[clang] constexpr built-in reduce or and xor function. (#116976)

Part of #51787.
Follow up of #116822.

This patch adds constexpr support for the built-in reduce `or` and `xor`
functions.

Author: c8ef

clang/docs/LanguageExtensions.rst

@@ -732,6 +732,10 @@ at the end to the next power of 2.
 
 These reductions support both fixed-sized and scalable vector types.
 
+The integer reduction intrinsics, including ``__builtin_reduce_add``,
+``__builtin_reduce_mul``, ``__builtin_reduce_and``, ``__builtin_reduce_or``,
+and ``__builtin_reduce_xor``, can be called in a ``constexpr`` context.
+
 Example:
 
 .. code-block:: c++

clang/docs/ReleaseNotes.rst

@@ -358,6 +358,7 @@ Non-comprehensive list of changes in this release
 - ``__builtin_reduce_add`` function can now be used in constant expressions.
 - ``__builtin_reduce_mul`` function can now be used in constant expressions.
 - ``__builtin_reduce_and`` function can now be used in constant expressions.
+- ``__builtin_reduce_or`` and ``__builtin_reduce_xor`` functions can now be used in constant expressions.
 
 New Compiler Flags
 ------------------

clang/include/clang/Basic/Builtins.td

@@ -1486,13 +1486,13 @@ def ReduceMinimum : Builtin {
 
 def ReduceXor : Builtin {
   let Spellings = ["__builtin_reduce_xor"];
-  let Attributes = [NoThrow, Const, CustomTypeChecking];
+  let Attributes = [NoThrow, Const, CustomTypeChecking, Constexpr];
   let Prototype = "void(...)";
 }
 
 def ReduceOr : Builtin {
   let Spellings = ["__builtin_reduce_or"];
-  let Attributes = [NoThrow, Const, CustomTypeChecking];
+  let Attributes = [NoThrow, Const, CustomTypeChecking, Constexpr];
   let Prototype = "void(...)";
 }
 

clang/lib/AST/ExprConstant.cpp

@@ -13529,7 +13529,9 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
 
   case Builtin::BI__builtin_reduce_add:
   case Builtin::BI__builtin_reduce_mul:
-  case Builtin::BI__builtin_reduce_and: {
+  case Builtin::BI__builtin_reduce_and:
+  case Builtin::BI__builtin_reduce_or:
+  case Builtin::BI__builtin_reduce_xor: {
     APValue Source;
     if (!EvaluateAsRValue(Info, E->getArg(0), Source))
       return false;
@@ -13558,6 +13560,14 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
         Reduced &= Source.getVectorElt(EltNum).getInt();
         break;
       }
+      case Builtin::BI__builtin_reduce_or: {
+        Reduced |= Source.getVectorElt(EltNum).getInt();
+        break;
+      }
+      case Builtin::BI__builtin_reduce_xor: {
+        Reduced ^= Source.getVectorElt(EltNum).getInt();
+        break;
+      }
       }
     }
 

clang/test/Sema/constant_builtins_vector.cpp

@@ -777,3 +777,23 @@ static_assert(__builtin_reduce_and((vector4int){(int)~0x11111111, (int)~0x222222
 static_assert(__builtin_reduce_and((vector4long){(long long)~0x1111111111111111L, (long long)~0x2222222222222222L, (long long)~0x4444444444444444L, (long long)-1}) == 0x8888888888888888L);
 static_assert(__builtin_reduce_and((vector4uint){0x11111111U, 0x22222222U, 0x44444444U, 0x88888888U}) == 0U);
 static_assert(__builtin_reduce_and((vector4ulong){0x1111111111111111UL, 0x2222222222222222UL, 0x4444444444444444UL, 0x8888888888888888UL}) == 0L);
+
+static_assert(__builtin_reduce_or((vector4char){}) == 0);
+static_assert(__builtin_reduce_or((vector4char){(char)0x11, (char)0x22, (char)0x44, (char)0x88}) == (char)0xFF);
+static_assert(__builtin_reduce_or((vector4short){(short)0x1111, (short)0x2222, (short)0x4444, (short)0x8888}) == (short)0xFFFF);
+static_assert(__builtin_reduce_or((vector4int){(int)0x11111111, (int)0x22222222, (int)0x44444444, (int)0x88888888}) == (int)0xFFFFFFFF);
+static_assert(__builtin_reduce_or((vector4long){(long long)0x1111111111111111L, (long long)0x2222222222222222L, (long long)0x4444444444444444L, (long long)0x8888888888888888L}) == (long long)0xFFFFFFFFFFFFFFFFL);
+static_assert(__builtin_reduce_or((vector4char){(char)0, (char)0x22, (char)0x44, (char)0x88}) == ~0x11);
+static_assert(__builtin_reduce_or((vector4short){(short)0x1111, (short)0, (short)0x4444, (short)0x8888}) == ~0x2222);
+static_assert(__builtin_reduce_or((vector4int){(int)0x11111111, (int)0x22222222, (int)0, (int)0x88888888}) == ~0x44444444);
+static_assert(__builtin_reduce_or((vector4long){(long long)0x1111111111111111L, (long long)0x2222222222222222L, (long long)0x4444444444444444L, (long long)0}) == ~0x8888888888888888L);
+static_assert(__builtin_reduce_or((vector4uint){0x11111111U, 0x22222222U, 0x44444444U, 0x88888888U}) == 0xFFFFFFFFU);
+static_assert(__builtin_reduce_or((vector4ulong){0x1111111111111111UL, 0x2222222222222222UL, 0x4444444444444444UL, 0x8888888888888888UL}) == 0xFFFFFFFFFFFFFFFFL);
+
+static_assert(__builtin_reduce_xor((vector4char){}) == 0);
+static_assert(__builtin_reduce_xor((vector4char){(char)0x11, (char)0x22, (char)0x44, (char)0x88}) == (char)0xFF);
+static_assert(__builtin_reduce_xor((vector4short){(short)0x1111, (short)0x2222, (short)0x4444, (short)0x8888}) == (short)0xFFFF);
+static_assert(__builtin_reduce_xor((vector4int){(int)0x11111111, (int)0x22222222, (int)0x44444444, (int)0x88888888}) == (int)0xFFFFFFFF);
+static_assert(__builtin_reduce_xor((vector4long){(long long)0x1111111111111111L, (long long)0x2222222222222222L, (long long)0x4444444444444444L, (long long)0x8888888888888888L}) == (long long)0xFFFFFFFFFFFFFFFFL);
+static_assert(__builtin_reduce_xor((vector4uint){0x11111111U, 0x22222222U, 0x44444444U, 0x88888888U}) == 0xFFFFFFFFU);
+static_assert(__builtin_reduce_xor((vector4ulong){0x1111111111111111UL, 0x2222222222222222UL, 0x4444444444444444UL, 0x8888888888888888UL}) == 0xFFFFFFFFFFFFFFFFUL);