bool forUnrollCheck(AstNode* nodep,
AstNode* initp, // Maybe under nodep (no nextp), or standalone (ignore nextp)
AstNode* precondsp, AstNode* condp,
AstNode* incp, // Maybe under nodep or in bodysp
AstNode* bodysp) {
// To keep the IF levels low, we return as each test fails.
UINFO(4, " FOR Check "<<nodep<<endl);
if (initp) UINFO(6, " Init "<<initp<<endl);
if (precondsp) UINFO(6, " Pcon "<<precondsp<<endl);
if (condp) UINFO(6, " Cond "<<condp<<endl);
if (incp) UINFO(6, " Inc "<<incp<<endl);
// Initial value check
AstAssign* initAssp = initp->castAssign();
if (!initAssp) return cantUnroll(nodep, "no initial assignment");
if (initp->nextp() && initp->nextp()!=nodep) nodep->v3fatalSrc("initial assignment shouldn't be a list");
if (!initAssp->lhsp()->castVarRef()) return cantUnroll(nodep, "no initial assignment to simple variable");
//
// Condition check
if (condp->nextp()) nodep->v3fatalSrc("conditional shouldn't be a list");
//
// Assignment of next value check
AstAssign* incAssp = incp->castAssign();
if (!incAssp) return cantUnroll(nodep, "no increment assignment");
if (incAssp->nextp()) nodep->v3fatalSrc("increment shouldn't be a list");
m_forVarp = initAssp->lhsp()->castVarRef()->varp();
m_forVscp = initAssp->lhsp()->castVarRef()->varScopep();
if (nodep->castGenFor() && !m_forVarp->isGenVar()) {
nodep->v3error("Non-genvar used in generate for: "<<m_forVarp->prettyName()<<endl);
}
if (m_generate) V3Const::constifyParamsEdit(initAssp->rhsp()); // rhsp may change
// This check shouldn't be needed when using V3Simulate
// however, for repeat loops, the loop variable is auto-generated
// and the initp statements will reference a variable outside of the initp scope
// alas, failing to simulate.
AstConst* constInitp = initAssp->rhsp()->castConst();
if (!constInitp) return cantUnroll(nodep, "non-constant initializer");
//
// Now, make sure there's no assignment to this variable in the loop
m_varModeCheck = true;
m_varAssignHit = false;
m_ignoreIncp = incp;
precondsp->iterateAndNext(*this);
bodysp->iterateAndNext(*this);
incp->iterateAndNext(*this);
m_varModeCheck = false;
m_ignoreIncp = NULL;
if (m_varAssignHit) return cantUnroll(nodep, "genvar assigned *inside* loop");
//
if (m_forVscp) { UINFO(8, " Loop Variable: "<<m_forVscp<<endl); }
else { UINFO(8, " Loop Variable: "<<m_forVarp<<endl); }
if (debug()>=9) nodep->dumpTree(cout,"- for: ");
if (!m_generate) {
AstAssign *incpAssign = incp->castAssign();
if (!canSimulate(incpAssign->rhsp())) return cantUnroll(incp, "Unable to simulate increment");
if (!canSimulate(condp)) return cantUnroll(condp, "Unable to simulate condition");
// Check whether to we actually want to try and unroll.
int loops;
if (!countLoops(initAssp, condp, incp, unrollCount(), loops))
return cantUnroll(nodep, "Unable to simulate loop");
// Less than 10 statements in the body?
int bodySize = 0;
int bodyLimit = v3Global.opt.unrollStmts();
if (loops>0) bodyLimit = v3Global.opt.unrollStmts() / loops;
if (bodySizeOverRecurse(precondsp, bodySize/*ref*/, bodyLimit)
|| bodySizeOverRecurse(bodysp, bodySize/*ref*/, bodyLimit)
|| bodySizeOverRecurse(incp, bodySize/*ref*/, bodyLimit)) {
return cantUnroll(nodep, "too many statements");
}
}
// Finally, we can do it
if (!forUnroller(nodep, initAssp, condp, precondsp, incp, bodysp)) {
return cantUnroll(nodep, "Unable to unroll loop");
}
VL_DANGLING(nodep);
// Cleanup
return true;
}
bool forUnrollCheck(AstNode* nodep,
AstNode* initp, // Maybe under nodep (no nextp), or standalone (ignore nextp)
AstNode* precondsp, AstNode* condp,
AstNode* incp, // Maybe under nodep or in bodysp
AstNode* bodysp) {
// To keep the IF levels low, we return as each test fails.
UINFO(4, " FOR Check "<<nodep<<endl);
if (initp) UINFO(6, " Init "<<initp<<endl);
if (precondsp) UINFO(6, " Pcon "<<precondsp<<endl);
if (condp) UINFO(6, " Cond "<<condp<<endl);
if (incp) UINFO(6, " Inc "<<incp<<endl);
// Initial value check
AstAssign* initAssp = initp->castAssign();
if (!initAssp) return cantUnroll(nodep, "no initial assignment");
if (initp->nextp() && initp->nextp()!=nodep) nodep->v3fatalSrc("initial assignment shouldn't be a list");
if (!initAssp->lhsp()->castVarRef()) return cantUnroll(nodep, "no initial assignment to simple variable");
m_forVarp = initAssp->lhsp()->castVarRef()->varp();
m_forVscp = initAssp->lhsp()->castVarRef()->varScopep();
if (nodep->castGenFor() && !m_forVarp->isGenVar()) {
nodep->v3error("Non-genvar used in generate for: "<<m_forVarp->name()<<endl);
}
if (m_generate) V3Const::constifyParamsEdit(initAssp->rhsp()); // rhsp may change
AstConst* constInitp = initAssp->rhsp()->castConst();
if (!constInitp) return cantUnroll(nodep, "non-constant initializer");
//
// Condition check
if (condp->nextp()) nodep->v3fatalSrc("conditional shouldn't be a list");
//
// Assignment of next value check
AstAssign* incAssp = incp->castAssign();
if (!incAssp) return cantUnroll(nodep, "no increment assignment");
if (incAssp->nextp()) nodep->v3fatalSrc("increment shouldn't be a list");
AstNodeBiop* incInstrp = incAssp->rhsp()->castNodeBiop();
//
if (m_forVscp) { UINFO(8, " Loop Variable: "<<m_forVscp<<endl); }
else { UINFO(8, " Loop Variable: "<<m_forVarp<<endl); }
if (debug()>=9) nodep->dumpTree(cout,"- for: ");
//
// Extract the constant loop bounds
bool subtract = incInstrp->castSub();
{
if (!subtract && !incInstrp->castAdd()) return cantUnroll(nodep, "missing add/sub for incrementer");
AstVarRef* incVarrp = (subtract ? incInstrp->lhsp()->castVarRef()
: incInstrp->rhsp()->castVarRef());
if (!incVarrp) return cantUnroll(nodep, "missing variable in incrementer");
if (incVarrp->varp() != m_forVarp
|| incVarrp->varScopep() != m_forVscp) {
return cantUnroll(nodep, "different variables in incrementer");
}
}
//
// Adds have the # on the lhsp because V3Const pushes rhs consts over to the lhs
// Subtracts have it on the rhs, because you write i=i-1; i=1-i is non-sensible.
AstConst* preconstIncp = (subtract ? incInstrp->rhsp()->castConst()
: incInstrp->lhsp()->castConst());
if (m_generate) preconstIncp = V3Const::constifyParamsEdit(preconstIncp)->castConst();
AstConst* constIncp = (subtract ? incInstrp->rhsp()->castConst()
: incInstrp->lhsp()->castConst());
UINFO(8, " Inc expr ok: "<<constIncp<<endl);
if (!constIncp) return cantUnroll(nodep, "non-constant increment");
if (constIncp->isZero()) return cantUnroll(nodep, "zero increment"); // Or we could loop forever below...
bool lt = condp->castLt() || condp->castLtS();
bool lte = condp->castLte() || condp->castLteS();
bool gt = condp->castGt() || condp->castGtS();
bool gte = condp->castGte() || condp->castGteS();
if (!lt && !lte && !gt && !gte)
return cantUnroll(nodep, "condition not <= or <");
AstNodeBiop* condBip = condp->castNodeBiop();
if (!condBip->lhsp()->castVarRef())
return cantUnroll(nodep, "no variable on lhs of condition");
if (condBip->lhsp()->castVarRef()->varp() != m_forVarp
|| condBip->lhsp()->castVarRef()->varScopep() != m_forVscp)
return cantUnroll(nodep, "different variable in condition");
if (m_generate) V3Const::constifyParamsEdit(condBip->rhsp()); // rhsp may change
AstConst* constStopp = condBip->rhsp()->castConst();
if (!constStopp) return cantUnroll(nodep, "non-constant final value");
UINFO(8, " Stop expr ok: "<<constStopp<<endl);
//
if (constInitp->width()>32 || constInitp->num().isFourState()
|| constStopp->width()>32 || constStopp->num().isFourState()
|| constIncp->width()>32 || constIncp->num().isFourState())
return cantUnroll(nodep, "init/final/increment too large or four state");
vlsint32_t valInit = constInitp->num().toSInt();
vlsint32_t valStop = constStopp->num().toSInt();
if (lte) valStop++; if (gte) valStop--;
vlsint32_t valInc = constIncp->num().toSInt();
if (subtract) valInc = -valInc;
UINFO(8," In Numbers: for (v="<<valInit<<"; v<"<<valStop<<"; v=v+"<<valInc<<")\n");
//
if (!m_generate) {
int loops = ((valStop - valInit)/valInc);
if (loops < 0) { loops += (1ULL<<constStopp->width()); } // Will roll around
UINFO(8, " ~Iters: "<<loops<<" c="<<unrollCount()<<endl);
if (loops > unrollCount())
return cantUnroll(nodep, "too many iterations");
// Less than 10 statements in the body?
int bodySize = 0;
int bodyLimit = v3Global.opt.unrollStmts();
if (loops>0) bodyLimit = v3Global.opt.unrollStmts() / loops;
if (bodySizeOverRecurse(precondsp, bodySize/*ref*/, bodyLimit)
|| bodySizeOverRecurse(bodysp, bodySize/*ref*/, bodyLimit)
|| bodySizeOverRecurse(incp, bodySize/*ref*/, bodyLimit)) {
return cantUnroll(nodep, "too many statements");
}
}
//
// Now, make sure there's no assignment to this variable in the loop
m_varModeCheck = true;
m_varAssignHit = false;
m_ignoreIncp = incp;
precondsp->iterateAndNext(*this);
bodysp->iterateAndNext(*this);
incp->iterateAndNext(*this);
m_varModeCheck = false;
m_ignoreIncp = NULL;
if (m_varAssignHit) return cantUnroll(nodep, "genvar assigned *inside* loop");
//
// Finally, we can do it
forUnroller(nodep, initp, precondsp, condp, incp, bodysp,
constInitp->num(),
condBip, constStopp->num(),
incInstrp, constIncp->num()); nodep = NULL;
// Cleanup
return true;
}
