ART: Templatize IsInt & IsUint

Ensure that things are used correctly.

Change-Id: I76f082b32dcee28bbfb4c519daa401ac595873b3

13 files changed, 112 insertions, 87 deletions

diff --git a/compiler/dex/dex_to_dex_compiler.cc b/compiler/dex/dex_to_dex_compiler.cc
index f7968c2..7e916be 100644
--- a/compiler/dex/dex_to_dex_compiler.cc
+++ b/compiler/dex/dex_to_dex_compiler.cc
@@ -238,7 +238,7 @@ void DexCompiler::CompileInstanceFieldAccess(Instruction* inst,
   bool is_volatile;
   bool fast_path = driver_.ComputeInstanceFieldInfo(field_idx, &unit_, is_put,
                                                     &field_offset, &is_volatile);
-  if (fast_path && !is_volatile && IsUint(16, field_offset.Int32Value())) {
+  if (fast_path && !is_volatile && IsUint<16>(field_offset.Int32Value())) {
     VLOG(compiler) << "Quickening " << Instruction::Name(inst->Opcode())
                    << " to " << Instruction::Name(new_opcode)
                    << " by replacing field index " << field_idx
@@ -274,7 +274,7 @@ void DexCompiler::CompileInvokeVirtual(Instruction* inst,
                                              &target_method, &vtable_idx,
                                              &direct_code, &direct_method);
   if (fast_path && original_invoke_type == invoke_type) {
-    if (vtable_idx >= 0 && IsUint(16, vtable_idx)) {
+    if (vtable_idx >= 0 && IsUint<16>(vtable_idx)) {
       VLOG(compiler) << "Quickening " << Instruction::Name(inst->Opcode())
                      << "(" << PrettyMethod(method_idx, GetDexFile(), true) << ")"
                      << " to " << Instruction::Name(new_opcode)
diff --git a/compiler/dex/quick/mips/utility_mips.cc b/compiler/dex/quick/mips/utility_mips.cc
index 6f6bf68..ec6edab 100644
--- a/compiler/dex/quick/mips/utility_mips.cc
+++ b/compiler/dex/quick/mips/utility_mips.cc
@@ -56,7 +56,8 @@ LIR* MipsMir2Lir::OpFpRegCopy(RegStorage r_dest, RegStorage r_src) {
 }
 
 bool MipsMir2Lir::InexpensiveConstantInt(int32_t value) {
-  return ((value == 0) || IsUint(16, value) || ((value < 0) && (value >= -32768)));
+  // For encodings, see LoadConstantNoClobber below.
+  return ((value == 0) || IsUint<16>(value) || IsInt<16>(value));
 }
 
 bool MipsMir2Lir::InexpensiveConstantFloat(int32_t value) {
@@ -96,9 +97,11 @@ LIR* MipsMir2Lir::LoadConstantNoClobber(RegStorage r_dest, int value) {
   /* See if the value can be constructed cheaply */
   if (value == 0) {
     res = NewLIR2(kMipsMove, r_dest.GetReg(), rZERO);
-  } else if ((value > 0) && (value <= 65535)) {
+  } else if (IsUint<16>(value)) {
+    // Use OR with (unsigned) immediate to encode 16b unsigned int.
     res = NewLIR3(kMipsOri, r_dest.GetReg(), rZERO, value);
-  } else if ((value < 0) && (value >= -32768)) {
+  } else if (IsInt<16>(value)) {
+    // Use ADD with (signed) immediate to encode 16b signed int.
     res = NewLIR3(kMipsAddiu, r_dest.GetReg(), rZERO, value);
   } else {
     res = NewLIR2(kMipsLui, r_dest.GetReg(), value >> 16);
diff --git a/compiler/utils/arm/assembler_arm.cc b/compiler/utils/arm/assembler_arm.cc
index 1f44f19..a52e6eb 100644
--- a/compiler/utils/arm/assembler_arm.cc
+++ b/compiler/utils/arm/assembler_arm.cc
@@ -166,7 +166,7 @@ uint32_t ShifterOperand::encodingThumb() const {
 }
 
 uint32_t Address::encodingArm() const {
-  CHECK(IsAbsoluteUint(12, offset_));
+  CHECK(IsAbsoluteUint<12>(offset_));
   uint32_t encoding;
   if (is_immed_offset_) {
     if (offset_ < 0) {
@@ -278,11 +278,12 @@ uint32_t Address::encoding3() const {
 
 // Encoding for vfp load/store addressing.
 uint32_t Address::vencoding() const {
+  CHECK(IsAbsoluteUint<10>(offset_));  // In the range -1020 to +1020.
+  CHECK_ALIGNED(offset_, 2);  // Multiple of 4.
+
   const uint32_t offset_mask = (1 << 12) - 1;
   uint32_t encoding = encodingArm();
   uint32_t offset = encoding & offset_mask;
-  CHECK(IsAbsoluteUint(10, offset));  // In the range -1020 to +1020.
-  CHECK_ALIGNED(offset, 2);  // Multiple of 4.
   CHECK((am_ == Offset) || (am_ == NegOffset));
   uint32_t vencoding_value = (encoding & (0xf << kRnShift)) | (offset >> 2);
   if (am_ == Offset) {
@@ -298,13 +299,13 @@ bool Address::CanHoldLoadOffsetArm(LoadOperandType type, int offset) {
     case kLoadSignedHalfword:
     case kLoadUnsignedHalfword:
     case kLoadWordPair:
-      return IsAbsoluteUint(8, offset);  // Addressing mode 3.
+      return IsAbsoluteUint<8>(offset);  // Addressing mode 3.
     case kLoadUnsignedByte:
     case kLoadWord:
-      return IsAbsoluteUint(12, offset);  // Addressing mode 2.
+      return IsAbsoluteUint<12>(offset);  // Addressing mode 2.
     case kLoadSWord:
     case kLoadDWord:
-      return IsAbsoluteUint(10, offset);  // VFP addressing mode.
+      return IsAbsoluteUint<10>(offset);  // VFP addressing mode.
     default:
       LOG(FATAL) << "UNREACHABLE";
       UNREACHABLE();
@@ -316,13 +317,13 @@ bool Address::CanHoldStoreOffsetArm(StoreOperandType type, int offset) {
   switch (type) {
     case kStoreHalfword:
     case kStoreWordPair:
-      return IsAbsoluteUint(8, offset);  // Addressing mode 3.
+      return IsAbsoluteUint<8>(offset);  // Addressing mode 3.
     case kStoreByte:
     case kStoreWord:
-      return IsAbsoluteUint(12, offset);  // Addressing mode 2.
+      return IsAbsoluteUint<12>(offset);  // Addressing mode 2.
     case kStoreSWord:
     case kStoreDWord:
-      return IsAbsoluteUint(10, offset);  // VFP addressing mode.
+      return IsAbsoluteUint<10>(offset);  // VFP addressing mode.
     default:
       LOG(FATAL) << "UNREACHABLE";
       UNREACHABLE();
@@ -336,12 +337,12 @@ bool Address::CanHoldLoadOffsetThumb(LoadOperandType type, int offset) {
     case kLoadUnsignedHalfword:
     case kLoadUnsignedByte:
     case kLoadWord:
-      return IsAbsoluteUint(12, offset);
+      return IsAbsoluteUint<12>(offset);
     case kLoadSWord:
     case kLoadDWord:
-      return IsAbsoluteUint(10, offset);  // VFP addressing mode.
+      return IsAbsoluteUint<10>(offset);  // VFP addressing mode.
     case kLoadWordPair:
-      return IsAbsoluteUint(10, offset);
+      return IsAbsoluteUint<10>(offset);
     default:
       LOG(FATAL) << "UNREACHABLE";
       UNREACHABLE();
@@ -354,12 +355,12 @@ bool Address::CanHoldStoreOffsetThumb(StoreOperandType type, int offset) {
     case kStoreHalfword:
     case kStoreByte:
     case kStoreWord:
-      return IsAbsoluteUint(12, offset);
+      return IsAbsoluteUint<12>(offset);
     case kStoreSWord:
     case kStoreDWord:
-      return IsAbsoluteUint(10, offset);  // VFP addressing mode.
+      return IsAbsoluteUint<10>(offset);  // VFP addressing mode.
     case kStoreWordPair:
-      return IsAbsoluteUint(10, offset);
+      return IsAbsoluteUint<10>(offset);
     default:
       LOG(FATAL) << "UNREACHABLE";
       UNREACHABLE();
diff --git a/compiler/utils/arm/assembler_arm32.cc b/compiler/utils/arm/assembler_arm32.cc
index 8d1fb60..9579691 100644
--- a/compiler/utils/arm/assembler_arm32.cc
+++ b/compiler/utils/arm/assembler_arm32.cc
@@ -1254,7 +1254,7 @@ void Arm32Assembler::vmstat(Condition cond) {  // VMRS APSR_nzcv, FPSCR
 
 
 void Arm32Assembler::svc(uint32_t imm24) {
-  CHECK(IsUint(24, imm24)) << imm24;
+  CHECK(IsUint<24>(imm24)) << imm24;
   int32_t encoding = (AL << kConditionShift) | B27 | B26 | B25 | B24 | imm24;
   Emit(encoding);
 }
diff --git a/compiler/utils/arm/assembler_thumb2.cc b/compiler/utils/arm/assembler_thumb2.cc
index 5383c28..6d0571e 100644
--- a/compiler/utils/arm/assembler_thumb2.cc
+++ b/compiler/utils/arm/assembler_thumb2.cc
@@ -2080,7 +2080,7 @@ void Thumb2Assembler::vmstat(Condition cond) {  // VMRS APSR_nzcv, FPSCR.
 
 
 void Thumb2Assembler::svc(uint32_t imm8) {
-  CHECK(IsUint(8, imm8)) << imm8;
+  CHECK(IsUint<8>(imm8)) << imm8;
   int16_t encoding = B15 | B14 | B12 |
        B11 | B10 | B9 | B8 |
        imm8;
@@ -2089,7 +2089,7 @@ void Thumb2Assembler::svc(uint32_t imm8) {
 
 
 void Thumb2Assembler::bkpt(uint16_t imm8) {
-  CHECK(IsUint(8, imm8)) << imm8;
+  CHECK(IsUint<8>(imm8)) << imm8;
   int16_t encoding = B15 | B13 | B12 |
       B11 | B10 | B9 |
       imm8;
diff --git a/compiler/utils/x86/assembler_x86.cc b/compiler/utils/x86/assembler_x86.cc
index 03744e4..8f4208b 100644
--- a/compiler/utils/x86/assembler_x86.cc
+++ b/compiler/utils/x86/assembler_x86.cc
@@ -1290,7 +1290,7 @@ void X86Assembler::j(Condition condition, Label* label) {
     static const int kLongSize = 6;
     int offset = label->Position() - buffer_.Size();
     CHECK_LE(offset, 0);
-    if (IsInt(8, offset - kShortSize)) {
+    if (IsInt<8>(offset - kShortSize)) {
       EmitUint8(0x70 + condition);
       EmitUint8((offset - kShortSize) & 0xFF);
     } else {
@@ -1325,7 +1325,7 @@ void X86Assembler::jmp(Label* label) {
     static const int kLongSize = 5;
     int offset = label->Position() - buffer_.Size();
     CHECK_LE(offset, 0);
-    if (IsInt(8, offset - kShortSize)) {
+    if (IsInt<8>(offset - kShortSize)) {
       EmitUint8(0xEB);
       EmitUint8((offset - kShortSize) & 0xFF);
     } else {
diff --git a/compiler/utils/x86/assembler_x86.h b/compiler/utils/x86/assembler_x86.h
index 3a44ace..2dde907 100644
--- a/compiler/utils/x86/assembler_x86.h
+++ b/compiler/utils/x86/assembler_x86.h
@@ -35,10 +35,10 @@ class Immediate : public ValueObject {
 
   int32_t value() const { return value_; }
 
-  bool is_int8() const { return IsInt(8, value_); }
-  bool is_uint8() const { return IsUint(8, value_); }
-  bool is_int16() const { return IsInt(16, value_); }
-  bool is_uint16() const { return IsUint(16, value_); }
+  bool is_int8() const { return IsInt<8>(value_); }
+  bool is_uint8() const { return IsUint<8>(value_); }
+  bool is_int16() const { return IsInt<16>(value_); }
+  bool is_uint16() const { return IsUint<16>(value_); }
 
  private:
   const int32_t value_;
diff --git a/compiler/utils/x86_64/assembler_x86_64.cc b/compiler/utils/x86_64/assembler_x86_64.cc
index 556fa9b..f2704b7 100644
--- a/compiler/utils/x86_64/assembler_x86_64.cc
+++ b/compiler/utils/x86_64/assembler_x86_64.cc
@@ -1515,7 +1515,7 @@ void X86_64Assembler::imull(CpuRegister reg, const Immediate& imm) {
 
   // See whether imm can be represented as a sign-extended 8bit value.
   int32_t v32 = static_cast<int32_t>(imm.value());
-  if (IsInt32(8, v32)) {
+  if (IsInt<8>(v32)) {
     // Sign-extension works.
     EmitUint8(0x6B);
     EmitOperand(reg.LowBits(), Operand(reg));
@@ -1555,7 +1555,7 @@ void X86_64Assembler::imulq(CpuRegister reg, const Immediate& imm) {
 
   // See whether imm can be represented as a sign-extended 8bit value.
   int64_t v64 = imm.value();
-  if (IsInt64(8, v64)) {
+  if (IsInt<8>(v64)) {
     // Sign-extension works.
     EmitUint8(0x6B);
     EmitOperand(reg.LowBits(), Operand(reg));
@@ -1705,7 +1705,7 @@ void X86_64Assembler::notq(CpuRegister reg) {
 void X86_64Assembler::enter(const Immediate& imm) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0xC8);
-  CHECK(imm.is_uint16());
+  CHECK(imm.is_uint16()) << imm.value();
   EmitUint8(imm.value() & 0xFF);
   EmitUint8((imm.value() >> 8) & 0xFF);
   EmitUint8(0x00);
@@ -1759,7 +1759,7 @@ void X86_64Assembler::j(Condition condition, Label* label) {
     static const int kLongSize = 6;
     int offset = label->Position() - buffer_.Size();
     CHECK_LE(offset, 0);
-    if (IsInt(8, offset - kShortSize)) {
+    if (IsInt<8>(offset - kShortSize)) {
       EmitUint8(0x70 + condition);
       EmitUint8((offset - kShortSize) & 0xFF);
     } else {
@@ -1796,7 +1796,7 @@ void X86_64Assembler::jmp(Label* label) {
     static const int kLongSize = 5;
     int offset = label->Position() - buffer_.Size();
     CHECK_LE(offset, 0);
-    if (IsInt(8, offset - kShortSize)) {
+    if (IsInt<8>(offset - kShortSize)) {
       EmitUint8(0xEB);
       EmitUint8((offset - kShortSize) & 0xFF);
     } else {
diff --git a/compiler/utils/x86_64/assembler_x86_64.h b/compiler/utils/x86_64/assembler_x86_64.h
index a1c704e..5dfcf45 100644
--- a/compiler/utils/x86_64/assembler_x86_64.h
+++ b/compiler/utils/x86_64/assembler_x86_64.h
@@ -42,15 +42,11 @@ class Immediate : public ValueObject {
 
   int64_t value() const { return value_; }
 
-  bool is_int8() const { return IsInt(8, value_); }
-  bool is_uint8() const { return IsUint(8, value_); }
-  bool is_int16() const { return IsInt(16, value_); }
-  bool is_uint16() const { return IsUint(16, value_); }
-  bool is_int32() const {
-    // This does not work on 32b machines: return IsInt(32, value_);
-    int64_t limit = static_cast<int64_t>(1) << 31;
-    return (-limit <= value_) && (value_ < limit);
-  }
+  bool is_int8() const { return IsInt<8>(value_); }
+  bool is_uint8() const { return IsUint<8>(value_); }
+  bool is_int16() const { return IsInt<16>(value_); }
+  bool is_uint16() const { return IsUint<16>(value_); }
+  bool is_int32() const { return IsInt<32>(value_); }
 
  private:
   const int64_t value_;
diff --git a/compiler/utils/x86_64/assembler_x86_64_test.cc b/compiler/utils/x86_64/assembler_x86_64_test.cc
index 6df4144..00f508b 100644
--- a/compiler/utils/x86_64/assembler_x86_64_test.cc
+++ b/compiler/utils/x86_64/assembler_x86_64_test.cc
@@ -44,10 +44,10 @@ static constexpr size_t kRandomIterations = 100000;  // Hosts are pretty powerfu
 TEST(AssemblerX86_64, SignExtension) {
   // 32bit.
   for (int32_t i = 0; i < 128; i++) {
-    EXPECT_TRUE(IsInt32(8, i)) << i;
+    EXPECT_TRUE(IsInt<8>(i)) << i;
   }
   for (int32_t i = 128; i < 255; i++) {
-    EXPECT_FALSE(IsInt32(8, i)) << i;
+    EXPECT_FALSE(IsInt<8>(i)) << i;
   }
   // Do some higher ones randomly.
   std::random_device rd;
@@ -55,54 +55,65 @@ TEST(AssemblerX86_64, SignExtension) {
   std::uniform_int_distribution<int32_t> uniform_dist(256, INT32_MAX);
   for (size_t i = 0; i < kRandomIterations; i++) {
     int32_t value = uniform_dist(e1);
-    EXPECT_FALSE(IsInt32(8, value)) << value;
+    EXPECT_FALSE(IsInt<8>(value)) << value;
   }
 
   // Negative ones.
   for (int32_t i = -1; i >= -128; i--) {
-    EXPECT_TRUE(IsInt32(8, i)) << i;
+    EXPECT_TRUE(IsInt<8>(i)) << i;
   }
 
   for (int32_t i = -129; i > -256; i--) {
-    EXPECT_FALSE(IsInt32(8, i)) << i;
+    EXPECT_FALSE(IsInt<8>(i)) << i;
   }
 
   // Do some lower ones randomly.
   std::uniform_int_distribution<int32_t> uniform_dist2(INT32_MIN, -256);
   for (size_t i = 0; i < 100; i++) {
     int32_t value = uniform_dist2(e1);
-    EXPECT_FALSE(IsInt32(8, value)) << value;
+    EXPECT_FALSE(IsInt<8>(value)) << value;
   }
 
   // 64bit.
   for (int64_t i = 0; i < 128; i++) {
-    EXPECT_TRUE(IsInt64(8, i)) << i;
+    EXPECT_TRUE(IsInt<8>(i)) << i;
   }
   for (int32_t i = 128; i < 255; i++) {
-    EXPECT_FALSE(IsInt64(8, i)) << i;
+    EXPECT_FALSE(IsInt<8>(i)) << i;
   }
   // Do some higher ones randomly.
   std::uniform_int_distribution<int64_t> uniform_dist3(256, INT64_MAX);
   for (size_t i = 0; i < 100; i++) {
     int64_t value = uniform_dist3(e1);
-    EXPECT_FALSE(IsInt64(8, value)) << value;
+    EXPECT_FALSE(IsInt<8>(value)) << value;
   }
 
   // Negative ones.
   for (int64_t i = -1; i >= -128; i--) {
-    EXPECT_TRUE(IsInt64(8, i)) << i;
+    EXPECT_TRUE(IsInt<8>(i)) << i;
   }
 
   for (int64_t i = -129; i > -256; i--) {
-    EXPECT_FALSE(IsInt64(8, i)) << i;
+    EXPECT_FALSE(IsInt<8>(i)) << i;
   }
 
   // Do some lower ones randomly.
   std::uniform_int_distribution<int64_t> uniform_dist4(INT64_MIN, -256);
   for (size_t i = 0; i < kRandomIterations; i++) {
     int64_t value = uniform_dist4(e1);
-    EXPECT_FALSE(IsInt64(8, value)) << value;
+    EXPECT_FALSE(IsInt<8>(value)) << value;
   }
+
+  int64_t value = INT64_C(0x1200000010);
+  x86_64::Immediate imm(value);
+  EXPECT_FALSE(imm.is_int8());
+  EXPECT_FALSE(imm.is_int16());
+  EXPECT_FALSE(imm.is_int32());
+  value = INT64_C(0x8000000000000001);
+  x86_64::Immediate imm2(value);
+  EXPECT_FALSE(imm2.is_int8());
+  EXPECT_FALSE(imm2.is_int16());
+  EXPECT_FALSE(imm2.is_int32());
 }
 
 struct X86_64CpuRegisterCompare {
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index 3592d2c..33456cf 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -4812,7 +4812,7 @@ bool ClassLinker::LinkMethods(Thread* self, Handle<mirror::Class> klass,
   if (klass->IsInterface()) {
     // No vtable.
     size_t count = klass->NumVirtualMethods();
-    if (!IsUint(16, count)) {
+    if (!IsUint<16>(count)) {
       ThrowClassFormatError(klass.Get(), "Too many methods on interface: %zd", count);
       return false;
     }
@@ -5033,7 +5033,7 @@ bool ClassLinker::LinkVirtualMethods(Thread* self, Handle<mirror::Class> klass)
       local_method->SetMethodIndex(actual_count);
       ++actual_count;
     }
-    if (!IsUint(16, actual_count)) {
+    if (!IsUint<16>(actual_count)) {
       ThrowClassFormatError(klass.Get(), "Too many methods defined on class: %zd", actual_count);
       return false;
     }
@@ -5049,7 +5049,7 @@ bool ClassLinker::LinkVirtualMethods(Thread* self, Handle<mirror::Class> klass)
     klass->SetVTable(vtable.Get());
   } else {
     CHECK_EQ(klass.Get(), GetClassRoot(kJavaLangObject));
-    if (!IsUint(16, num_virtual_methods)) {
+    if (!IsUint<16>(num_virtual_methods)) {
       ThrowClassFormatError(klass.Get(), "Too many methods: %d",
                             static_cast<int>(num_virtual_methods));
       return false;
diff --git a/runtime/dex_file.cc b/runtime/dex_file.cc
index 94d62db..19a4bd0 100644
--- a/runtime/dex_file.cc
+++ b/runtime/dex_file.cc
@@ -1164,15 +1164,15 @@ void EncodedStaticFieldValueIterator::Next() {
     break;
   case kByte:
     jval_.i = ReadSignedInt(ptr_, value_arg);
-    CHECK(IsInt(8, jval_.i));
+    CHECK(IsInt<8>(jval_.i));
     break;
   case kShort:
     jval_.i = ReadSignedInt(ptr_, value_arg);
-    CHECK(IsInt(16, jval_.i));
+    CHECK(IsInt<16>(jval_.i));
     break;
   case kChar:
     jval_.i = ReadUnsignedInt(ptr_, value_arg, false);
-    CHECK(IsUint(16, jval_.i));
+    CHECK(IsUint<16>(jval_.i));
     break;
   case kInt:
     jval_.i = ReadSignedInt(ptr_, value_arg);
diff --git a/runtime/utils.h b/runtime/utils.h
index 1c2576c..0fbc9df 100644
--- a/runtime/utils.h
+++ b/runtime/utils.h
@@ -22,6 +22,7 @@
 #include <limits>
 #include <memory>
 #include <string>
+#include <type_traits>
 #include <vector>
 
 #include "arch/instruction_set.h"
@@ -115,32 +116,45 @@ static inline bool IsInt(int N, intptr_t value) {
   return (-limit <= value) && (value < limit);
 }
 
-static inline bool IsInt32(int N, int32_t value) {
-  CHECK_LT(0, N);
-  CHECK_LT(static_cast<size_t>(N), 8 * sizeof(int32_t));
-  int32_t limit = static_cast<int32_t>(1) << (N - 1);
-  return (-limit <= value) && (value < limit);
-}
-
-static inline bool IsInt64(int N, int64_t value) {
-  CHECK_LT(0, N);
-  CHECK_LT(static_cast<size_t>(N), 8 * sizeof(int64_t));
-  int64_t limit = static_cast<int64_t>(1) << (N - 1);
-  return (-limit <= value) && (value < limit);
-}
-
-static inline bool IsUint(int N, intptr_t value) {
-  CHECK_LT(0, N);
-  CHECK_LT(N, kBitsPerIntPtrT);
-  intptr_t limit = static_cast<intptr_t>(1) << N;
-  return (0 <= value) && (value < limit);
-}
-
-static inline bool IsAbsoluteUint(int N, intptr_t value) {
-  CHECK_LT(0, N);
-  CHECK_LT(N, kBitsPerIntPtrT);
-  if (value < 0) value = -value;
-  return IsUint(N, value);
+template <typename T>
+static constexpr T GetIntLimit(size_t bits) {
+  return
+      DCHECK_CONSTEXPR(bits > 0, "bits cannot be zero", 0)
+      DCHECK_CONSTEXPR(bits < kBitsPerByte * sizeof(T), "kBits must be < max.", 0)
+      static_cast<T>(1) << (bits - 1);
+}
+
+template <size_t kBits, typename T>
+static constexpr bool IsInt(T value) {
+  static_assert(kBits > 0, "kBits cannot be zero.");
+  static_assert(kBits <= kBitsPerByte * sizeof(T), "kBits must be <= max.");
+  static_assert(std::is_signed<T>::value, "Needs a signed type.");
+  // Corner case for "use all bits." Can't use the limits, as they would overflow, but it is
+  // trivially true.
+  return (kBits == kBitsPerByte * sizeof(T)) ?
+      true :
+      (-GetIntLimit<T>(kBits) <= value) && (value < GetIntLimit<T>(kBits));
+}
+
+template <size_t kBits, typename T>
+static constexpr bool IsUint(T value) {
+  static_assert(kBits > 0, "kBits cannot be zero.");
+  static_assert(kBits <= kBitsPerByte * sizeof(T), "kBits must be <= max.");
+  static_assert(std::is_integral<T>::value, "Needs an integral type.");
+  // Corner case for "use all bits." Can't use the limits, as they would overflow, but it is
+  // trivially true.
+  return (0 <= value) &&
+      (kBits == kBitsPerByte * sizeof(T) ||
+          (static_cast<typename std::make_unsigned<T>::type>(value) <=
+               GetIntLimit<typename std::make_unsigned<T>::type>(kBits + 1) - 1));
+}
+
+template <size_t kBits, typename T>
+static constexpr bool IsAbsoluteUint(T value) {
+  static_assert(kBits <= kBitsPerByte * sizeof(T), "kBits must be < max.");
+  return (kBits == kBitsPerByte * sizeof(T)) ?
+      true :
+      IsUint<kBits, T>(value < 0 ? -value : value);
 }
 
 static inline uint16_t Low16Bits(uint32_t value) {