[llvm] Reapply [IR] Add new Range attribute using new ConstantRange Attribute type (PR #84617)

Andreas Jonson via llvm-commits llvm-commits at lists.llvm.org
Sat Mar 9 00:41:04 PST 2024


https://github.com/andjo403 created https://github.com/llvm/llvm-project/pull/84617

only change from https://github.com/llvm/llvm-project/pull/83171 it the change of the allocator so the destructor is called for ConstantRangeAttributeImpl

reverts https://github.com/llvm/llvm-project/pull/84549

CC @nikic 

>From 740c588325897887ada4aaddc224b9966cd03422 Mon Sep 17 00:00:00 2001
From: Andreas Jonson <andjo403 at hotmail.com>
Date: Sat, 9 Mar 2024 09:00:21 +0100
Subject: [PATCH] [IR] Add new Range attribute using new ConstantRange
 Attribute type

---
 llvm/docs/LangRef.rst                         | 16 ++++
 llvm/include/llvm/ADT/FoldingSet.h            |  7 ++
 llvm/include/llvm/AsmParser/LLParser.h        |  1 +
 llvm/include/llvm/Bitcode/LLVMBitCodes.h      |  1 +
 llvm/include/llvm/IR/Attributes.h             | 23 ++++++
 llvm/include/llvm/IR/Attributes.td            |  6 ++
 llvm/lib/AsmParser/LLParser.cpp               | 43 ++++++++++
 llvm/lib/Bitcode/Reader/BitcodeReader.cpp     | 41 ++++++++++
 llvm/lib/Bitcode/Writer/BitcodeWriter.cpp     | 61 +++++++++-----
 llvm/lib/IR/AttributeImpl.h                   | 28 ++++++-
 llvm/lib/IR/Attributes.cpp                    | 81 ++++++++++++++++++-
 llvm/lib/IR/LLVMContextImpl.h                 |  3 +
 llvm/lib/IR/Verifier.cpp                      |  5 ++
 llvm/lib/Transforms/Utils/CodeExtractor.cpp   |  1 +
 .../range-attribute-invalid-range.ll          |  6 ++
 .../Assembler/range-attribute-invalid-type.ll |  6 ++
 llvm/test/Bitcode/attributes.ll               | 10 +++
 llvm/test/Verifier/range-attr.ll              | 19 +++++
 llvm/utils/TableGen/Attributes.cpp            |  9 ++-
 19 files changed, 341 insertions(+), 26 deletions(-)
 create mode 100644 llvm/test/Assembler/range-attribute-invalid-range.ll
 create mode 100644 llvm/test/Assembler/range-attribute-invalid-type.ll
 create mode 100644 llvm/test/Verifier/range-attr.ll

diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index a7b77d6f776a7e..b70220dec92615 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -1635,6 +1635,22 @@ Currently, only the following parameter attributes are defined:
 
     This attribute cannot be applied to return values.
 
+``range(<ty> <a>, <b>)``
+    This attribute expresses the possible range of the parameter or return value.
+    If the value is not in the specified range, it is converted to poison.
+    The arguments passed to ``range`` have the following properties:
+
+    -  The type must match the scalar type of the parameter or return value.
+    -  The pair ``a,b`` represents the range ``[a,b)``.
+    -  Both ``a`` and ``b`` are constants.
+    -  The range is allowed to wrap.
+    -  The range should not represent the full or empty set. That is, ``a!=b``.
+    
+    This attribute may only be applied to parameters or return values with integer 
+    or vector of integer types.
+    
+    For vector-typed parameters, the range is applied element-wise.
+
 .. _gc:
 
 Garbage Collector Strategy Names
diff --git a/llvm/include/llvm/ADT/FoldingSet.h b/llvm/include/llvm/ADT/FoldingSet.h
index f82eabd5044b22..ddc3e52255d6c0 100644
--- a/llvm/include/llvm/ADT/FoldingSet.h
+++ b/llvm/include/llvm/ADT/FoldingSet.h
@@ -16,6 +16,7 @@
 #ifndef LLVM_ADT_FOLDINGSET_H
 #define LLVM_ADT_FOLDINGSET_H
 
+#include "llvm/ADT/APInt.h"
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/STLForwardCompat.h"
 #include "llvm/ADT/SmallVector.h"
@@ -354,6 +355,12 @@ class FoldingSetNodeID {
     AddInteger(unsigned(I));
     AddInteger(unsigned(I >> 32));
   }
+  void AddInteger(const APInt &Int) {
+    const auto *Parts = Int.getRawData();
+    for (int i = 0, N = Int.getNumWords(); i < N; ++i) {
+      AddInteger(Parts[i]);
+    }
+  }
 
   void AddBoolean(bool B) { AddInteger(B ? 1U : 0U); }
   void AddString(StringRef String);
diff --git a/llvm/include/llvm/AsmParser/LLParser.h b/llvm/include/llvm/AsmParser/LLParser.h
index e5e1ade8b38b36..e85728aa3c0da0 100644
--- a/llvm/include/llvm/AsmParser/LLParser.h
+++ b/llvm/include/llvm/AsmParser/LLParser.h
@@ -369,6 +369,7 @@ namespace llvm {
     bool parseFnAttributeValuePairs(AttrBuilder &B,
                                     std::vector<unsigned> &FwdRefAttrGrps,
                                     bool inAttrGrp, LocTy &BuiltinLoc);
+    bool parseRangeAttr(AttrBuilder &B);
     bool parseRequiredTypeAttr(AttrBuilder &B, lltok::Kind AttrToken,
                                Attribute::AttrKind AttrKind);
 
diff --git a/llvm/include/llvm/Bitcode/LLVMBitCodes.h b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
index c6f0ddf29a6da8..c0a52d64a101d0 100644
--- a/llvm/include/llvm/Bitcode/LLVMBitCodes.h
+++ b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
@@ -724,6 +724,7 @@ enum AttributeKindCodes {
   ATTR_KIND_WRITABLE = 89,
   ATTR_KIND_CORO_ONLY_DESTROY_WHEN_COMPLETE = 90,
   ATTR_KIND_DEAD_ON_UNWIND = 91,
+  ATTR_KIND_RANGE = 92,
 };
 
 enum ComdatSelectionKindCodes {
diff --git a/llvm/include/llvm/IR/Attributes.h b/llvm/include/llvm/IR/Attributes.h
index a4ebe5d732f568..0c2a02514ba0e6 100644
--- a/llvm/include/llvm/IR/Attributes.h
+++ b/llvm/include/llvm/IR/Attributes.h
@@ -37,6 +37,7 @@ class AttributeMask;
 class AttributeImpl;
 class AttributeListImpl;
 class AttributeSetNode;
+class ConstantRange;
 class FoldingSetNodeID;
 class Function;
 class LLVMContext;
@@ -103,6 +104,9 @@ class Attribute {
   static bool isTypeAttrKind(AttrKind Kind) {
     return Kind >= FirstTypeAttr && Kind <= LastTypeAttr;
   }
+  static bool isConstantRangeAttrKind(AttrKind Kind) {
+    return Kind >= FirstConstantRangeAttr && Kind <= LastConstantRangeAttr;
+  }
 
   static bool canUseAsFnAttr(AttrKind Kind);
   static bool canUseAsParamAttr(AttrKind Kind);
@@ -125,6 +129,8 @@ class Attribute {
   static Attribute get(LLVMContext &Context, StringRef Kind,
                        StringRef Val = StringRef());
   static Attribute get(LLVMContext &Context, AttrKind Kind, Type *Ty);
+  static Attribute get(LLVMContext &Context, AttrKind Kind,
+                       const ConstantRange &CR);
 
   /// Return a uniquified Attribute object that has the specific
   /// alignment set.
@@ -180,6 +186,9 @@ class Attribute {
   /// Return true if the attribute is a type attribute.
   bool isTypeAttribute() const;
 
+  /// Return true if the attribute is a ConstantRange attribute.
+  bool isConstantRangeAttribute() const;
+
   /// Return true if the attribute is any kind of attribute.
   bool isValid() const { return pImpl; }
 
@@ -213,6 +222,10 @@ class Attribute {
   /// a type attribute.
   Type *getValueAsType() const;
 
+  /// Return the attribute's value as a ConstantRange. This requires the
+  /// attribute to be a ConstantRange attribute.
+  ConstantRange getValueAsConstantRange() const;
+
   /// Returns the alignment field of an attribute as a byte alignment
   /// value.
   MaybeAlign getAlignment() const;
@@ -251,6 +264,9 @@ class Attribute {
   /// Return the FPClassTest for nofpclass
   FPClassTest getNoFPClass() const;
 
+  /// Returns the value of the range attribute.
+  ConstantRange getRange() const;
+
   /// The Attribute is converted to a string of equivalent mnemonic. This
   /// is, presumably, for writing out the mnemonics for the assembly writer.
   std::string getAsString(bool InAttrGrp = false) const;
@@ -1189,6 +1205,13 @@ class AttrBuilder {
   // Add nofpclass attribute
   AttrBuilder &addNoFPClassAttr(FPClassTest NoFPClassMask);
 
+  /// Add a ConstantRange attribute with the given range.
+  AttrBuilder &addConstantRangeAttr(Attribute::AttrKind Kind,
+                                    const ConstantRange &CR);
+
+  /// Add range attribute.
+  AttrBuilder &addRangeAttr(const ConstantRange &CR);
+
   ArrayRef<Attribute> attrs() const { return Attrs; }
 
   bool operator==(const AttrBuilder &B) const;
diff --git a/llvm/include/llvm/IR/Attributes.td b/llvm/include/llvm/IR/Attributes.td
index 08afecf3201512..cef8b17769f0d0 100644
--- a/llvm/include/llvm/IR/Attributes.td
+++ b/llvm/include/llvm/IR/Attributes.td
@@ -44,6 +44,9 @@ class StrBoolAttr<string S> : Attr<S, []>;
 /// Arbitrary string attribute.
 class ComplexStrAttr<string S, list<AttrProperty> P> : Attr<S, P>;
 
+/// ConstantRange attribute.
+class ConstantRangeAttr<string S, list<AttrProperty> P> : Attr<S, P>;
+
 /// Target-independent enum attributes.
 
 /// Alignment of parameter (5 bits) stored as log2 of alignment with +1 bias.
@@ -218,6 +221,9 @@ def OptimizeNone : EnumAttr<"optnone", [FnAttr]>;
 /// Similar to byval but without a copy.
 def Preallocated : TypeAttr<"preallocated", [FnAttr, ParamAttr]>;
 
+/// Parameter or return value is within the specified range.
+def Range : ConstantRangeAttr<"range", [ParamAttr, RetAttr]>;
+
 /// Function does not access memory.
 def ReadNone : EnumAttr<"readnone", [ParamAttr]>;
 
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index e140c94195205a..78bcd94e23fae1 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -1596,6 +1596,8 @@ bool LLParser::parseEnumAttribute(Attribute::AttrKind Attr, AttrBuilder &B,
 
     return true;
   }
+  case Attribute::Range:
+    return parseRangeAttr(B);
   default:
     B.addAttribute(Attr);
     Lex.Lex();
@@ -3008,6 +3010,47 @@ bool LLParser::parseRequiredTypeAttr(AttrBuilder &B, lltok::Kind AttrToken,
   return false;
 }
 
+/// parseRangeAttr
+///   ::= range(<ty> <n>,<n>)
+bool LLParser::parseRangeAttr(AttrBuilder &B) {
+  Lex.Lex();
+
+  APInt Lower;
+  APInt Upper;
+  Type *Ty = nullptr;
+  LocTy TyLoc;
+
+  auto ParseAPSInt = [&](unsigned BitWidth, APInt &Val) {
+    if (Lex.getKind() != lltok::APSInt)
+      return tokError("expected integer");
+    if (Lex.getAPSIntVal().getBitWidth() > BitWidth)
+      return tokError(
+          "integer is too large for the bit width of specified type");
+    Val = Lex.getAPSIntVal().extend(BitWidth);
+    Lex.Lex();
+    return false;
+  };
+
+  if (parseToken(lltok::lparen, "expected '('") || parseType(Ty, TyLoc))
+    return true;
+  if (!Ty->isIntegerTy())
+    return error(TyLoc, "the range must have integer type!");
+
+  unsigned BitWidth = Ty->getPrimitiveSizeInBits();
+
+  if (ParseAPSInt(BitWidth, Lower) ||
+      parseToken(lltok::comma, "expected ','") || ParseAPSInt(BitWidth, Upper))
+    return true;
+  if (Lower == Upper)
+    return tokError("the range should not represent the full or empty set!");
+
+  if (parseToken(lltok::rparen, "expected ')'"))
+    return true;
+
+  B.addRangeAttr(ConstantRange(Lower, Upper));
+  return false;
+}
+
 /// parseOptionalOperandBundles
 ///    ::= /*empty*/
 ///    ::= '[' OperandBundle [, OperandBundle ]* ']'
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 832907a3f53f5f..9c63116114f3c5 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -815,6 +815,30 @@ class BitcodeReader : public BitcodeReaderBase, public GVMaterializer {
     return getFnValueByID(ValNo, Ty, TyID, ConstExprInsertBB);
   }
 
+  Expected<ConstantRange> readConstantRange(ArrayRef<uint64_t> Record,
+                                            unsigned &OpNum) {
+    if (Record.size() - OpNum < 3)
+      return error("Too few records for range");
+    unsigned BitWidth = Record[OpNum++];
+    if (BitWidth > 64) {
+      unsigned LowerActiveWords = Record[OpNum];
+      unsigned UpperActiveWords = Record[OpNum++] >> 32;
+      if (Record.size() - OpNum < LowerActiveWords + UpperActiveWords)
+        return error("Too few records for range");
+      APInt Lower =
+          readWideAPInt(ArrayRef(&Record[OpNum], LowerActiveWords), BitWidth);
+      OpNum += LowerActiveWords;
+      APInt Upper =
+          readWideAPInt(ArrayRef(&Record[OpNum], UpperActiveWords), BitWidth);
+      OpNum += UpperActiveWords;
+      return ConstantRange(Lower, Upper);
+    } else {
+      int64_t Start = BitcodeReader::decodeSignRotatedValue(Record[OpNum++]);
+      int64_t End = BitcodeReader::decodeSignRotatedValue(Record[OpNum++]);
+      return ConstantRange(APInt(BitWidth, Start), APInt(BitWidth, End));
+    }
+  }
+
   /// Upgrades old-style typeless byval/sret/inalloca attributes by adding the
   /// corresponding argument's pointee type. Also upgrades intrinsics that now
   /// require an elementtype attribute.
@@ -2103,6 +2127,8 @@ static Attribute::AttrKind getAttrFromCode(uint64_t Code) {
     return Attribute::CoroDestroyOnlyWhenComplete;
   case bitc::ATTR_KIND_DEAD_ON_UNWIND:
     return Attribute::DeadOnUnwind;
+  case bitc::ATTR_KIND_RANGE:
+    return Attribute::Range;
   }
 }
 
@@ -2272,6 +2298,21 @@ Error BitcodeReader::parseAttributeGroupBlock() {
             return error("Not a type attribute");
 
           B.addTypeAttr(Kind, HasType ? getTypeByID(Record[++i]) : nullptr);
+        } else if (Record[i] == 7) {
+          Attribute::AttrKind Kind;
+
+          i++;
+          if (Error Err = parseAttrKind(Record[i++], &Kind))
+            return Err;
+          if (!Attribute::isConstantRangeAttrKind(Kind))
+            return error("Not a ConstantRange attribute");
+
+          Expected<ConstantRange> MaybeCR = readConstantRange(Record, i);
+          if (!MaybeCR)
+            return MaybeCR.takeError();
+          i--;
+
+          B.addConstantRangeAttr(Kind, MaybeCR.get());
         } else {
           return error("Invalid attribute group entry");
         }
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 656f2a6ce870f5..597f49332fad25 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -844,6 +844,8 @@ static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
     return bitc::ATTR_KIND_CORO_ONLY_DESTROY_WHEN_COMPLETE;
   case Attribute::DeadOnUnwind:
     return bitc::ATTR_KIND_DEAD_ON_UNWIND;
+  case Attribute::Range:
+    return bitc::ATTR_KIND_RANGE;
   case Attribute::EndAttrKinds:
     llvm_unreachable("Can not encode end-attribute kinds marker.");
   case Attribute::None:
@@ -856,6 +858,39 @@ static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
   llvm_unreachable("Trying to encode unknown attribute");
 }
 
+static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
+  if ((int64_t)V >= 0)
+    Vals.push_back(V << 1);
+  else
+    Vals.push_back((-V << 1) | 1);
+}
+
+static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
+  // We have an arbitrary precision integer value to write whose
+  // bit width is > 64. However, in canonical unsigned integer
+  // format it is likely that the high bits are going to be zero.
+  // So, we only write the number of active words.
+  unsigned NumWords = A.getActiveWords();
+  const uint64_t *RawData = A.getRawData();
+  for (unsigned i = 0; i < NumWords; i++)
+    emitSignedInt64(Vals, RawData[i]);
+}
+
+static void emitConstantRange(SmallVectorImpl<uint64_t> &Record,
+                              const ConstantRange &CR) {
+  unsigned BitWidth = CR.getBitWidth();
+  Record.push_back(BitWidth);
+  if (BitWidth > 64) {
+    Record.push_back(CR.getLower().getActiveWords() |
+                     (uint64_t(CR.getUpper().getActiveWords()) << 32));
+    emitWideAPInt(Record, CR.getLower());
+    emitWideAPInt(Record, CR.getUpper());
+  } else {
+    emitSignedInt64(Record, CR.getLower().getSExtValue());
+    emitSignedInt64(Record, CR.getUpper().getSExtValue());
+  }
+}
+
 void ModuleBitcodeWriter::writeAttributeGroupTable() {
   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
       VE.getAttributeGroups();
@@ -889,13 +924,17 @@ void ModuleBitcodeWriter::writeAttributeGroupTable() {
           Record.append(Val.begin(), Val.end());
           Record.push_back(0);
         }
-      } else {
-        assert(Attr.isTypeAttribute());
+      } else if (Attr.isTypeAttribute()) {
         Type *Ty = Attr.getValueAsType();
         Record.push_back(Ty ? 6 : 5);
         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
         if (Ty)
           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
+      } else {
+        assert(Attr.isConstantRangeAttribute());
+        Record.push_back(7);
+        Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
+        emitConstantRange(Record, Attr.getValueAsConstantRange());
       }
     }
 
@@ -1716,24 +1755,6 @@ void ModuleBitcodeWriter::writeDIGenericSubrange(
   Record.clear();
 }
 
-static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
-  if ((int64_t)V >= 0)
-    Vals.push_back(V << 1);
-  else
-    Vals.push_back((-V << 1) | 1);
-}
-
-static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
-  // We have an arbitrary precision integer value to write whose
-  // bit width is > 64. However, in canonical unsigned integer
-  // format it is likely that the high bits are going to be zero.
-  // So, we only write the number of active words.
-  unsigned NumWords = A.getActiveWords();
-  const uint64_t *RawData = A.getRawData();
-  for (unsigned i = 0; i < NumWords; i++)
-    emitSignedInt64(Vals, RawData[i]);
-}
-
 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
                                             SmallVectorImpl<uint64_t> &Record,
                                             unsigned Abbrev) {
diff --git a/llvm/lib/IR/AttributeImpl.h b/llvm/lib/IR/AttributeImpl.h
index 78496786b0ae95..9a6427bbc3d557 100644
--- a/llvm/lib/IR/AttributeImpl.h
+++ b/llvm/lib/IR/AttributeImpl.h
@@ -20,6 +20,7 @@
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/IR/Attributes.h"
+#include "llvm/IR/ConstantRange.h"
 #include "llvm/Support/TrailingObjects.h"
 #include <cassert>
 #include <cstddef>
@@ -46,6 +47,7 @@ class AttributeImpl : public FoldingSetNode {
     IntAttrEntry,
     StringAttrEntry,
     TypeAttrEntry,
+    ConstantRangeAttrEntry,
   };
 
   AttributeImpl(AttrEntryKind KindID) : KindID(KindID) {}
@@ -59,6 +61,9 @@ class AttributeImpl : public FoldingSetNode {
   bool isIntAttribute() const { return KindID == IntAttrEntry; }
   bool isStringAttribute() const { return KindID == StringAttrEntry; }
   bool isTypeAttribute() const { return KindID == TypeAttrEntry; }
+  bool isConstantRangeAttribute() const {
+    return KindID == ConstantRangeAttrEntry;
+  }
 
   bool hasAttribute(Attribute::AttrKind A) const;
   bool hasAttribute(StringRef Kind) const;
@@ -72,6 +77,8 @@ class AttributeImpl : public FoldingSetNode {
 
   Type *getValueAsType() const;
 
+  ConstantRange getValueAsConstantRange() const;
+
   /// Used when sorting the attributes.
   bool operator<(const AttributeImpl &AI) const;
 
@@ -82,8 +89,10 @@ class AttributeImpl : public FoldingSetNode {
       Profile(ID, getKindAsEnum(), getValueAsInt());
     else if (isStringAttribute())
       Profile(ID, getKindAsString(), getValueAsString());
-    else
+    else if (isTypeAttribute())
       Profile(ID, getKindAsEnum(), getValueAsType());
+    else
+      Profile(ID, getKindAsEnum(), getValueAsConstantRange());
   }
 
   static void Profile(FoldingSetNodeID &ID, Attribute::AttrKind Kind) {
@@ -108,6 +117,13 @@ class AttributeImpl : public FoldingSetNode {
     ID.AddInteger(Kind);
     ID.AddPointer(Ty);
   }
+
+  static void Profile(FoldingSetNodeID &ID, Attribute::AttrKind Kind,
+                      const ConstantRange &CR) {
+    ID.AddInteger(Kind);
+    ID.AddInteger(CR.getLower());
+    ID.AddInteger(CR.getUpper());
+  }
 };
 
 static_assert(std::is_trivially_destructible<AttributeImpl>::value,
@@ -196,6 +212,16 @@ class TypeAttributeImpl : public EnumAttributeImpl {
   Type *getTypeValue() const { return Ty; }
 };
 
+class ConstantRangeAttributeImpl : public EnumAttributeImpl {
+  ConstantRange CR;
+
+public:
+  ConstantRangeAttributeImpl(Attribute::AttrKind Kind, const ConstantRange &CR)
+      : EnumAttributeImpl(ConstantRangeAttrEntry, Kind), CR(CR) {}
+
+  ConstantRange getConstantRangeValue() const { return CR; }
+};
+
 class AttributeBitSet {
   /// Bitset with a bit for each available attribute Attribute::AttrKind.
   uint8_t AvailableAttrs[12] = {};
diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
index 00acbbe7989d8a..b2d9992cdc0258 100644
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -24,6 +24,7 @@
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/IR/AttributeMask.h"
+#include "llvm/IR/ConstantRange.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Type.h"
@@ -165,6 +166,31 @@ Attribute Attribute::get(LLVMContext &Context, Attribute::AttrKind Kind,
   return Attribute(PA);
 }
 
+Attribute Attribute::get(LLVMContext &Context, Attribute::AttrKind Kind,
+                         const ConstantRange &CR) {
+  assert(Attribute::isConstantRangeAttrKind(Kind) &&
+         "Not a ConstantRange attribute");
+  LLVMContextImpl *pImpl = Context.pImpl;
+  FoldingSetNodeID ID;
+  ID.AddInteger(Kind);
+  ID.AddInteger(CR.getLower());
+  ID.AddInteger(CR.getUpper());
+
+  void *InsertPoint;
+  AttributeImpl *PA = pImpl->AttrsSet.FindNodeOrInsertPos(ID, InsertPoint);
+
+  if (!PA) {
+    // If we didn't find any existing attributes of the same shape then create a
+    // new one and insert it.
+    PA = new (pImpl->ConstantRangeAttributeAlloc.Allocate())
+        ConstantRangeAttributeImpl(Kind, CR);
+    pImpl->AttrsSet.InsertNode(PA, InsertPoint);
+  }
+
+  // Return the Attribute that we found or created.
+  return Attribute(PA);
+}
+
 Attribute Attribute::getWithAlignment(LLVMContext &Context, Align A) {
   assert(A <= llvm::Value::MaximumAlignment && "Alignment too large.");
   return get(Context, Alignment, A.value());
@@ -287,9 +313,14 @@ bool Attribute::isTypeAttribute() const {
   return pImpl && pImpl->isTypeAttribute();
 }
 
+bool Attribute::isConstantRangeAttribute() const {
+  return pImpl && pImpl->isConstantRangeAttribute();
+}
+
 Attribute::AttrKind Attribute::getKindAsEnum() const {
   if (!pImpl) return None;
-  assert((isEnumAttribute() || isIntAttribute() || isTypeAttribute()) &&
+  assert((isEnumAttribute() || isIntAttribute() || isTypeAttribute() ||
+          isConstantRangeAttribute()) &&
          "Invalid attribute type to get the kind as an enum!");
   return pImpl->getKindAsEnum();
 }
@@ -329,6 +360,11 @@ Type *Attribute::getValueAsType() const {
   return pImpl->getValueAsType();
 }
 
+ConstantRange Attribute::getValueAsConstantRange() const {
+  assert(isConstantRangeAttribute() &&
+         "Invalid attribute type to get the value as a ConstantRange!");
+  return pImpl->getValueAsConstantRange();
+}
 
 bool Attribute::hasAttribute(AttrKind Kind) const {
   return (pImpl && pImpl->hasAttribute(Kind)) || (!pImpl && Kind == None);
@@ -408,6 +444,12 @@ FPClassTest Attribute::getNoFPClass() const {
   return static_cast<FPClassTest>(pImpl->getValueAsInt());
 }
 
+ConstantRange Attribute::getRange() const {
+  assert(hasAttribute(Attribute::Range) &&
+         "Trying to get range args from non-range attribute");
+  return pImpl->getValueAsConstantRange();
+}
+
 static const char *getModRefStr(ModRefInfo MR) {
   switch (MR) {
   case ModRefInfo::NoModRef:
@@ -562,6 +604,18 @@ std::string Attribute::getAsString(bool InAttrGrp) const {
     return Result;
   }
 
+  if (hasAttribute(Attribute::Range)) {
+    std::string Result;
+    raw_string_ostream OS(Result);
+    ConstantRange CR = getValueAsConstantRange();
+    OS << "range(";
+    OS << "i" << CR.getBitWidth() << " ";
+    OS << CR.getLower() << ", " << CR.getUpper();
+    OS << ")";
+    OS.flush();
+    return Result;
+  }
+
   // Convert target-dependent attributes to strings of the form:
   //
   //   "kind"
@@ -651,7 +705,8 @@ bool AttributeImpl::hasAttribute(StringRef Kind) const {
 }
 
 Attribute::AttrKind AttributeImpl::getKindAsEnum() const {
-  assert(isEnumAttribute() || isIntAttribute() || isTypeAttribute());
+  assert(isEnumAttribute() || isIntAttribute() || isTypeAttribute() ||
+         isConstantRangeAttribute());
   return static_cast<const EnumAttributeImpl *>(this)->getEnumKind();
 }
 
@@ -680,6 +735,12 @@ Type *AttributeImpl::getValueAsType() const {
   return static_cast<const TypeAttributeImpl *>(this)->getTypeValue();
 }
 
+ConstantRange AttributeImpl::getValueAsConstantRange() const {
+  assert(isConstantRangeAttribute());
+  return static_cast<const ConstantRangeAttributeImpl *>(this)
+      ->getConstantRangeValue();
+}
+
 bool AttributeImpl::operator<(const AttributeImpl &AI) const {
   if (this == &AI)
     return false;
@@ -693,6 +754,7 @@ bool AttributeImpl::operator<(const AttributeImpl &AI) const {
       return getKindAsEnum() < AI.getKindAsEnum();
     assert(!AI.isEnumAttribute() && "Non-unique attribute");
     assert(!AI.isTypeAttribute() && "Comparison of types would be unstable");
+    assert(!AI.isConstantRangeAttribute() && "Unclear how to compare ranges");
     // TODO: Is this actually needed?
     assert(AI.isIntAttribute() && "Only possibility left");
     return getValueAsInt() < AI.getValueAsInt();
@@ -1881,6 +1943,15 @@ AttrBuilder &AttrBuilder::addInAllocaAttr(Type *Ty) {
   return addTypeAttr(Attribute::InAlloca, Ty);
 }
 
+AttrBuilder &AttrBuilder::addConstantRangeAttr(Attribute::AttrKind Kind,
+                                               const ConstantRange &CR) {
+  return addAttribute(Attribute::get(Ctx, Kind, CR));
+}
+
+AttrBuilder &AttrBuilder::addRangeAttr(const ConstantRange &CR) {
+  return addConstantRangeAttr(Attribute::Range, CR);
+}
+
 AttrBuilder &AttrBuilder::merge(const AttrBuilder &B) {
   // TODO: Could make this O(n) as we're merging two sorted lists.
   for (const auto &I : B.attrs())
@@ -1952,6 +2023,12 @@ AttributeMask AttributeFuncs::typeIncompatible(Type *Ty,
       Incompatible.addAttribute(Attribute::SExt).addAttribute(Attribute::ZExt);
   }
 
+  if (!Ty->isIntOrIntVectorTy()) {
+    // Attributes that only apply to integers or vector of integers.
+    if (ASK & ASK_SAFE_TO_DROP)
+      Incompatible.addAttribute(Attribute::Range);
+  }
+
   if (!Ty->isPointerTy()) {
     // Attributes that only apply to pointers.
     if (ASK & ASK_SAFE_TO_DROP)
diff --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
index 2ee1080a1ffa29..e1ef705a4d4abe 100644
--- a/llvm/lib/IR/LLVMContextImpl.h
+++ b/llvm/lib/IR/LLVMContextImpl.h
@@ -14,6 +14,7 @@
 #ifndef LLVM_LIB_IR_LLVMCONTEXTIMPL_H
 #define LLVM_LIB_IR_LLVMCONTEXTIMPL_H
 
+#include "AttributeImpl.h"
 #include "ConstantsContext.h"
 #include "llvm/ADT/APFloat.h"
 #include "llvm/ADT/APInt.h"
@@ -1562,6 +1563,8 @@ class LLVMContextImpl {
 
   BumpPtrAllocator Alloc;
   UniqueStringSaver Saver{Alloc};
+  SpecificBumpPtrAllocator<ConstantRangeAttributeImpl>
+      ConstantRangeAttributeAlloc;
 
   DenseMap<unsigned, IntegerType *> IntegerTypes;
 
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index fd5f7d57c258d4..3cf5e81efb3b1a 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -2039,6 +2039,11 @@ void Verifier::verifyParameterAttrs(AttributeSet Attrs, Type *Ty,
     Check((Val & ~static_cast<unsigned>(fcAllFlags)) == 0,
           "Invalid value for 'nofpclass' test mask", V);
   }
+  if (Attrs.hasAttribute(Attribute::Range)) {
+    auto CR = Attrs.getAttribute(Attribute::Range).getValueAsConstantRange();
+    Check(Ty->isIntOrIntVectorTy(CR.getBitWidth()),
+          "Range bit width must match type bit width!", V);
+  }
 }
 
 void Verifier::checkUnsignedBaseTenFuncAttr(AttributeList Attrs, StringRef Attr,
diff --git a/llvm/lib/Transforms/Utils/CodeExtractor.cpp b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
index 3071ec0c911321..ab2d25c3f17c7d 100644
--- a/llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -999,6 +999,7 @@ Function *CodeExtractor::constructFunction(const ValueSet &inputs,
       case Attribute::WriteOnly:
       case Attribute::Writable:
       case Attribute::DeadOnUnwind:
+      case Attribute::Range:
       //  These are not really attributes.
       case Attribute::None:
       case Attribute::EndAttrKinds:
diff --git a/llvm/test/Assembler/range-attribute-invalid-range.ll b/llvm/test/Assembler/range-attribute-invalid-range.ll
new file mode 100644
index 00000000000000..cf6d3f0801838c
--- /dev/null
+++ b/llvm/test/Assembler/range-attribute-invalid-range.ll
@@ -0,0 +1,6 @@
+; RUN: not llvm-as < %s -o /dev/null 2>&1 | FileCheck %s
+
+; CHECK: the range should not represent the full or empty set!
+define void @range_empty(i8 range(i8 0, 0) %a) {
+  ret void
+}
diff --git a/llvm/test/Assembler/range-attribute-invalid-type.ll b/llvm/test/Assembler/range-attribute-invalid-type.ll
new file mode 100644
index 00000000000000..cc09149a94dc6f
--- /dev/null
+++ b/llvm/test/Assembler/range-attribute-invalid-type.ll
@@ -0,0 +1,6 @@
+; RUN: not llvm-as < %s -o /dev/null 2>&1 | FileCheck %s
+
+; CHECK: the range must have integer type!
+define void @range_vector_type(i8 range(<4 x i32> 0, 0) %a) {
+  ret void
+}
diff --git a/llvm/test/Bitcode/attributes.ll b/llvm/test/Bitcode/attributes.ll
index 6921f11a352ddf..26163b4d38c89d 100644
--- a/llvm/test/Bitcode/attributes.ll
+++ b/llvm/test/Bitcode/attributes.ll
@@ -526,6 +526,16 @@ define void @f91(ptr dead_on_unwind %p) {
   ret void
 }
 
+; CHECK: define range(i32 -1, 42) i32 @range_attribute(<4 x i32> range(i32 -1, 42) %a)
+define range(i32 -1, 42) i32 @range_attribute(<4 x i32> range(i32 -1, 42) %a) {
+  ret i32 0
+}
+
+; CHECK: define void @wide_range_attribute(i128 range(i128 618970019642690137449562111, 618970019642690137449562114) %a)
+define void @wide_range_attribute(i128 range(i128 618970019642690137449562111, 618970019642690137449562114) %a) {
+  ret void
+}
+
 ; CHECK: attributes #0 = { noreturn }
 ; CHECK: attributes #1 = { nounwind }
 ; CHECK: attributes #2 = { memory(none) }
diff --git a/llvm/test/Verifier/range-attr.ll b/llvm/test/Verifier/range-attr.ll
new file mode 100644
index 00000000000000..f985ab696eacba
--- /dev/null
+++ b/llvm/test/Verifier/range-attr.ll
@@ -0,0 +1,19 @@
+; RUN: not llvm-as %s -o /dev/null 2>&1 | FileCheck %s
+
+; CHECK: Range bit width must match type bit width!
+; CHECK-NEXT: ptr @bit_widths_do_not_match
+define void @bit_widths_do_not_match(i32 range(i8 1, 0) %a) {
+  ret void
+}
+
+; CHECK: Range bit width must match type bit width!
+; CHECK-NEXT: ptr @bit_widths_do_not_match_vector
+define void @bit_widths_do_not_match_vector(<4 x i32> range(i8 1, 0) %a) {
+  ret void
+}
+
+; CHECK: Attribute 'range(i8 1, 0)' applied to incompatible type!
+; CHECK-NEXT: ptr @not-integer-type
+define void @not-integer-type(ptr range(i8 1, 0) %a) {
+  ret void
+}
diff --git a/llvm/utils/TableGen/Attributes.cpp b/llvm/utils/TableGen/Attributes.cpp
index db3c4decccb4cf..d9fc7834416cfb 100644
--- a/llvm/utils/TableGen/Attributes.cpp
+++ b/llvm/utils/TableGen/Attributes.cpp
@@ -53,7 +53,8 @@ void Attributes::emitTargetIndependentNames(raw_ostream &OS) {
   };
 
   // Emit attribute enums in the same order llvm::Attribute::operator< expects.
-  Emit({"EnumAttr", "TypeAttr", "IntAttr"}, "ATTRIBUTE_ENUM");
+  Emit({"EnumAttr", "TypeAttr", "IntAttr", "ConstantRangeAttr"},
+       "ATTRIBUTE_ENUM");
   Emit({"StrBoolAttr"}, "ATTRIBUTE_STRBOOL");
   Emit({"ComplexStrAttr"}, "ATTRIBUTE_COMPLEXSTR");
 
@@ -63,7 +64,8 @@ void Attributes::emitTargetIndependentNames(raw_ostream &OS) {
   OS << "#ifdef GET_ATTR_ENUM\n";
   OS << "#undef GET_ATTR_ENUM\n";
   unsigned Value = 1; // Leave zero for AttrKind::None.
-  for (StringRef KindName : {"EnumAttr", "TypeAttr", "IntAttr"}) {
+  for (StringRef KindName :
+       {"EnumAttr", "TypeAttr", "IntAttr", "ConstantRangeAttr"}) {
     OS << "First" << KindName << " = " << Value << ",\n";
     for (auto *A : Records.getAllDerivedDefinitions(KindName)) {
       OS << A->getName() << " = " << Value << ",\n";
@@ -117,7 +119,8 @@ void Attributes::emitAttributeProperties(raw_ostream &OS) {
   OS << "#ifdef GET_ATTR_PROP_TABLE\n";
   OS << "#undef GET_ATTR_PROP_TABLE\n";
   OS << "static const uint8_t AttrPropTable[] = {\n";
-  for (StringRef KindName : {"EnumAttr", "TypeAttr", "IntAttr"}) {
+  for (StringRef KindName :
+       {"EnumAttr", "TypeAttr", "IntAttr", "ConstantRangeAttr"}) {
     for (auto *A : Records.getAllDerivedDefinitions(KindName)) {
       OS << "0";
       for (Init *P : *A->getValueAsListInit("Properties"))



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