[clang][Interp] Implement __builtin_parity (#71662)

Author: tbaederr

clang/lib/AST/Interp/InterpBuiltin.cpp

@@ -439,6 +439,15 @@ static bool interp__builtin_popcount(InterpState &S, CodePtr OpPC,
   return true;
 }
 
+static bool interp__builtin_parity(InterpState &S, CodePtr OpPC,
+                                   const InterpFrame *Frame,
+                                   const Function *Func, const CallExpr *Call) {
+  PrimType ArgT = *S.getContext().classify(Call->getArg(0)->getType());
+  APSInt Val = peekToAPSInt(S.Stk, ArgT);
+  pushInt(S, Val.popcount() % 2);
+  return true;
+}
+
 bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
                       const CallExpr *Call) {
   InterpFrame *Frame = S.Current;
@@ -576,6 +585,13 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
       return retInt(S, OpPC, Dummy);
     break;
 
+  case Builtin::BI__builtin_parity:
+  case Builtin::BI__builtin_parityl:
+  case Builtin::BI__builtin_parityll:
+    if (interp__builtin_parity(S, OpPC, Frame, F, Call))
+      return retInt(S, OpPC, Dummy);
+    break;
+
   default:
     return false;
   }

clang/test/AST/Interp/builtin-functions.cpp

@@ -274,6 +274,7 @@ namespace SourceLocation {
   }
 }
 
+#define BITSIZE(x) (sizeof(x) * 8)
 namespace popcount {
   static_assert(__builtin_popcount(~0u) == __CHAR_BIT__ * sizeof(unsigned int), "");
   static_assert(__builtin_popcount(0) == 0, "");
@@ -283,7 +284,6 @@ namespace popcount {
   static_assert(__builtin_popcountll(0) == 0, "");
 
   /// From test/Sema/constant-builtins-2.c
-#define BITSIZE(x) (sizeof(x) * 8)
   char popcount1[__builtin_popcount(0) == 0 ? 1 : -1];
   char popcount2[__builtin_popcount(0xF0F0) == 8 ? 1 : -1];
   char popcount3[__builtin_popcount(~0) == BITSIZE(int) ? 1 : -1];
@@ -295,3 +295,18 @@ namespace popcount {
   char popcount9[__builtin_popcountll(0xF0F0LL) == 8 ? 1 : -1];
   char popcount10[__builtin_popcountll(~0LL) == BITSIZE(long long) ? 1 : -1];
 }
+
+namespace parity {
+  /// From test/Sema/constant-builtins-2.c
+  char parity1[__builtin_parity(0) == 0 ? 1 : -1];
+  char parity2[__builtin_parity(0xb821) == 0 ? 1 : -1];
+  char parity3[__builtin_parity(0xb822) == 0 ? 1 : -1];
+  char parity4[__builtin_parity(0xb823) == 1 ? 1 : -1];
+  char parity5[__builtin_parity(0xb824) == 0 ? 1 : -1];
+  char parity6[__builtin_parity(0xb825) == 1 ? 1 : -1];
+  char parity7[__builtin_parity(0xb826) == 1 ? 1 : -1];
+  char parity8[__builtin_parity(~0) == 0 ? 1 : -1];
+  char parity9[__builtin_parityl(1L << (BITSIZE(long) - 1)) == 1 ? 1 : -1];
+  char parity10[__builtin_parityll(1LL << (BITSIZE(long long) - 1)) == 1 ? 1 : -1];
+}
+