[clang] [CIR] Add X86 prefetch builtins (PR #168051)

[Andy Kaylor via cfe-commits]

================
@@ -558,6 +590,9 @@ CIRGenFunction::emitX86BuiltinExpr(unsigned builtinID, const CallExpr *expr) {
     return emitIntrinsicCallOp(builder, getLoc(expr->getExprLoc()),
                                "x86.sse.sfence", voidTy);
   case X86::BI_mm_prefetch:
+  case X86::BI_m_prefetch:
+  case X86::BI_m_prefetchw:
+    return emitPrefetch(*this, builtinID, expr, ops);
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andykaylor wrote:

```suggestion
    emitPrefetch(*this, builtinID, expr, ops);
    return {};
```

https://github.com/llvm/llvm-project/pull/168051