[PATCH] D78092: [GlobalISel] add legalization for G_FREEZE

[Dominik Montada via Phabricator via llvm-commits]

gargaroff marked an inline comment as done.
gargaroff added inline comments.


================
Comment at: llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp:1772
+    Observer.changingInstr(MI);
+    widenScalarSrc(MI, WideTy, 1, TargetOpcode::G_ANYEXT);
+    widenScalarDst(MI, WideTy);
----------------
arsenm wrote:
> Is this what the DAG does? I would be slightly surprised that undef high bits would be OK
I'm not familiar with SelectionDAG, so I might have misunderstood the extension used.

This is the code in the DAG:

```
SDValue DAGTypeLegalizer::PromoteIntRes_FREEZE(SDNode *N) {
  SDValue V = GetPromotedInteger(N->getOperand(0));
  return DAG.getNode(ISD::FREEZE, SDLoc(N),
                     V.getValueType(), V);
}
```

In the documentation of `GetPromotedInteger` it says that the upper bits contain rubbish, which suggested to me that this corresponds to `G_ANYEXT`


Repository:
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  https://reviews.llvm.org/D78092/new/

https://reviews.llvm.org/D78092