[clang] [X86][Clang] allow CRC32 intrinsics to be used in constexp (PR #173908)

[Simon Pilgrim via cfe-commits]

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@@ -717,6 +717,52 @@ static bool interp__builtin_popcount(InterpState &S, CodePtr OpPC,
   return true;
 }
 
+static bool interp__builtin_ia32_crc32(InterpState &S, CodePtr OpPC,
+                                       const InterpFrame *Frame,
+                                       const CallExpr *Call,
+                                       unsigned BuiltinID) {
+  APSInt Data = popToAPSInt(S, Call->getArg(1));
+  APSInt CRC = popToAPSInt(S, Call->getArg(0));
+
+  uint64_t CRCVal = CRC.getZExtValue();
+  uint64_t DataVal = Data.getZExtValue();
+
+  // Determine the data width based on the builtin
+  unsigned DataBytes;
+  switch (BuiltinID) {
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RKSimon wrote:

We can avoid this switch statement by passing in unsigned DataBytes as an additional argument to interp__builtin_ia32_crc32

https://github.com/llvm/llvm-project/pull/173908