Same as the other ConstantRange overflow checking methods, but for
unsigned mul. In this case there is no cheap overflow criterion, so
using umul_ov for the implementation.
Differential Revision: https://reviews.llvm.org/D60574
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358228 91177308-0d34-0410-b5e6-96231b3b80d8
This extends D59959 to unionWith(), allowing to specify that a
non-wrapping unsigned/signed range is preferred. This is somewhat
less useful than the intersect case, because union operations are
rarer. An example use would the the phi union computed in SCEV.
The implementation is mostly a straightforward use of getPreferredRange(),
but I also had to adjust some <=/< checks to make sure that no ranges with
lower==upper get constructed before they're passed to getPreferredRange(),
as these have additional constraints.
Differential Revision: https://reviews.llvm.org/D60377
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357876 91177308-0d34-0410-b5e6-96231b3b80d8
Extract the exhaustive intersection tests into a separate function,
so that it may be reused for unions as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357874 91177308-0d34-0410-b5e6-96231b3b80d8
The intersection of two ConstantRanges may consist of two disjoint
ranges. As we can only return one range as the result, we need to
return one of the two possible ranges that cover both. Currently the
result is picked based on set size. However, this is not always
optimal: If we're in an unsigned context, we'd prefer to get a large
unsigned range over a small signed range -- the latter effectively
becomes a full set in the unsigned domain.
This revision adds a PreferredRangeType, which can be either Smallest,
Unsigned or Signed. Smallest is the current behavior and Unsigned and
Signed are new variants that prefer not to wrap the unsigned/signed
domain. The new type isn't used anywhere yet (but SCEV will be a good
first user, see D60035).
I've also added some comments to illustrate the various cases in
intersectWith(), which should hopefully make it more obvious what is
going on.
Differential Revision: https://reviews.llvm.org/D59959
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357873 91177308-0d34-0410-b5e6-96231b3b80d8
Add isAllNegative() and isAllNonNegative() methods to ConstantRange,
which determine whether all values in the constant range are
negative/non-negative.
This is useful for replacing KnownBits isNegative() and isNonNegative()
calls when changing code to use constant ranges.
Differential Revision: https://reviews.llvm.org/D60264
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357871 91177308-0d34-0410-b5e6-96231b3b80d8
if we do SHL of two 16-bit ranges like [0, 30000) with [1,2) we get
"full-set" instead of what I would have expected [0, 60000) which is
still in the 16-bit unsigned range.
This patch changes the SHL algorithm to allow getting a usable range
even in this case.
Differential Revision: https://reviews.llvm.org/D57983
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357854 91177308-0d34-0410-b5e6-96231b3b80d8
Add a test that checks the intersectWith() implementation against
all 4-bit range pairs. The test uses a more explicit way of
calculating the possible intersections, and checks that the right
one is picked out according to the smallest set heuristic.
This is in preparation for introducing intersectWith() variants that
use different heuristics to pick an intersection range, if there are
multiple possibilities.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357119 91177308-0d34-0410-b5e6-96231b3b80d8
Split off from D59749. This adds isWrappedSet() and
isUpperSignWrapped() set with the same behavior as isSignWrappedSet()
and isUpperWrapped() for the respectively other domain.
The methods isWrappedSet() and isSignWrappedSet() will not consider
ranges of the form [X, Max] == [X, 0) and [X, SignedMax] == [X, SignedMin)
to be wrapping, while isUpperWrapped() and isUpperSignWrapped() will.
Also replace the checks in getUnsignedMin() and friends with method
calls that implement the same logic.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357112 91177308-0d34-0410-b5e6-96231b3b80d8
Split out from D59749. The current implementation of isWrappedSet()
doesn't do what it says on the tin, and treats ranges like
[X, Max] as wrapping, because they are represented as [X, 0) when
using half-inclusive ranges. This also makes it inconsistent with
the semantics of isSignWrappedSet().
This patch renames isWrappedSet() to isUpperWrapped(), in preparation
for the introduction of a new isWrappedSet() method with corrected
behavior.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357107 91177308-0d34-0410-b5e6-96231b3b80d8
Split off from D59749. This uses a simpler and more efficient
implementation of isSignWrappedSet(), and considers full sets
as non-wrapped, to be consistent with isWrappedSet(). Otherwise
the behavior is unchanged.
There are currently only two users of this function and both already
check for isFullSet() || isSignWrappedSet(), so this is not going to
cause a change in overall behavior.
Differential Revision: https://reviews.llvm.org/D59848
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357039 91177308-0d34-0410-b5e6-96231b3b80d8
This adds ConstantRange::getFull(BitWidth) and
ConstantRange::getEmpty(BitWidth) named constructors as more readable
alternatives to the current ConstantRange(BitWidth, /* full */ false)
and similar. Additionally private getFull() and getEmpty() member
functions are added which return a full/empty range with the same bit
width -- these are commonly needed inside ConstantRange.cpp.
The IsFullSet argument in the ConstantRange(BitWidth, IsFullSet)
constructor is now mandatory for the few usages that still make use of it.
Differential Revision: https://reviews.llvm.org/D59716
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@356852 91177308-0d34-0410-b5e6-96231b3b80d8
Following the suggestion in D59450, I'm moving the code for constructing
a ConstantRange from KnownBits out of ValueTracking, which also allows us
to test this code independently.
I'm adding this method to ConstantRange rather than KnownBits (which
would have been a bit nicer API wise) to avoid creating a dependency
from Support to IR, where ConstantRange lives.
Differential Revision: https://reviews.llvm.org/D59475
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@356339 91177308-0d34-0410-b5e6-96231b3b80d8
Add functions to ConstantRange that determine whether the
unsigned/signed addition/subtraction of two ConstantRanges
may/always/never overflows. This will allow checking overflow
conditions based on known constant ranges in addition to known bits.
I'm implementing these methods on ConstantRange to allow them to be
unit tested independently of any ValueTracking machinery. The tests
include exhaustive testing on 4-bit ranges, to make sure the result
is both conservatively correct and maximally precise.
The OverflowResult enum is redeclared on ConstantRange, because
I wanted to avoid a dependency in either direction between
ValueTracking.h and ConstantRange.h.
Differential Revision: https://reviews.llvm.org/D59193
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@356276 91177308-0d34-0410-b5e6-96231b3b80d8
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351636 91177308-0d34-0410-b5e6-96231b3b80d8
Extend the ConstantRange implementation to compute the range of possible values resulting from an arithmetic right shift operation.
There will be a follow up patch to leverage this constant range infrastructure in LazyValueInfo.
Patch by Surya Kumari Jangala!
Differential Revision: https://reviews.llvm.org/D40881
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320976 91177308-0d34-0410-b5e6-96231b3b80d8
r271020 added an early out to skip the signed multiply portion of ConstantRange::multiply. The comment says we don't need to do signed multiply if the range is only positive numbers, but the implemented check only ensures that the start of the range is positive. It doesn't look at the end of the range.
This patch checks the end of the range instead. Because Upper is one more than the end we have to see if its positive or if its one past the last positive number.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302717 91177308-0d34-0410-b5e6-96231b3b80d8
This change teaches getEquivalentICmp to be smarter about generating
ICMP_NE and ICMP_EQ predicates.
An earlier version of this change was landed as rL283057 which had a
use-after-free bug. This new version has a fix for that bug, and a (C++
unittests/) test case that would have triggered it rL283057.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283078 91177308-0d34-0410-b5e6-96231b3b80d8
They've broken the sanitizer-bootstrap bots. Reverting while I investigate.
Original commit messages:
r283057: "[ConstantRange] Make getEquivalentICmp smarter"
r283058: "[SCEV] Rely on ConstantRange instead of custom logic; NFCI"
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283062 91177308-0d34-0410-b5e6-96231b3b80d8
Currently only its unit test uses it, but this will be used in a later
change to simplify some logic in the GuardWidening pass.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270018 91177308-0d34-0410-b5e6-96231b3b80d8
This will be used in a later patch to ScalarEvolution. Right now only
the unit tests exercise the newly added code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262637 91177308-0d34-0410-b5e6-96231b3b80d8
Rename makeNoWrapRegion to a more obvious makeGuaranteedNoWrapRegion,
and add a comment about the counter-intuitive aspects of the function.
This is to help prevent cases like PR26628.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261532 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
Multiplication is not dependent on signedness, so just treating
all input ranges as unsigned is not incorrect. However it will cause
overly pessimistic ranges (such as full-set) when used with signed
negative values.
Teach multiply to try to interpret its inputs as both signed and
unsigned, and then to take the most specific (smallest population)
as its result.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231483 91177308-0d34-0410-b5e6-96231b3b80d8
a bit surprising, as the class is almost entirely abstracted away from
any particular IR, however it encodes the comparsion predicates which
mutate ranges as ICmp predicate codes. This is reasonable as they're
used for both instructions and constants. Thus, it belongs in the IR
library with instructions and constants.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202838 91177308-0d34-0410-b5e6-96231b3b80d8
Nikita Popov