[clang] [clang] Implement __builtin_stdc_rotate_left, __builtin_stdc_rotate_right (PR #160259)

NagaChaitanya Vellanki via cfe-commits cfe-commits at lists.llvm.org
Fri Oct 10 17:58:21 PDT 2025


https://github.com/chaitanyav updated https://github.com/llvm/llvm-project/pull/160259

>From 379a5ac140077268545c0e49e5d9bd68261304a8 Mon Sep 17 00:00:00 2001
From: NagaChaitanya Vellanki <pnagato at protonmail.com>
Date: Tue, 23 Sep 2025 02:17:49 -0700
Subject: [PATCH] [clang] Implement __builtin_stdc_rotate_left and
 __builtin_stdc_rotate_right

This patch adds type-generic rotate builtins that accept any unsigned integer
type. These builtins provide:

- Support for all unsigned integer types, including _BitInt
- Constexpr evaluation capability
- Automatic normalization of rotation counts modulo the bit-width
- Proper handling of negative rotation counts (converted to equivalent
  positive rotations in the opposite direction)
- Implicit conversion support for both arguments, allowing bool, float, and
  types with conversion operators (not limited to record types)

The builtins follow C23 naming conventions.

Resolves #122819
---
 clang/docs/LanguageExtensions.rst             |  36 +++
 clang/docs/ReleaseNotes.rst                   |   5 +
 clang/include/clang/Basic/Builtins.td         |  12 +
 clang/lib/AST/ExprConstant.cpp                |  60 +++--
 clang/lib/CodeGen/CGBuiltin.cpp               |  35 ++-
 clang/lib/Sema/SemaChecking.cpp               |  67 +++++
 clang/test/CodeGen/builtin-rotate.c           | 235 ++++++++++++++++++
 clang/test/Sema/builtin-stdc-rotate.c         | 126 ++++++++++
 .../SemaCXX/constexpr-builtin-stdc-rotate.cpp | 199 +++++++++++++++
 9 files changed, 759 insertions(+), 16 deletions(-)
 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 6bb99c757cd19..3a650e4aa13bd 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -3680,6 +3680,42 @@ 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
+
+    T __builtin_stdc_rotate_left(T value, count)
+    T __builtin_stdc_rotate_right(T value, count)
+
+where ``T`` is any unsigned integer type and ``count`` is any integer type.
+
+**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. The first
+argument (``value``) must be an unsigned integer type, including ``_BitInt`` types.
+The second argument (``count``) can be any integer type. The rotation count is
+normalized modulo the bit-width of the value being rotated, with negative
+counts converted to equivalent positive rotations (e.g., rotating left
+by ``-1`` is equivalent to rotating left by ``BitWidth-1``). 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 char neg_rotate = __builtin_stdc_rotate_left((unsigned char)0xB1, -1);
+
+  unsigned _BitInt(20) value = 0xABCDE;
+  unsigned _BitInt(20) rotated = __builtin_stdc_rotate_left(value, 5);
+
 ``__builtin_unreachable``
 -------------------------
 
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 65b086caf3652..f42ff26f06653 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -265,6 +265,11 @@ Non-comprehensive list of changes in this release
   allocation functions with a token ID can be enabled via the
   ``-fsanitize=alloc-token`` flag.
 
+- Added ``__builtin_stdc_rotate_left`` and ``__builtin_stdc_rotate_right``
+  for bit rotation of unsigned integers including ``_BitInt`` types. Rotation
+  counts are normalized modulo the bit-width and support negative values.
+  Usable in constant expressions.
+
 New Compiler Flags
 ------------------
 - New option ``-fno-sanitize-debug-trap-reasons`` added to disable emitting trap reasons into the debug info when compiling with trapping UBSan (e.g. ``-fsanitize-trap=undefined``).
diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td
index 792e2e07ec594..d220f66b10737 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 35a866ea5010f..e5a541bf6aec0 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -14394,23 +14394,17 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
   case Builtin::BI__builtin_rotateleft16:
   case Builtin::BI__builtin_rotateleft32:
   case Builtin::BI__builtin_rotateleft64:
-  case Builtin::BI_rotl8: // Microsoft variants of rotate right
-  case Builtin::BI_rotl16:
-  case Builtin::BI_rotl:
-  case Builtin::BI_lrotl:
-  case Builtin::BI_rotl64: {
-    APSInt Val, Amt;
-    if (!EvaluateInteger(E->getArg(0), Val, Info) ||
-        !EvaluateInteger(E->getArg(1), Amt, Info))
-      return false;
-
-    return Success(Val.rotl(Amt), E);
-  }
-
   case Builtin::BI__builtin_rotateright8:
   case Builtin::BI__builtin_rotateright16:
   case Builtin::BI__builtin_rotateright32:
   case Builtin::BI__builtin_rotateright64:
+  case Builtin::BI__builtin_stdc_rotate_left:
+  case Builtin::BI__builtin_stdc_rotate_right:
+  case Builtin::BI_rotl8: // Microsoft variants of rotate left
+  case Builtin::BI_rotl16:
+  case Builtin::BI_rotl:
+  case Builtin::BI_lrotl:
+  case Builtin::BI_rotl64:
   case Builtin::BI_rotr8: // Microsoft variants of rotate right
   case Builtin::BI_rotr16:
   case Builtin::BI_rotr:
@@ -14421,7 +14415,45 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
         !EvaluateInteger(E->getArg(1), Amt, Info))
       return false;
 
-    return Success(Val.rotr(Amt), E);
+    // Normalize shift amount to [0, BitWidth) range to match runtime behavior
+    unsigned BitWidth = Val.getBitWidth();
+    unsigned AmtBitWidth = Amt.getBitWidth();
+    if (BitWidth == 1) {
+      // if BitWidth is 1, Amt % Divisor = 0
+      // No need for rotation
+      Amt = APSInt(APInt(AmtBitWidth, 0), Amt.isUnsigned());
+    } else {
+      APSInt Divisor;
+      if (AmtBitWidth > BitWidth) {
+        Divisor = APSInt(llvm::APInt(AmtBitWidth, BitWidth), Amt.isUnsigned());
+      } else {
+        Divisor = APSInt(llvm::APInt(BitWidth, BitWidth), Amt.isUnsigned());
+        if (AmtBitWidth < BitWidth) {
+          Amt = Amt.extend(BitWidth);
+        }
+      }
+
+      Amt = Amt % Divisor;
+      if (Amt.isNegative()) {
+        Amt += Divisor;
+      }
+    }
+
+    switch (BuiltinOp) {
+    case Builtin::BI__builtin_rotateright8:
+    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:
+    case Builtin::BI_rotr16:
+    case Builtin::BI_rotr:
+    case Builtin::BI_lrotr:
+    case Builtin::BI_rotr64:
+      return Success(APSInt(Val.rotr(Amt.getZExtValue()), Val.isUnsigned()), E);
+    default:
+      return Success(APSInt(Val.rotl(Amt.getZExtValue()), Val.isUnsigned()), E);
+    }
   }
 
   case Builtin::BI__builtin_elementwise_add_sat: {
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 9ee810c9d5775..f464b3f11130d 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -2492,12 +2492,41 @@ RValue CodeGenFunction::emitRotate(const CallExpr *E, bool IsRotateRight) {
   // The builtin's shift arg may have a different type than the source arg and
   // result, but the LLVM intrinsic uses the same type for all values.
   llvm::Type *Ty = Src->getType();
-  ShiftAmt = Builder.CreateIntCast(ShiftAmt, Ty, false);
+  llvm::Type *ShiftTy = ShiftAmt->getType();
+
+  unsigned BitWidth = Ty->getIntegerBitWidth();
+
+  if (!llvm::isPowerOf2_32(BitWidth) &&
+      E->getArg(1)->getType()->isSignedIntegerType()) {
+    // converting BitWidth to the type of ShiftAmt
+    llvm::Value *BitWidthInShiftTy = ConstantInt::get(ShiftTy, BitWidth);
+
+    // if ShiftAmt is negative, normalize ShiftAmt to [0, BitWidth - 1]
+    llvm::Value *RemResult = Builder.CreateSRem(ShiftAmt, BitWidthInShiftTy);
+    llvm::Value *PositiveShift =
+        Builder.CreateAdd(RemResult, BitWidthInShiftTy);
+
+    llvm::Value *Zero = ConstantInt::get(ShiftTy, 0);
+    llvm::Value *IsRemNegative = Builder.CreateICmpSLT(RemResult, Zero);
+
+    ShiftAmt = Builder.CreateSelect(IsRemNegative, PositiveShift, RemResult);
+  }
+
+  unsigned ShiftAmtBitWidth = ShiftTy->getIntegerBitWidth();
+  if (ShiftAmtBitWidth > BitWidth) {
+    llvm::Value *BitWidthInShiftTy = ConstantInt::get(ShiftTy, BitWidth);
+    ShiftAmt = Builder.CreateURem(ShiftAmt, BitWidthInShiftTy);
+    ShiftAmt = Builder.CreateIntCast(ShiftAmt, Ty, false);
+  } else {
+    llvm::Value *BitWidthInShiftTy = ConstantInt::get(Ty, BitWidth);
+    ShiftAmt = Builder.CreateIntCast(ShiftAmt, Ty, false);
+    ShiftAmt = Builder.CreateURem(ShiftAmt, BitWidthInShiftTy);
+  }
 
   // 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);
-  return RValue::get(Builder.CreateCall(F, { Src, Src, ShiftAmt }));
+  return RValue::get(Builder.CreateCall(F, {Src, Src, ShiftAmt}));
 }
 
 // Map math builtins for long-double to f128 version.
@@ -3642,6 +3671,7 @@ 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 +3683,7 @@ 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 063db05665af1..b99016d6eb8f5 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -2267,6 +2267,67 @@ 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()) {
+    ExprResult ConvArg0Res = S.PerformImplicitConversion(
+        TheCall->getArg(0), S.Context.UnsignedIntTy, AssignmentAction::Passing);
+    if (ConvArg0Res.isUsable()) {
+      Arg0 = ConvArg0Res.get();
+      Arg0Ty = Arg0->getType();
+      TheCall->setArg(0, Arg0);
+    }
+  }
+
+  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()) {
+    ExprResult ConvArg1Res = S.PerformImplicitConversion(
+        TheCall->getArg(1), S.Context.IntTy, AssignmentAction::Passing);
+    if (ConvArg1Res.isUsable()) {
+      Arg1 = ConvArg1Res.get();
+      Arg1Ty = Arg1->getType();
+      TheCall->setArg(1, Arg1);
+    }
+  }
+
+  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, bool AllowConst,
                                    bool AllowAS) {
@@ -3458,6 +3519,12 @@ 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..522416be8cf3e 100644
--- a/clang/test/CodeGen/builtin-rotate.c
+++ b/clang/test/CodeGen/builtin-rotate.c
@@ -64,3 +64,238 @@ long long rotr64(long long x, unsigned long long y) {
   return __builtin_rotateright64(x, y);
 }
 
+// CHECK-LABEL: test_builtin_stdc_rotate_left
+// CHECK:  call i8 @llvm.fshl.i8(i8 %{{.*}}, i8 %{{.*}}, i8 3)
+// CHECK:  call i16 @llvm.fshl.i16(i16 %{{.*}}, i16 %{{.*}}, i16 5)
+// CHECK:  call i32 @llvm.fshl.i32(i32 %{{.*}}, i32 %{{.*}}, i32 8)
+// CHECK:  call i64 @llvm.fshl.i64(i64 %{{.*}}, i64 %{{.*}}, i64 8)
+// CHECK:  call i64 @llvm.fshl.i64(i64 %{{.*}}, i64 %{{.*}}, i64 16)
+// CHECK:  call i128 @llvm.fshl.i128(i128 %{{.*}}, i128 %{{.*}}, i128 32)
+// CHECK:  call i8 @llvm.fshl.i8(i8 %{{.*}}, i8 %{{.*}}, i8 7)
+// CHECK:  call i16 @llvm.fshl.i16(i16 %{{.*}}, i16 %{{.*}}, i16 11)
+// CHECK:  call i32 @llvm.fshl.i32(i32 %{{.*}}, i32 %{{.*}}, i32 29)
+// CHECK:  call i8 @llvm.fshl.i8(i8 %{{.*}}, i8 %{{.*}}, i8 0)
+// CHECK:  call i32 @llvm.fshl.i32(i32 %{{.*}}, i32 %{{.*}}, i32 27)
+// CHECK:  call i32 @llvm.fshl.i32(i32 42, i32 42, i32 %{{.*}})
+// CHECK:  call i9 @llvm.fshl.i9(i9 %{{.*}}, i9 %{{.*}}, i9 1)
+// CHECK:  call i37 @llvm.fshl.i37(i37 %{{.*}}, i37 %{{.*}}, i37 36)
+// CHECK:  call i9 @llvm.fshl.i9(i9 %{{.*}}, i9 %{{.*}}, i9 8)
+// CHECK:  call i37 @llvm.fshl.i37(i37 %{{.*}}, i37 %{{.*}}, i37 32)
+// CHECK:  call i10 @llvm.fshl.i10(i10 %{{.*}}, i10 %{{.*}}, i10 3)
+// CHECK:  call i16 @llvm.fshl.i16(i16 %{{.*}}, i16 %{{.*}}, i16 8)
+// CHECK:  call i24 @llvm.fshl.i24(i24 %{{.*}}, i24 %{{.*}}, i24 12)
+// CHECK:  call i48 @llvm.fshl.i48(i48 %{{.*}}, i48 %{{.*}}, i48 24)
+// CHECK:  call i8 @llvm.fshl.i8(i8 %{{.*}}, i8 %{{.*}}, i8 0)
+// CHECK:  call i8 @llvm.fshr.i8(i8 %{{.*}}, i8 %{{.*}}, i8 0)
+// CHECK:  call i32 @llvm.fshl.i32(i32 %{{.*}}, i32 %{{.*}}, i32 16)
+// CHECK:  call i32 @llvm.fshl.i32(i32 %{{.*}}, i32 %{{.*}}, i32 31)
+// CHECK:  call i8 @llvm.fshr.i8(i8 %{{.*}}, i8 %{{.*}}, i8 0)
+// CHECK:  call i8 @llvm.fshl.i8(i8 %{{.*}}, i8 %{{.*}}, i8 0)
+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(9) val9, unsigned _BitInt(37) val37,
+                                   unsigned _BitInt(10) val10, unsigned _BitInt(16) val16,
+                                   unsigned _BitInt(24) val24, unsigned _BitInt(48) val48) {
+
+  volatile unsigned char result_uc;
+  volatile unsigned short result_us;
+  volatile unsigned int result_ui;
+  volatile unsigned long result_ul;
+  volatile unsigned long long result_ull;
+  volatile unsigned __int128 result_ui128;
+  volatile unsigned _BitInt(9) result_9;
+  volatile unsigned _BitInt(37) result_37;
+  volatile unsigned _BitInt(10) result_10;
+  volatile unsigned _BitInt(16) result_16;
+  volatile unsigned _BitInt(24) result_24;
+  volatile unsigned _BitInt(48) result_48;
+
+  result_uc = __builtin_stdc_rotate_left(uc, 3);
+  result_us = __builtin_stdc_rotate_left(us, 5);
+  result_ui = __builtin_stdc_rotate_left(ui, 8);
+  result_ul = __builtin_stdc_rotate_left(ul, 8);
+  result_ull = __builtin_stdc_rotate_left(ull, 16);
+  result_ui128 = __builtin_stdc_rotate_left(ui128, 32);
+
+  result_uc = __builtin_stdc_rotate_left(uc, -1);
+  result_us = __builtin_stdc_rotate_left(us, -5);
+  result_ui = __builtin_stdc_rotate_left(ui, -3);
+  result_uc = __builtin_stdc_rotate_left(uc, -65536);
+  result_ui = __builtin_stdc_rotate_left(ui, -4294967333LL);
+
+  int var = 3;
+  result_ui = __builtin_stdc_rotate_left(42U, var);
+
+  result_9 = __builtin_stdc_rotate_left(val9, 1);
+  result_37 = __builtin_stdc_rotate_left(val37, 36);
+  result_9 = __builtin_stdc_rotate_left(val9, -1);
+  result_37 = __builtin_stdc_rotate_left(val37, -5);
+
+  result_uc = __builtin_stdc_rotate_left((unsigned char)0xAB, 1000000);
+  result_ui = __builtin_stdc_rotate_left(0x12345678U, 4294967295U);
+  result_uc = __builtin_stdc_rotate_left((unsigned char)0xAB, -1000000);
+  result_uc = __builtin_stdc_rotate_left((unsigned char)0x01, 2147483647);
+
+  result_uc = __builtin_stdc_rotate_left((unsigned char)0xAB, 7);
+  result_uc = __builtin_stdc_rotate_left((unsigned char)0xAB, 8);
+  result_uc = __builtin_stdc_rotate_left((unsigned char)0xAB, 9);
+
+  result_uc = __builtin_stdc_rotate_left((unsigned char)0xFF, 1073741824);
+  result_ui = __builtin_stdc_rotate_left(0U, 2147483647);
+  result_uc = __builtin_stdc_rotate_left((unsigned char)0x01, 1000000007);
+
+  result_37 = __builtin_stdc_rotate_left((unsigned _BitInt(37))0x1000000000ULL, 1000000000);
+
+  result_10 = __builtin_stdc_rotate_left(val10, 3);
+  result_16 = __builtin_stdc_rotate_left(val16, 8);
+  result_24 = __builtin_stdc_rotate_left(val24, 12);
+  result_48 = __builtin_stdc_rotate_left(val48, 24);
+
+  result_10 = __builtin_stdc_rotate_left((unsigned _BitInt(10))0x3FF, -1);
+  result_16 = __builtin_stdc_rotate_left((unsigned _BitInt(16))0xFFFF, -5);
+  result_24 = __builtin_stdc_rotate_left((unsigned _BitInt(24))0xABCDEF, 1000000);
+  result_48 = __builtin_stdc_rotate_left((unsigned _BitInt(48))0x123456789ABC, -2147483648);
+
+  unsigned char x = 0x42;
+  unsigned int z = 0x12345678;
+  result_uc = __builtin_stdc_rotate_right(__builtin_stdc_rotate_left(x, 1000000), -1000000);
+  result_ui = __builtin_stdc_rotate_left(__builtin_stdc_rotate_left(z, 50000), 4294967295U);
+
+  unsigned char temp = (unsigned char)x ^ __builtin_stdc_rotate_right((unsigned char)x, 1073741824);
+  result_uc = __builtin_stdc_rotate_left(temp, 0x12345678);
+}
+
+// CHECK-LABEL: test_builtin_stdc_rotate_right
+// CHECK:  call i8 @llvm.fshr.i8(i8 %{{.*}}, i8 %{{.*}}, i8 3)
+// CHECK:  call i16 @llvm.fshr.i16(i16 %{{.*}}, i16 %{{.*}}, i16 5)
+// CHECK:  call i32 @llvm.fshr.i32(i32 %{{.*}}, i32 %{{.*}}, i32 8)
+// CHECK:  call i64 @llvm.fshr.i64(i64 %{{.*}}, i64 %{{.*}}, i64 8)
+// CHECK:  call i64 @llvm.fshr.i64(i64 %{{.*}}, i64 %{{.*}}, i64 16)
+// CHECK:  call i128 @llvm.fshr.i128(i128 %{{.*}}, i128 %{{.*}}, i128 32)
+// CHECK:  call i8 @llvm.fshr.i8(i8 %{{.*}}, i8 %{{.*}}, i8 7)
+// CHECK:  call i16 @llvm.fshr.i16(i16 %{{.*}}, i16 %{{.*}}, i16 13)
+// CHECK:  call i64 @llvm.fshr.i64(i64 %{{.*}}, i64 %{{.*}}, i64 48)
+// CHECK:  call i9 @llvm.fshr.i9(i9 %{{.*}}, i9 %{{.*}}, i9 1)
+// CHECK:  call i9 @llvm.fshr.i9(i9 %{{.*}}, i9 %{{.*}}, i9 8)
+// CHECK:  call i12 @llvm.fshr.i12(i12 %{{.*}}, i12 %{{.*}}, i12 6)
+// CHECK:  call i20 @llvm.fshr.i20(i20 %{{.*}}, i20 %{{.*}}, i20 10)
+// CHECK:  call i32 @llvm.fshr.i32(i32 %{{.*}}, i32 %{{.*}}, i32 16)
+// CHECK:  call i16 @llvm.fshr.i16(i16 %{{.*}}, i16 %{{.*}}, i16 15)
+// CHECK:  call i16 @llvm.fshl.i16(i16 %{{.*}}, i16 %{{.*}}, i16 1)
+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(9) val9, unsigned _BitInt(12) val12,
+                                    unsigned _BitInt(20) val20, unsigned _BitInt(32) val32) {
+
+  volatile unsigned char result_uc;
+  volatile unsigned short result_us;
+  volatile unsigned int result_ui;
+  volatile unsigned long result_ul;
+  volatile unsigned long long result_ull;
+  volatile unsigned __int128 result_ui128;
+  volatile unsigned _BitInt(9) result_9;
+  volatile unsigned _BitInt(12) result_12;
+  volatile unsigned _BitInt(20) result_20;
+  volatile unsigned _BitInt(32) result_32;
+
+  result_uc = __builtin_stdc_rotate_right(uc, 3);
+  result_us = __builtin_stdc_rotate_right(us, 5);
+  result_ui = __builtin_stdc_rotate_right(ui, 8);
+  result_ul = __builtin_stdc_rotate_right(ul, 8);
+  result_ull = __builtin_stdc_rotate_right(ull, 16);
+  result_ui128 = __builtin_stdc_rotate_right(ui128, 32);
+
+  result_uc = __builtin_stdc_rotate_right(uc, -1);
+  result_us = __builtin_stdc_rotate_right(us, -3);
+  result_ull = __builtin_stdc_rotate_right(ull, -16);
+
+  result_9 = __builtin_stdc_rotate_right(val9, 1);
+  result_9 = __builtin_stdc_rotate_right(val9, -1);
+
+  result_us = __builtin_stdc_rotate_right((unsigned short)0x1234, 2147483647);
+  result_us = __builtin_stdc_rotate_right((unsigned short)0x1234, -2147483647);
+  result_uc = __builtin_stdc_rotate_right((unsigned char)0x80, -2147483648);
+
+  result_us = __builtin_stdc_rotate_right((unsigned short)0xFFFF, -1073741824);
+  result_ull = __builtin_stdc_rotate_right(0ULL, -2147483648);
+  result_uc = __builtin_stdc_rotate_right((unsigned char)0x80, -1000000007);
+
+  result_12 = __builtin_stdc_rotate_right(val12, 6);
+  result_20 = __builtin_stdc_rotate_right(val20, 10);
+  result_32 = __builtin_stdc_rotate_right(val32, 16);
+
+  result_12 = __builtin_stdc_rotate_right((unsigned _BitInt(12))0xFFF, -3);
+  result_20 = __builtin_stdc_rotate_right((unsigned _BitInt(20))0x12345, 1000000);
+  result_32 = __builtin_stdc_rotate_right((unsigned _BitInt(32))0xABCDEF01, -2147483647);
+
+  unsigned short y = 0x1234;
+  result_us = __builtin_stdc_rotate_left(__builtin_stdc_rotate_right(y, 2147483647), -2147483647);
+}
+
+// Test _BitInt types with various bit widths
+// CHECK-LABEL: test_bitint_extremes
+// CHECK:  call i3 @llvm.fshl.i3(i3 %{{.*}}, i3 %{{.*}}, i3 %{{.*}})
+// CHECK:  call i23 @llvm.fshl.i23(i23 1193046, i23 1193046, i23 %{{.*}})
+// CHECK:  call i37 @llvm.fshl.i37(i37 %{{.*}}, i37 %{{.*}}, i37 %{{.*}})
+// CHECK:  call i67 @llvm.fshl.i67(i67 81985529216486895, i67 81985529216486895, i67 %{{.*}})
+// CHECK:  call i127 @llvm.fshl.i127(i127 1, i127 1, i127 %{{.*}})
+// CHECK:  call i3 @llvm.fshr.i3(i3 %{{.*}}, i3 %{{.*}}, i3 %{{.*}})
+// CHECK:  call i23 @llvm.fshr.i23(i23 1193046, i23 1193046, i23 %{{.*}})
+// CHECK:  call i37 @llvm.fshr.i37(i37 %{{.*}}, i37 %{{.*}}, i37 %{{.*}})
+// CHECK:  call i67 @llvm.fshr.i67(i67 1311768467463790320, i67 1311768467463790320, i67 %{{.*}})
+// CHECK:  call i127 @llvm.fshr.i127(i127 1, i127 1, i127 %{{.*}})
+void test_bitint_extremes(unsigned _BitInt(3) val3, unsigned _BitInt(37) val37, int shift) {
+  volatile unsigned _BitInt(3) result_3;
+  volatile unsigned _BitInt(23) result_23;
+  volatile unsigned _BitInt(37) result_37;
+  volatile unsigned _BitInt(67) result_67;
+  volatile unsigned _BitInt(127) result_127;
+
+  result_3 = __builtin_stdc_rotate_left(val3, shift);
+  result_23 = __builtin_stdc_rotate_left((unsigned _BitInt(23))0x123456, shift);
+  result_37 = __builtin_stdc_rotate_left(val37, shift);
+  result_67 = __builtin_stdc_rotate_left((unsigned _BitInt(67))0x123456789ABCDEFULL, shift);
+  result_127 = __builtin_stdc_rotate_left((unsigned _BitInt(127))1, shift);
+
+  result_3 = __builtin_stdc_rotate_right(val3, shift);
+  result_23 = __builtin_stdc_rotate_right((unsigned _BitInt(23))0x123456, shift);
+  result_37 = __builtin_stdc_rotate_right(val37, shift);
+  result_67 = __builtin_stdc_rotate_right((unsigned _BitInt(67))0x123456789ABCDEF0ULL, shift);
+  result_127 = __builtin_stdc_rotate_right((unsigned _BitInt(127))1, shift);
+}
+
+// CHECK-LABEL: test_wider_shift_amount
+// CHECK: call i8 @llvm.fshl.i8(i8 %{{.*}}, i8 %{{.*}}, i8 7)
+// CHECK: call i8 @llvm.fshr.i8(i8 %{{.*}}, i8 %{{.*}}, i8 0)
+// CHECK: call i16 @llvm.fshl.i16(i16 %{{.*}}, i16 %{{.*}}, i16 11)
+// CHECK: call i16 @llvm.fshr.i16(i16 %{{.*}}, i16 %{{.*}}, i16 12)
+// CHECK: call i32 @llvm.fshl.i32(i32 %{{.*}}, i32 %{{.*}}, i32 0)
+// CHECK: call i32 @llvm.fshr.i32(i32 %{{.*}}, i32 %{{.*}}, i32 0)
+// CHECK: call i9 @llvm.fshl.i9(i9 %{{.*}}, i9 %{{.*}}, i9 8)
+// CHECK: call i9 @llvm.fshr.i9(i9 %{{.*}}, i9 %{{.*}}, i9 8)
+void test_wider_shift_amount(unsigned char uc, unsigned short us, unsigned int ui, unsigned _BitInt(9) val9) {
+  volatile unsigned char result_uc;
+  volatile unsigned short result_us;
+  volatile unsigned int result_ui;
+  volatile unsigned _BitInt(9) result_9;
+
+  result_uc = __builtin_stdc_rotate_left(uc, (long long)-1);
+  result_uc = __builtin_stdc_rotate_right(uc, (long long)-1000);
+
+  result_us = __builtin_stdc_rotate_left(us, (long long)-5);
+  result_us = __builtin_stdc_rotate_right(us, (long long)-100);
+
+  result_ui = __builtin_stdc_rotate_left(ui, (long long)-2147483648);
+  result_ui = __builtin_stdc_rotate_right(ui, (long long)-1073741824);
+
+  result_9 = __builtin_stdc_rotate_left(val9, (long long)-1);
+  result_9 = __builtin_stdc_rotate_right(val9, (long long)-1000000);
+
+  result_uc = __builtin_stdc_rotate_left((unsigned char)0xFF, (long long)-2147483648);
+  result_us = __builtin_stdc_rotate_right((unsigned short)0x1234, (long long)-1073741824);
+  result_ui = __builtin_stdc_rotate_left(0x12345678U, (long long)-4294967296);
+
+  result_9 = __builtin_stdc_rotate_left((unsigned _BitInt(9))0x1FF, (long long)-2147483647);
+}
diff --git a/clang/test/Sema/builtin-stdc-rotate.c b/clang/test/Sema/builtin-stdc-rotate.c
new file mode 100644
index 0000000000000..d9111c2c6f0a6
--- /dev/null
+++ b/clang/test/Sema/builtin-stdc-rotate.c
@@ -0,0 +1,126 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -verify %s
+
+_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 _BitInt(13))1, 12) == ((unsigned _BitInt(13))1 << 12), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(17))0x10000, 16) == ((unsigned _BitInt(17))1), "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(65))1, 64) == ((unsigned _BitInt(65))1 << 64), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(7))0x01, 1) == ((unsigned _BitInt(7))0x40), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(9))0x100, 1) == ((unsigned _BitInt(9))0x001), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(9))0x001, 1) == ((unsigned _BitInt(9))0x100), "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(9))0x1FF, 4) == ((unsigned _BitInt(9))0x1FF), "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(9))1, 8) == ((unsigned _BitInt(9))0x100), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(9))0x100, 8) == ((unsigned _BitInt(9))1), "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(9))0x155, 1) == ((unsigned _BitInt(9))0xAB), "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(9))1, 9) == ((unsigned _BitInt(9))1), "");
+
+_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) == 0x200ULL, "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, -8) == (unsigned char)0xAB, "");
+_Static_assert(__builtin_stdc_rotate_left(0x12345678U, -32) == 0x12345678U, "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0x12, -25) == __builtin_stdc_rotate_left((unsigned char)0x12, 7), "");
+_Static_assert(__builtin_stdc_rotate_right(0x12345678U, -100) == __builtin_stdc_rotate_right(0x12345678U, 28), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned short)0x1234, -65541) == __builtin_stdc_rotate_left((unsigned short)0x1234, -5), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned char)0x80, -261) == __builtin_stdc_rotate_right((unsigned char)0x80, -5), "");
+_Static_assert(__builtin_stdc_rotate_left(0x12345678U, -4294967333LL) == __builtin_stdc_rotate_left(0x12345678U, -37), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned short)0x1234, 0) == (unsigned short)0x1234, "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned long long)0x123456789ABCDEF0ULL, 0) == 0x123456789ABCDEF0ULL, "");
+_Static_assert(__builtin_stdc_rotate_left(0U, 15) == 0U, "");
+_Static_assert(__builtin_stdc_rotate_right(0U, 7) == 0U, "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, 1000000) == __builtin_stdc_rotate_left((unsigned char)0xAB, 1000000 % 8), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned short)0x1234, 2147483647) == __builtin_stdc_rotate_right((unsigned short)0x1234, 2147483647 % 16), "");
+_Static_assert(__builtin_stdc_rotate_left(0x12345678U, 4294967295U) == __builtin_stdc_rotate_left(0x12345678U, 4294967295U % 32), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, -1000000) == __builtin_stdc_rotate_left((unsigned char)0xAB, -1000000 % 8), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned short)0x1234, -2147483647) == __builtin_stdc_rotate_right((unsigned short)0x1234, -2147483647 % 16), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(127))1, 1000000) == __builtin_stdc_rotate_left((unsigned _BitInt(127))1, 1000000 % 127), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(127))1, -1000000) == __builtin_stdc_rotate_right((unsigned _BitInt(127))1, -1000000 % 127), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0x01, 2147483647) == __builtin_stdc_rotate_left((unsigned char)0x01, 2147483647 % 8), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned char)0x80, -2147483648) == __builtin_stdc_rotate_right((unsigned char)0x80, -2147483648 % 8), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, -9) == __builtin_stdc_rotate_left((unsigned char)0xAB, 7), "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, -17) == __builtin_stdc_rotate_left((unsigned char)0xAB, 7), "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, -25) == __builtin_stdc_rotate_left((unsigned char)0xAB, 7), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0x12, 64 + 3) == __builtin_stdc_rotate_left((unsigned char)0x12, 3), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned short)0x1234, 128 + 5) == __builtin_stdc_rotate_right((unsigned short)0x1234, 5), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(31))1, 1000) == __builtin_stdc_rotate_left((unsigned _BitInt(31))1, 1000 % 31), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(61))1, -1000) == __builtin_stdc_rotate_right((unsigned _BitInt(61))1, -1000 % 61), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(128))0xFFFFFFFFFFFFFFFFULL, 50000) == __builtin_stdc_rotate_left((unsigned _BitInt(128))0xFFFFFFFFFFFFFFFFULL, 50000 % 128), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(128))0xAAAAAAAAAAAAAAAAULL, -50000) == __builtin_stdc_rotate_right((unsigned _BitInt(128))0xAAAAAAAAAAAAAAAAULL, -50000 % 128), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, 7) == __builtin_stdc_rotate_left((unsigned char)0xAB, 7), "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, 8) == (unsigned char)0xAB, "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, 9) == __builtin_stdc_rotate_left((unsigned char)0xAB, 1), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(9))0x155, 1000) == __builtin_stdc_rotate_left((unsigned _BitInt(9))0x155, 1000 % 9), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(9))0xAA, -1000) == __builtin_stdc_rotate_right((unsigned _BitInt(9))0xAA, -1000 % 9), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0xFF, 1073741824) == (unsigned char)0xFF, "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned short)0xFFFF, -1073741824) == (unsigned short)0xFFFF, "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned char)0x42, 1000000000) == __builtin_stdc_rotate_left((unsigned char)0x42, 1000000000 % 8), "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned char)0x42, -1000000000) == __builtin_stdc_rotate_right((unsigned char)0x42, -1000000000 % 8), "");
+
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(1))0, -1) == (unsigned _BitInt(1))0, "");
+_Static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(1))1, -1) == (unsigned _BitInt(1))1, "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(1))0, 5) == (unsigned _BitInt(1))0, "");
+_Static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(1))1, 5) == (unsigned _BitInt(1))1, "");
+
+void test_errors(int si, float f) {
+  unsigned int ui = 5;
+
+  __builtin_stdc_rotate_left(ui); // expected-error {{too few arguments to function call}}
+  __builtin_stdc_rotate_left(ui, 1, 2); // expected-error {{too many arguments to function call}}
+}
+
+void test_implicit_conversions(_Bool b, float f, int si) {
+  unsigned int ui = 5;
+
+  // Test implicit conversions for second argument
+  (void)__builtin_stdc_rotate_left(ui, b);
+  (void)__builtin_stdc_rotate_left(ui, f);
+  (void)__builtin_stdc_rotate_left(ui, 1.5); // expected-warning {{implicit conversion from 'double' to 'int' changes value from 1.5 to 1}}
+  (void)__builtin_stdc_rotate_right(ui, b);
+  (void)__builtin_stdc_rotate_right(ui, f);
+
+  // Test implicit conversions for first argument
+  (void)__builtin_stdc_rotate_left(si, 1);
+  (void)__builtin_stdc_rotate_left(-5, 1);
+  (void)__builtin_stdc_rotate_right(3.0, 1.5); // expected-warning {{implicit conversion from 'double' to 'int' changes value from 1.5 to 1}}
+
+  // Test narrowing conversion in assignment
+  unsigned _BitInt(17) rotated_odd = __builtin_stdc_rotate_left(0x1ABCD, 5); // expected-warning {{implicit conversion from 'unsigned int' to 'unsigned _BitInt(17)' changes value from 3504544 to 96672}}
+  (void)rotated_odd;
+}
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..ab2888fbcb271
--- /dev/null
+++ b/clang/test/SemaCXX/constexpr-builtin-stdc-rotate.cpp
@@ -0,0 +1,199 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -std=c++14 -fsyntax-only -verify %s
+
+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(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))0x200ULL, "");
+static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(37))0x800000000ULL, -3) == (unsigned _BitInt(37))0x100000000ULL, "");
+
+} // namespace test_negative_counts
+
+namespace test_boundaries {
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0x01, 7) == (unsigned char)0x80, "");
+static_assert(__builtin_stdc_rotate_right((unsigned char)0x80, 7) == (unsigned char)0x01, "");
+static_assert(__builtin_stdc_rotate_left((unsigned char)0xFF, 1) == (unsigned char)0xFF, "");
+static_assert(__builtin_stdc_rotate_left((unsigned short)0x0001, 15) == (unsigned short)0x8000, "");
+static_assert(__builtin_stdc_rotate_right((unsigned short)0x8000, 15) == (unsigned short)0x0001, "");
+static_assert(__builtin_stdc_rotate_left(0x00000001U, 31) == 0x80000000U, "");
+static_assert(__builtin_stdc_rotate_right(0x80000000U, 31) == 0x00000001U, "");
+static_assert(__builtin_stdc_rotate_left(0x0000000000000001ULL, 63) == 0x8000000000000000ULL, "");
+static_assert(__builtin_stdc_rotate_right(0x8000000000000000ULL, 63) == 0x0000000000000001ULL, "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0x01, -7) == (unsigned char)0x02, "");
+static_assert(__builtin_stdc_rotate_right((unsigned char)0x80, -7) == (unsigned char)0x40, "");
+static_assert(__builtin_stdc_rotate_left(0x00000001U, -31) == 0x00000002U, "");
+static_assert(__builtin_stdc_rotate_right(0x80000000U, -31) == 0x40000000U, "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, -8) == (unsigned char)0xAB, "");
+static_assert(__builtin_stdc_rotate_left(0x12345678U, -32) == 0x12345678U, "");
+static_assert(__builtin_stdc_rotate_left((unsigned char)0x12, -25) == __builtin_stdc_rotate_left((unsigned char)0x12, 7), "");
+static_assert(__builtin_stdc_rotate_left(0x12345678U, -100) == __builtin_stdc_rotate_left(0x12345678U, 28), "");
+
+constexpr unsigned __int128 int128_one = 1;
+constexpr unsigned __int128 int128_msb = int128_one << 127;
+static_assert(__builtin_stdc_rotate_left(int128_one, 127) == int128_msb, "");
+static_assert(__builtin_stdc_rotate_right(int128_msb, 127) == int128_one, "");
+static_assert(__builtin_stdc_rotate_left(int128_one, -127) == (int128_one << 1), "");
+
+constexpr unsigned _BitInt(37) bi37_one = 1;
+constexpr unsigned _BitInt(37) bi37_msb = bi37_one << 36;
+static_assert(__builtin_stdc_rotate_left(bi37_one, 36) == bi37_msb, "");
+static_assert(__builtin_stdc_rotate_right(bi37_msb, 36) == bi37_one, "");
+static_assert(__builtin_stdc_rotate_left(bi37_one, -36) == (bi37_one << 1), "");
+
+} // namespace test_boundaries
+
+namespace test_extreme_cases {
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, 1000000) == __builtin_stdc_rotate_left((unsigned char)0xAB, 1000000 % 8), "");
+static_assert(__builtin_stdc_rotate_right((unsigned short)0x1234, 2147483647) == __builtin_stdc_rotate_right((unsigned short)0x1234, 2147483647 % 16), "");
+static_assert(__builtin_stdc_rotate_left(0x12345678U, 4294967295U) == __builtin_stdc_rotate_left(0x12345678U, 4294967295U % 32), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, -1000000) == __builtin_stdc_rotate_left((unsigned char)0xAB, -1000000 % 8), "");
+static_assert(__builtin_stdc_rotate_right((unsigned short)0x1234, -2147483647) == __builtin_stdc_rotate_right((unsigned short)0x1234, -2147483647 % 16), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(127))1, 1000000) == __builtin_stdc_rotate_left((unsigned _BitInt(127))1, 1000000 % 127), "");
+static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(127))1, -1000000) == __builtin_stdc_rotate_right((unsigned _BitInt(127))1, -1000000 % 127), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0x01, 2147483647) == __builtin_stdc_rotate_left((unsigned char)0x01, 2147483647 % 8), "");
+static_assert(__builtin_stdc_rotate_right((unsigned char)0x80, -2147483648) == __builtin_stdc_rotate_right((unsigned char)0x80, -2147483648 % 8), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, -9) == __builtin_stdc_rotate_left((unsigned char)0xAB, 7), "");
+static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, -17) == __builtin_stdc_rotate_left((unsigned char)0xAB, 7), "");
+static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, -25) == __builtin_stdc_rotate_left((unsigned char)0xAB, 7), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0x12, 64 + 3) == __builtin_stdc_rotate_left((unsigned char)0x12, 3), "");
+static_assert(__builtin_stdc_rotate_right((unsigned short)0x1234, 128 + 5) == __builtin_stdc_rotate_right((unsigned short)0x1234, 5), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(31))1, 1000) == __builtin_stdc_rotate_left((unsigned _BitInt(31))1, 1000 % 31), "");
+static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(61))1, -1000) == __builtin_stdc_rotate_right((unsigned _BitInt(61))1, -1000 % 61), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(128))0xFFFFFFFFFFFFFFFFULL, 50000) == __builtin_stdc_rotate_left((unsigned _BitInt(128))0xFFFFFFFFFFFFFFFFULL, 50000 % 128), "");
+static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(128))0xAAAAAAAAAAAAAAAAULL, -50000) == __builtin_stdc_rotate_right((unsigned _BitInt(128))0xAAAAAAAAAAAAAAAAULL, -50000 % 128), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, 7) == __builtin_stdc_rotate_left((unsigned char)0xAB, 7), "");
+static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, 8) == (unsigned char)0xAB, "");
+static_assert(__builtin_stdc_rotate_left((unsigned char)0xAB, 9) == __builtin_stdc_rotate_left((unsigned char)0xAB, 1), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(9))0x155, 1000) == __builtin_stdc_rotate_left((unsigned _BitInt(9))0x155, 1000 % 9), "");
+static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(9))0xAA, -1000) == __builtin_stdc_rotate_right((unsigned _BitInt(9))0xAA, -1000 % 9), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0xFF, 1073741824) == (unsigned char)0xFF, "");
+static_assert(__builtin_stdc_rotate_right((unsigned short)0xFFFF, -1073741824) == (unsigned short)0xFFFF, "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0x42, 1000000000) == __builtin_stdc_rotate_left((unsigned char)0x42, 1000000000 % 8), "");
+static_assert(__builtin_stdc_rotate_right((unsigned char)0x42, -1000000000) == __builtin_stdc_rotate_right((unsigned char)0x42, -1000000000 % 8), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned char)0x12, -1000001) == __builtin_stdc_rotate_right((unsigned char)0x12, 1000001), "");
+static_assert(__builtin_stdc_rotate_right((unsigned short)0x1234, -65537) == __builtin_stdc_rotate_left((unsigned short)0x1234, 65537), "");
+
+constexpr unsigned _BitInt(67) large_pattern = 0x123456789ABCDEF0ULL;
+static_assert(__builtin_stdc_rotate_left(large_pattern, 1000000) == __builtin_stdc_rotate_left(large_pattern, 1000000 % 67), "");
+static_assert(__builtin_stdc_rotate_right(large_pattern, -1000000) == __builtin_stdc_rotate_right(large_pattern, -1000000 % 67), "");
+
+static_assert(__builtin_stdc_rotate_left((unsigned _BitInt(23))0x123456, 1048576) == __builtin_stdc_rotate_left((unsigned _BitInt(23))0x123456, 1048576 % 23), "");
+static_assert(__builtin_stdc_rotate_right((unsigned _BitInt(23))0x123456, -1048576) == __builtin_stdc_rotate_right((unsigned _BitInt(23))0x123456, -1048576 % 23), "");
+
+} // namespace test_extreme_cases
+
+} // namespace test_constexpr_stdc_rotate
+
+namespace test_conversions {
+
+struct UnsignedWrapper {
+  operator unsigned int() const { return 42; }
+};
+
+struct RotateCount {
+  operator int() const { return 5; }
+};
+
+enum RotateAmount {
+  ROTATE_BY_4 = 4,
+  ROTATE_BY_8 = 8
+};
+
+struct NoConversion {};
+
+void test_implicit_conversions() {
+  UnsignedWrapper uw;
+  RotateCount rc;
+
+  auto result1 = __builtin_stdc_rotate_left(uw, 3);
+  auto result2 = __builtin_stdc_rotate_left(5U, rc);
+  auto result3 = __builtin_stdc_rotate_left(uw, rc);
+  auto result4 = __builtin_stdc_rotate_right(uw, RotateAmount::ROTATE_BY_4);
+
+  bool b = true;
+  float f = 3.7f;
+  auto result5 = __builtin_stdc_rotate_left(10U, b);
+  auto result6 = __builtin_stdc_rotate_left(10U, f);
+  auto result7 = __builtin_stdc_rotate_right(10U, 2.9f); // expected-warning {{implicit conversion from 'float' to 'int' changes value from 2.9000001 to 2}}
+}
+
+void test_no_conversions() {
+  NoConversion nc;
+  auto result1 = __builtin_stdc_rotate_left(5U, nc); // expected-error {{passing 'NoConversion' to parameter of incompatible type 'int'}} expected-error {{2nd argument must be a scalar signed integer type (was 'NoConversion')}}
+}
+
+} // namespace test_conversions



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