[SCCP] Avoid some uses of SCCPSolver::isOverdefined (NFCI)

This is a confusingly named helper than means "is not unknown,
undef or constant". Prefer the more obvious ValueLattice API
instead. Most of these checks are for values which are forced to
overdefined by undef resolution, in which case only actual
overdefined values are relevant.

Author: nikic

llvm/lib/Transforms/Utils/SCCPSolver.cpp

@@ -1364,7 +1364,7 @@ void SCCPInstVisitor::visitInsertValueInst(InsertValueInst &IVI) {
 
   // resolvedUndefsIn might mark I as overdefined. Bail out, even if we would
   // discover a concrete value later.
-  if (SCCPSolver::isOverdefined(ValueState[&IVI]))
+  if (ValueState[&IVI].isOverdefined())
     return (void)markOverdefined(&IVI);
 
   // If this has more than one index, we can't handle it, drive all results to
@@ -1436,7 +1436,7 @@ void SCCPInstVisitor::visitUnaryOperator(Instruction &I) {
   ValueLatticeElement &IV = ValueState[&I];
   // resolvedUndefsIn might mark I as overdefined. Bail out, even if we would
   // discover a concrete value later.
-  if (SCCPSolver::isOverdefined(IV))
+  if (IV.isOverdefined())
     return (void)markOverdefined(&I);
 
   // If something is unknown/undef, wait for it to resolve.
@@ -1461,7 +1461,7 @@ void SCCPInstVisitor::visitFreezeInst(FreezeInst &I) {
   ValueLatticeElement &IV = ValueState[&I];
   // resolvedUndefsIn might mark I as overdefined. Bail out, even if we would
   // discover a concrete value later.
-  if (SCCPSolver::isOverdefined(IV))
+  if (IV.isOverdefined())
     return (void)markOverdefined(&I);
 
   // If something is unknown/undef, wait for it to resolve.
@@ -1541,7 +1541,7 @@ void SCCPInstVisitor::visitBinaryOperator(Instruction &I) {
 void SCCPInstVisitor::visitCmpInst(CmpInst &I) {
   // Do not cache this lookup, getValueState calls later in the function might
   // invalidate the reference.
-  if (SCCPSolver::isOverdefined(ValueState[&I]))
+  if (ValueState[&I].isOverdefined())
     return (void)markOverdefined(&I);
 
   Value *Op1 = I.getOperand(0);
@@ -1571,7 +1571,7 @@ void SCCPInstVisitor::visitCmpInst(CmpInst &I) {
 // Handle getelementptr instructions.  If all operands are constants then we
 // can turn this into a getelementptr ConstantExpr.
 void SCCPInstVisitor::visitGetElementPtrInst(GetElementPtrInst &I) {
-  if (SCCPSolver::isOverdefined(ValueState[&I]))
+  if (ValueState[&I].isOverdefined())
     return (void)markOverdefined(&I);
 
   SmallVector<Constant *, 8> Operands;
@@ -1582,9 +1582,6 @@ void SCCPInstVisitor::visitGetElementPtrInst(GetElementPtrInst &I) {
     if (State.isUnknownOrUndef())
       return; // Operands are not resolved yet.
 
-    if (SCCPSolver::isOverdefined(State))
-      return (void)markOverdefined(&I);
-
     if (Constant *C = getConstant(State, I.getOperand(i)->getType())) {
       Operands.push_back(C);
       continue;