bool executive::ReconvergenceBarrier::eval_Bra(executive::CTAContext &context,
const ir::PTXInstruction &instr,
const boost::dynamic_bitset<> & branch,
const boost::dynamic_bitset<> & fallthrough) {
bool isDivergent = false;
if (instr.uni) {
// unfiorm
if (branch.count()) {
// all threads branch
context.PC = instr.branchTargetInstruction;
}
else {
// all threads fall through
context.PC ++;
}
}
else {
// divergence - complicated
CTAContext branchContext(context), fallthroughContext(context);
branchContext.active = branch;
branchContext.PC = instr.branchTargetInstruction;
fallthroughContext.active = fallthrough;
fallthroughContext.PC++;
runtimeStack.pop_back();
if (branchContext.active.any()) {
runtimeStack.push_back(branchContext);
}
if (fallthroughContext.active.any()) {
runtimeStack.push_back(fallthroughContext);
}
isDivergent = true;
}
return isDivergent;
}
/// \brief Check if the split is informative
///
/// \param p The split
bool informative(const boost::dynamic_bitset<>& p) {
int N = p.size();
int C = p.count();
return (C >= 2) and ((N-C) >= 2);
}
std::size_t range_calculate_size(boost::dynamic_bitset<I,A> const& c) {
return c.count();
}
bool executive::ReconvergenceIPDOM::eval_Bra(executive::CTAContext &context,
const ir::PTXInstruction &instr,
const boost::dynamic_bitset<> & branch,
const boost::dynamic_bitset<> & fallthrough) {
bool isDivergent = false;
if (instr.uni) {
// unfiorm
if (branch.count()) {
// all threads branch
context.PC = instr.branchTargetInstruction;
}
else {
// all threads fall through
context.PC ++;
}
}
else {
// divergence - complicated
CTAContext branchContext(context), fallthroughContext(context),
reconvergeContext(context);
int pc = context.PC + 1;
branchContext.active = branch;
branchContext.PC = instr.branchTargetInstruction;
fallthroughContext.active = fallthrough;
fallthroughContext.PC = pc;
reconvergeContext.PC = instr.reconvergeInstruction + 1;
int reconverge = pcStack.back();
Token token = tokenStack.back();
runtimeStack.pop_back();
pcStack.pop_back();
tokenStack.pop_back();
bool reconvergeContextAlreadyExists = false;
// only look for existing contexts in the current stack frame
if(token != Call) {
auto ti = tokenStack.rbegin();
for(auto si = runtimeStack.rbegin();
si != runtimeStack.rend(); ++si, ++ti) {
assert(ti != tokenStack.rend());
if(si->PC == reconvergeContext.PC) {
reconvergeContextAlreadyExists = true;
break;
}
if(*ti != Branch) {
continue;
}
}
}
if(!reconvergeContextAlreadyExists) {
report(" (" << pc << ") Pushing reconvergence context at "
<< reconvergeContext.PC << " (type " << toString(token) << ")");
runtimeStack.push_back(reconvergeContext);
pcStack.push_back(reconverge);
tokenStack.push_back(token);
}
if (branchContext.active.any()) {
report(" (" << pc << ") Pushing branch context at "
<< branchContext.PC << ", reconverge at "
<< instr.reconvergeInstruction
<< " (type " << toString(Branch) << ")");
runtimeStack.push_back(branchContext);
pcStack.push_back(instr.reconvergeInstruction);
tokenStack.push_back(Branch);
}
if (fallthroughContext.active.any()) {
report(" (" << pc << ") Pushing fallthrough context at "
<< fallthroughContext.PC << ", reconverge at "
<< instr.reconvergeInstruction
<< " (type " << toString(Branch) << ")");
runtimeStack.push_back(fallthroughContext);
pcStack.push_back(instr.reconvergeInstruction);
tokenStack.push_back(Branch);
}
}
return isDivergent;
}