}
}
+ /// InsertInOverdefinedPHIs - Insert an entry in the UsersOfOverdefinedPHIS
+ /// map for I and PN, but if one is there already, do not create another.
+ /// (Duplicate entries do not break anything directly, but can lead to
+ /// exponential growth of the table in rare cases.)
+ void InsertInOverdefinedPHIs(Instruction *I, PHINode *PN) {
+ std::multimap<PHINode*, Instruction*>::iterator J, E;
+ bool found = false;
+ tie(J, E) = UsersOfOverdefinedPHIs.equal_range(PN);
+ for (; J != E; ++J)
+ if (J->second == I) {
+ found = true;
+ break;
+ }
+ if (!found)
+ UsersOfOverdefinedPHIs.insert(std::make_pair(PN, I));
+ }
+
private:
friend class InstVisitor<SCCPSolver>;
if (Result.isConstant()) {
markConstant(IV, &I, Result.getConstant());
// Remember that this instruction is virtually using the PHI node
- // operands.
- UsersOfOverdefinedPHIs.insert(std::make_pair(PN1, &I));
- UsersOfOverdefinedPHIs.insert(std::make_pair(PN2, &I));
+ // operands.
+ InsertInOverdefinedPHIs(&I, PN1);
+ InsertInOverdefinedPHIs(&I, PN2);
return;
}
markConstant(&I, Result.getConstant());
// Remember that this instruction is virtually using the PHI node
// operands.
- UsersOfOverdefinedPHIs.insert(std::make_pair(PN1, &I));
- UsersOfOverdefinedPHIs.insert(std::make_pair(PN2, &I));
+ InsertInOverdefinedPHIs(&I, PN1);
+ InsertInOverdefinedPHIs(&I, PN2);
return;
}