[clang] [Clang] Generalize interp__builtin_ia32_shuffle_generic to handle single op permute shuffles. (PR #167236)

[Simon Pilgrim via cfe-commits]

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@@ -12993,7 +12927,20 @@ bool VectorExprEvaluator::VisitCallExpr(const CallExpr *E) {
   case X86::BI__builtin_ia32_pshufb256:
   case X86::BI__builtin_ia32_pshufb512: {
     APValue R;
-    if (!evalPshufbBuiltin(Info, E, R))
+    if (!evalShuffleGeneric(
+            Info, E, R,
+            [](unsigned DstIdx,
+               unsigned ShuffleMask) -> std::pair<unsigned, int> {
+              uint8_t Ctlb = static_cast<uint8_t>(ShuffleMask);
+              if (Ctlb & 0x80) {
+                return std::make_pair(0, -1);
+              } else {
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RKSimon wrote:

(style) break if-else chain

https://github.com/llvm/llvm-project/pull/167236