V3MergeCond merges consecutive conditional `_ = cond ? _ : _` and
`if (cond) ...` statements. This patch adds an analysis and ordering
phase that moves statements with identical conditions closer to each
other, in order to enable more merging opportunities. This in turn
eliminates a lot of repeated conditionals which reduced dynamic branch
count and branch misprediction rate. Observed 6.5% improvement on
multi-threaded large designs, at the cost of less than 2% increase in
Verilation speed.
* Tests:Add some more signals to t_const_opt_red.v
* Optimize bit op trees such as ~a[2] & a[1] & ~a[0] to 3'b010 == (3'111 & a)
* Update src/V3Const.cpp
Co-authored-by: Wilson Snyder <wsnyder@wsnyder.org>
* Update src/V3Const.cpp
Co-authored-by: Wilson Snyder <wsnyder@wsnyder.org>
* Update src/V3Const.cpp
Co-authored-by: Wilson Snyder <wsnyder@wsnyder.org>
* Apply clang-format
* Don't edit and-or tree.
* Call matchBitOpTree() after V3Expand does its job.
* Internals: Rename newNodep -> newp. No functional change is intended.
* Internals: Remove m_sels. No functional change is intended.
* Internals: Remove stringstream. No functional change is intended.
* Internals: Use V3Number::bitIs1(). No functional change is intended.
* Internals: Use V3Number instead of std::map. Resolved laek. Result should be same.
* Internals: Resolve overload of setPolarity. No functional change is intended.
* Internals: Pass failure reason. No functional change is intended.
* Internals: Add VNUser::toPtr(). No functional change is intended.
* Internals: Use user4 instead of std::map. No functional change is intended.
* Catch up with the AST style aftre V3Expand
* Internals: Rename Context to VarInfo. No functional change is intended.
* Add some more test case
* tests:Add stats to tests
Update stats in t_merge_cond.pl as matchBitopTree does some of them.
* insert CCast if necessary
* small optimization to remove redundant bit mask
* No quick exit even when unoptimizable node is found.
* Simplify removing redundant And
* simplify
* Revert "Internals: Add VNUser::toPtr(). No functional change is intended."
This reverts commit f98dce10db.
* Consider AstWordSel and cleanup
* Update test
* Update src/V3Const.cpp
Co-authored-by: Wilson Snyder <wsnyder@wsnyder.org>
* Update src/V3Const.cpp
Co-authored-by: Wilson Snyder <wsnyder@wsnyder.org>
* Update src/V3Const.cpp
Co-authored-by: Wilson Snyder <wsnyder@wsnyder.org>
* Update src/V3Const.cpp
Co-authored-by: Wilson Snyder <wsnyder@wsnyder.org>
* Update src/V3Const.cpp
Co-authored-by: Wilson Snyder <wsnyder@wsnyder.org>
* Update src/V3Const.cpp
Co-authored-by: Wilson Snyder <wsnyder@wsnyder.org>
* Apply clang-format
* Internals: rename variables. No functional change is intended.
Co-authored-by: Wilson Snyder <wsnyder@wsnyder.org>
Co-authored-by: github action <action@example.com>
- Do try to merge after assignment to condition when possible.
- Do not try to merge reduced form if not the expected statement.
This used to cause a crash.
This provides minor simulation performance benefit, but can provide
large C++ compilation time improvement, notably with Clang (4x).
This patch implements #2366 .
