This patch adds a new transferToOtherSystem helper that tries to
transfer information from signed predicates to the unsigned system and
vice versa.
The initial version adds A >=u B for A >=s B && B >=s 0
https://alive2.llvm.org/ce/z/8b6F9i
This patch adds initial support for signed conditions. To do so,
ConstraintElimination maintains two separate systems, one with facts
from signed and one for unsigned conditions.
To start with this means information from signed and unsigned conditions
is kept completely separate. When it is safe to do so, information from
signed conditions may be also transferred to the unsigned system and
vice versa. That's left for follow-ups.
In the initial version, de-composition of signed values just handles
constants and otherwise just uses the value, without trying to
decompose the operation. Again this can be extended in follow-up
changes.
The main benefit of this limited signed support is proving >=s 0
pre-conditions added in D118799. But even this initial version also
fixes PR53273.
Depends on D118799.
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D118806
With this patch pre-conditions can be added to a list of constraints.
Constraints with pre-conditions can only be used if all pre-conditions
are satisfied when the constraint is used.
The pre-conditions at the moment are specified as a list of
(Predicate, Value *,Value *) tuples. This allow easily checking them
like any other condition, using the existing infrastructure.
This then is used to limit GEP decomposition to cases where we can
prove that offsets are signed positive.
This fixes a couple of incorrect transforms where GEP offsets where
assumed to be signed positive, but they were not.
Note that this effectively disables GEP decomposition, as there's no
support for reasoning about signed predicates. D118806 adds initial
signed support.
Fixes PR49624.
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D118799
The legacy PM is deprecated, so update a bunch of lit tests running
opt to use the new PM syntax when specifying the pipeline.
In this patch focus has been put on test cases for ConstantMerge,
ConstraintElimination, CorrelatedValuePropagation, GlobalDCE,
GlobalOpt, SCCP, TailCallElim and PredicateInfo.
Differential Revision: https://reviews.llvm.org/D114516
This patch reduces the bitwidth of types certain tests operate and gets
rid of a number of @use(i1) calls and xor's the conditions together
instead, which eliminates all timeouts when verifying the tests.
See https://github.com/AliveToolkit/alive2/issues/744 for more details.
Florian Hahn