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

[via cfe-commits]

https://github.com/c8ef updated https://github.com/llvm/llvm-project/pull/116976

>From 4d13a8267dd5d0e99063bb088a85406af5266c80 Mon Sep 17 00:00:00 2001
From: c8ef <c8ef at outlook.com>
Date: Wed, 20 Nov 2024 22:07:35 +0800
Subject: [PATCH 1/2] constexpr reduce or/xor

---
 clang/docs/ReleaseNotes.rst                  |  1 +
 clang/include/clang/Basic/Builtins.td        |  4 ++--
 clang/lib/AST/ExprConstant.cpp               | 12 +++++++++++-
 clang/test/Sema/constant_builtins_vector.cpp | 20 ++++++++++++++++++++
 4 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 999c88455b64a5..98ed21d09305b2 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/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
 ------------------
diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td
index aa65f94e68f9c3..daf90b9570160e 100644
--- a/clang/include/clang/Basic/Builtins.td
+++ b/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(...)";
 }
 
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 33206f5cda2021..261de141637020 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/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;
+      }
       }
     }
 
diff --git a/clang/test/Sema/constant_builtins_vector.cpp b/clang/test/Sema/constant_builtins_vector.cpp
index 7063c290479f6c..e84d09b24672b4 100644
--- a/clang/test/Sema/constant_builtins_vector.cpp
+++ b/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);

>From 7537ffdfdd418ab2c9e08e8522fd144ecef1db63 Mon Sep 17 00:00:00 2001
From: c8ef <c8ef at outlook.com>
Date: Thu, 21 Nov 2024 09:42:11 +0800
Subject: [PATCH 2/2] add doc

---
 clang/docs/LanguageExtensions.rst | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index ff8e841ee53a2b..5a5d5bf699f660 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/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 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++