[clang] Implement __builtin_popcountg (#82359)

Fixes #82058.

clang/docs/LanguageExtensions.rst

@@ -3473,6 +3473,37 @@ builtin, the mangler emits their usual pattern without any special treatment.
   // Computes a unique stable name for the given type.
   constexpr const char * __builtin_sycl_unique_stable_name( type-id );
 
+``__builtin_popcountg``
+-----------------------
+
+``__builtin_popcountg`` returns the number of 1 bits in the argument. The
+argument can be of any integer type.
+
+**Syntax**:
+
+.. code-block:: c++
+
+  int __builtin_popcountg(type x)
+
+**Examples**:
+
+.. code-block:: c++
+
+  int x = 1;
+  int x_pop = __builtin_popcountg(x);
+
+  unsigned long y = 3;
+  int y_pop = __builtin_popcountg(y);
+
+  _BitInt(128) z = 7;
+  int z_pop = __builtin_popcountg(z);
+
+**Description**:
+
+``__builtin_popcountg`` is meant to be a type-generic alternative to the
+``__builtin_popcount{,l,ll}`` builtins, with support for other integer types,
+such as ``__int128`` and C23 ``_BitInt(N)``.
+
 Multiprecision Arithmetic Builtins
 ----------------------------------
 

clang/include/clang/Basic/Builtins.td

@@ -688,6 +688,12 @@ def Popcount : Builtin, BitInt_Long_LongLongTemplate {
   let Prototype = "int(unsigned T)";
 }
 
+def Popcountg : Builtin {
+  let Spellings = ["__builtin_popcountg"];
+  let Attributes = [NoThrow, Const];
+  let Prototype = "int(...)";
+}
+
 def Clrsb : Builtin, BitInt_Long_LongLongTemplate {
   let Spellings = ["__builtin_clrsb"];
   let Attributes = [NoThrow, Const, Constexpr];

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -11983,7 +11983,8 @@ def err_builtin_invalid_arg_type: Error <
   "pointer to a valid matrix element type|"
   "signed integer or floating point type|vector type|"
   "floating point type|"
-  "vector of integers}1 (was %2)">;
+  "vector of integers|"
+  "type of integer}1 (was %2)">;
 
 def err_builtin_matrix_disabled: Error<
   "matrix types extension is disabled. Pass -fenable-matrix to enable it">;

clang/lib/CodeGen/CGBuiltin.cpp

@@ -3217,7 +3217,8 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
   case Builtin::BI__popcnt64:
   case Builtin::BI__builtin_popcount:
   case Builtin::BI__builtin_popcountl:
-  case Builtin::BI__builtin_popcountll: {
+  case Builtin::BI__builtin_popcountll:
+  case Builtin::BI__builtin_popcountg: {
     Value *ArgValue = EmitScalarExpr(E->getArg(0));
 
     llvm::Type *ArgType = ArgValue->getType();

clang/lib/Sema/SemaChecking.cpp

@@ -2189,6 +2189,23 @@ static bool SemaBuiltinCpu(Sema &S, const TargetInfo &TI, CallExpr *TheCall,
   return false;
 }
 
+/// Checks that __builtin_popcountg was called with a single argument, which is
+/// an integer.
+static bool SemaBuiltinPopcountg(Sema &S, CallExpr *TheCall) {
+  if (checkArgCount(S, TheCall, 1))
+    return true;
+
+  Expr *Arg = TheCall->getArg(0);
+  QualType ArgTy = Arg->getType();
+
+  if (!ArgTy->isIntegerType()) {
+    S.Diag(Arg->getBeginLoc(), diag::err_builtin_invalid_arg_type)
+        << 1 << /*integer ty*/ 7 << ArgTy;
+    return true;
+  }
+  return false;
+}
+
 ExprResult
 Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
                                CallExpr *TheCall) {
@@ -2959,7 +2976,12 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
            diag::err_hip_invalid_args_builtin_mangled_name);
       return ExprError();
     }
+    break;
   }
+  case Builtin::BI__builtin_popcountg:
+    if (SemaBuiltinPopcountg(*this, TheCall))
+      return ExprError();
+    break;
   }
 
   if (getLangOpts().HLSL && CheckHLSLBuiltinFunctionCall(BuiltinID, TheCall))

clang/test/CodeGen/builtins.c

@@ -940,4 +940,47 @@ void test_builtin_os_log_long_double(void *buf, long double ld) {
 // CHECK: %[[V3:.*]] = load i128, ptr %[[ARG0_ADDR]], align 16
 // CHECK: store i128 %[[V3]], ptr %[[ARGDATA]], align 1
 
+// CHECK-LABEL: define{{.*}} void @test_builtin_popcountg
+void test_builtin_popcountg(unsigned char uc, unsigned short us,
+                            unsigned int ui, unsigned long ul,
+                            unsigned long long ull, unsigned __int128 ui128,
+                            unsigned _BitInt(128) ubi128) {
+  volatile int pop;
+  pop = __builtin_popcountg(uc);
+  // CHECK: %1 = load i8, ptr %uc.addr, align 1
+  // CHECK-NEXT: %conv = zext i8 %1 to i32
+  // CHECK-NEXT: %2 = call i32 @llvm.ctpop.i32(i32 %conv)
+  // CHECK-NEXT: store volatile i32 %2, ptr %pop, align 4
+  pop = __builtin_popcountg(us);
+  // CHECK-NEXT: %3 = load i16, ptr %us.addr, align 2
+  // CHECK-NEXT: %conv1 = zext i16 %3 to i32
+  // CHECK-NEXT: %4 = call i32 @llvm.ctpop.i32(i32 %conv1)
+  // CHECK-NEXT: store volatile i32 %4, ptr %pop, align 4
+  pop = __builtin_popcountg(ui);
+  // CHECK-NEXT: %5 = load i32, ptr %ui.addr, align 4
+  // CHECK-NEXT: %6 = call i32 @llvm.ctpop.i32(i32 %5)
+  // CHECK-NEXT: store volatile i32 %6, ptr %pop, align 4
+  pop = __builtin_popcountg(ul);
+  // CHECK-NEXT: %7 = load i64, ptr %ul.addr, align 8
+  // CHECK-NEXT: %8 = call i64 @llvm.ctpop.i64(i64 %7)
+  // CHECK-NEXT: %cast = trunc i64 %8 to i32
+  // CHECK-NEXT: store volatile i32 %cast, ptr %pop, align 4
+  pop = __builtin_popcountg(ull);
+  // CHECK-NEXT: %9 = load i64, ptr %ull.addr, align 8
+  // CHECK-NEXT: %10 = call i64 @llvm.ctpop.i64(i64 %9)
+  // CHECK-NEXT: %cast2 = trunc i64 %10 to i32
+  // CHECK-NEXT: store volatile i32 %cast2, ptr %pop, align 4
+  pop = __builtin_popcountg(ui128);
+  // CHECK-NEXT: %11 = load i128, ptr %ui128.addr, align 16
+  // CHECK-NEXT: %12 = call i128 @llvm.ctpop.i128(i128 %11)
+  // CHECK-NEXT: %cast3 = trunc i128 %12 to i32
+  // CHECK-NEXT: store volatile i32 %cast3, ptr %pop, align 4
+  pop = __builtin_popcountg(ubi128);
+  // CHECK-NEXT: %13 = load i128, ptr %ubi128.addr, align 8
+  // CHECK-NEXT: %14 = call i128 @llvm.ctpop.i128(i128 %13)
+  // CHECK-NEXT: %cast4 = trunc i128 %14 to i32
+  // CHECK-NEXT: store volatile i32 %cast4, ptr %pop, align 4
+  // CHECK-NEXT: ret void
+}
+
 #endif

clang/test/Sema/builtin-popcountg.c

@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -triple=x86_64-pc-linux-gnu -fsyntax-only -verify -Wpedantic %s
+
+typedef int int2 __attribute__((ext_vector_type(2)));
+
+void test_builtin_popcountg(int i, double d, int2 i2) {
+  __builtin_popcountg();
+  // expected-error@-1 {{too few arguments to function call, expected 1, have 0}}
+  __builtin_popcountg(i, i);
+  // expected-error@-1 {{too many arguments to function call, expected 1, have 2}}
+  __builtin_popcountg(d);
+  // expected-error@-1 {{1st argument must be a type of integer (was 'double')}}
+  __builtin_popcountg(i2);
+  // expected-error@-1 {{1st argument must be a type of integer (was 'int2' (vector of 2 'int' values))}}
+}