https://github.com/chaitanyav updated
https://github.com/llvm/llvm-project/pull/160259
>From 3fae000a82a85a8d9a137b128c781cbc1ef76964 Mon Sep 17 00:00:00 2001
From: NagaChaitanya Vellanki <pnag...@protonmail.com>
Date: Tue, 23 Sep 2025 02:17:49 -0700
Subject: [PATCH] [clang] Implement __builtin_stdc_rotate_{left,right}
Resolves #122819
---
clang/docs/LanguageExtensions.rst | 31 ++++++++
clang/include/clang/Basic/Builtins.td | 12 +++
clang/lib/AST/ExprConstant.cpp | 2 +
clang/lib/CodeGen/CGBuiltin.cpp | 8 ++
clang/lib/Sema/SemaChecking.cpp | 48 ++++++++++++
clang/test/CodeGen/builtin-rotate.c | 73 +++++++++++++++++++
clang/test/Sema/builtin-stdc-rotate.c | 30 ++++++++
.../SemaCXX/constexpr-builtin-stdc-rotate.cpp | 72 ++++++++++++++++++
8 files changed, 276 insertions(+)
create mode 100644 clang/test/Sema/builtin-stdc-rotate.c
create mode 100644 clang/test/SemaCXX/constexpr-builtin-stdc-rotate.cpp
diff --git a/clang/docs/LanguageExtensions.rst
b/clang/docs/LanguageExtensions.rst
index b503283559db4..5ef1176f60940 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -3680,6 +3680,37 @@ the arguments. Both arguments and the result have the
bitwidth specified
by the name of the builtin. These builtins can be used within constant
expressions.
+``__builtin_stdc_rotate_left`` and ``__builtin_stdc_rotate_right``
+------------------------------------------------------------------
+
+**Syntax**:
+
+.. code-block:: c
+
+ __builtin_stdc_rotate_left(value, count)
+ __builtin_stdc_rotate_right(value, count)
+
+**Description**:
+
+These builtins rotate the bits in ``value`` by ``count`` positions. The
+``__builtin_stdc_rotate_left`` builtin rotates bits to the left, while
+``__builtin_stdc_rotate_right`` rotates bits to the right. These builtins
+accept any unsigned integer type, including ``_BitInt`` types. The rotation
+count is treated as an unsigned value and taken modulo the bit-width of the
+value being rotated. Negative rotation counts are converted to their unsigned
+equivalent before the modulo operation. These builtins can be used within
+constant expressions.
+
+**Example of use**:
+
+.. code-block:: c
+
+ unsigned char rotated_left = __builtin_stdc_rotate_left((unsigned char)0xB1,
3);
+ unsigned int rotated_right = __builtin_stdc_rotate_right(0x12345678U, 8);
+
+ unsigned _BitInt(128) big_val = 0x123456789ULL;
+ unsigned _BitInt(128) rotated = __builtin_stdc_rotate_left(big_val, 5);
+
``__builtin_unreachable``
-------------------------
diff --git a/clang/include/clang/Basic/Builtins.td
b/clang/include/clang/Basic/Builtins.td
index 9bc70ea5e5858..3550e14e6fd83 100644
--- a/clang/include/clang/Basic/Builtins.td
+++ b/clang/include/clang/Basic/Builtins.td
@@ -767,12 +767,24 @@ def RotateLeft : BitInt8_16_32_64BuiltinsTemplate,
Builtin {
let Prototype = "T(T, T)";
}
+def StdcRotateLeft : Builtin {
+ let Spellings = ["__builtin_stdc_rotate_left"];
+ let Attributes = [NoThrow, Const, Constexpr, CustomTypeChecking];
+ let Prototype = "void(...)";
+}
+
def RotateRight : BitInt8_16_32_64BuiltinsTemplate, Builtin {
let Spellings = ["__builtin_rotateright"];
let Attributes = [NoThrow, Const, Constexpr];
let Prototype = "T(T, T)";
}
+def StdcRotateRight : Builtin {
+ let Spellings = ["__builtin_stdc_rotate_right"];
+ let Attributes = [NoThrow, Const, Constexpr, CustomTypeChecking];
+ let Prototype = "void(...)";
+}
+
// Random GCC builtins
// FIXME: The builtins marked FunctionWithBuiltinPrefix below should be
// merged with the library definitions. They are currently not because
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index a4fca1811c92b..974ad68434030 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -14139,6 +14139,7 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const
CallExpr *E,
case Builtin::BI__builtin_rotateleft16:
case Builtin::BI__builtin_rotateleft32:
case Builtin::BI__builtin_rotateleft64:
+ case Builtin::BI__builtin_stdc_rotate_left:
case Builtin::BI_rotl8: // Microsoft variants of rotate right
case Builtin::BI_rotl16:
case Builtin::BI_rotl:
@@ -14156,6 +14157,7 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const
CallExpr *E,
case Builtin::BI__builtin_rotateright16:
case Builtin::BI__builtin_rotateright32:
case Builtin::BI__builtin_rotateright64:
+ case Builtin::BI__builtin_stdc_rotate_right:
case Builtin::BI_rotr8: // Microsoft variants of rotate right
case Builtin::BI_rotr16:
case Builtin::BI_rotr:
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 1cff1e0de71b7..c6ab721dfddb2 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -2494,6 +2494,12 @@ RValue CodeGenFunction::emitRotate(const CallExpr *E,
bool IsRotateRight) {
llvm::Type *Ty = Src->getType();
ShiftAmt = Builder.CreateIntCast(ShiftAmt, Ty, false);
+ unsigned BitWidth = Ty->getIntegerBitWidth();
+ llvm::Value *BitWidthVal = ConstantInt::get(Ty, BitWidth);
+ llvm::Value *SignedRem = Builder.CreateSRem(ShiftAmt, BitWidthVal);
+ llvm::Value *WrappedShift = Builder.CreateAdd(SignedRem, BitWidthVal);
+ ShiftAmt = Builder.CreateURem(WrappedShift, BitWidthVal);
+
// Rotate is a special case of LLVM funnel shift - 1st 2 args are the same.
unsigned IID = IsRotateRight ? Intrinsic::fshr : Intrinsic::fshl;
Function *F = CGM.getIntrinsic(IID, Ty);
@@ -3642,6 +3648,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl
GD, unsigned BuiltinID,
case Builtin::BI__builtin_rotateleft16:
case Builtin::BI__builtin_rotateleft32:
case Builtin::BI__builtin_rotateleft64:
+ case Builtin::BI__builtin_stdc_rotate_left:
case Builtin::BI_rotl8: // Microsoft variants of rotate left
case Builtin::BI_rotl16:
case Builtin::BI_rotl:
@@ -3653,6 +3660,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl
GD, unsigned BuiltinID,
case Builtin::BI__builtin_rotateright16:
case Builtin::BI__builtin_rotateright32:
case Builtin::BI__builtin_rotateright64:
+ case Builtin::BI__builtin_stdc_rotate_right:
case Builtin::BI_rotr8: // Microsoft variants of rotate right
case Builtin::BI_rotr16:
case Builtin::BI_rotr:
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 0723516b38253..453e31ffe04ad 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -2267,6 +2267,48 @@ static bool BuiltinCountZeroBitsGeneric(Sema &S,
CallExpr *TheCall) {
return false;
}
+/// Checks that __builtin_stdc_rotate_{left,right} was called with two
+/// arguments, that the first argument is an unsigned integer type, and that
+/// the second argument is an integer type.
+static bool BuiltinRotateGeneric(Sema &S, CallExpr *TheCall) {
+ if (S.checkArgCount(TheCall, 2))
+ return true;
+
+ ExprResult Arg0Res = S.DefaultLvalueConversion(TheCall->getArg(0));
+ if (Arg0Res.isInvalid())
+ return true;
+
+ Expr *Arg0 = Arg0Res.get();
+ TheCall->setArg(0, Arg0);
+
+ QualType Arg0Ty = Arg0->getType();
+
+ if (!Arg0Ty->isUnsignedIntegerType()) {
+ S.Diag(Arg0->getBeginLoc(), diag::err_builtin_invalid_arg_type)
+ << 1 << /* scalar */ 1 << /* unsigned integer ty */ 3 << /* no fp */ 0
+ << Arg0Ty;
+ return true;
+ }
+
+ ExprResult Arg1Res = S.DefaultLvalueConversion(TheCall->getArg(1));
+ if (Arg1Res.isInvalid())
+ return true;
+
+ Expr *Arg1 = Arg1Res.get();
+ TheCall->setArg(1, Arg1);
+
+ QualType Arg1Ty = Arg1->getType();
+
+ if (!Arg1Ty->isIntegerType()) {
+ S.Diag(Arg1->getBeginLoc(), diag::err_builtin_invalid_arg_type)
+ << 2 << /* scalar */ 1 << /* integer ty */ 2 << /* no fp */ 0 <<
Arg1Ty;
+ return true;
+ }
+
+ TheCall->setType(Arg0Ty);
+ return false;
+}
+
static bool CheckMaskedBuiltinArgs(Sema &S, Expr *MaskArg, Expr *PtrArg,
unsigned Pos) {
QualType MaskTy = MaskArg->getType();
@@ -3400,6 +3442,12 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl,
unsigned BuiltinID,
return ExprError();
break;
+ case Builtin::BI__builtin_stdc_rotate_left:
+ case Builtin::BI__builtin_stdc_rotate_right:
+ if (BuiltinRotateGeneric(*this, TheCall))
+ return ExprError();
+ break;
+
case Builtin::BI__builtin_allow_runtime_check: {
Expr *Arg = TheCall->getArg(0);
// Check if the argument is a string literal.
diff --git a/clang/test/CodeGen/builtin-rotate.c
b/clang/test/CodeGen/builtin-rotate.c
index 8fc1701c6c9bb..5a3e5501e9c45 100644
--- a/clang/test/CodeGen/builtin-rotate.c
+++ b/clang/test/CodeGen/builtin-rotate.c
@@ -32,6 +32,43 @@ unsigned long long rotl64(unsigned long long x, long long y)
{
return __builtin_rotateleft64(x, y);
}
+// CHECK-LABEL: test_builtin_stdc_rotate_left
+void test_builtin_stdc_rotate_left(unsigned char uc, unsigned short us,
+ unsigned int ui, unsigned long ul,
+ unsigned long long ull, unsigned __int128 ui128,
+ unsigned _BitInt(128) ubi128) {
+
+volatile unsigned char result_uc;
+volatile unsigned int result_ui;
+volatile unsigned short result_us;
+volatile unsigned long result_ul;
+volatile unsigned long long result_ull;
+volatile unsigned __int128 result_ui128;
+volatile unsigned _BitInt(128) result_ubi128;
+
+ // CHECK: call i8 @llvm.fshl.i8(i8 %{{.*}}, i8 %{{.*}}, i8 3)
+ result_uc = __builtin_stdc_rotate_left(uc, 3);
+
+ // CHECK: call i16 @llvm.fshl.i16(i16 %{{.*}}, i16 %{{.*}}, i16 5)
+ result_us = __builtin_stdc_rotate_left(us, 5);
+
+ // CHECK: call i32 @llvm.fshl.i32(i32 %{{.*}}, i32 %{{.*}}, i32 8)
+ result_ui = __builtin_stdc_rotate_left(ui, 8);
+
+ // CHECK: call i{{32|64}} @llvm.fshl.i{{32|64}}(i{{32|64}} %{{.*}},
i{{32|64}} %{{.*}}, i{{32|64}} 8)
+ result_ul = __builtin_stdc_rotate_left(ul, 8);
+
+ // CHECK: call i64 @llvm.fshl.i64(i64 %{{.*}}, i64 %{{.*}}, i64 16)
+ result_ull = __builtin_stdc_rotate_left(ull, 16);
+
+ // CHECK: call i128 @llvm.fshl.i128(i128 %{{.*}}, i128 %{{.*}}, i128 32)
+ result_ui128 = __builtin_stdc_rotate_left(ui128, 32);
+
+ // CHECK: call i128 @llvm.fshl.i128(i128 %{{.*}}, i128 %{{.*}}, i128 64)
+ result_ubi128 = __builtin_stdc_rotate_left(ubi128, 64);
+
+}
+
char rotr8(char x, char y) {
// CHECK-LABEL: rotr8
// CHECK: [[F:%.*]] = call i8 @llvm.fshr.i8(i8 [[X:%.*]], i8 [[X]], i8
[[Y:%.*]])
@@ -64,3 +101,39 @@ long long rotr64(long long x, unsigned long long y) {
return __builtin_rotateright64(x, y);
}
+// CHECK-LABEL: test_builtin_stdc_rotate_right
+void test_builtin_stdc_rotate_right(unsigned char uc, unsigned short us,
+ unsigned int ui, unsigned long ul,
+ unsigned long long ull, unsigned __int128 ui128,
+ unsigned _BitInt(128) ubi128) {
+
+ volatile unsigned char result_uc;
+ volatile unsigned int result_ui;
+ volatile unsigned short result_us;
+ volatile unsigned long result_ul;
+ volatile unsigned long long result_ull;
+ volatile unsigned __int128 result_ui128;
+ volatile unsigned _BitInt(128) result_ubi128;
+
+ // CHECK: call i8 @llvm.fshr.i8(i8 %{{.*}}, i8 %{{.*}}, i8 3)
+ result_uc = __builtin_stdc_rotate_right(uc, 3);
+
+ // CHECK: call i16 @llvm.fshr.i16(i16 %{{.*}}, i16 %{{.*}}, i16 5)
+ result_us = __builtin_stdc_rotate_right(us, 5);
+
+ // CHECK: call i32 @llvm.fshr.i32(i32 %{{.*}}, i32 %{{.*}}, i32 8)
+ result_ui = __builtin_stdc_rotate_right(ui, 8);
+
+ // CHECK: call i{{32|64}} @llvm.fshr.i{{32|64}}(i{{32|64}} %{{.*}},
i{{32|64}} %{{.*}}, i{{32|64}} 8)
+ result_ul = __builtin_stdc_rotate_right(ul, 8);
+
+ // CHECK: call i64 @llvm.fshr.i64(i64 %{{.*}}, i64 %{{.*}}, i64 16)
+ result_ull = __builtin_stdc_rotate_right(ull, 16);
+
+ // CHECK: call i128 @llvm.fshr.i128(i128 %{{.*}}, i128 %{{.*}}, i128 32)
+ result_ui128 = __builtin_stdc_rotate_right(ui128, 32);
+
+ // CHECK: call i128 @llvm.fshr.i128(i128 %{{.*}}, i128 %{{.*}}, i128 64)
+ result_ubi128 = __builtin_stdc_rotate_right(ubi128, 64);
+
+}
diff --git a/clang/test/Sema/builtin-stdc-rotate.c
b/clang/test/Sema/builtin-stdc-rotate.c
new file mode 100644
index 0000000000000..1d3d53ef07e71
--- /dev/null
+++ b/clang/test/Sema/builtin-stdc-rotate.c
@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0xB1, 3) == 0x8D, "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned char)0xB1, 3) == 0x36,
"");
+_Static_assert(__builtin_stdc_rotate_left((unsigned short)0x1234, 4) ==
0x2341, "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned short)0x1234, 4) ==
0x4123, "");
+_Static_assert(__builtin_stdc_rotate_left(0x12345678U, 8) == 0x34567812U, "");
+_Static_assert(__builtin_stdc_rotate_right(0x12345678U, 8) == 0x78123456U, "");
+_Static_assert(__builtin_stdc_rotate_left(0x123456789ABCDEF0ULL, 16) ==
0x56789ABCDEF01234ULL, "");
+_Static_assert(__builtin_stdc_rotate_right(0x123456789ABCDEF0ULL, 16) ==
0xDEF0123456789ABCULL, "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned __int128)1, 127) ==
((unsigned __int128)1 << 127), "");
+_Static_assert(__builtin_stdc_rotate_right(((unsigned __int128)1 << 127), 127)
== (unsigned __int128)1, "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(37))1, 36) ==
((unsigned _BitInt(37))1 << 36), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(37))1, 36) ==
((unsigned _BitInt(37))1 << 1), "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(128))1, 1) ==
((unsigned _BitInt(128))2), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0x80, 9) ==
__builtin_stdc_rotate_left((unsigned char)0x80, 1), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned short)0x8000, 17) ==
__builtin_stdc_rotate_right((unsigned short)0x8000, 1), "");
+_Static_assert(__builtin_stdc_rotate_left(0x80000000U, 33) ==
__builtin_stdc_rotate_left(0x80000000U, 1), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned
_BitInt(37))0x1000000000ULL, 40) == __builtin_stdc_rotate_left((unsigned
_BitInt(37))0x1000000000ULL, 3), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned
_BitInt(37))0x1000000000ULL, 74) == 0x1000000000ULL, "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0x80, -1) ==
__builtin_stdc_rotate_left((unsigned char)0x80, 7), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned short)0x8000, -1) ==
__builtin_stdc_rotate_right((unsigned short)0x8000, 15), "");
+_Static_assert(__builtin_stdc_rotate_left(0x80000000U, -5) ==
__builtin_stdc_rotate_left(0x80000000U, 27), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned
_BitInt(37))0x1000000000ULL, -10) == 0x4ULL, "");
diff --git a/clang/test/SemaCXX/constexpr-builtin-stdc-rotate.cpp
b/clang/test/SemaCXX/constexpr-builtin-stdc-rotate.cpp
new file mode 100644
index 0000000000000..1d3672e08d8c2
--- /dev/null
+++ b/clang/test/SemaCXX/constexpr-builtin-stdc-rotate.cpp
@@ -0,0 +1,72 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -std=c++14 -fsyntax-only
-verify %s
+// expected-no-diagnostics
+
+namespace test_constexpr_stdc_rotate {
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0b10110001, 3) ==
(unsigned char)0b10001101, "");
+static_assert(__builtin_stdc_rotate_left((unsigned short)0x1234, 4) ==
(unsigned short)0x2341, "");
+static_assert(__builtin_stdc_rotate_left(0x12345678U, 8) == 0x34567812U, "");
+static_assert(__builtin_stdc_rotate_left(0x123456789ABCDEF0ULL, 16) ==
0x56789ABCDEF01234ULL, "");
+static_assert(__builtin_stdc_rotate_right((unsigned char)0b10110001, 3) ==
(unsigned char)0b00110110, "");
+static_assert(__builtin_stdc_rotate_right(0x12345678U, 8) == 0x78123456U, "");
+static_assert(__builtin_stdc_rotate_right(0x123456789ABCDEF0ULL, 16) ==
0xDEF0123456789ABCULL, "");
+static_assert(__builtin_stdc_rotate_left(0x12345678U, 0) == 0x12345678U, "");
+static_assert(__builtin_stdc_rotate_left(0x12345678U, 32) == 0x12345678U, "");
+static_assert(__builtin_stdc_rotate_left(0x80000000U, 1) == 0x00000001U, "");
+static_assert(__builtin_stdc_rotate_right(__builtin_stdc_rotate_left(0x12345678U,
8), 8) == 0x12345678U, "");
+static_assert(__builtin_stdc_rotate_left(0x12345678U, 40) ==
__builtin_stdc_rotate_left(0x12345678U, 8), "");
+static_assert(__builtin_stdc_rotate_left(0x00000000U, 7) == 0x00000000U, "");
+static_assert(__builtin_stdc_rotate_left((unsigned char)0x01, 2) == (unsigned
char)0x04, "");
+static_assert(__builtin_stdc_rotate_left((unsigned char)0xAA, 1) == (unsigned
char)0x55, "");
+static_assert(__builtin_stdc_rotate_left((unsigned char)0x12, 4) == (unsigned
char)0x21, "");
+static_assert(__builtin_stdc_rotate_left((unsigned short)0x1234, 4) ==
(unsigned short)0x2341, "");
+static_assert(__builtin_stdc_rotate_left(0x12345678U, 4) == 0x23456781U, "");
+
+namespace test_int128 {
+
+static_assert(__builtin_stdc_rotate_left((unsigned __int128)1, 127) ==
(unsigned __int128)1 << 127, "");
+
+constexpr unsigned __int128 test_pattern = 0x123456789ABCDEF0ULL;
+static_assert(__builtin_stdc_rotate_left(test_pattern, 1) == test_pattern <<
1, "");
+
+} // namespace test_int128
+
+namespace test_bitint {
+
+static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(37))1, 36) ==
((unsigned _BitInt(37))1 << 36), "");
+
+constexpr unsigned _BitInt(128) bi128_pattern = 0x123456789ABCDEF0ULL;
+static_assert(__builtin_stdc_rotate_left(bi128_pattern, 1) == bi128_pattern <<
1, "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(3))0b101, 1) ==
(unsigned _BitInt(3))0b011, "");
+
+} // namespace test_bitint
+
+namespace test_modulo_behavior {
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0x80, 9) ==
__builtin_stdc_rotate_left((unsigned char)0x80, 1), "");
+static_assert(__builtin_stdc_rotate_right((unsigned short)0x8000, 17) ==
__builtin_stdc_rotate_right((unsigned short)0x8000, 1), "");
+static_assert(__builtin_stdc_rotate_left(0x80000000U, 33) ==
__builtin_stdc_rotate_left(0x80000000U, 1), "");
+static_assert(__builtin_stdc_rotate_right(0x8000000000000000ULL, 65) ==
__builtin_stdc_rotate_right(0x8000000000000000ULL, 1), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned
_BitInt(37))0x1000000000ULL, 40) == __builtin_stdc_rotate_left((unsigned
_BitInt(37))0x1000000000ULL, 3), "");
+static_assert(__builtin_stdc_rotate_right((unsigned
_BitInt(37))0x1000000000ULL, 74) == (unsigned _BitInt(37))0x1000000000ULL, "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(37))0x123456789ULL,
0) == (unsigned _BitInt(37))0x123456789ULL, "");
+static_assert(__builtin_stdc_rotate_right((unsigned
_BitInt(37))0x123456789ULL, 37) == (unsigned _BitInt(37))0x123456789ULL, "");
+
+} // namespace test_modulo_behavior
+
+namespace test_negative_counts {
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0x80, -1) ==
__builtin_stdc_rotate_left((unsigned char)0x80, 7), "");
+static_assert(__builtin_stdc_rotate_right((unsigned short)0x8000, -1) ==
__builtin_stdc_rotate_right((unsigned short)0x8000, 15), "");
+static_assert(__builtin_stdc_rotate_left(0x80000000U, -5) ==
__builtin_stdc_rotate_left(0x80000000U, 27), "");
+static_assert(__builtin_stdc_rotate_right(0x8000000000000000ULL, -8) ==
__builtin_stdc_rotate_right(0x8000000000000000ULL, 56), "");
+
+static_assert(__builtin_stdc_rotate_right((unsigned
_BitInt(37))0x1000000000ULL, -10) == (unsigned _BitInt(37))0x4ULL, "");
+static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(37))0x800000000ULL,
-3) == (unsigned _BitInt(37))0x4ULL, "");
+
+} // namespace test_negative_counts
+
+} // namespace test_constexpr_stdc_rotate
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