This patch implements #6480. All loop statements are represented using
AstLoop and AstLoopTest.
This necessitates rework of the loop unroller to handle loops of
arbitrary form. To enable this, I have split the old unroller used for
'generate for' statements and moved it into V3Param, and subsequently
rewrote V3Unroll to handle the new representation. V3Unroll can now
unroll more complex loops, including with loop conditions containing
multiple variable references or inlined functions.
Handling the more generic code also requires some restrictions. If a
loop contains any of the following, it cannot be unrolled:
- A timing control that might suspend the loop
- A non-inlined call to a non-pure function
These constructs can change the values of variables in the loop, so are
generally not safe to unroll if they are present. (We could still unroll
if all the variables needed for unrolling are automatic, however we
don't do that right now.)
These restrictions seem ok in the benchmark suite, where the new
unroller can generally unroll many more loops than before.
Added test for a particularly convoluted case requiring fixup in
V3Premit. To help with statistics stability, also prevent V3Premit from
introducing temporaries for assignment where the RHS reads the LHS, but
the assignment is known to be atomic (by emitted C++ semantics).
Also rename `createWideTemp` to `createTemp`, as it is used for non-wide
expressions as well.
When the condition of an AstWhile loop contains a statement (e.g.
through an AstExprStmt), temporaries inserted in that statement need to
go before that statement, not in the AstWhile precondition.
- Enable creating constant pool entries for RHS of simple
var = const assignments
- Never extract ArraySel (it's just pointer arithmetic)
- Remove unnecessary AstTraceInc precond child tree
- Always fully recurse expressions (fix transplanted from #4617)
- General cleanup
Overall the patch is performance neutral to slightly positive, but saves
~10% peak Verialtor memory usage due to not creating temporaries (which
are later expanded) for any ArraySels.
Apart from the representational changes below, this patch renames
AstNodeMath to AstNodeExpr, and AstCMath to AstCExpr.
Now every expression (i.e.: those AstNodes that represent a [possibly
void] value, with value being interpreted in a very general sense) has
AstNodeExpr as a super class. This necessitates the introduction of an
AstStmtExpr, which represents an expression in statement position, e.g :
'foo();' would be represented as AstStmtExpr(AstCCall(foo)). In exchange
we can get rid of isStatement() in AstNodeStmt, which now really always
represent a statement
Peak memory consumption and verilation speed are not measurably changed.
Partial step towards #3420
- Rename `--dump-treei` option to `--dumpi-tree`, which itself is now a
special case of `--dumpi-<tag>` where tag can be a magic word, or a
filename
- Control dumping via static `dump*()` functions, analogous to `debug()`
- Make dumping independent of the value of `debug()` (so dumping always
works even without the debug flag)
- Add separate `--dumpi-graph` for dumping V3Graphs, which is again a
special case of `--dumpi-<tag>`
- Alias `--dump-<tag>` to `--dumpi-<tag> 3` as before
Introduce the @astgen directives parsed by astgen, currently used for
the generation child node (operand) accessors. Please see the updated
internal documentation for details.
Geza Lore
Wilson Snyder
Ryszard Rozak
Brian Li
Arkadiusz Kozdra
Szymon Gizler
github action
Mariusz Glebocki
HungMingWu