Fixes#6455
This commit adds support for array reduction methods (sum, product, and, or, xor)
with 'with' clauses in randomization constraints. Previously, expressions like
'array.sum() with (int'(item == value))' were not supported in constraints.
Implementation details:
- Added handler in ConstraintExprVisitor::visit(AstCMethodHard*) for
ARRAY_R_SUM, ARRAY_R_PRODUCT, ARRAY_R_AND, ARRAY_R_OR, ARRAY_R_XOR
- Substitutes lambda argument references (item/index) in the with expression
- Generates appropriate SMT operations (bvadd, bvmul, bvand, bvor, bvxor)
- Uses correct identity elements for each reduction operation
- Marks non-constant nodes with user1() flag to ensure proper SMT code generation
The implementation follows the same pattern as the existing ARRAY_INSIDE handler,
generating SMT expressions at Verilator compile time that are evaluated by the
constraint solver at runtime.
- Allow reordering pure statements with DPI import calls iff no public
variables (including those read via a DPI export) are involved. This
ensures the DPI import can't observe the reordering
- Allow reordering of pure statements with AstDisplay and AstStop. This
requires an assumption that AstDisplay and AstStop will not read or
write model state other than via a VarRef explicitly present int the
Ast.
Overall this allows eliminating a lot of conditionals around assertions,
which were previously not possible.
Introduce new pass that converts impure expressions, or those with
function and method calls into simple assignment statements. Please see
the blurb at the top of the file why this is useful and how it works.
In particular currently it enables more Dfg optimization as functions
will be inlined without AstExprStmt.
Ideally we should enforce this lowering is applied to every procedural
statement (there are still a handful of exceptions). With that, long
term with this pass + #6820, there should be no need to ever use an
AstExprStmt past this new lowering pass, which should enable more easier
optimization down the line.
Also ideally this should be run earlier. Currently it's after V3Tristate
as that calls pinReconnectSimple so we don't have to touch Cell ports.
Currently disabled when code coverage is enabled due to #7119.
Rahul Behl
dependabot[bot]
Yilou Wang
Wilson Snyder
Geza Lore
Pawel Kojma
Szymon Gizler
Ryszard Rozak
Kamil Danecki
Todd Strader
Nick Brereton
Veripool API Bot
em2machine
AUDIY
Gilberto Abram