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split-join fix for unanimous branches

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This commit is contained in:
Meghana
2016-03-07 21:13:10 -05:00
parent 8e51332932
commit 4c13eaf8ce
2 changed files with 37 additions and 4 deletions
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36
src/instruction.cpp
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@@ -112,6 +112,28 @@ ostream &Harp::operator<<(ostream& os, Instruction &inst) {
return os;
}
bool checkUnanimous(unsigned p, const std::vector<std::vector<Reg<bool> > >& m,
const std::vector<bool> &tm) {
bool same;
unsigned i;
for (i = 0; i < m.size(); ++i) {
if (tm[i]) {
same = m[i][p];
break;
}
}
if (i == m.size())
throw DivergentBranchException();
for (; i < m.size(); ++i) {
if (tm[i]) {
if (same != (bool(m[i][p]))) {
return false;
}
}
}
return true;
}
void Instruction::executeOn(Warp &c) {
D(3, "Begin instruction execute.");
@@ -345,7 +367,12 @@ void Instruction::executeOn(Warp &c) {
break;
case SPLIT: if (sjOnce) {
sjOnce = false;
// TODO: if mask becomes all-zero, fall through
if (checkUnanimous(pred, c.pred, c.tmask)) {
DomStackEntry e(c.tmask);
e.uni = true;
c.domStack.push(e);
break;
}
DomStackEntry e(pred, c.pred, c.tmask, c.pc);
c.domStack.push(c.tmask);
c.domStack.push(e);
@@ -355,7 +382,12 @@ void Instruction::executeOn(Warp &c) {
break;
case JOIN: if (sjOnce) {
sjOnce = false;
// TODO: if mask becomes all-zero, fall through
if (!c.domStack.empty() && c.domStack.top().uni) {
D(2, "Uni branch at join");
c.tmask = c.domStack.top().tmask;
c.domStack.pop();
break;
}
if (!c.domStack.top().fallThrough) {
if (!pcSet) nextPc = c.domStack.top().pc;
pcSet = true;