private static void GenerateCandidateForNonUniformGuardVariables(GPUVerifier verifier, Implementation impl, IRegion region)
{
if (!verifier.ContainsBarrierCall(region) && !GPUVerifyVCGenCommandLineOptions.WarpSync)
{
return;
}
HashSet <Variable> partitionVars = region.PartitionVariablesOfHeader();
HashSet <Variable> guardVars = new HashSet <Variable>();
var formals = impl.InParams.Select(x => x.Name);
var modset = region.GetModifiedVariables().Select(x => x.Name);
foreach (var v in partitionVars)
{
Expr expr = verifier.VarDefAnalysesRegion[impl].DefOfVariableName(v.Name);
if (expr == null)
{
continue;
}
var visitor = new VariablesOccurringInExpressionVisitor();
visitor.Visit(expr);
guardVars.UnionWith(
visitor.GetVariables().Where(x => x.Name.StartsWith("$") &&
!formals.Contains(x.Name) && modset.Contains(x.Name) &&
!verifier.UniformityAnalyser.IsUniform(impl.Name, x.Name) &&
x.TypedIdent.Type.IsBv && (x.TypedIdent.Type.BvBits % 8 == 0)));
}
List <AssignCmd> assignments = new List <AssignCmd>();
foreach (Block b in region.PreHeaders())
{
foreach (AssignCmd c in b.Cmds.Where(x => x is AssignCmd))
{
assignments.Add(c);
}
}
foreach (var v in guardVars)
{
foreach (AssignCmd c in assignments)
{
foreach (var a in c.Lhss.Zip(c.Rhss))
{
var lhs = a.Item1;
var rhs = a.Item2;
if (!(lhs is SimpleAssignLhs))
{
continue;
}
var sLhs = (SimpleAssignLhs)lhs;
var theVar = sLhs.DeepAssignedVariable;
if (theVar.Name == v.Name)
{
var sub = verifier.IntRep.MakeSub(new IdentifierExpr(Token.NoToken, v), rhs as Expr);
List <Expr> args = new List <Expr>();
args.Add(sub);
Function otherbv = verifier.FindOrCreateOther(sub.Type);
var inv = Expr.Eq(sub, new NAryExpr(Token.NoToken, new FunctionCall(otherbv), args));
verifier.AddCandidateInvariant(region, inv, "guardMinusInitialIsUniform");
var groupInv = Expr.Imp(verifier.ThreadsInSameGroup(), inv);
verifier.AddCandidateInvariant(region, groupInv, "guardMinusInitialIsUniform");
}
}
}
}
}