[clang] constexpr built-in reduce and function. (#116822)

Part of #51787.
Follow up of #116626.

This patch adds constexpr support for the built-in reduce and function.

Author: c8ef

clang/docs/ReleaseNotes.rst

@@ -357,6 +357,7 @@ 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.
 
 New Compiler Flags
 ------------------

clang/include/clang/Basic/Builtins.td

@@ -1498,7 +1498,7 @@ def ReduceOr : Builtin {
 
 def ReduceAnd : Builtin {
   let Spellings = ["__builtin_reduce_and"];
-  let Attributes = [NoThrow, Const, CustomTypeChecking];
+  let Attributes = [NoThrow, Const, CustomTypeChecking, Constexpr];
   let Prototype = "void(...)";
 }
 

clang/lib/AST/ExprConstant.cpp

@@ -13528,7 +13528,8 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
   }
 
   case Builtin::BI__builtin_reduce_add:
-  case Builtin::BI__builtin_reduce_mul: {
+  case Builtin::BI__builtin_reduce_mul:
+  case Builtin::BI__builtin_reduce_and: {
     APValue Source;
     if (!EvaluateAsRValue(Info, E->getArg(0), Source))
       return false;
@@ -13553,6 +13554,10 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
           return false;
         break;
       }
+      case Builtin::BI__builtin_reduce_and: {
+        Reduced &= Source.getVectorElt(EltNum).getInt();
+        break;
+      }
       }
     }
 

clang/test/Sema/constant_builtins_vector.cpp

@@ -765,3 +765,15 @@ constexpr long long reduceMulLong2 = __builtin_reduce_mul((vector4long){(1LL <<
 // expected-note@-1 {{outside the range of representable values of type 'long long'}}
 static_assert(__builtin_reduce_mul((vector4uint){~0U, 1, 1, 2}) == ~0U - 1);
 static_assert(__builtin_reduce_mul((vector4ulong){~0ULL, 1, 1, 2}) == ~0ULL - 1);
+
+static_assert(__builtin_reduce_and((vector4char){}) == 0);
+static_assert(__builtin_reduce_and((vector4char){(char)0x11, (char)0x22, (char)0x44, (char)0x88}) == 0);
+static_assert(__builtin_reduce_and((vector4short){(short)0x1111, (short)0x2222, (short)0x4444, (short)0x8888}) == 0);
+static_assert(__builtin_reduce_and((vector4int){(int)0x11111111, (int)0x22222222, (int)0x44444444, (int)0x88888888}) == 0);
+static_assert(__builtin_reduce_and((vector4long){(long long)0x1111111111111111L, (long long)0x2222222222222222L, (long long)0x4444444444444444L, (long long)0x8888888888888888L}) == 0L);
+static_assert(__builtin_reduce_and((vector4char){(char)-1, (char)~0x22, (char)~0x44, (char)~0x88}) == 0x11);
+static_assert(__builtin_reduce_and((vector4short){(short)~0x1111, (short)-1, (short)~0x4444, (short)~0x8888}) == 0x2222);
+static_assert(__builtin_reduce_and((vector4int){(int)~0x11111111, (int)~0x22222222, (int)-1, (int)~0x88888888}) == 0x44444444);
+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);