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Fix array and slice flattening in assignment pattern initialisation

This commit is contained in:
Greg Davill 2026-04-10 14:41:08 +09:30
parent d4613ed1a4
commit fee71d420c
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GPG Key ID: 80EE31ACCEBEA6DA
1 changed files with 81 additions and 4 deletions
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85
src/V3Width.cpp
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@ -5492,8 +5492,6 @@ class WidthVisitor final : public VNVisitor {
}
if (patp) {
// Don't want the RHS an array
allConstant &= VN_IS(patp->lhssp(), Const);
patp->dtypep(arrayDtp->subDTypep());
AstNodeExpr* const valuep = patternMemberValueIterate(patp);
if (VN_IS(arrayDtp, UnpackArrayDType)) {
@ -5502,7 +5500,50 @@ class WidthVisitor final : public VNVisitor {
= new AstInitArray{nodep->fileline(), arrayDtp, nullptr};
newp = newap;
}
VN_AS(newp, InitArray)->addIndexValuep(ent - range.lo(), valuep);
// If valuep is a reference to an array constant (or a
// slice of one), flatten its elements into the target
// array. Note: at this point width resolution has run,
// so slices appear as AstSliceSel (the pre-resolution
// AstSelExtract is handled in patVectorMap).
const AstInitArray* subInitp = nullptr;
int flattenLo = 0;
int flattenElements = 0;
if (const auto* vrp = VN_CAST(valuep, VarRef)) {
subInitp = VN_CAST(vrp->varp()->valuep(), InitArray);
if (subInitp) {
if (const auto* adtp
= VN_CAST(vrp->varp()->dtypep()->skipRefp(), NodeArrayDType)) {
flattenElements = adtp->declRange().elements();
}
}
} else if (const auto* slicep = VN_CAST(valuep, SliceSel)) {
if (const auto* vrp = VN_CAST(slicep->fromp(), VarRef)) {
subInitp = VN_CAST(vrp->varp()->valuep(), InitArray);
if (subInitp) {
flattenLo = slicep->declRange().lo();
flattenElements = slicep->declRange().elements();
}
}
}
if (subInitp && flattenElements > 0) {
// Sub-array values are always constant
VL_DO_DANGLING(pushDeletep(valuep), valuep);
for (int sn = 0; sn < flattenElements; ++sn) {
UASSERT_OBJ(entn < range.elements(), nodep,
"Flattened sub-array overflows target array");
VN_AS(newp, InitArray)
->addIndexValuep(ent - range.lo(),
subInitp->getIndexDefaultedValuep(flattenLo + sn)
->cloneTree(false));
if (sn < flattenElements - 1) {
++entn;
ent += range.leftToRightInc();
}
}
} else {
allConstant &= VN_IS(valuep, Const);
VN_AS(newp, InitArray)->addIndexValuep(ent - range.lo(), valuep);
}
} else { // Packed. Convert to concat for now.
if (!newp) {
newp = valuep;
@ -9502,6 +9543,36 @@ class WidthVisitor final : public VNVisitor {
return testp;
}
// Return how many target-array positions a single pattern member
// occupies. For scalar values this is 1; for a full array reference
// or an array slice it is the element count of that array/slice.
// Called before width resolution, so slices are still AstSelExtract
// and VarRef dtypes may not be set yet — use varp()->dtypep() instead.
static int patMemberArrayElements(AstPatMember* patp) {
AstNodeExpr* const exprp = patp->lhssp();
// For slice expressions (pre-width: SelExtract), compute from bounds
if (auto* selp = VN_CAST(exprp, SelExtract)) {
if (const auto* vrp = VN_CAST(selp->fromp(), VarRef)) {
if (!VN_CAST(vrp->varp()->valuep(), InitArray)) return 1;
// Bounds may be parameter expressions; constify before reading
V3Const::constifyParamsNoWarnEdit(selp->leftp());
V3Const::constifyParamsNoWarnEdit(selp->rightp());
const auto* msbp = VN_CAST(selp->leftp(), Const);
const auto* lsbp = VN_CAST(selp->rightp(), Const);
if (msbp && lsbp) return std::abs(msbp->toSInt() - lsbp->toSInt()) + 1;
}
return 1;
}
// Full array reference: check via the variable's dtype (not the
// expression's dtype, which may be unset before width resolution).
if (const auto* vrp = VN_CAST(exprp, NodeVarRef)) {
if (!VN_CAST(vrp->varp()->valuep(), InitArray)) return 1;
if (const auto* adtp = VN_CAST(vrp->varp()->dtypep()->skipRefp(), NodeArrayDType))
return adtp->declRange().elements();
}
return 1;
}
PatVecMap patVectorMap(AstPattern* nodep, const VNumRange& range) {
PatVecMap patmap;
int element = range.left();
@ -9523,7 +9594,13 @@ class WidthVisitor final : public VNVisitor {
if (!newEntry) {
patp->v3error("Assignment pattern key used multiple times: " << element);
}
element += range.leftToRightInc();
// For positional members that reference an array (or a slice
// of one), advance by that array/slice's element count so
// subsequent members are mapped correctly. Note: this runs
// before width resolution, so slices are still AstSelExtract
// (the post-resolution AstSliceSel is handled in patternArray).
const int elementAdvance = patMemberArrayElements(patp);
element += range.leftToRightInc() * elementAdvance;
}
return patmap;
}