[clang] Draft (PR #116822)

[via cfe-commits]

https://github.com/c8ef created https://github.com/llvm/llvm-project/pull/116822

None

>From 5923208aebdaae2a7a121a1378a911b7f13f1f3e Mon Sep 17 00:00:00 2001
From: c8ef <c8ef at outlook.com>
Date: Tue, 19 Nov 2024 23:07:43 +0800
Subject: [PATCH] constexpr reduce and

---
 clang/docs/ReleaseNotes.rst                  | 1 +
 clang/include/clang/Basic/Builtins.td        | 2 +-
 clang/lib/AST/ExprConstant.cpp               | 7 ++++++-
 clang/test/Sema/constant_builtins_vector.cpp | 8 ++++++++
 4 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 6cdd7f0cdf46cc..043b9a358cec88 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/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
 ------------------
diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td
index 83e5b52b4e3a9e..aa65f94e68f9c3 100644
--- a/clang/include/clang/Basic/Builtins.td
+++ b/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(...)";
 }
 
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index f597f05807069c..33206f5cda2021 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/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;
+      }
       }
     }
 
diff --git a/clang/test/Sema/constant_builtins_vector.cpp b/clang/test/Sema/constant_builtins_vector.cpp
index b9dc17f73f7a92..40eea1cb28cf1b 100644
--- a/clang/test/Sema/constant_builtins_vector.cpp
+++ b/clang/test/Sema/constant_builtins_vector.cpp
@@ -765,3 +765,11 @@ constexpr long long reduceMulLong2 = __builtin_reduce_mul((vector4long){(1LL <<
 // expected-note at -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((vector4uint){0x11111111U, 0x22222222U, 0x44444444U, 0x88888888U}) == 0U);
+static_assert(__builtin_reduce_and((vector4ulong){0x1111111111111111UL, 0x2222222222222222UL, 0x4444444444444444UL, 0x8888888888888888UL}) == 0L);