[clang] 487cfbe - [Clang] Implement constexpr support for `__builtin_popcountg` (#84318)

[via cfe-commits]

Author: OverMighty
Date: 2024-03-08T01:01:37+01:00
New Revision: 487cfbe494413e12123b55dead5ef8742ef49fb2

URL: https://github.com/llvm/llvm-project/commit/487cfbe494413e12123b55dead5ef8742ef49fb2
DIFF: https://github.com/llvm/llvm-project/commit/487cfbe494413e12123b55dead5ef8742ef49fb2.diff

LOG: [Clang] Implement constexpr support for `__builtin_popcountg` (#84318)

Added: 
    

Modified: 
    clang/docs/LanguageExtensions.rst
    clang/docs/ReleaseNotes.rst
    clang/include/clang/Basic/Builtins.td
    clang/lib/AST/ExprConstant.cpp
    clang/test/Sema/constant-builtins-2.c

Removed: 
    


################################################################################
diff  --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index 2b54dffd058a35..06af93fd3c15ca 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -5378,6 +5378,7 @@ The following builtin intrinsics can be used in constant expressions:
 * ``__builtin_popcount``
 * ``__builtin_popcountl``
 * ``__builtin_popcountll``
+* ``__builtin_popcountg``
 * ``__builtin_rotateleft8``
 * ``__builtin_rotateleft16``
 * ``__builtin_rotateleft32``

diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 42c4a7c4d4bd14..fa23c215790f11 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -157,6 +157,11 @@ Non-comprehensive list of changes in this release
 - ``__builtin_addc``, ``__builtin_subc``, and the other sizes of those
   builtins are now constexpr and may be used in constant expressions.
 
+- Added ``__builtin_popcountg`` as a type-generic alternative to
+  ``__builtin_popcount{,l,ll}`` with support for any unsigned integer type. Like
+  the previous builtins, this new builtin is constexpr and may 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 a81131d82c4cb4..9c703377ca8d3e 100644
--- a/clang/include/clang/Basic/Builtins.td
+++ b/clang/include/clang/Basic/Builtins.td
@@ -706,7 +706,7 @@ def Popcount : Builtin, BitInt_Long_LongLongTemplate {
 
 def Popcountg : Builtin {
   let Spellings = ["__builtin_popcountg"];
-  let Attributes = [NoThrow, Const, CustomTypeChecking];
+  let Attributes = [NoThrow, Const, Constexpr, CustomTypeChecking];
   let Prototype = "int(...)";
 }
 

diff  --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index d8ca35740fbc35..4a7c7755e1d6fd 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -12483,6 +12483,7 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
   case Builtin::BI__builtin_popcount:
   case Builtin::BI__builtin_popcountl:
   case Builtin::BI__builtin_popcountll:
+  case Builtin::BI__builtin_popcountg:
   case Builtin::BI__popcnt16: // Microsoft variants of popcount
   case Builtin::BI__popcnt:
   case Builtin::BI__popcnt64: {

diff  --git a/clang/test/Sema/constant-builtins-2.c b/clang/test/Sema/constant-builtins-2.c
index 2bdd7b06daabfe..0935abe4c65fbe 100644
--- a/clang/test/Sema/constant-builtins-2.c
+++ b/clang/test/Sema/constant-builtins-2.c
@@ -237,6 +237,13 @@ char popcount7[__builtin_popcountl(~0L) == BITSIZE(long) ? 1 : -1];
 char popcount8[__builtin_popcountll(0LL) == 0 ? 1 : -1];
 char popcount9[__builtin_popcountll(0xF0F0LL) == 8 ? 1 : -1];
 char popcount10[__builtin_popcountll(~0LL) == BITSIZE(long long) ? 1 : -1];
+char popcount11[__builtin_popcountg(0U) == 0 ? 1 : -1];
+char popcount12[__builtin_popcountg(0xF0F0U) == 8 ? 1 : -1];
+char popcount13[__builtin_popcountg(~0U) == BITSIZE(int) ? 1 : -1];
+char popcount14[__builtin_popcountg(~0UL) == BITSIZE(long) ? 1 : -1];
+char popcount15[__builtin_popcountg(~0ULL) == BITSIZE(long long) ? 1 : -1];
+char popcount16[__builtin_popcountg(~(unsigned __int128)0) == BITSIZE(__int128) ? 1 : -1];
+char popcount17[__builtin_popcountg(~(unsigned _BitInt(128))0) == BITSIZE(_BitInt(128)) ? 1 : -1];
 
 char parity1[__builtin_parity(0) == 0 ? 1 : -1];
 char parity2[__builtin_parity(0xb821) == 0 ? 1 : -1];