r231483 taught ConstantRange::multiply to be clever about signed vs unsigned ranges. For example, an unsigned range could be full-set while the signed range is more specific than that.
In looking at the allocations trace for LTO'ing verify-uselistorder (see r236629 for details), millions of allocations are from APInt, many of which come from ConstantRange's.
This change tries to avoid some (3.2 million) allocations by returning the unsigned range if its suitable. The checks here are that it should not be a wrapping range, and should be positive. That should be enough to check for ranges such as [1, 10) which the signed range will be equal to, if we were to calculate it.
Differential Revision: http://reviews.llvm.org/D20723
Reviewed by James Molloy
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271020 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 reapplies commit r268521, that was reverted in r268530 due to a test failure in select-implied.ll
Modified the test case to reflect the new change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268557 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
