[llvm] [FuncSpec] Improve handling of Comparison Instructions (PR #114073)

[David Sherwood via llvm-commits]

================
@@ -468,16 +468,25 @@ Constant *InstCostVisitor::visitCastInst(CastInst &I) {
 Constant *InstCostVisitor::visitCmpInst(CmpInst &I) {
   assert(LastVisited != KnownConstants.end() && "Invalid iterator!");
 
+  Constant *Const = LastVisited->second;
   bool Swap = I.getOperand(1) == LastVisited->first;
   Value *V = Swap ? I.getOperand(0) : I.getOperand(1);
   Constant *Other = findConstantFor(V, KnownConstants);
-  if (!Other)
-    return nullptr;
 
-  Constant *Const = LastVisited->second;
-  return Swap ?
-        ConstantFoldCompareInstOperands(I.getPredicate(), Other, Const, DL)
-      : ConstantFoldCompareInstOperands(I.getPredicate(), Const, Other, DL);
+  if (Other)
+    return Swap ? ConstantFoldCompareInstOperands(I.getPredicate(), Other,
----------------
david-arm wrote:

I realise you maybe didn't write the original code, but perhaps this is more readable:

```
  if (Other) {
    if (Swap)
      std::swap(Const, Other)
    return ConstantFoldCompareInstOperands(I.getPredicate(), Const, Other, DL);
  }
```

What do you think?

https://github.com/llvm/llvm-project/pull/114073