Commit Graph

4 Commits

Author SHA1 Message Date
Sanjoy Das
da5f3a3ca5 [ConstantRange] Split makeICmpRegion in two.
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
2015-03-18 00:41:24 +00:00
James Molloy
4e022da51e [ConstantRange] Teach multiply to be cleverer about signed ranges.
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
2015-03-06 15:50:47 +00:00
Craig Topper
b177041dfa [C++11] Use 'nullptr'.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210442 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-08 22:29:17 +00:00
Chandler Carruth
19d764fb05 [Modules] Move the ConstantRange class into the IR library. This is
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
2014-03-04 12:24:34 +00:00