Introduce support for applying the stripe operator to sum expressions, as in
(x + A) # B = x + A - (x + A) mod B.
This is required to represent a combination of tiling and padding in the SDBM
framework, and is a valid SDBM construct that was not originally supported.
PiperOrigin-RevId: 269758807
Extend SDBM simplification patterns to support more cases where the addition of
two expressions each involving one or two variables would result in a sum
expression that only contains one variable and thus remains in the SDBM domain.
This is made possible by the new canonical structure of SDBM where the constant
term appears once. This simplification will be necessary to support
round-tripping of stripe expressions containing constant terms on the LHS
through affine expressions.
PiperOrigin-RevId: 269757732
Swap the allowed nesting of sum and diff expressions: now a diff expression can
contain a sum expression, but only on the left hand side. A difference of two
expressions sum must be canonicalized by grouping their constant terms in a
single expression. This change of sturcture became possible thanks to the
introduction of the "direct" super-kind. It is necessary to enable support of
sum expressions on the left hand side of the stripe expression.
SDBM expressions are now grouped into the following structure
- expression
- varying
- direct
- sum <- (term, constant)
- term
- symbol
- dimension
- stripe <- (term, constant)
- negation <- (direct)
- difference <- (direct, term)
- constant
The notation <- (...) denotes the types of subexpressions a compound
expression can combine.
PiperOrigin-RevId: 269337222
Direct expressions are those that do not negate any of the variables they
involve. They include input expressions (dimensions and symbols), stripe and
sum expressions, and combinations of those. Reifying direct expressions as a
class is a precondition for enabling additions on the LHS of a stripe
expression.
PiperOrigin-RevId: 269336031
This better reflects how this kind of expressions is used and avoids the
potential confusion since the expression can take negative values. Term
expressions comprise dimensions, symbols and stripe expressions. In an SDBM
domain, a stripe expression always corresponds to a variable, input or
temporary. This expression can appear anywhere an input variable can,
including on the LHS of other stripe expressions.
PiperOrigin-RevId: 268486066
Otherwise, GCC < 7 does not link in the dialect registration, fails to look up
the dialect in the context and cannot construct SDBM objects.
--
PiperOrigin-RevId: 249259758
MLIRContext does not have to be aware of the SDBM unique data structures
directly. Move the SDBM storage uniquer from MLIRContext to the SDBM dialect
instance. Expressions that previously required a context to be constructed now
require an instance of the dialect in order to access the uniquer. While they
could look up the dialect in the context, it would have introduced a rather
expensive lookup into each construction. Instead, the caller is expected to
obtain the dialect instance and cache it.
--
PiperOrigin-RevId: 249245199
We now have sufficient extensibility in dialects to move attribute components
such as SDBM out of the core IR into a dedicated dialect and make them
optional. Introduce an SDBM dialect and move the code. This is a mostly
non-functional change.
--
PiperOrigin-RevId: 249244802
Mehdi Amini