0d34-0410-b5e6-96231b3b80d8
We know that an argmemonly function can only access memory pointed to by it's pointer arguments. Rather than needing to consider all possible stores as aliasing (as we do for a readonly function), we can only consider the aliasing of the pointer arguments.
Note that this change only addresses hoisting. I'm thinking about how to address speculation safety as well, but that will be a different change.
FYI, argmemonly disallows accessing memory through non-pointer typed arguments.
Differential Revision: http://reviews.llvm.org/D12771
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248220 91177308-0d34-0410-b5e6-96231b3b80d8
We're currently losing any fast-math flags when synthesizing fcmps for
min/max reductions. In LV, make sure we copy over the scalar inst's
flags. In LoopUtils, we know we only ever match patterns with
hasUnsafeAlgebra, so apply that to any synthesized ops.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248201 91177308-0d34-0410-b5e6-96231b3b80d8
evaluate whether 'readonly' or 'readnone' apply to a given function.
This both reduces indentation and will make it easy to share the logic
with a new pass manager implementation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248181 91177308-0d34-0410-b5e6-96231b3b80d8
Because -indvars widens induction variables through arithmetic,
`NeverNegative` cannot be a property of the `WidenIV` (a `WidenIV`
manages information for all transitive uses of an IV being widened,
including uses of `-1 * IV`). Instead it must live on `NarrowIVDefUse`
which manages information for a specific def-use edge in the transitive
use list of an induction variable.
This change also adds a test case that demonstrates the problem with
r248045.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248107 91177308-0d34-0410-b5e6-96231b3b80d8
(icmp eq (ashr C1, %V) -1) may have multiple answers if C1 is not a
power of two and has the sign bit set.
This fixes PR24873.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248074 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
If an induction variable is provably non-negative, its sign extension is
equal to its zero extension. This means narrow uses like
icmp slt iNarrow %indvar, %rhs
can be widened into
icmp slt iWide zext(%indvar), sext(%rhs)
Reviewers: atrick, mcrosier, hfinkel
Subscribers: hfinkel, reames, llvm-commits
Differential Revision: http://reviews.llvm.org/D12745
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248045 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
`signum(x)` is sometimes implemented as `(x >> 63) | (-x >>> 63)` (for
an `i64` `x`). This change adds a matcher for that pattern, and an
instcombine rule to optimize `signum(x) s< 1`.
Later, we can also consider optimizing:
icmp slt signum(x), 0 --> icmp slt x, 0
icmp sle signum(x), 1 --> true
etc.
Reviewers: majnemer
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D12703
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247846 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds support for msan on aarch64-linux for both 39 and
42-bit VMA. The support is enabled by defining the
SANITIZER_AARCH64_VMA compiler flag to either 39 or 42 at build time
for both clang/llvm and compiler-rt. The default VMA is 39 bits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247807 91177308-0d34-0410-b5e6-96231b3b80d8
We only checked that a global is initialized with constants, which is
incorrect. We should be checking that GlobalVariable *is* a constant,
not just initialized with it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247769 91177308-0d34-0410-b5e6-96231b3b80d8
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
