[clang] [Clang] feat: Allow AVX/AVX2 permute operations in constexpr (PR #172149)

[Timm Baeder via cfe-commits]

================
@@ -5101,6 +5101,36 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call,
           unsigned SrcIdx = (ShuffleMask >> 6) & 0x1;
           return std::pair<unsigned, int>{SrcIdx, Offset};
         });
+  case X86::BI__builtin_ia32_vperm2f128_pd256:
+    return interp__builtin_ia32_shuffle_generic(
+        S, OpPC, Call, [](unsigned DstIdx, unsigned ShuffleMask) {
+          unsigned i = DstIdx >> 1;
----------------
tbaederr wrote:

```suggestion
          unsigned I = DstIdx >> 1;
```

https://github.com/llvm/llvm-project/pull/172149