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Add --fno-slice to disable array assignment slicing (#5644).

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This commit is contained in:
Wilson Snyder
2024-11-28 13:49:34 -05:00
parent e0ad430cd9
commit 7a8f71e7d8
8 changed files with 117 additions and 28 deletions
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src/V3Slice.cpp
+50 -27
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@@ -39,6 +39,8 @@
#include "V3Slice.h"
#include "V3Stats.h"
VL_DEFINE_DEBUG_FUNCTIONS;
//*************************************************************************
@@ -54,6 +56,9 @@ class SliceVisitor final : public VNVisitor {
// AstInitItem::user2() -> Corresponding first elemIdx
const VNUser2InUse m_inuser2;
// STATE - across all visitors
VDouble0 m_statAssigns; // Statistic tracking
// STATE - for current visit position (use VL_RESTORER)
AstNode* m_assignp = nullptr; // Assignment we are under
bool m_assignError = false; // True if the current assign already has an error
@@ -218,6 +223,46 @@ class SliceVisitor final : public VNVisitor {
return newp;
}
bool assignOptimize(AstNodeAssign* nodep) {
// Return true if did optimization
AstNodeDType* const dtp = nodep->lhsp()->dtypep()->skipRefp();
AstNode* stp = nodep->rhsp();
const AstUnpackArrayDType* const arrayp = VN_CAST(dtp, UnpackArrayDType);
if (!arrayp) return false;
if (VN_IS(stp, CvtPackedToArray)) return false;
// Any isSc variables must be expanded regardless of --fno-slice
const bool hasSc
= nodep->exists([&](const AstVarRef* refp) -> bool { return refp->varp()->isSc(); });
if (!hasSc && !v3Global.opt.fSlice()) {
m_okInitArray = true; // VL_RESTORER in visit(AstNodeAssign)
return false;
}
UINFO(4, "Slice optimizing " << nodep << endl);
++m_statAssigns;
// Left and right could have different ascending/descending range,
// but #elements is common and all variables are realigned to start at zero
// Assign of an ascending range slice to a descending range one must reverse
// the elements
AstNodeAssign* newlistp = nullptr;
const int elements = arrayp->rangep()->elementsConst();
for (int elemIdx = 0; elemIdx < elements; ++elemIdx) {
AstNodeAssign* const newp
= nodep->cloneType(cloneAndSel(nodep->lhsp(), elements, elemIdx),
cloneAndSel(nodep->rhsp(), elements, elemIdx));
if (debug() >= 9) newp->dumpTree("- new: ");
newlistp = AstNode::addNext(newlistp, newp);
}
if (debug() >= 9) nodep->dumpTree("- Deslice-Dn: ");
nodep->replaceWith(newlistp);
VL_DO_DANGLING(nodep->deleteTree(), nodep);
// Normal edit iterator will now iterate on all of the expansion assignments
// This will potentially call this function again to resolve next level of slicing
return true;
}
void visit(AstNodeAssign* nodep) override {
// Called recursively on newly created assignments
if (nodep->user1SetOnce()) return; // Process once
@@ -225,34 +270,10 @@ class SliceVisitor final : public VNVisitor {
if (debug() >= 9) nodep->dumpTree("- Deslice-In: ");
VL_RESTORER(m_assignError);
VL_RESTORER(m_assignp);
VL_RESTORER(m_okInitArray); // Set in assignOptimize
m_assignError = false;
m_assignp = nodep;
AstNodeDType* const dtp = nodep->lhsp()->dtypep()->skipRefp();
AstNode* stp = nodep->rhsp();
if (const AstUnpackArrayDType* const arrayp = VN_CAST(dtp, UnpackArrayDType)) {
if (!VN_IS(stp, CvtPackedToArray)) {
// Left and right could have different ascending/descending range,
// but #elements is common and all variables are realigned to start at zero
// Assign of an ascending range slice to a descending range one must reverse
// the elements
AstNodeAssign* newlistp = nullptr;
const int elements = arrayp->rangep()->elementsConst();
for (int elemIdx = 0; elemIdx < elements; ++elemIdx) {
AstNodeAssign* const newp
= nodep->cloneType(cloneAndSel(nodep->lhsp(), elements, elemIdx),
cloneAndSel(nodep->rhsp(), elements, elemIdx));
if (debug() >= 9) newp->dumpTree("- new: ");
newlistp = AstNode::addNext(newlistp, newp);
}
if (debug() >= 9) nodep->dumpTree("- Deslice-Dn: ");
nodep->replaceWith(newlistp);
VL_DO_DANGLING(nodep->deleteTree(), nodep);
// Normal edit iterator will now iterate on all of the expansion assignments
// This will potentially call this function again to resolve next level of
// slicing
return;
}
}
if (assignOptimize(nodep)) return;
iterateChildren(nodep);
}
@@ -337,7 +358,9 @@ class SliceVisitor final : public VNVisitor {
public:
// CONSTRUCTORS
explicit SliceVisitor(AstNetlist* nodep) { iterate(nodep); }
~SliceVisitor() override = default;
~SliceVisitor() override {
V3Stats::addStat("Optimizations, Slice array assignments", m_statAssigns);
}
};
//######################################################################