private void AddBarrierDivergenceCandidates(HashSet <Variable> localVars, Implementation impl, IRegion region)
{
if (!verifier.ContainsBarrierCall(region) && !GPUVerifyVCGenCommandLineOptions.WarpSync)
{
return;
}
Expr guard = region.Guard();
if (guard != null && verifier.UniformityAnalyser.IsUniform(impl.Name, guard))
{
return;
}
if (IsDisjunctionOfPredicates(guard))
{
string loopPredicate = ((guard as NAryExpr).Args[0] as IdentifierExpr).Name;
loopPredicate = loopPredicate.Substring(0, loopPredicate.IndexOf('$'));
// Int type used here, but it doesn't matter as we will print and then re-parse the program
var uniformEnabledPredicate = Expr.Eq(
new IdentifierExpr(Token.NoToken, new LocalVariable(Token.NoToken, new TypedIdent(Token.NoToken, loopPredicate + "$1", Type.Int))),
new IdentifierExpr(Token.NoToken, new LocalVariable(Token.NoToken, new TypedIdent(Token.NoToken, loopPredicate + "$2", Type.Int))));
verifier.AddCandidateInvariant(region, uniformEnabledPredicate, "loopPredicateEquality");
verifier.AddCandidateInvariant(region, Expr.Imp(verifier.ThreadsInSameGroup(), uniformEnabledPredicate), "loopPredicateEquality");
Dictionary <string, int> assignmentCounts = GetAssignmentCounts(impl);
HashSet <string> alreadyConsidered = new HashSet <string>();
foreach (var v in localVars)
{
string lv = Utilities.StripThreadIdentifier(v.Name);
if (alreadyConsidered.Contains(lv))
{
continue;
}
alreadyConsidered.Add(lv);
if (verifier.UniformityAnalyser.IsUniform(impl.Name, v.Name))
{
continue;
}
if (GPUVerifier.IsPredicate(lv))
{
continue;
}
if (!assignmentCounts.ContainsKey(lv) || assignmentCounts[lv] <= 1)
{
continue;
}
if (!verifier.ContainsNamedVariable(region.GetModifiedVariables(), lv))
{
continue;
}
AddPredicatedEqualityCandidateInvariant(region, loopPredicate, new LocalVariable(Token.NoToken, new TypedIdent(Token.NoToken, lv, Type.Int)));
}
}
}