[llvm-branch-commits] [llvm] [AMDGPU][SDAG] Handle ISD::PTRADD in various special cases (PR #145330)

[Matt Arsenault via llvm-branch-commits]

================
@@ -2960,10 +2971,10 @@ bool TargetLowering::SimplifyDemandedBits(
 
     if (Op.getOpcode() == ISD::MUL) {
       Known = KnownBits::mul(KnownOp0, KnownOp1);
-    } else { // Op.getOpcode() is either ISD::ADD or ISD::SUB.
+    } else { // Op.getOpcode() is either ISD::ADD, ISD::PTRADD, or ISD::SUB.
       Known = KnownBits::computeForAddSub(
-          Op.getOpcode() == ISD::ADD, Flags.hasNoSignedWrap(),
-          Flags.hasNoUnsignedWrap(), KnownOp0, KnownOp1);
+          Op->isAnyAdd(), Flags.hasNoSignedWrap(), Flags.hasNoUnsignedWrap(),
----------------
arsenm wrote:

```suggestion
          Op.getOpcode() != ISD::SUB, Flags.hasNoSignedWrap(), Flags.hasNoUnsignedWrap(),
```

https://github.com/llvm/llvm-project/pull/145330