diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index f081ff0313e0a..4b444bece68a7 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -174,7 +174,12 @@ C Language Changes in Clang
   ``_BitInt(N)`` is supported as an extension in older C modes and in all C++
   modes. Note: the ABI for ``_BitInt(N)`` is still in the process of being
   stabilized, so this type should not yet be used in interfaces that require
-  ABI stability.
+  ABI stability. The maximum width supported by Clang can be obtained from the
+  ``BITINT_MAXWIDTH`` macro in ``<limits.h>``. Currently, Clang supports bit
+  widths <= 128 because backends are not yet able to cope with some math
+  operations (like division) on wider integer types. See
+  `PR44994 <https://github.com/llvm/llvm-project/issues/44994>`_ for more
+  information.
 - When using ``asm goto`` with outputs whose constraint modifier is ``"+"``, we
   now change the numbering of the labels to occur after hidden tied inputs for
   better compatibility with GCC.  For better portability between different
diff --git a/clang/include/clang/Basic/TargetInfo.h b/clang/include/clang/Basic/TargetInfo.h
index 642c8500364bb..a49342a34f3e8 100644
--- a/clang/include/clang/Basic/TargetInfo.h
+++ b/clang/include/clang/Basic/TargetInfo.h
@@ -590,6 +590,17 @@ class TargetInfo : public virtual TransferrableTargetInfo,
     return false;
   }
 
+  // Different targets may support a different maximum width for the _BitInt
+  // type, depending on what operations are supported.
+  virtual size_t getMaxBitIntWidth() const {
+    // FIXME: this value should be llvm::IntegerType::MAX_INT_BITS, which is
+    // maximum bit width that LLVM claims its IR can support. However, most
+    // backends currently have a bug where they only support division
+    // operations on types that are <= 128 bits and crash otherwise. We're
+    // setting the max supported value to 128 to be conservative.
+    return 128;
+  }
+
   /// Determine whether _Float16 is supported on this target.
   virtual bool hasLegalHalfType() const { return HasLegalHalfType; }
 
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index a9023a7a1171e..e259ab47c5589 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -25,6 +25,7 @@
 #include "clang/Serialization/ASTReader.h"
 #include "llvm/ADT/APFloat.h"
 #include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
 using namespace clang;
 
 static bool MacroBodyEndsInBackslash(StringRef MacroBody) {
@@ -914,6 +915,13 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   Builder.defineMacro("__LONG_WIDTH__", Twine(TI.getLongWidth()));
   Builder.defineMacro("__LLONG_WIDTH__", Twine(TI.getLongLongWidth()));
 
+  size_t BitIntMaxWidth = TI.getMaxBitIntWidth();
+  assert(BitIntMaxWidth <= llvm::IntegerType::MAX_INT_BITS &&
+         "Target defined a max bit width larger than LLVM can support!");
+  assert(BitIntMaxWidth >= TI.getLongLongWidth() &&
+         "Target defined a max bit width smaller than the C standard allows!");
+  Builder.defineMacro("__BITINT_MAXWIDTH__", Twine(BitIntMaxWidth));
+
   DefineTypeSize("__SCHAR_MAX__", TargetInfo::SignedChar, TI, Builder);
   DefineTypeSize("__SHRT_MAX__", TargetInfo::SignedShort, TI, Builder);
   DefineTypeSize("__INT_MAX__", TargetInfo::SignedInt, TI, Builder);
diff --git a/clang/lib/Headers/limits.h b/clang/lib/Headers/limits.h
index c2d3a7cf43539..cfd23a219ee55 100644
--- a/clang/lib/Headers/limits.h
+++ b/clang/lib/Headers/limits.h
@@ -78,6 +78,8 @@
 #define LONG_WIDTH   __LONG_WIDTH__
 #define ULLONG_WIDTH __LLONG_WIDTH__
 #define LLONG_WIDTH  __LLONG_WIDTH__
+
+#define BITINT_MAXWIDTH __BITINT_MAXWIDTH__
 #endif
 
 #ifdef __CHAR_UNSIGNED__  /* -funsigned-char */
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 959f4903b0306..ab47e9f03eaf2 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -2257,7 +2257,7 @@ QualType Sema::BuildBitIntType(bool IsUnsigned, Expr *BitWidth,
   if (ICE.isInvalid())
     return QualType();
 
-  int64_t NumBits = Bits.getSExtValue();
+  size_t NumBits = Bits.getZExtValue();
   if (!IsUnsigned && NumBits < 2) {
     Diag(Loc, diag::err_bit_int_bad_size) << 0;
     return QualType();
@@ -2268,9 +2268,10 @@ QualType Sema::BuildBitIntType(bool IsUnsigned, Expr *BitWidth,
     return QualType();
   }
 
-  if (NumBits > llvm::IntegerType::MAX_INT_BITS) {
+  const TargetInfo &TI = getASTContext().getTargetInfo();
+  if (NumBits > TI.getMaxBitIntWidth()) {
     Diag(Loc, diag::err_bit_int_max_size)
-        << IsUnsigned << llvm::IntegerType::MAX_INT_BITS;
+        << IsUnsigned << static_cast<uint64_t>(TI.getMaxBitIntWidth());
     return QualType();
   }
 
diff --git a/clang/test/CodeGen/ext-int-cc.c b/clang/test/CodeGen/ext-int-cc.c
index 1603d5ec0fb08..517e3cd2f8587 100644
--- a/clang/test/CodeGen/ext-int-cc.c
+++ b/clang/test/CodeGen/ext-int-cc.c
@@ -28,65 +28,64 @@
 // RUN: %clang_cc1 -disable-noundef-analysis -triple arm64_32-apple-ios -target-abi darwinpcs -O3 -disable-llvm-passes -emit-llvm -o - %s | FileCheck %s --check-prefixes=AARCH64DARWIN
 // RUN: %clang_cc1 -disable-noundef-analysis -triple arm -O3 -disable-llvm-passes -emit-llvm -o - %s | FileCheck %s --check-prefixes=ARM
 
-// Make sure 128 and 64 bit versions are passed like integers, and that >128
-// is passed indirectly.
-void ParamPassing(_BitInt(129) a, _BitInt(128) b, _BitInt(64) c) {}
-// LIN64: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i64 %{{.+}}, i64 %{{.+}}, i64 %{{.+}})
-// WIN64: define dso_local void @ParamPassing(i129* %{{.+}}, i128* %{{.+}}, i64 %{{.+}})
-// LIN32: define{{.*}} void @ParamPassing(i129* %{{.+}}, i128* %{{.+}}, i64 %{{.+}})
-// WIN32: define dso_local void @ParamPassing(i129* %{{.+}}, i128* %{{.+}}, i64 %{{.+}})
-// NACL: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
-// NVPTX64: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128 %{{.+}}, i64 %{{.+}})
-// NVPTX: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
-// SPARCV9: define{{.*}} void @ParamPassing(i129* %{{.+}}, i128 %{{.+}}, i64 %{{.+}})
-// SPARC: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
-// MIPS64: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128 signext  %{{.+}}, i64 signext %{{.+}})
-// MIPS: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 signext %{{.+}})
-// SPIR64: define{{.*}} spir_func void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
-// SPIR: define{{.*}} spir_func void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
-// HEX: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
-// LANAI: define{{.*}} void @ParamPassing(i129* byval(i129) align 4 %{{.+}}, i128* byval(i128) align 4 %{{.+}}, i64 %{{.+}})
-// R600: define{{.*}} void @ParamPassing(i129 addrspace(5)* byval(i129) align 8 %{{.+}}, i128 addrspace(5)* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
-// ARC: define{{.*}} void @ParamPassing(i129* byval(i129) align 4 %{{.+}}, i128* byval(i128) align 4 %{{.+}}, i64 inreg %{{.+}})
-// XCORE: define{{.*}} void @ParamPassing(i129* byval(i129) align 4 %{{.+}}, i128* byval(i128) align 4 %{{.+}}, i64 %{{.+}})
-// RISCV64: define{{.*}} void @ParamPassing(i129* %{{.+}}, i128 %{{.+}}, i64 %{{.+}})
-// RISCV32: define{{.*}} void @ParamPassing(i129* %{{.+}}, i128* %{{.+}}, i64 %{{.+}})
-// WASM: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128 %{{.+}}, i64 %{{.+}})
-// SYSTEMZ: define{{.*}} void @ParamPassing(i129* %{{.+}}, i128* %{{.+}}, i64 %{{.+}})
-// PPC64: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128 %{{.+}}, i64 %{{.+}})
-// PPC32: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
-// AARCH64: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128 %{{.+}}, i64 %{{.+}})
-// AARCH64DARWIN: define{{.*}} void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128 %{{.+}}, i64 %{{.+}})
-// ARM: define{{.*}} arm_aapcscc void @ParamPassing(i129* byval(i129) align 8 %{{.+}}, i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
+// Make sure 128 and 64 bit versions are passed like integers.
+void ParamPassing(_BitInt(128) b, _BitInt(64) c) {}
+// LIN64: define{{.*}} void @ParamPassing(i64 %{{.+}}, i64 %{{.+}}, i64 %{{.+}})
+// WIN64: define dso_local void @ParamPassing(i128* %{{.+}}, i64 %{{.+}})
+// LIN32: define{{.*}} void @ParamPassing(i128* %{{.+}}, i64 %{{.+}})
+// WIN32: define dso_local void @ParamPassing(i128* %{{.+}}, i64 %{{.+}})
+// NACL: define{{.*}} void @ParamPassing(i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
+// NVPTX64: define{{.*}} void @ParamPassing(i128 %{{.+}}, i64 %{{.+}})
+// NVPTX: define{{.*}} void @ParamPassing(i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
+// SPARCV9: define{{.*}} void @ParamPassing(i128 %{{.+}}, i64 %{{.+}})
+// SPARC: define{{.*}} void @ParamPassing(i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
+// MIPS64: define{{.*}} void @ParamPassing(i128 signext  %{{.+}}, i64 signext %{{.+}})
+// MIPS: define{{.*}} void @ParamPassing(i128* byval(i128) align 8 %{{.+}}, i64 signext %{{.+}})
+// SPIR64: define{{.*}} spir_func void @ParamPassing(i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
+// SPIR: define{{.*}} spir_func void @ParamPassing(i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
+// HEX: define{{.*}} void @ParamPassing(i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
+// LANAI: define{{.*}} void @ParamPassing(i128* byval(i128) align 4 %{{.+}}, i64 %{{.+}})
+// R600: define{{.*}} void @ParamPassing(i128 addrspace(5)* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
+// ARC: define{{.*}} void @ParamPassing(i128* byval(i128) align 4 %{{.+}}, i64 inreg %{{.+}})
+// XCORE: define{{.*}} void @ParamPassing(i128* byval(i128) align 4 %{{.+}}, i64 %{{.+}})
+// RISCV64: define{{.*}} void @ParamPassing(i128 %{{.+}}, i64 %{{.+}})
+// RISCV32: define{{.*}} void @ParamPassing(i128* %{{.+}}, i64 %{{.+}})
+// WASM: define{{.*}} void @ParamPassing(i128 %{{.+}}, i64 %{{.+}})
+// SYSTEMZ: define{{.*}} void @ParamPassing(i128* %{{.+}}, i64 %{{.+}})
+// PPC64: define{{.*}} void @ParamPassing(i128 %{{.+}}, i64 %{{.+}})
+// PPC32: define{{.*}} void @ParamPassing(i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
+// AARCH64: define{{.*}} void @ParamPassing(i128 %{{.+}}, i64 %{{.+}})
+// AARCH64DARWIN: define{{.*}} void @ParamPassing(i128 %{{.+}}, i64 %{{.+}})
+// ARM: define{{.*}} arm_aapcscc void @ParamPassing(i128* byval(i128) align 8 %{{.+}}, i64 %{{.+}})
 
-void ParamPassing2(_BitInt(129) a, _BitInt(127) b, _BitInt(63) c) {}
-// LIN64: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i64 %{{.+}}, i64 %{{.+}}, i64 %{{.+}})
-// WIN64: define dso_local void @ParamPassing2(i129* %{{.+}}, i127* %{{.+}}, i63 %{{.+}})
-// LIN32: define{{.*}} void @ParamPassing2(i129* %{{.+}}, i127* %{{.+}}, i63 %{{.+}})
-// WIN32: define dso_local void @ParamPassing2(i129* %{{.+}}, i127* %{{.+}}, i63 %{{.+}})
-// NACL: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
-// NVPTX64: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127 %{{.+}}, i63 %{{.+}})
-// NVPTX: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
-// SPARCV9: define{{.*}} void @ParamPassing2(i129* %{{.+}}, i127 %{{.+}}, i63 signext %{{.+}})
-// SPARC: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
-// MIPS64: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127 signext  %{{.+}}, i63 signext %{{.+}})
-// MIPS: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 signext %{{.+}})
-// SPIR64: define{{.*}} spir_func void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
-// SPIR: define{{.*}} spir_func void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
-// HEX: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
-// LANAI: define{{.*}} void @ParamPassing2(i129* byval(i129) align 4 %{{.+}}, i127* byval(i127) align 4 %{{.+}}, i63 %{{.+}})
-// R600: define{{.*}} void @ParamPassing2(i129 addrspace(5)* byval(i129) align 8 %{{.+}}, i127 addrspace(5)* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
-// ARC: define{{.*}} void @ParamPassing2(i129* byval(i129) align 4 %{{.+}}, i127* byval(i127) align 4 %{{.+}}, i63 inreg %{{.+}})
-// XCORE: define{{.*}} void @ParamPassing2(i129* byval(i129) align 4 %{{.+}}, i127* byval(i127) align 4 %{{.+}}, i63 %{{.+}})
-// RISCV64: define{{.*}} void @ParamPassing2(i129* %{{.+}}, i127 %{{.+}}, i63 signext %{{.+}})
-// RISCV32: define{{.*}} void @ParamPassing2(i129* %{{.+}}, i127* %{{.+}}, i63 %{{.+}})
-// WASM: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127 %{{.+}}, i63 %{{.+}})
-// SYSTEMZ: define{{.*}} void @ParamPassing2(i129* %{{.+}}, i127* %{{.+}}, i63 signext %{{.+}})
-// PPC64: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127 %{{.+}}, i63 signext %{{.+}})
-// PPC32: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
-// AARCH64: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127 %{{.+}}, i63 %{{.+}})
-// AARCH64DARWIN: define{{.*}} void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127 %{{.+}}, i63 %{{.+}})
-// ARM: define{{.*}} arm_aapcscc void @ParamPassing2(i129* byval(i129) align 8 %{{.+}}, i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
+void ParamPassing2(_BitInt(127) b, _BitInt(63) c) {}
+// LIN64: define{{.*}} void @ParamPassing2(i64 %{{.+}}, i64 %{{.+}}, i64 %{{.+}})
+// WIN64: define dso_local void @ParamPassing2(i127* %{{.+}}, i63 %{{.+}})
+// LIN32: define{{.*}} void @ParamPassing2(i127* %{{.+}}, i63 %{{.+}})
+// WIN32: define dso_local void @ParamPassing2(i127* %{{.+}}, i63 %{{.+}})
+// NACL: define{{.*}} void @ParamPassing2(i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
+// NVPTX64: define{{.*}} void @ParamPassing2(i127 %{{.+}}, i63 %{{.+}})
+// NVPTX: define{{.*}} void @ParamPassing2(i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
+// SPARCV9: define{{.*}} void @ParamPassing2(i127 %{{.+}}, i63 signext %{{.+}})
+// SPARC: define{{.*}} void @ParamPassing2(i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
+// MIPS64: define{{.*}} void @ParamPassing2(i127 signext  %{{.+}}, i63 signext %{{.+}})
+// MIPS: define{{.*}} void @ParamPassing2(i127* byval(i127) align 8 %{{.+}}, i63 signext %{{.+}})
+// SPIR64: define{{.*}} spir_func void @ParamPassing2(i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
+// SPIR: define{{.*}} spir_func void @ParamPassing2(i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
+// HEX: define{{.*}} void @ParamPassing2(i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
+// LANAI: define{{.*}} void @ParamPassing2(i127* byval(i127) align 4 %{{.+}}, i63 %{{.+}})
+// R600: define{{.*}} void @ParamPassing2(i127 addrspace(5)* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
+// ARC: define{{.*}} void @ParamPassing2(i127* byval(i127) align 4 %{{.+}}, i63 inreg %{{.+}})
+// XCORE: define{{.*}} void @ParamPassing2(i127* byval(i127) align 4 %{{.+}}, i63 %{{.+}})
+// RISCV64: define{{.*}} void @ParamPassing2(i127 %{{.+}}, i63 signext %{{.+}})
+// RISCV32: define{{.*}} void @ParamPassing2(i127* %{{.+}}, i63 %{{.+}})
+// WASM: define{{.*}} void @ParamPassing2(i127 %{{.+}}, i63 %{{.+}})
+// SYSTEMZ: define{{.*}} void @ParamPassing2(i127* %{{.+}}, i63 signext %{{.+}})
+// PPC64: define{{.*}} void @ParamPassing2(i127 %{{.+}}, i63 signext %{{.+}})
+// PPC32: define{{.*}} void @ParamPassing2(i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
+// AARCH64: define{{.*}} void @ParamPassing2(i127 %{{.+}}, i63 %{{.+}})
+// AARCH64DARWIN: define{{.*}} void @ParamPassing2(i127 %{{.+}}, i63 %{{.+}})
+// ARM: define{{.*}} arm_aapcscc void @ParamPassing2(i127* byval(i127) align 8 %{{.+}}, i63 %{{.+}})
 
 // Make sure we follow the signext rules for promotable integer types.
 void ParamPassing3(_BitInt(15) a, _BitInt(31) b) {}
@@ -118,6 +117,41 @@ void ParamPassing3(_BitInt(15) a, _BitInt(31) b) {}
 // AARCH64DARWIN: define{{.*}} void @ParamPassing3(i15 signext %{{.+}}, i31 signext %{{.+}})
 // ARM: define{{.*}} arm_aapcscc void @ParamPassing3(i15 signext %{{.+}}, i31 signext %{{.+}})
 
+#if __BITINT_MAXWIDTH__ > 128
+// When supported, bit-precise types that are >128 are passed indirectly. Note,
+// FileCheck doesn't pay attention to the preprocessor, so all of these tests
+// are negated. This will give an error when a target does support larger
+// _BitInt widths to alert us to enable the test.
+void ParamPassing4(_BitInt(129) a) {}
+// LIN64-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// WIN64-NOT: define dso_local void @ParamPassing4(i129* %{{.+}})
+// LIN32-NOT: define{{.*}} void @ParamPassing4(i129* %{{.+}})
+// WIN32-NOT: define dso_local void @ParamPassing4(i129* %{{.+}})
+// NACL-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// NVPTX64-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// NVPTX-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// SPARCV9-NOT: define{{.*}} void @ParamPassing4(i129* %{{.+}})
+// SPARC-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// MIPS64-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// MIPS-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// SPIR64-NOT: define{{.*}} spir_func void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// SPIR-NOT: define{{.*}} spir_func void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// HEX-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// LANAI-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 4 %{{.+}})
+// R600-NOT: define{{.*}} void @ParamPassing4(i129 addrspace(5)* byval(i129) align 8 %{{.+}})
+// ARC-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 4 %{{.+}})
+// XCORE-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 4 %{{.+}})
+// RISCV64-NOT: define{{.*}} void @ParamPassing4(i129* %{{.+}})
+// RISCV32-NOT: define{{.*}} void @ParamPassing4(i129* %{{.+}})
+// WASM-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// SYSTEMZ-NOT: define{{.*}} void @ParamPassing4(i129* %{{.+}})
+// PPC64-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// PPC32-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// AARCH64-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// AARCH64DARWIN-NOT: define{{.*}} void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+// ARM-NOT: define{{.*}} arm_aapcscc void @ParamPassing4(i129* byval(i129) align 8 %{{.+}})
+#endif
+
 _BitInt(63) ReturnPassing(){}
 // LIN64: define{{.*}} i64 @ReturnPassing(
 // WIN64: define dso_local i63 @ReturnPassing(
@@ -236,38 +270,40 @@ _BitInt(128) ReturnPassing4(){}
 // AARCH64DARWIN: define{{.*}} i128 @ReturnPassing4(
 // ARM: define{{.*}} arm_aapcscc void @ReturnPassing4(i128* noalias sret
 
+#if __BITINT_MAXWIDTH__ > 128
 _BitInt(129) ReturnPassing5(){}
-// LIN64: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// WIN64: define dso_local void @ReturnPassing5(i129* noalias sret
-// LIN32: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// WIN32: define dso_local void @ReturnPassing5(i129* noalias sret
-// NACL: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// NVPTX64: define{{.*}} i129 @ReturnPassing5(
-// NVPTX: define{{.*}} i129 @ReturnPassing5(
-// SPARCV9: define{{.*}} i129 @ReturnPassing5(
-// SPARC: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// MIPS64: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// MIPS: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// SPIR64: define{{.*}} spir_func void @ReturnPassing5(i129* noalias sret
-// SPIR: define{{.*}} spir_func void @ReturnPassing5(i129* noalias sret
-// HEX: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// LANAI: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// R600: define{{.*}} void @ReturnPassing5(i129 addrspace(5)* noalias sret
-// ARC: define{{.*}} void @ReturnPassing5(i129* inreg noalias sret
-// XCORE: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// RISCV64: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// RISCV32: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// WASM: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// SYSTEMZ: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// PPC64: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// PPC32: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// AARCH64: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// AARCH64DARWIN: define{{.*}} void @ReturnPassing5(i129* noalias sret
-// ARM: define{{.*}} arm_aapcscc void @ReturnPassing5(i129* noalias sret
+// LIN64-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// WIN64-NOT: define dso_local void @ReturnPassing5(i129* noalias sret
+// LIN32-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// WIN32-NOT: define dso_local void @ReturnPassing5(i129* noalias sret
+// NACL-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// NVPTX64-NOT: define{{.*}} i129 @ReturnPassing5(
+// NVPTX-NOT: define{{.*}} i129 @ReturnPassing5(
+// SPARCV9-NOT: define{{.*}} i129 @ReturnPassing5(
+// SPARC-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// MIPS64-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// MIPS-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// SPIR64-NOT: define{{.*}} spir_func void @ReturnPassing5(i129* noalias sret
+// SPIR-NOT: define{{.*}} spir_func void @ReturnPassing5(i129* noalias sret
+// HEX-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// LANAI-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// R600-NOT: define{{.*}} void @ReturnPassing5(i129 addrspace(5)* noalias sret
+// ARC-NOT: define{{.*}} void @ReturnPassing5(i129* inreg noalias sret
+// XCORE-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// RISCV64-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// RISCV32-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// WASM-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// SYSTEMZ-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// PPC64-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// PPC32-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// AARCH64-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// AARCH64DARWIN-NOT: define{{.*}} void @ReturnPassing5(i129* noalias sret
+// ARM-NOT: define{{.*}} arm_aapcscc void @ReturnPassing5(i129* noalias sret
 
 // SparcV9 is odd in that it has a return-size limit of 256, not 128 or 64
 // like other platforms, so test to make sure this behavior will still work.
 _BitInt(256) ReturnPassing6() {}
-// SPARCV9: define{{.*}} i256 @ReturnPassing6(
+// SPARCV9-NOT: define{{.*}} i256 @ReturnPassing6(
 _BitInt(257) ReturnPassing7() {}
-// SPARCV9: define{{.*}} void @ReturnPassing7(i257* noalias sret
+// SPARCV9-NOT: define{{.*}} void @ReturnPassing7(i257* noalias sret
+#endif
diff --git a/clang/test/CodeGen/ext-int.c b/clang/test/CodeGen/ext-int.c
index fbc627d22cb2a..295fa11cf57a4 100644
--- a/clang/test/CodeGen/ext-int.c
+++ b/clang/test/CodeGen/ext-int.c
@@ -13,7 +13,7 @@ void GenericTest(_BitInt(3) a, unsigned _BitInt(3) b, _BitInt(4) c) {
   // CHECK: store i32 3
 }
 
-void VLATest(_BitInt(3) A, _BitInt(99) B, _BitInt(123456) C) {
+void VLATest(_BitInt(3) A, _BitInt(99) B, _BitInt(123) C) {
   // CHECK: define {{.*}}void @VLATest
   int AR1[A];
   // CHECK: %[[A:.+]] = zext i3 %{{.+}} to i[[INDXSIZE:[0-9]+]]
@@ -22,13 +22,13 @@ void VLATest(_BitInt(3) A, _BitInt(99) B, _BitInt(123456) C) {
   // CHECK: %[[B:.+]] = trunc i99 %{{.+}} to i[[INDXSIZE]]
   // CHECK: %[[VLA2:.+]] = alloca i32, i[[INDXSIZE]] %[[B]]
   int AR3[C];
-  // CHECK: %[[C:.+]] = trunc i123456 %{{.+}} to i[[INDXSIZE]]
+  // CHECK: %[[C:.+]] = trunc i123 %{{.+}} to i[[INDXSIZE]]
   // CHECK: %[[VLA3:.+]] = alloca i32, i[[INDXSIZE]] %[[C]]
 }
 
 struct S {
   _BitInt(17) A;
-  _BitInt(8388600) B;
+  _BitInt(128) B;
   _BitInt(17) C;
 };
 
@@ -41,9 +41,9 @@ void OffsetOfTest() {
   // LIN32: store i32 4, i32* %{{.+}}
   // WINCHECK32: store i32 8, i32* %{{.+}}
   int C = __builtin_offsetof(struct S,C);
-  // CHECK64: store i32 1048584, i32* %{{.+}}
-  // LIN32: store i32 1048580, i32* %{{.+}}
-  // WIN32: store i32 1048584, i32* %{{.+}}
+  // CHECK64: store i32 24, i32* %{{.+}}
+  // LIN32: store i32 20, i32* %{{.+}}
+  // WIN32: store i32 24, i32* %{{.+}}
 }
 
 void Size1ExtIntParam(unsigned _BitInt(1) A) {
diff --git a/clang/test/CodeGenCXX/ext-int.cpp b/clang/test/CodeGenCXX/ext-int.cpp
index 99b441eeb7093..cc61977fc95e3 100644
--- a/clang/test/CodeGenCXX/ext-int.cpp
+++ b/clang/test/CodeGenCXX/ext-int.cpp
@@ -272,71 +272,6 @@ void TakesVarargs(int i, ...) {
   // WIN32: %[[LOADV3:.+]] = load i16, i16* %[[BC3]]
   // WIN32: store i16 %[[LOADV3]], i16*
 
-
-  _BitInt(129) D = __builtin_va_arg(args, _BitInt(129));
-  // LIN64: %[[AD4:.+]] = getelementptr inbounds [1 x %struct.__va_list_tag], [1 x %struct.__va_list_tag]* %[[ARGS]]
-  // LIN64: %[[OFA_P4:.+]] = getelementptr inbounds %struct.__va_list_tag, %struct.__va_list_tag* %[[AD4]], i32 0, i32 2
-  // LIN64: %[[OFA4:.+]] = load i8*, i8** %[[OFA_P4]]
-  // LIN64: %[[BC4:.+]] = bitcast i8* %[[OFA4]] to i129*
-  // LIN64: %[[OFANEXT4:.+]] = getelementptr i8, i8* %[[OFA4]], i32 24
-  // LIN64: store i8* %[[OFANEXT4]], i8** %[[OFA_P4]]
-  // LIN64: %[[LOAD4:.+]] = load i129, i129* %[[BC4]]
-  // LIN64: store i129 %[[LOAD4]], i129*
-
-  // LIN32: %[[CUR4:.+]] = load i8*, i8** %[[ARGS]]
-  // LIN32: %[[NEXT4:.+]] = getelementptr inbounds i8, i8* %[[CUR4]], i32 20
-  // LIN32: store i8* %[[NEXT4]], i8** %[[ARGS]]
-  // LIN32: %[[BC4:.+]] = bitcast i8* %[[CUR4]] to i129*
-  // LIN32: %[[LOADV4:.+]] = load i129, i129* %[[BC4]]
-  // LIN32: store i129 %[[LOADV4]], i129*
-
-  // WIN64: %[[CUR4:.+]] = load i8*, i8** %[[ARGS]]
-  // WIN64: %[[NEXT4:.+]] = getelementptr inbounds i8, i8* %[[CUR4]], i64 8
-  // WIN64: store i8* %[[NEXT4]], i8** %[[ARGS]]
-  // WIN64: %[[BC4:.+]] = bitcast i8* %[[CUR4]] to i129**
-  // WIN64: %[[LOADP4:.+]] = load i129*, i129** %[[BC4]]
-  // WIN64: %[[LOADV4:.+]] = load i129, i129* %[[LOADP4]]
-  // WIN64: store i129 %[[LOADV4]], i129*
-
-  // WIN32: %[[CUR4:.+]] = load i8*, i8** %[[ARGS]]
-  // WIN32: %[[NEXT4:.+]] = getelementptr inbounds i8, i8* %[[CUR4]], i32 24
-  // WIN32: store i8* %[[NEXT4]], i8** %[[ARGS]]
-  // WIN32: %[[BC4:.+]] = bitcast i8* %[[CUR4]] to i129*
-  // WIN32: %[[LOADV4:.+]] = load i129, i129* %[[BC4]]
-  // WIN32: store i129 %[[LOADV4]], i129*
-
-  _BitInt(8388600) E = __builtin_va_arg(args, _BitInt(8388600));
-  // LIN64: %[[AD5:.+]] = getelementptr inbounds [1 x %struct.__va_list_tag], [1 x %struct.__va_list_tag]* %[[ARGS]]
-  // LIN64: %[[OFA_P5:.+]] = getelementptr inbounds %struct.__va_list_tag, %struct.__va_list_tag* %[[AD5]], i32 0, i32 2
-  // LIN64: %[[OFA5:.+]] = load i8*, i8** %[[OFA_P5]]
-  // LIN64: %[[BC5:.+]] = bitcast i8* %[[OFA5]] to i8388600*
-  // LIN64: %[[OFANEXT5:.+]] = getelementptr i8, i8* %[[OFA5]], i32 1048576
-  // LIN64: store i8* %[[OFANEXT5]], i8** %[[OFA_P5]]
-  // LIN64: %[[LOAD5:.+]] = load i8388600, i8388600* %[[BC5]]
-  // LIN64: store i8388600 %[[LOAD5]], i8388600*
-
-  // LIN32: %[[CUR5:.+]] = load i8*, i8** %[[ARGS]]
-  // LIN32: %[[NEXT5:.+]] = getelementptr inbounds i8, i8* %[[CUR5]], i32 1048576
-  // LIN32: store i8* %[[NEXT5]], i8** %[[ARGS]]
-  // LIN32: %[[BC5:.+]] = bitcast i8* %[[CUR5]] to i8388600*
-  // LIN32: %[[LOADV5:.+]] = load i8388600, i8388600* %[[BC5]]
-  // LIN32: store i8388600 %[[LOADV5]], i8388600*
-
-  // WIN64: %[[CUR5:.+]] = load i8*, i8** %[[ARGS]]
-  // WIN64: %[[NEXT5:.+]] = getelementptr inbounds i8, i8* %[[CUR5]], i64 8
-  // WIN64: store i8* %[[NEXT5]], i8** %[[ARGS]]
-  // WIN64: %[[BC5:.+]] = bitcast i8* %[[CUR5]] to i8388600**
-  // WIN64: %[[LOADP5:.+]] = load i8388600*, i8388600** %[[BC5]]
-  // WIN64: %[[LOADV5:.+]] = load i8388600, i8388600* %[[LOADP5]]
-  // WIN64: store i8388600 %[[LOADV5]], i8388600*
-
-  // WIN32: %[[CUR5:.+]] = load i8*, i8** %[[ARGS]]
-  // WIN32: %[[NEXT5:.+]] = getelementptr inbounds i8, i8* %[[CUR5]], i32 1048576
-  // WIN32: store i8* %[[NEXT5]], i8** %[[ARGS]]
-  // WIN32: %[[BC5:.+]] = bitcast i8* %[[CUR5]] to i8388600*
-  // WIN32: %[[LOADV5:.+]] = load i8388600, i8388600* %[[BC5]]
-  // WIN32: store i8388600 %[[LOADV5]], i8388600*
-
   __builtin_va_end(args);
   // LIN64: %[[ENDAD:.+]] = getelementptr inbounds [1 x %struct.__va_list_tag], [1 x %struct.__va_list_tag]* %[[ARGS]]
   // LIN64: %[[ENDAD1:.+]] = bitcast %struct.__va_list_tag* %[[ENDAD]] to i8*
@@ -405,7 +340,7 @@ void ExplicitCasts() {
 
 struct S {
   _BitInt(17) A;
-  _BitInt(8388600) B;
+  _BitInt(128) B;
   _BitInt(17) C;
 };
 
@@ -420,9 +355,9 @@ void OffsetOfTest() {
   // LIN32: store i{{.+}} 4, i{{.+}}* %{{.+}}
   // WIN: store i{{.+}} 8, i{{.+}}* %{{.+}}
   auto C = __builtin_offsetof(S,C);
-  // LIN64: store i{{.+}} 1048584, i{{.+}}* %{{.+}}
-  // LIN32: store i{{.+}} 1048580, i{{.+}}* %{{.+}}
-  // WIN: store i{{.+}} 1048584, i{{.+}}* %{{.+}}
+  // LIN64: store i{{.+}} 24, i{{.+}}* %{{.+}}
+  // LIN32: store i{{.+}} 20, i{{.+}}* %{{.+}}
+  // WIN: store i{{.+}} 24, i{{.+}}* %{{.+}}
 }
 
 
diff --git a/clang/test/Headers/limits.cpp b/clang/test/Headers/limits.cpp
index 36a9523151574..730a73982631a 100644
--- a/clang/test/Headers/limits.cpp
+++ b/clang/test/Headers/limits.cpp
@@ -74,8 +74,11 @@ _Static_assert(ULLONG_WIDTH >= 64);
 _Static_assert(ULLONG_WIDTH / CHAR_BIT == sizeof(unsigned long long));
 _Static_assert(LLONG_WIDTH == ULLONG_WIDTH);
 _Static_assert(LLONG_WIDTH / CHAR_BIT == sizeof(signed long long));
+
+_Static_assert(BITINT_MAXWIDTH >= ULLONG_WIDTH);
 #else
 /* None of these are defined. */
 int BOOL_WIDTH, CHAR_WIDTH, SCHAR_WIDTH, UCHAR_WIDTH, USHRT_WIDTH, SHRT_WIDTH,
-    UINT_WIDTH, INT_WIDTH, ULONG_WIDTH, LONG_WIDTH, ULLONG_WIDTH, LLONG_WIDTH;
+    UINT_WIDTH, INT_WIDTH, ULONG_WIDTH, LONG_WIDTH, ULLONG_WIDTH, LLONG_WIDTH,
+    BITINT_MAXWIDTH;
 #endif
diff --git a/clang/test/Preprocessor/init-aarch64.c b/clang/test/Preprocessor/init-aarch64.c
index 598b3c75507ca..f6809d8d9b48f 100644
--- a/clang/test/Preprocessor/init-aarch64.c
+++ b/clang/test/Preprocessor/init-aarch64.c
@@ -40,6 +40,7 @@
 // AARCH64-NEXT: #define __ATOMIC_SEQ_CST 5
 // AARCH64:      #define __BIGGEST_ALIGNMENT__ 16
 // AARCH64_BE-NEXT: #define __BIG_ENDIAN__ 1
+// AARCH64-NEXT: #define __BITINT_MAXWIDTH__ 128
 // AARCH64-NEXT: #define __BOOL_WIDTH__ 8
 // AARCH64_BE-NEXT: #define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__
 // AARCH64_LE-NEXT: #define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
diff --git a/clang/test/Preprocessor/init.c b/clang/test/Preprocessor/init.c
index f11f600beed15..dd645bf6003ce 100644
--- a/clang/test/Preprocessor/init.c
+++ b/clang/test/Preprocessor/init.c
@@ -1520,6 +1520,7 @@
 // WEBASSEMBLY-NEXT:#define __ATOMIC_RELEASE 3
 // WEBASSEMBLY-NEXT:#define __ATOMIC_SEQ_CST 5
 // WEBASSEMBLY-NEXT:#define __BIGGEST_ALIGNMENT__ 16
+// WEBASSEMBLY-NEXT:#define __BITINT_MAXWIDTH__ 128
 // WEBASSEMBLY-NEXT:#define __BOOL_WIDTH__ 8
 // WEBASSEMBLY-NEXT:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__
 // WEBASSEMBLY-NEXT:#define __CHAR16_TYPE__ unsigned short
diff --git a/clang/test/Sema/builtins-overflow.c b/clang/test/Sema/builtins-overflow.c
index 348a3a0306430..f41fddd2cafb4 100644
--- a/clang/test/Sema/builtins-overflow.c
+++ b/clang/test/Sema/builtins-overflow.c
@@ -26,6 +26,7 @@ void test(void) {
     _BitInt(128) result;
     _Bool status = __builtin_mul_overflow(x, y, &result); // expect ok
   }
+#if __BITINT_MAXWIDTH__ > 128
   {
     unsigned _BitInt(129) x = 1;
     unsigned _BitInt(129) y = 1;
@@ -38,4 +39,5 @@ void test(void) {
     _BitInt(129) result;
     _Bool status = __builtin_mul_overflow(x, y, &result); // expected-error {{__builtin_mul_overflow does not support 'signed _BitInt' operands of more than 128 bits}}
   }
+#endif
 }
diff --git a/clang/test/SemaCXX/ext-int.cpp b/clang/test/SemaCXX/ext-int.cpp
index 675aaa7598df1..5d4d8966cde2b 100644
--- a/clang/test/SemaCXX/ext-int.cpp
+++ b/clang/test/SemaCXX/ext-int.cpp
@@ -17,7 +17,7 @@ _BitInt(33) Declarations(_BitInt(48) &Param) { // Useable in params and returns.
   unsigned _BitInt(5) e = 5;
   _BitInt(5) unsigned f;
 
-  _BitInt(-3) g; // expected-error{{signed _BitInt must have a bit size of at least 2}}
+  _BitInt(-3) g; // expected-error{{signed _BitInt of bit sizes greater than 128 not supported}}
   _BitInt(0) h; // expected-error{{signed _BitInt must have a bit size of at least 2}}
   _BitInt(1) i; // expected-error{{signed _BitInt must have a bit size of at least 2}}
   _BitInt(2) j;;
@@ -28,13 +28,13 @@ _BitInt(33) Declarations(_BitInt(48) &Param) { // Useable in params and returns.
   constexpr _BitInt(6) n = 33; // expected-warning{{implicit conversion from 'int' to 'const _BitInt(6)' changes value from 33 to -31}}
   constexpr _BitInt(7) o = 33;
 
-  // Check LLVM imposed max size.
-  _BitInt(8388609) p;               // expected-error {{signed _BitInt of bit sizes greater than 8388608 not supported}}
-  unsigned _BitInt(0xFFFFFFFFFF) q; // expected-error {{unsigned _BitInt of bit sizes greater than 8388608 not supported}}
+  // Check imposed max size.
+  _BitInt(129) p;               // expected-error {{signed _BitInt of bit sizes greater than 128 not supported}}
+  unsigned _BitInt(0xFFFFFFFFFF) q; // expected-error {{unsigned _BitInt of bit sizes greater than 128 not supported}}
 
 // Ensure template params are instantiated correctly.
-  // expected-error@5{{signed _BitInt must have a bit size of at least 2}}
-  // expected-error@6{{unsigned _BitInt must have a bit size of at least 1}}
+  // expected-error@5{{signed _BitInt of bit sizes greater than 128 not supported}}
+  // expected-error@6{{unsigned _BitInt of bit sizes greater than 128 not supported}}
   // expected-note@+1{{in instantiation of template class }}
   HasExtInt<-1> r;
   // expected-error@5{{signed _BitInt must have a bit size of at least 2}}
@@ -186,14 +186,8 @@ void Ops() {
   static_assert(sizeof(x43_s) == 8, "");
   static_assert(sizeof(x4_s) == 1, "");
 
-  static_assert(sizeof(_BitInt(3340)) == 424, ""); // 424 * 8 == 3392.
-  static_assert(sizeof(_BitInt(1049)) == 136, ""); // 136  *  8 == 1088.
-
   static_assert(alignof(decltype(x43_s)) == 8, "");
   static_assert(alignof(decltype(x4_s)) == 1, "");
-
-  static_assert(alignof(_BitInt(3340)) == 8, "");
-  static_assert(alignof(_BitInt(1049)) == 8, "");
 }
 
 constexpr int func() { return 42;}