[llvm] [WebAssembly][FastISel] Emit signed loads for sext of i8/i16/i32 (PR #182333)

[Derek Schuff via llvm-commits]

================
@@ -1323,6 +1354,16 @@ bool WebAssemblyFastISel::selectLoad(const Instruction *I) {
 
   addLoadStoreOperands(Addr, MIB, createMachineMemOperandFor(Load));
 
+  if (FoldExt) {
+    unsigned ExtReg = lookUpRegForValue(Ext);
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dschuff wrote:

```suggestion
    Register ExtReg = lookUpRegForValue(Ext);
```

https://github.com/llvm/llvm-project/pull/182333