[llvm] [DAGCombine] `visitANY_EXTEND` - fold `(aext (freeze (load x)))` -> `(aext (truncate (freeze (extload x))))` (PR #218454)

[Simon Pilgrim via llvm-commits]

================
@@ -16718,33 +16719,43 @@ SDValue DAGCombiner::visitANY_EXTEND(SDNode *N) {
             tryToFoldExtOfLoad(DAG, *this, TLI, VT, LegalOperations, N, N0,
                                ISD::ZEXTLOAD, ISD::ZERO_EXTEND))
       return foldedExt;
-  } else if (ISD::isNON_EXTLoad(N0.getNode()) &&
-             ISD::isUNINDEXEDLoad(N0.getNode())) {
-    LoadSDNode *LN0 = cast<LoadSDNode>(N0);
-    if (TLI.isLoadLegalOrCustom(VT, N0.getValueType(), LN0->getAlign(),
-                                LN0->getAddressSpace(), ISD::EXTLOAD, false)) {
-      bool DoXform = true;
-      SmallVector<SDNode *, 4> SetCCs;
-      if (!N0.hasOneUse())
-        DoXform =
-            ExtendUsesToFormExtLoad(VT, N, N0, ISD::ANY_EXTEND, SetCCs, TLI);
-      if (DoXform) {
-        SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, DL, VT, LN0->getChain(),
-                                         LN0->getBasePtr(), N0.getValueType(),
-                                         LN0->getMemOperand());
-        ExtendSetCCUses(SetCCs, N0, ExtLoad, ISD::ANY_EXTEND);
-        // If the load value is used only by N, replace it via CombineTo N.
-        bool NoReplaceTrunc = N0.hasOneUse();
-        CombineTo(N, ExtLoad);
-        if (NoReplaceTrunc) {
-          DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
-          recursivelyDeleteUnusedNodes(LN0);
-        } else {
-          SDValue Trunc =
-              DAG.getNode(ISD::TRUNCATE, SDLoc(N0), N0.getValueType(), ExtLoad);
-          CombineTo(LN0, Trunc, ExtLoad.getValue(1));
+  } else {
+    bool Frozen = N0.getOpcode() == ISD::FREEZE;
----------------
RKSimon wrote:

I think this will help you simplify some of the later one use logic:
```suggestion
    bool Frozen = N0.getOpcode() == ISD::FREEZE && N0.getOperand(0).hasOneUse();
```

https://github.com/llvm/llvm-project/pull/218454