[llvm] [GlobalISel] Import llvm.stepvector (PR #115721)

[Thorsten Schütt via llvm-commits]

================
@@ -2597,6 +2597,10 @@ bool IRTranslator::translateKnownIntrinsic(const CallInst &CI, Intrinsic::ID ID,
     return translateExtractVector(CI, MIRBuilder);
   case Intrinsic::vector_insert:
     return translateInsertVector(CI, MIRBuilder);
+  case Intrinsic::stepvector: {
+    MIRBuilder.buildStepVector(getOrCreateVReg(CI), 1);
----------------
tschuett wrote:

Slightly above:
```
  case Intrinsic::vscale: {
    MIRBuilder.buildVScale(getOrCreateVReg(CI), 1);
    return true;
  }
```

https://github.com/llvm/llvm-project/pull/115721