[PATCH] D76228: [ValueTracking] Use Inst::comesBefore in isValidAssumeForCtx (NFC).

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


================
Comment at: llvm/lib/Analysis/ValueTracking.cpp:602
+  // in the BB.
+  if (Inv->comesBefore(CxtI))
+    return true;
----------------
Isn't the `!DT` condition still relevant here? If we have DT, then this was already covered by the domination check.

Generally, I think this code is a bit convoluted, and I think it would be clearer to rewrite along these lines:

```
BasicBlock *InvBB = Inv->getParent(), *CxtBB = CxtI->getParent();
if (InvBB != CxtBB) {
  if (DT)
    return DT->dominates(InvBB, CxtBB);
  else
    // We don't have a DT, but this trivially dominates.
    return InvBB == CxtBB->getSinglePredecessor();
}

// If Inv and CtxI are in the same block, check if the assume (Inv) is first
// in the BB.
if (Inv->comesBefore(CxtI))
  return true;

// Rest of the code...
```


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https://reviews.llvm.org/D76228