forked from github/verilator
575 lines
26 KiB
C++
575 lines
26 KiB
C++
// -*- mode: C++; c-file-style: "cc-mode" -*-
|
|
//*************************************************************************
|
|
// DESCRIPTION: Verilator: Break case statements up and add Unknown assigns
|
|
//
|
|
// Code available from: https://verilator.org
|
|
//
|
|
//*************************************************************************
|
|
//
|
|
// Copyright 2003-2023 by Wilson Snyder. This program is free software; you
|
|
// can redistribute it and/or modify it under the terms of either the GNU
|
|
// Lesser General Public License Version 3 or the Perl Artistic License
|
|
// Version 2.0.
|
|
// SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
|
|
//
|
|
//*************************************************************************
|
|
// V3Case's Transformations:
|
|
//
|
|
// Each module:
|
|
// TBD: Eliminate tristates by adding __in, __inen, __en wires in parallel
|
|
// Need __en in changed list if a signal is on the LHS of a assign
|
|
// Cases:
|
|
// CASE(v) CASEITEM(items,body) -> IF (OR (EQ (AND v mask)
|
|
// (AND item1 mask))
|
|
// (other items))
|
|
// body
|
|
// Or, converts to a if/else tree.
|
|
// FUTURES:
|
|
// Large 16+ bit tables with constants and no masking (address muxes)
|
|
// Enter all into std::multimap, sort by value and use a tree of < and == compares.
|
|
// "Diagonal" find of {rightmost,leftmost} bit {set,clear}
|
|
// Ignoring mask, check each value is unique (using std::multimap as above?)
|
|
// Each branch is then mask-and-compare operation (IE
|
|
// <000000001_000000000 at midpoint.)
|
|
//
|
|
//*************************************************************************
|
|
|
|
#include "config_build.h"
|
|
#include "verilatedos.h"
|
|
|
|
#include "V3Case.h"
|
|
|
|
#include "V3Ast.h"
|
|
#include "V3Global.h"
|
|
#include "V3Stats.h"
|
|
|
|
#include <algorithm>
|
|
|
|
VL_DEFINE_DEBUG_FUNCTIONS;
|
|
|
|
#define CASE_OVERLAP_WIDTH 16 // Maximum width we can check for overlaps in
|
|
#define CASE_BARF 999999 // Magic width when non-constant
|
|
#define CASE_ENCODER_GROUP_DEPTH 8 // Levels of priority to be ORed together in top IF tree
|
|
|
|
//######################################################################
|
|
|
|
class CaseLintVisitor final : public VNVisitorConst {
|
|
private:
|
|
const AstNodeCase* m_caseExprp
|
|
= nullptr; // Under a CASE value node, if so the relevant case statement
|
|
|
|
// METHODS
|
|
|
|
void visit(AstNodeCase* nodep) override {
|
|
if (VN_IS(nodep, Case) && VN_AS(nodep, Case)->casex()) {
|
|
nodep->v3warn(CASEX, "Suggest casez (with ?'s) in place of casex (with X's)");
|
|
}
|
|
// Detect multiple defaults
|
|
bool hitDefault = false;
|
|
for (AstCaseItem* itemp = nodep->itemsp(); itemp;
|
|
itemp = VN_AS(itemp->nextp(), CaseItem)) {
|
|
if (itemp->isDefault()) {
|
|
if (hitDefault) {
|
|
itemp->v3error("Multiple default statements in case statement.");
|
|
}
|
|
hitDefault = true;
|
|
}
|
|
}
|
|
|
|
// Check for X/Z in non-casex statements
|
|
{
|
|
m_caseExprp = nodep;
|
|
iterateConst(nodep->exprp());
|
|
for (AstCaseItem* itemp = nodep->itemsp(); itemp;
|
|
itemp = VN_AS(itemp->nextp(), CaseItem)) {
|
|
iterateAndNextConstNull(itemp->condsp());
|
|
}
|
|
m_caseExprp = nullptr;
|
|
}
|
|
}
|
|
void visit(AstConst* nodep) override {
|
|
// See also neverItem
|
|
if (m_caseExprp && nodep->num().isFourState()) {
|
|
if (VN_IS(m_caseExprp, GenCase)) {
|
|
nodep->v3error("Use of x/? constant in generate case statement, "
|
|
"(no such thing as 'generate casez')");
|
|
} else if (VN_IS(m_caseExprp, Case) && VN_AS(m_caseExprp, Case)->casex()) {
|
|
// Don't sweat it, we already complained about casex in general
|
|
} else if (VN_IS(m_caseExprp, Case)
|
|
&& (VN_AS(m_caseExprp, Case)->casez()
|
|
|| VN_AS(m_caseExprp, Case)->caseInside())) {
|
|
if (nodep->num().isAnyX()) {
|
|
nodep->v3warn(CASEWITHX, "Use of x constant in casez statement, "
|
|
"(perhaps intended ?/z in constant)");
|
|
}
|
|
} else {
|
|
nodep->v3warn(CASEWITHX, "Use of x/? constant in case statement, "
|
|
"(perhaps intended casex/casez)");
|
|
}
|
|
}
|
|
}
|
|
void visit(AstNode* nodep) override { iterateChildrenConst(nodep); }
|
|
|
|
public:
|
|
// CONSTRUCTORS
|
|
explicit CaseLintVisitor(AstNodeCase* nodep) { iterateConst(nodep); }
|
|
~CaseLintVisitor() override = default;
|
|
};
|
|
|
|
//######################################################################
|
|
// Case state, as a visitor of each AstNode
|
|
|
|
class CaseVisitor final : public VNVisitor {
|
|
private:
|
|
// NODE STATE
|
|
// Cleared each Case
|
|
// AstIf::user3() -> bool. Set true to indicate clone not needed
|
|
const VNUser3InUse m_inuser3;
|
|
|
|
// STATE
|
|
VDouble0 m_statCaseFast; // Statistic tracking
|
|
VDouble0 m_statCaseSlow; // Statistic tracking
|
|
const AstNode* m_alwaysp = nullptr; // Always in which case is located
|
|
|
|
// Per-CASE
|
|
int m_caseWidth = 0; // Width of valueItems
|
|
int m_caseItems = 0; // Number of caseItem unique values
|
|
bool m_caseNoOverlapsAllCovered = false; // Proven to be synopsys parallel_case compliant
|
|
// For each possible value, the case branch we need
|
|
std::array<AstNode*, 1 << CASE_OVERLAP_WIDTH> m_valueItem;
|
|
|
|
// METHODS
|
|
bool caseIsEnumComplete(AstCase* nodep, uint32_t numCases) {
|
|
// Return true if case is across an enum, and every value in the case
|
|
// statement corresponds to one of the enum values
|
|
if (!nodep->uniquePragma() && !nodep->unique0Pragma()) return false;
|
|
AstEnumDType* const enumDtp
|
|
= VN_CAST(nodep->exprp()->dtypep()->skipRefToEnump(), EnumDType);
|
|
if (!enumDtp) return false; // Case isn't enum
|
|
AstBasicDType* const basicp = enumDtp->subDTypep()->basicp();
|
|
if (!basicp) return false; // Not simple type (perhaps IEEE illegal)
|
|
if (basicp->width() > 32) return false;
|
|
// Find all case values into a set
|
|
std::set<uint32_t> caseSet;
|
|
for (uint32_t i = 0; i < numCases; ++i) { // All case items
|
|
if (m_valueItem[i]) caseSet.emplace(i);
|
|
}
|
|
// Find all enum values into a set
|
|
std::set<uint32_t> enumSet;
|
|
for (AstEnumItem* itemp = enumDtp->itemsp(); itemp;
|
|
itemp = VN_AS(itemp->nextp(), EnumItem)) {
|
|
AstConst* const econstp = VN_AS(itemp->valuep(), Const);
|
|
const uint32_t val = econstp->toUInt();
|
|
// UINFO(9, "Complete enum item " << val << ": " << itemp << endl);
|
|
enumSet.emplace(val);
|
|
}
|
|
// If sets match, all covered
|
|
return (caseSet == enumSet);
|
|
}
|
|
bool isCaseTreeFast(AstCase* nodep) {
|
|
int width = 0;
|
|
bool opaque = false;
|
|
m_caseItems = 0;
|
|
m_caseNoOverlapsAllCovered = true;
|
|
for (AstCaseItem* itemp = nodep->itemsp(); itemp;
|
|
itemp = VN_AS(itemp->nextp(), CaseItem)) {
|
|
for (AstNode* icondp = itemp->condsp(); icondp; icondp = icondp->nextp()) {
|
|
if (icondp->width() > width) width = icondp->width();
|
|
if (icondp->isDouble()) opaque = true;
|
|
if (!VN_IS(icondp, Const)) width = CASE_BARF; // Can't parse; not a constant
|
|
m_caseItems++;
|
|
}
|
|
}
|
|
m_caseWidth = width;
|
|
if (width == 0 || width > CASE_OVERLAP_WIDTH || opaque) {
|
|
m_caseNoOverlapsAllCovered = false;
|
|
return false; // Too wide for analysis
|
|
}
|
|
UINFO(8, "Simple case statement: " << nodep << endl);
|
|
const uint32_t numCases = 1UL << m_caseWidth;
|
|
// Zero list of items for each value
|
|
for (uint32_t i = 0; i < numCases; ++i) m_valueItem[i] = nullptr;
|
|
// Now pick up the values for each assignment
|
|
// We can cheat and use uint32_t's because we only support narrow case's
|
|
bool reportedOverlap = false;
|
|
bool reportedSubcase = false;
|
|
for (AstCaseItem* itemp = nodep->itemsp(); itemp;
|
|
itemp = VN_AS(itemp->nextp(), CaseItem)) {
|
|
for (AstNode* icondp = itemp->condsp(); icondp; icondp = icondp->nextp()) {
|
|
// if (debug() >= 9) icondp->dumpTree("- caseitem: ");
|
|
AstConst* const iconstp = VN_AS(icondp, Const);
|
|
UASSERT_OBJ(iconstp, nodep, "above 'can't parse' should have caught this");
|
|
if (neverItem(nodep, iconstp)) {
|
|
// X in casez can't ever be executed
|
|
} else {
|
|
V3Number nummask{itemp, iconstp->width()};
|
|
nummask.opBitsNonX(iconstp->num());
|
|
const uint32_t mask = nummask.toUInt();
|
|
V3Number numval{itemp, iconstp->width()};
|
|
numval.opBitsOne(iconstp->num());
|
|
const uint32_t val = numval.toUInt();
|
|
|
|
uint32_t firstOverlap = 0;
|
|
bool foundOverlap = false;
|
|
bool foundHit = false;
|
|
for (uint32_t i = 0; i < numCases; ++i) {
|
|
if ((i & mask) == val) {
|
|
if (!m_valueItem[i]) {
|
|
m_valueItem[i] = itemp;
|
|
foundHit = true;
|
|
} else if (!foundOverlap) {
|
|
firstOverlap = i;
|
|
foundOverlap = true;
|
|
m_caseNoOverlapsAllCovered = false;
|
|
}
|
|
}
|
|
}
|
|
if (!nodep->priorityPragma()) {
|
|
// If this case statement doesn't have the priority
|
|
// keyword, we want to warn on any overlap.
|
|
if (!reportedOverlap && foundOverlap) {
|
|
icondp->v3warn(CASEOVERLAP, "Case values overlap (example pattern 0x"
|
|
<< std::hex << firstOverlap << ")");
|
|
reportedOverlap = true;
|
|
}
|
|
} else {
|
|
// If this is a priority case, we only want to complain
|
|
// if every possible value for this item is already hit
|
|
// by some other item. This is true if foundHit is
|
|
// false.
|
|
if (!reportedSubcase && !foundHit) {
|
|
icondp->v3warn(CASEOVERLAP,
|
|
"Case item ignored: every matching value is covered "
|
|
"by an earlier item");
|
|
reportedSubcase = true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
// Defaults were moved to last in the caseitem list by V3LinkDot
|
|
if (itemp->isDefault()) { // Case statement's default... Fill the table
|
|
for (uint32_t i = 0; i < numCases; ++i) {
|
|
if (!m_valueItem[i]) m_valueItem[i] = itemp;
|
|
}
|
|
}
|
|
}
|
|
if (!caseIsEnumComplete(nodep, numCases)) {
|
|
for (uint32_t i = 0; i < numCases; ++i) {
|
|
if (!m_valueItem[i]) {
|
|
nodep->v3warn(CASEINCOMPLETE, "Case values incompletely covered "
|
|
"(example pattern 0x"
|
|
<< std::hex << i << ")");
|
|
m_caseNoOverlapsAllCovered = false;
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (m_caseItems <= 3
|
|
// Avoid e.g. priority expanders from going crazy in expansion
|
|
|| (m_caseWidth >= 8 && (m_caseItems <= (m_caseWidth + 1)))) {
|
|
return false; // Not worth simplifying
|
|
}
|
|
|
|
// Convert valueItem from AstCaseItem* to the expression
|
|
// Not done earlier, as we may now have a nullptr because it's just a ";" NOP branch
|
|
for (uint32_t i = 0; i < numCases; ++i) {
|
|
if (AstCaseItem* const itemp = VN_AS(m_valueItem[i], CaseItem)) {
|
|
m_valueItem[i] = itemp->stmtsp();
|
|
}
|
|
}
|
|
return true; // All is fine
|
|
}
|
|
|
|
AstNode* replaceCaseFastRecurse(AstNodeExpr* cexprp, int msb, uint32_t upperValue) {
|
|
if (msb < 0) {
|
|
// There's no space for a IF. We know upperValue is thus down to a specific
|
|
// exact value, so just return the tree value
|
|
// Note can't clone here, as we're going to check for equivalence above
|
|
AstNode* const foundp = m_valueItem[upperValue];
|
|
return foundp;
|
|
} else {
|
|
// Make left and right subtrees
|
|
// cexpr[msb:lsb] == 1
|
|
AstNode* tree0p = replaceCaseFastRecurse(cexprp, msb - 1, upperValue | 0);
|
|
AstNode* tree1p = replaceCaseFastRecurse(
|
|
cexprp, msb - 1, upperValue | (1UL << static_cast<uint32_t>(msb)));
|
|
|
|
if (tree0p == tree1p) {
|
|
// Same logic on both sides, so we can just return one of 'em
|
|
return tree0p;
|
|
}
|
|
// We could have a "checkerboard" with A B A B, we can use the same IF on both edges
|
|
bool same = true;
|
|
for (uint32_t a = upperValue, b = (upperValue | (1UL << msb));
|
|
a < (upperValue | (1UL << msb)); a++, b++) {
|
|
if (m_valueItem[a] != m_valueItem[b]) {
|
|
same = false;
|
|
break;
|
|
}
|
|
}
|
|
if (same) {
|
|
VL_DO_DANGLING(tree1p->deleteTree(), tree1p);
|
|
return tree0p;
|
|
}
|
|
|
|
// Must have differing logic, so make a selection
|
|
|
|
// Case expressions can't be linked twice, so clone them
|
|
if (tree0p && !tree0p->user3()) tree0p = tree0p->cloneTree(true);
|
|
if (tree1p && !tree1p->user3()) tree1p = tree1p->cloneTree(true);
|
|
|
|
// Alternate scheme if we ever do multiple bits at a time:
|
|
// V3Number nummask (cexprp, cexprp->width(), (1UL<<msb));
|
|
// AstNode* and1p = new AstAnd(cexprp->fileline(), cexprp->cloneTree(false),
|
|
// new AstConst(cexprp->fileline(), nummask));
|
|
AstNodeExpr* const and1p
|
|
= new AstSel{cexprp->fileline(), cexprp->cloneTree(false), msb, 1};
|
|
AstNodeExpr* const eqp
|
|
= new AstNeq{cexprp->fileline(), new AstConst{cexprp->fileline(), 0}, and1p};
|
|
AstIf* const ifp = new AstIf{cexprp->fileline(), eqp, tree1p, tree0p};
|
|
ifp->user3(1); // So we don't bother to clone it
|
|
return ifp;
|
|
}
|
|
}
|
|
|
|
void replaceCaseFast(AstCase* nodep) {
|
|
// CASEx(cexpr,....
|
|
// -> tree of IF(msb, IF(msb-1, 11, 10)
|
|
// IF(msb-1, 01, 00))
|
|
AstNodeExpr* const cexprp = nodep->exprp()->unlinkFrBack();
|
|
|
|
if (debug() >= 9) { // LCOV_EXCL_START
|
|
for (uint32_t i = 0; i < (1UL << m_caseWidth); ++i) {
|
|
if (const AstNode* const itemp = m_valueItem[i]) {
|
|
UINFO(9, "Value " << std::hex << i << " " << itemp << endl);
|
|
}
|
|
}
|
|
} // LCOV_EXCL_STOP
|
|
|
|
// Handle any assertions
|
|
replaceCaseParallel(nodep, m_caseNoOverlapsAllCovered);
|
|
|
|
AstNode::user3ClearTree();
|
|
AstNode* ifrootp = replaceCaseFastRecurse(cexprp, m_caseWidth - 1, 0UL);
|
|
// Case expressions can't be linked twice, so clone them
|
|
if (ifrootp && !ifrootp->user3()) ifrootp = ifrootp->cloneTree(true);
|
|
|
|
if (ifrootp) {
|
|
nodep->replaceWith(ifrootp);
|
|
} else {
|
|
nodep->unlinkFrBack();
|
|
}
|
|
VL_DO_DANGLING(nodep->deleteTree(), nodep);
|
|
VL_DO_DANGLING(cexprp->deleteTree(), cexprp);
|
|
if (debug() >= 9) ifrootp->dumpTree("- _simp: ");
|
|
}
|
|
|
|
void replaceCaseComplicated(AstCase* nodep) {
|
|
// CASEx(cexpr,ITEM(icond1,istmts1),ITEM(icond2,istmts2),ITEM(default,istmts3))
|
|
// -> IF((cexpr==icond1),istmts1,
|
|
// IF((EQ (AND MASK cexpr) (AND MASK icond1)
|
|
// ,istmts2, istmts3
|
|
AstNodeExpr* const cexprp = nodep->exprp()->unlinkFrBack();
|
|
// We'll do this in two stages. First stage, convert the conditions to
|
|
// the appropriate IF AND terms.
|
|
if (debug() >= 9) nodep->dumpTree("- _comp_IN::: ");
|
|
bool hadDefault = false;
|
|
for (AstCaseItem* itemp = nodep->itemsp(); itemp;
|
|
itemp = VN_AS(itemp->nextp(), CaseItem)) {
|
|
if (!itemp->condsp()) {
|
|
// Default clause. Just make true, we'll optimize it away later
|
|
itemp->addCondsp(new AstConst{itemp->fileline(), AstConst::BitTrue{}});
|
|
hadDefault = true;
|
|
} else {
|
|
// Expressioned clause
|
|
AstNodeExpr* icondNextp = nullptr;
|
|
AstNodeExpr* ifexprp = nullptr; // If expression to test
|
|
for (AstNodeExpr* icondp = itemp->condsp(); icondp; icondp = icondNextp) {
|
|
icondNextp = VN_AS(icondp->nextp(), NodeExpr);
|
|
icondp->unlinkFrBack();
|
|
|
|
AstNodeExpr* condp = nullptr; // Default is to use and1p/and2p
|
|
AstConst* const iconstp = VN_CAST(icondp, Const);
|
|
if (iconstp && neverItem(nodep, iconstp)) {
|
|
// X in casez can't ever be executed
|
|
VL_DO_DANGLING(icondp->deleteTree(), icondp);
|
|
VL_DANGLING(iconstp);
|
|
// For simplicity, make expression that is not equal, and let later
|
|
// optimizations remove it
|
|
condp = new AstConst{itemp->fileline(), AstConst::BitFalse{}};
|
|
} else if (AstInsideRange* const irangep = VN_CAST(icondp, InsideRange)) {
|
|
// Similar logic in V3Width::visit(AstInside)
|
|
condp = irangep->newAndFromInside(cexprp, irangep->lhsp()->unlinkFrBack(),
|
|
irangep->rhsp()->unlinkFrBack());
|
|
} else if (iconstp && iconstp->num().isFourState()
|
|
&& (nodep->casex() || nodep->casez() || nodep->caseInside())) {
|
|
V3Number nummask{itemp, iconstp->width()};
|
|
nummask.opBitsNonX(iconstp->num());
|
|
V3Number numval{itemp, iconstp->width()};
|
|
numval.opBitsOne(iconstp->num());
|
|
AstNodeExpr* const and1p
|
|
= new AstAnd{itemp->fileline(), cexprp->cloneTree(false),
|
|
new AstConst{itemp->fileline(), nummask}};
|
|
AstNodeExpr* const and2p = new AstAnd{
|
|
itemp->fileline(), new AstConst{itemp->fileline(), numval},
|
|
new AstConst{itemp->fileline(), nummask}};
|
|
VL_DO_DANGLING(icondp->deleteTree(), icondp);
|
|
VL_DANGLING(iconstp);
|
|
condp = AstEq::newTyped(itemp->fileline(), and1p, and2p);
|
|
} else {
|
|
// Not a caseX mask, we can build CASEEQ(cexpr icond)
|
|
AstNodeExpr* const and1p = cexprp->cloneTree(false);
|
|
AstNodeExpr* const and2p = icondp;
|
|
condp = AstEq::newTyped(itemp->fileline(), and1p, and2p);
|
|
}
|
|
if (!ifexprp) {
|
|
ifexprp = condp;
|
|
} else {
|
|
ifexprp = new AstLogOr{itemp->fileline(), ifexprp, condp};
|
|
}
|
|
}
|
|
// Replace expression in tree
|
|
itemp->addCondsp(ifexprp);
|
|
}
|
|
}
|
|
VL_DO_DANGLING(cexprp->deleteTree(), cexprp);
|
|
if (!hadDefault) {
|
|
// If there was no default, add a empty one, this greatly simplifies below code
|
|
// and constant propagation will just eliminate it for us later.
|
|
nodep->addItemsp(new AstCaseItem{
|
|
nodep->fileline(), new AstConst{nodep->fileline(), AstConst::BitTrue{}}, nullptr});
|
|
}
|
|
if (debug() >= 9) nodep->dumpTree("- _comp_COND: ");
|
|
// Now build the IF statement tree
|
|
// The tree can be quite huge. Pull ever group of 8 out, and make a OR tree.
|
|
// This reduces the depth for the bottom elements, at the cost of
|
|
// some of the top elements. If we ever have profiling data, we
|
|
// should pull out the most common item from here and instead make
|
|
// it the first IF branch.
|
|
int depth = 0;
|
|
AstNode* grouprootp = nullptr;
|
|
AstIf* groupnextp = nullptr;
|
|
AstIf* itemnextp = nullptr;
|
|
for (AstCaseItem* itemp = nodep->itemsp(); itemp;
|
|
itemp = VN_AS(itemp->nextp(), CaseItem)) {
|
|
AstNode* const istmtsp = itemp->stmtsp(); // Maybe null -- no action.
|
|
if (istmtsp) istmtsp->unlinkFrBackWithNext();
|
|
// Expressioned clause
|
|
AstNodeExpr* const ifexprp = itemp->condsp()->unlinkFrBack();
|
|
{ // Prepare for next group
|
|
if (++depth > CASE_ENCODER_GROUP_DEPTH) depth = 1;
|
|
if (depth == 1) { // First group or starting new group
|
|
itemnextp = nullptr;
|
|
AstIf* const newp = new AstIf{itemp->fileline(), ifexprp->cloneTree(true)};
|
|
if (groupnextp) {
|
|
groupnextp->addElsesp(newp);
|
|
} else {
|
|
grouprootp = newp;
|
|
}
|
|
groupnextp = newp;
|
|
} else { // Continue group, modify if condition to OR in this new condition
|
|
AstNodeExpr* const condp = groupnextp->condp()->unlinkFrBack();
|
|
groupnextp->condp(
|
|
new AstOr{ifexprp->fileline(), condp, ifexprp->cloneTree(true)});
|
|
}
|
|
}
|
|
{ // Make the new lower IF and attach in the tree
|
|
AstNodeExpr* itemexprp = ifexprp;
|
|
VL_DANGLING(ifexprp);
|
|
if (depth == CASE_ENCODER_GROUP_DEPTH) { // End of group - can skip the condition
|
|
VL_DO_DANGLING(itemexprp->deleteTree(), itemexprp);
|
|
itemexprp = new AstConst{itemp->fileline(), AstConst::BitTrue{}};
|
|
}
|
|
AstIf* const newp = new AstIf{itemp->fileline(), itemexprp, istmtsp};
|
|
if (itemnextp) {
|
|
itemnextp->addElsesp(newp);
|
|
} else {
|
|
groupnextp->addThensp(newp); // First in a new group
|
|
}
|
|
itemnextp = newp;
|
|
}
|
|
}
|
|
if (debug() >= 9) nodep->dumpTree("- _comp_TREE: ");
|
|
// Handle any assertions
|
|
replaceCaseParallel(nodep, false);
|
|
// Replace the CASE... with IF...
|
|
if (debug() >= 9 && grouprootp) grouprootp->dumpTree("- _new: ");
|
|
if (grouprootp) {
|
|
nodep->replaceWith(grouprootp);
|
|
} else {
|
|
nodep->unlinkFrBack();
|
|
}
|
|
VL_DO_DANGLING(nodep->deleteTree(), nodep);
|
|
}
|
|
|
|
void replaceCaseParallel(AstCase* nodep, bool noOverlapsAllCovered) {
|
|
// Take the notParallelp tree under the case statement created by V3Assert
|
|
// If the statement was proven to have no overlaps and all cases
|
|
// covered, we're done with it.
|
|
// Else, convert to a normal statement parallel with the case statement.
|
|
if (nodep->notParallelp() && !noOverlapsAllCovered) {
|
|
AstNode* const parp = nodep->notParallelp()->unlinkFrBackWithNext();
|
|
nodep->addNextHere(parp);
|
|
}
|
|
}
|
|
|
|
bool neverItem(AstCase* casep, AstConst* itemp) {
|
|
// Xs in case or casez are impossible due to two state simulations
|
|
if (casep->casex()) {
|
|
} else if (casep->casez() || casep->caseInside()) {
|
|
if (itemp->num().isAnyX()) return true;
|
|
} else {
|
|
if (itemp->num().isFourState()) return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// VISITORS
|
|
void visit(AstCase* nodep) override {
|
|
V3Case::caseLint(nodep);
|
|
iterateChildren(nodep);
|
|
if (debug() >= 9) nodep->dumpTree("- case_old: ");
|
|
if (isCaseTreeFast(nodep) && v3Global.opt.fCase()) {
|
|
// It's a simple priority encoder or complete statement
|
|
// we can make a tree of statements to avoid extra comparisons
|
|
++m_statCaseFast;
|
|
VL_DO_DANGLING(replaceCaseFast(nodep), nodep);
|
|
} else {
|
|
// If a case statement is whole, presume signals involved aren't forming a latch
|
|
if (m_alwaysp) m_alwaysp->fileline()->warnOff(V3ErrorCode::LATCH, true);
|
|
++m_statCaseSlow;
|
|
VL_DO_DANGLING(replaceCaseComplicated(nodep), nodep);
|
|
}
|
|
}
|
|
//--------------------
|
|
void visit(AstNode* nodep) override {
|
|
if (VN_IS(nodep, Always)) m_alwaysp = nodep;
|
|
iterateChildren(nodep);
|
|
}
|
|
|
|
public:
|
|
// CONSTRUCTORS
|
|
explicit CaseVisitor(AstNetlist* nodep) {
|
|
for (auto& itr : m_valueItem) itr = nullptr;
|
|
iterate(nodep);
|
|
}
|
|
~CaseVisitor() override {
|
|
V3Stats::addStat("Optimizations, Cases parallelized", m_statCaseFast);
|
|
V3Stats::addStat("Optimizations, Cases complex", m_statCaseSlow);
|
|
}
|
|
};
|
|
|
|
//######################################################################
|
|
// Case class functions
|
|
|
|
void V3Case::caseAll(AstNetlist* nodep) {
|
|
UINFO(2, __FUNCTION__ << ": " << endl);
|
|
{ CaseVisitor{nodep}; } // Destruct before checking
|
|
V3Global::dumpCheckGlobalTree("case", 0, dumpTree() >= 3);
|
|
}
|
|
void V3Case::caseLint(AstNodeCase* nodep) {
|
|
UINFO(4, __FUNCTION__ << ": " << endl);
|
|
{ CaseLintVisitor{nodep}; }
|
|
}
|