[IR] Add a dedicated FNeg IR Instruction

The IEEE-754 Standard makes it clear that fneg(x) and
fsub(-0.0, x) are two different operations. The former is a bitwise
operation, while the latter is an arithmetic operation. This patch
creates a dedicated FNeg IR Instruction to model that behavior.

Differential Revision: https://reviews.llvm.org/D53877



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@346774 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm-c/Core.h

@@ -54,6 +54,8 @@ extern "C" {
  * @{
  */
 
+/// External users depend on the following values being stable. It is not safe
+/// to reorder them.
 typedef enum {
   /* Terminator Instructions */
   LLVMRet            = 1,
@@ -64,6 +66,9 @@ typedef enum {
   /* removed 6 due to API changes */
   LLVMUnreachable    = 7,
 
+  /* Standard Unary Operators */
+  LLVMFNeg           = 66,
+
   /* Standard Binary Operators */
   LLVMAdd            = 8,
   LLVMFAdd           = 9,

include/llvm/Bitcode/LLVMBitCodes.h

@@ -342,6 +342,7 @@ enum ConstantsCodes {
   CST_CODE_INLINEASM = 23,       // INLINEASM:     [sideeffect|alignstack|
                                  //                 asmdialect,asmstr,conststr]
   CST_CODE_CE_GEP_WITH_INRANGE_INDEX = 24, //      [opty, flags, n x operands]
+  CST_CODE_CE_UNOP = 25,         // CE_UNOP:      [opcode, opval]
 };
 
 /// CastOpcodes - These are values used in the bitcode files to encode which
@@ -364,6 +365,14 @@ enum CastOpcodes {
   CAST_ADDRSPACECAST = 12
 };
 
+/// UnaryOpcodes - These are values used in the bitcode files to encode which
+/// unop a CST_CODE_CE_UNOP or a XXX refers to.  The values of these enums
+/// have no fixed relation to the LLVM IR enum values.  Changing these will
+/// break compatibility with old files.
+enum UnaryOpcodes {
+  UNOP_NEG = 0
+};
+
 /// BinaryOpcodes - These are values used in the bitcode files to encode which
 /// binop a CST_CODE_CE_BINOP or a XXX refers to.  The values of these enums
 /// have no fixed relation to the LLVM IR enum values.  Changing these will
@@ -524,6 +533,7 @@ enum FunctionCodes {
   // 53 is unused.
   // 54 is unused.
   FUNC_CODE_OPERAND_BUNDLE = 55, // OPERAND_BUNDLE: [tag#, value...]
+  FUNC_CODE_INST_UNOP = 56,      // UNOP:       [opcode, ty, opval]
 };
 
 enum UseListCodes {

include/llvm/CodeGen/GlobalISel/IRTranslator.h

@@ -300,6 +300,8 @@ class IRTranslator : public MachineFunctionPass {
 
   bool translateFSub(const User &U, MachineIRBuilder &MIRBuilder);
 
+  bool translateFNeg(const User &U, MachineIRBuilder &MIRBuilder);
+
   bool translateAdd(const User &U, MachineIRBuilder &MIRBuilder) {
     return translateBinaryOp(TargetOpcode::G_ADD, U, MIRBuilder);
   }

include/llvm/IR/Constants.h

@@ -1114,6 +1114,13 @@ class ConstantExpr : public Constant {
   static Constant *getSelect(Constant *C, Constant *V1, Constant *V2,
                              Type *OnlyIfReducedTy = nullptr);
 
+  /// get - Return a unary operator constant expression,
+  /// folding if possible.
+  ///
+  /// \param OnlyIfReducedTy see \a getWithOperands() docs.
+  static Constant *get(unsigned Opcode, Constant *C1, unsigned Flags = 0, 
+                       Type *OnlyIfReducedTy = nullptr);
+
   /// get - Return a binary or shift operator constant expression,
   /// folding if possible.
   ///

include/llvm/IR/InstVisitor.h

@@ -263,6 +263,7 @@ class InstVisitor {
   // of instructions...
   //
   RetTy visitCastInst(CastInst &I)                { DELEGATE(UnaryInstruction);}
+  RetTy visitUnaryOperator(UnaryOperator &I)      { DELEGATE(UnaryInstruction);}
   RetTy visitBinaryOperator(BinaryOperator &I)    { DELEGATE(Instruction);}
   RetTy visitCmpInst(CmpInst &I)                  { DELEGATE(Instruction);}
   RetTy visitUnaryInstruction(UnaryInstruction &I){ DELEGATE(Instruction);}

include/llvm/IR/Instruction.def

@@ -32,6 +32,20 @@
 #define LAST_TERM_INST(num)
 #endif
 
+#ifndef FIRST_UNARY_INST
+#define FIRST_UNARY_INST(num)
+#endif
+#ifndef HANDLE_UNARY_INST
+#ifndef HANDLE_INST
+#define HANDLE_UNARY_INST(num, opcode, instclass)
+#else
+#define HANDLE_UNARY_INST(num, opcode, Class) HANDLE_INST(num, opcode, Class)
+#endif
+#endif
+#ifndef LAST_UNARY_INST
+#define LAST_UNARY_INST(num)
+#endif
+
 #ifndef FIRST_BINARY_INST
 #define FIRST_BINARY_INST(num)
 #endif
@@ -123,87 +137,96 @@ HANDLE_TERM_INST  ( 9, CatchRet      , CatchReturnInst)
 HANDLE_TERM_INST  (10, CatchSwitch   , CatchSwitchInst)
   LAST_TERM_INST  (10)
 
+// Standard unary operators...
+ FIRST_UNARY_INST(11)
+HANDLE_UNARY_INST(11, FNeg  , UnaryOperator)
+  LAST_UNARY_INST(11)
+
 // Standard binary operators...
- FIRST_BINARY_INST(11)
-HANDLE_BINARY_INST(11, Add  , BinaryOperator)
-HANDLE_BINARY_INST(12, FAdd , BinaryOperator)
-HANDLE_BINARY_INST(13, Sub  , BinaryOperator)
-HANDLE_BINARY_INST(14, FSub , BinaryOperator)
-HANDLE_BINARY_INST(15, Mul  , BinaryOperator)
-HANDLE_BINARY_INST(16, FMul , BinaryOperator)
-HANDLE_BINARY_INST(17, UDiv , BinaryOperator)
-HANDLE_BINARY_INST(18, SDiv , BinaryOperator)
-HANDLE_BINARY_INST(19, FDiv , BinaryOperator)
-HANDLE_BINARY_INST(20, URem , BinaryOperator)
-HANDLE_BINARY_INST(21, SRem , BinaryOperator)
-HANDLE_BINARY_INST(22, FRem , BinaryOperator)
+ FIRST_BINARY_INST(12)
+HANDLE_BINARY_INST(12, Add  , BinaryOperator)
+HANDLE_BINARY_INST(13, FAdd , BinaryOperator)
+HANDLE_BINARY_INST(14, Sub  , BinaryOperator)
+HANDLE_BINARY_INST(15, FSub , BinaryOperator)
+HANDLE_BINARY_INST(16, Mul  , BinaryOperator)
+HANDLE_BINARY_INST(17, FMul , BinaryOperator)
+HANDLE_BINARY_INST(18, UDiv , BinaryOperator)
+HANDLE_BINARY_INST(19, SDiv , BinaryOperator)
+HANDLE_BINARY_INST(20, FDiv , BinaryOperator)
+HANDLE_BINARY_INST(21, URem , BinaryOperator)
+HANDLE_BINARY_INST(22, SRem , BinaryOperator)
+HANDLE_BINARY_INST(23, FRem , BinaryOperator)
 
 // Logical operators (integer operands)
-HANDLE_BINARY_INST(23, Shl  , BinaryOperator) // Shift left  (logical)
-HANDLE_BINARY_INST(24, LShr , BinaryOperator) // Shift right (logical)
-HANDLE_BINARY_INST(25, AShr , BinaryOperator) // Shift right (arithmetic)
-HANDLE_BINARY_INST(26, And  , BinaryOperator)
-HANDLE_BINARY_INST(27, Or   , BinaryOperator)
-HANDLE_BINARY_INST(28, Xor  , BinaryOperator)
-  LAST_BINARY_INST(28)
+HANDLE_BINARY_INST(24, Shl  , BinaryOperator) // Shift left  (logical)
+HANDLE_BINARY_INST(25, LShr , BinaryOperator) // Shift right (logical)
+HANDLE_BINARY_INST(26, AShr , BinaryOperator) // Shift right (arithmetic)
+HANDLE_BINARY_INST(27, And  , BinaryOperator)
+HANDLE_BINARY_INST(28, Or   , BinaryOperator)
+HANDLE_BINARY_INST(29, Xor  , BinaryOperator)
+  LAST_BINARY_INST(29)
 
 // Memory operators...
- FIRST_MEMORY_INST(29)
-HANDLE_MEMORY_INST(29, Alloca, AllocaInst)  // Stack management
-HANDLE_MEMORY_INST(30, Load  , LoadInst  )  // Memory manipulation instrs
-HANDLE_MEMORY_INST(31, Store , StoreInst )
-HANDLE_MEMORY_INST(32, GetElementPtr, GetElementPtrInst)
-HANDLE_MEMORY_INST(33, Fence , FenceInst )
-HANDLE_MEMORY_INST(34, AtomicCmpXchg , AtomicCmpXchgInst )
-HANDLE_MEMORY_INST(35, AtomicRMW , AtomicRMWInst )
-  LAST_MEMORY_INST(35)
+ FIRST_MEMORY_INST(30)
+HANDLE_MEMORY_INST(30, Alloca, AllocaInst)  // Stack management
+HANDLE_MEMORY_INST(31, Load  , LoadInst  )  // Memory manipulation instrs
+HANDLE_MEMORY_INST(32, Store , StoreInst )
+HANDLE_MEMORY_INST(33, GetElementPtr, GetElementPtrInst)
+HANDLE_MEMORY_INST(34, Fence , FenceInst )
+HANDLE_MEMORY_INST(35, AtomicCmpXchg , AtomicCmpXchgInst )
+HANDLE_MEMORY_INST(36, AtomicRMW , AtomicRMWInst )
+  LAST_MEMORY_INST(36)
 
 // Cast operators ...
 // NOTE: The order matters here because CastInst::isEliminableCastPair
 // NOTE: (see Instructions.cpp) encodes a table based on this ordering.
- FIRST_CAST_INST(36)
-HANDLE_CAST_INST(36, Trunc   , TruncInst   )  // Truncate integers
-HANDLE_CAST_INST(37, ZExt    , ZExtInst    )  // Zero extend integers
-HANDLE_CAST_INST(38, SExt    , SExtInst    )  // Sign extend integers
-HANDLE_CAST_INST(39, FPToUI  , FPToUIInst  )  // floating point -> UInt
-HANDLE_CAST_INST(40, FPToSI  , FPToSIInst  )  // floating point -> SInt
-HANDLE_CAST_INST(41, UIToFP  , UIToFPInst  )  // UInt -> floating point
-HANDLE_CAST_INST(42, SIToFP  , SIToFPInst  )  // SInt -> floating point
-HANDLE_CAST_INST(43, FPTrunc , FPTruncInst )  // Truncate floating point
-HANDLE_CAST_INST(44, FPExt   , FPExtInst   )  // Extend floating point
-HANDLE_CAST_INST(45, PtrToInt, PtrToIntInst)  // Pointer -> Integer
-HANDLE_CAST_INST(46, IntToPtr, IntToPtrInst)  // Integer -> Pointer
-HANDLE_CAST_INST(47, BitCast , BitCastInst )  // Type cast
-HANDLE_CAST_INST(48, AddrSpaceCast, AddrSpaceCastInst)  // addrspace cast
-  LAST_CAST_INST(48)
-
- FIRST_FUNCLETPAD_INST(49)
-HANDLE_FUNCLETPAD_INST(49, CleanupPad, CleanupPadInst)
-HANDLE_FUNCLETPAD_INST(50, CatchPad  , CatchPadInst)
-  LAST_FUNCLETPAD_INST(50)
+ FIRST_CAST_INST(37)
+HANDLE_CAST_INST(37, Trunc   , TruncInst   )  // Truncate integers
+HANDLE_CAST_INST(38, ZExt    , ZExtInst    )  // Zero extend integers
+HANDLE_CAST_INST(39, SExt    , SExtInst    )  // Sign extend integers
+HANDLE_CAST_INST(40, FPToUI  , FPToUIInst  )  // floating point -> UInt
+HANDLE_CAST_INST(41, FPToSI  , FPToSIInst  )  // floating point -> SInt
+HANDLE_CAST_INST(42, UIToFP  , UIToFPInst  )  // UInt -> floating point
+HANDLE_CAST_INST(43, SIToFP  , SIToFPInst  )  // SInt -> floating point
+HANDLE_CAST_INST(44, FPTrunc , FPTruncInst )  // Truncate floating point
+HANDLE_CAST_INST(45, FPExt   , FPExtInst   )  // Extend floating point
+HANDLE_CAST_INST(46, PtrToInt, PtrToIntInst)  // Pointer -> Integer
+HANDLE_CAST_INST(47, IntToPtr, IntToPtrInst)  // Integer -> Pointer
+HANDLE_CAST_INST(48, BitCast , BitCastInst )  // Type cast
+HANDLE_CAST_INST(49, AddrSpaceCast, AddrSpaceCastInst)  // addrspace cast
+  LAST_CAST_INST(49)
+
+ FIRST_FUNCLETPAD_INST(50)
+HANDLE_FUNCLETPAD_INST(50, CleanupPad, CleanupPadInst)
+HANDLE_FUNCLETPAD_INST(51, CatchPad  , CatchPadInst)
+  LAST_FUNCLETPAD_INST(51)
 
 // Other operators...
- FIRST_OTHER_INST(51)
-HANDLE_OTHER_INST(51, ICmp   , ICmpInst   )  // Integer comparison instruction
-HANDLE_OTHER_INST(52, FCmp   , FCmpInst   )  // Floating point comparison instr.
-HANDLE_OTHER_INST(53, PHI    , PHINode    )  // PHI node instruction
-HANDLE_OTHER_INST(54, Call   , CallInst   )  // Call a function
-HANDLE_OTHER_INST(55, Select , SelectInst )  // select instruction
-HANDLE_USER_INST (56, UserOp1, Instruction)  // May be used internally in a pass
-HANDLE_USER_INST (57, UserOp2, Instruction)  // Internal to passes only
-HANDLE_OTHER_INST(58, VAArg  , VAArgInst  )  // vaarg instruction
-HANDLE_OTHER_INST(59, ExtractElement, ExtractElementInst)// extract from vector
-HANDLE_OTHER_INST(60, InsertElement, InsertElementInst)  // insert into vector
-HANDLE_OTHER_INST(61, ShuffleVector, ShuffleVectorInst)  // shuffle two vectors.
-HANDLE_OTHER_INST(62, ExtractValue, ExtractValueInst)// extract from aggregate
-HANDLE_OTHER_INST(63, InsertValue, InsertValueInst)  // insert into aggregate
-HANDLE_OTHER_INST(64, LandingPad, LandingPadInst)  // Landing pad instruction.
-  LAST_OTHER_INST(64)
+ FIRST_OTHER_INST(52)
+HANDLE_OTHER_INST(52, ICmp   , ICmpInst   )  // Integer comparison instruction
+HANDLE_OTHER_INST(53, FCmp   , FCmpInst   )  // Floating point comparison instr.
+HANDLE_OTHER_INST(54, PHI    , PHINode    )  // PHI node instruction
+HANDLE_OTHER_INST(55, Call   , CallInst   )  // Call a function
+HANDLE_OTHER_INST(56, Select , SelectInst )  // select instruction
+HANDLE_USER_INST (57, UserOp1, Instruction)  // May be used internally in a pass
+HANDLE_USER_INST (58, UserOp2, Instruction)  // Internal to passes only
+HANDLE_OTHER_INST(59, VAArg  , VAArgInst  )  // vaarg instruction
+HANDLE_OTHER_INST(60, ExtractElement, ExtractElementInst)// extract from vector
+HANDLE_OTHER_INST(61, InsertElement, InsertElementInst)  // insert into vector
+HANDLE_OTHER_INST(62, ShuffleVector, ShuffleVectorInst)  // shuffle two vectors.
+HANDLE_OTHER_INST(63, ExtractValue, ExtractValueInst)// extract from aggregate
+HANDLE_OTHER_INST(64, InsertValue, InsertValueInst)  // insert into aggregate
+HANDLE_OTHER_INST(65, LandingPad, LandingPadInst)  // Landing pad instruction.
+  LAST_OTHER_INST(65)
 
 #undef  FIRST_TERM_INST
 #undef HANDLE_TERM_INST
 #undef   LAST_TERM_INST
 
+#undef  FIRST_UNARY_INST
+#undef HANDLE_UNARY_INST
+#undef   LAST_UNARY_INST
+
 #undef  FIRST_BINARY_INST
 #undef HANDLE_BINARY_INST
 #undef   LAST_BINARY_INST

include/llvm/IR/Instruction.h

@@ -127,6 +127,7 @@ class Instruction : public User,
 
   const char *getOpcodeName() const { return getOpcodeName(getOpcode()); }
   bool isTerminator() const { return isTerminator(getOpcode()); }
+  bool isUnaryOp() const { return isUnaryOp(getOpcode()); }
   bool isBinaryOp() const { return isBinaryOp(getOpcode()); }
   bool isIntDivRem() const { return isIntDivRem(getOpcode()); }
   bool isShift() { return isShift(getOpcode()); }
@@ -142,6 +143,9 @@ class Instruction : public User,
     return OpCode >= TermOpsBegin && OpCode < TermOpsEnd;
   }
 
+  static inline bool isUnaryOp(unsigned Opcode) {
+    return Opcode >= UnaryOpsBegin && Opcode < UnaryOpsEnd;
+  }
   static inline bool isBinaryOp(unsigned Opcode) {
     return Opcode >= BinaryOpsBegin && Opcode < BinaryOpsEnd;
   }
@@ -662,6 +666,13 @@ class Instruction : public User,
 #include "llvm/IR/Instruction.def"
   };
 
+  enum UnaryOps {
+#define  FIRST_UNARY_INST(N)             UnaryOpsBegin = N,
+#define HANDLE_UNARY_INST(N, OPC, CLASS) OPC = N,
+#define   LAST_UNARY_INST(N)             UnaryOpsEnd = N+1
+#include "llvm/IR/Instruction.def"
+  };
+
   enum BinaryOps {
 #define  FIRST_BINARY_INST(N)             BinaryOpsBegin = N,
 #define HANDLE_BINARY_INST(N, OPC, CLASS) OPC = N,

include/llvm/IR/Instructions.h

@@ -1103,6 +1103,71 @@ GetElementPtrInst::GetElementPtrInst(Type *PointeeType, Value *Ptr,
 
 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GetElementPtrInst, Value)
 
+//===----------------------------------------------------------------------===//
+//                                UnaryOperator Class
+//===----------------------------------------------------------------------===//
+
+/// a unary instruction 
+class UnaryOperator : public UnaryInstruction {
+  void AssertOK();
+
+protected:
+  UnaryOperator(UnaryOps iType, Value *S, Type *Ty,
+                const Twine &Name, Instruction *InsertBefore);
+  UnaryOperator(UnaryOps iType, Value *S, Type *Ty,
+                const Twine &Name, BasicBlock *InsertAtEnd);
+
+  // Note: Instruction needs to be a friend here to call cloneImpl.
+  friend class Instruction;
+
+  UnaryOperator *cloneImpl() const;
+
+public:
+
+  /// Construct a unary instruction, given the opcode and an operand.
+  /// Optionally (if InstBefore is specified) insert the instruction
+  /// into a BasicBlock right before the specified instruction.  The specified
+  /// Instruction is allowed to be a dereferenced end iterator.
+  ///
+  static UnaryOperator *Create(UnaryOps Op, Value *S,
+                               const Twine &Name = Twine(),
+                               Instruction *InsertBefore = nullptr);
+
+  /// Construct a unary instruction, given the opcode and an operand.
+  /// Also automatically insert this instruction to the end of the
+  /// BasicBlock specified.
+  ///
+  static UnaryOperator *Create(UnaryOps Op, Value *S,
+                               const Twine &Name,
+                               BasicBlock *InsertAtEnd);
+
+  /// These methods just forward to Create, and are useful when you
+  /// statically know what type of instruction you're going to create.  These
+  /// helpers just save some typing.
+#define HANDLE_UNARY_INST(N, OPC, CLASS) \
+  static UnaryInstruction *Create##OPC(Value *V, \
+                                       const Twine &Name = "") {\
+    return Create(Instruction::OPC, V, Name);\
+  }
+#include "llvm/IR/Instruction.def"
+#define HANDLE_UNARY_INST(N, OPC, CLASS) \
+  static UnaryInstruction *Create##OPC(Value *V, \
+                                       const Twine &Name, BasicBlock *BB) {\
+    return Create(Instruction::OPC, V, Name, BB);\
+  }
+#include "llvm/IR/Instruction.def"
+#define HANDLE_UNARY_INST(N, OPC, CLASS) \
+  static UnaryInstruction *Create##OPC(Value *V, \
+                                       const Twine &Name, Instruction *I) {\
+    return Create(Instruction::OPC, V, Name, I);\
+  }
+#include "llvm/IR/Instruction.def"
+
+  UnaryOps getOpcode() const {
+    return static_cast<UnaryOps>(Instruction::getOpcode());
+  }
+};
+
 //===----------------------------------------------------------------------===//
 //                               ICmpInst Class
 //===----------------------------------------------------------------------===//

lib/AsmParser/LLLexer.cpp

@@ -823,6 +823,8 @@ lltok::Kind LLLexer::LexIdentifier() {
     }                                                                          \
   } while (false)
 
+  INSTKEYWORD(fneg,  FNeg);
+
   INSTKEYWORD(add,   Add);  INSTKEYWORD(fadd,   FAdd);
   INSTKEYWORD(sub,   Sub);  INSTKEYWORD(fsub,   FSub);
   INSTKEYWORD(mul,   Mul);  INSTKEYWORD(fmul,   FMul);