content: {-
  (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
  
  \section[PrimOp]{Primitive operations (machine-level)}
  -}
  
  {-# LANGUAGE CPP #-}
  {-# LANGUAGE LambdaCase #-}
  
  module GHC.Builtin.PrimOps (
          PrimOp(..), PrimOpVecCat(..), allThePrimOps,
          primOpType, primOpSig, primOpResultType,
          primOpTag, maxPrimOpTag, primOpOcc,
          primOpWrapperId,
          pprPrimOp,
  
          tagToEnumKey,
  
          primOpOutOfLine, primOpCodeSize,
          primOpOkForSpeculation, primOpOkToDiscard,
          primOpIsWorkFree, primOpIsCheap, primOpFixity, primOpDocs, primOpDeprecations,
          primOpIsDiv, primOpIsReallyInline,
  
          PrimOpEffect(..), primOpEffect,
  
          getPrimOpResultInfo,  isComparisonPrimOp, PrimOpResultInfo(..),
  
          PrimCall(..)
      ) where
  
  import GHC.Prelude
  
  import GHC.Builtin.Types.Prim
  import GHC.Builtin.Types
  import GHC.Builtin.Uniques (mkPrimOpIdUnique, mkPrimOpWrapperUnique )
  import GHC.Builtin.Names ( gHC_PRIMOPWRAPPERS )
  
  import GHC.Core.TyCon    ( isPrimTyCon, isUnboxedTupleTyCon, PrimRep(..) )
  import GHC.Core.Type
  
  import GHC.Cmm.Type
  
  import GHC.Types.Demand
  import GHC.Types.Id
  import GHC.Types.Id.Info
  import GHC.Types.Name
  import GHC.Types.RepType ( tyConPrimRep )
  import GHC.Types.Basic
  import GHC.Types.Fixity  ( Fixity(..), FixityDirection(..) )
  import GHC.Types.SrcLoc  ( wiredInSrcSpan )
  import GHC.Types.ForeignCall ( CLabelString )
  import GHC.Types.Unique  ( Unique )
  
  import GHC.Unit.Types    ( Unit )
  
  import GHC.Utils.Binary
  import GHC.Utils.Outputable
  import GHC.Utils.Panic
  
  import GHC.Data.FastString
  import GHC.Data.SmallArray
  
  {-
  ************************************************************************
  *                                                                      *
  \subsection[PrimOp-datatype]{Datatype for @PrimOp@ (an enumeration)}
  *                                                                      *
  ************************************************************************
  
  These are in \tr{state-interface.verb} order.
  -}
  
  -- supplies:
  -- data PrimOp = ...
  #include "primop-data-decl.hs-incl"
  
  -- supplies
  -- primOpTag :: PrimOp -> Int
  #include "primop-tag.hs-incl"
  primOpTag _ = error "primOpTag: unknown primop"
  
  
  instance Eq PrimOp where
      op1 == op2 = primOpTag op1 == primOpTag op2
  
  instance Ord PrimOp where
      op1 <  op2 =  primOpTag op1 < primOpTag op2
      op1 <= op2 =  primOpTag op1 <= primOpTag op2
      op1 >= op2 =  primOpTag op1 >= primOpTag op2
      op1 >  op2 =  primOpTag op1 > primOpTag op2
      op1 `compare` op2 | op1 < op2  = LT
                        | op1 == op2 = EQ
                        | otherwise  = GT
  
  instance Outputable PrimOp where
      ppr op = pprPrimOp op
  
  data PrimOpVecCat = IntVec
                    | WordVec
                    | FloatVec
  
  -- An @Enum@-derived list would be better; meanwhile... (ToDo)
  
  allThePrimOps :: [PrimOp]
  allThePrimOps =
  #include "primop-list.hs-incl"
  
  tagToEnumKey :: Unique
  tagToEnumKey = mkPrimOpIdUnique (primOpTag TagToEnumOp)
  
  {-
  ************************************************************************
  *                                                                      *
  \subsection[PrimOp-info]{The essential info about each @PrimOp@}
  *                                                                      *
  ************************************************************************
  -}
  
  data PrimOpInfo
    = Compare     OccName         -- string :: T -> T -> Int#
                  Type
    | GenPrimOp   OccName         -- string :: \/a1..an . T1 -> .. -> Tk -> T
                  [TyVarBinder]
                  [Type]
                  Type
  
  mkCompare :: FastString -> Type -> PrimOpInfo
  mkCompare str ty = Compare (mkVarOccFS str) ty
  
  mkGenPrimOp :: FastString -> [TyVarBinder] -> [Type] -> Type -> PrimOpInfo
  mkGenPrimOp str tvs tys ty = GenPrimOp (mkVarOccFS str) tvs tys ty
  
  {-
  ************************************************************************
  *                                                                      *
  \subsubsection{Strictness}
  *                                                                      *
  ************************************************************************
  
  Not all primops are strict!
  -}
  
  primOpStrictness :: PrimOp -> Arity -> DmdSig
          -- See Demand.DmdSig for discussion of what the results
          -- The arity should be the arity of the primop; that's why
          -- this function isn't exported.
  #include "primop-strictness.hs-incl"
  
  {-
  ************************************************************************
  *                                                                      *
  \subsubsection{Fixity}
  *                                                                      *
  ************************************************************************
  -}
  
  primOpFixity :: PrimOp -> Maybe Fixity
  #include "primop-fixity.hs-incl"
  
  {-
  ************************************************************************
  *                                                                      *
  \subsubsection{Docs}
  *                                                                      *
  ************************************************************************
  
  See Note [GHC.Prim Docs] in GHC.Builtin.Utils
  -}
  
  primOpDocs :: [(FastString, String)]
  #include "primop-docs.hs-incl"
  
  primOpDeprecations :: [(OccName, FastString)]
  #include "primop-deprecations.hs-incl"
  
  {-
  ************************************************************************
  *                                                                      *
  \subsubsection[PrimOp-comparison]{PrimOpInfo basic comparison ops}
  *                                                                      *
  ************************************************************************
  
  @primOpInfo@ gives all essential information (from which everything
  else, notably a type, can be constructed) for each @PrimOp@.
  -}
  
  primOpInfo :: PrimOp -> PrimOpInfo
  #include "primop-primop-info.hs-incl"
  primOpInfo _ = error "primOpInfo: unknown primop"
  
  {-
  Here are a load of comments from the old primOp info:
  
  A @Word#@ is an unsigned @Int#@.
  
  @decodeFloat#@ is given w/ Integer-stuff (it's similar).
  
  @decodeDouble#@ is given w/ Integer-stuff (it's similar).
  
  Decoding of floating-point numbers is sorta Integer-related.  Encoding
  is done with plain ccalls now (see PrelNumExtra.hs).
  
  A @Weak@ Pointer is created by the @mkWeak#@ primitive:
  
          mkWeak# :: k -> v -> f -> State# RealWorld
                          -> (# State# RealWorld, Weak# v #)
  
  In practice, you'll use the higher-level
  
          data Weak v = Weak# v
          mkWeak :: k -> v -> IO () -> IO (Weak v)
  
  The following operation dereferences a weak pointer.  The weak pointer
  may have been finalized, so the operation returns a result code which
  must be inspected before looking at the dereferenced value.
  
          deRefWeak# :: Weak# v -> State# RealWorld ->
                          (# State# RealWorld, v, Int# #)
  
  Only look at v if the Int# returned is /= 0 !!
  
  The higher-level op is
  
          deRefWeak :: Weak v -> IO (Maybe v)
  
  Weak pointers can be finalized early by using the finalize# operation:
  
          finalizeWeak# :: Weak# v -> State# RealWorld ->
                             (# State# RealWorld, Int#, IO () #)
  
  The Int# returned is either
  
          0 if the weak pointer has already been finalized, or it has no
            finalizer (the third component is then invalid).
  
          1 if the weak pointer is still alive, with the finalizer returned
            as the third component.
  
  A {\em stable name/pointer} is an index into a table of stable name
  entries.  Since the garbage collector is told about stable pointers,
  it is safe to pass a stable pointer to external systems such as C
  routines.
  
  \begin{verbatim}
  makeStablePtr#  :: a -> State# RealWorld -> (# State# RealWorld, StablePtr# a #)
  freeStablePtr   :: StablePtr# a -> State# RealWorld -> State# RealWorld
  deRefStablePtr# :: StablePtr# a -> State# RealWorld -> (# State# RealWorld, a #)
  eqStablePtr#    :: StablePtr# a -> StablePtr# a -> Int#
  \end{verbatim}
  
  It may seem a bit surprising that @makeStablePtr#@ is a @IO@
  operation since it doesn't (directly) involve IO operations.  The
  reason is that if some optimisation pass decided to duplicate calls to
  @makeStablePtr#@ and we only pass one of the stable pointers over, a
  massive space leak can result.  Putting it into the IO monad
  prevents this.  (Another reason for putting them in a monad is to
  ensure correct sequencing wrt the side-effecting @freeStablePtr@
  operation.)
  
  An important property of stable pointers is that if you call
  makeStablePtr# twice on the same object you get the same stable
  pointer back.
  
  Note that we can implement @freeStablePtr#@ using @_ccall_@ (and,
  besides, it's not likely to be used from Haskell) so it's not a
  primop.
  
  Question: Why @RealWorld@ - won't any instance of @_ST@ do the job? [ADR]
  
  Stable Names
  ~~~~~~~~~~~~
  
  A stable name is like a stable pointer, but with three important differences:
  
          (a) You can't deRef one to get back to the original object.
          (b) You can convert one to an Int.
          (c) You don't need to 'freeStableName'
  
  The existence of a stable name doesn't guarantee to keep the object it
  points to alive (unlike a stable pointer), hence (a).
  
  Invariants:
  
          (a) makeStableName always returns the same value for a given
              object (same as stable pointers).
  
          (b) if two stable names are equal, it implies that the objects
              from which they were created were the same.
  
          (c) stableNameToInt always returns the same Int for a given
              stable name.
  
  
  These primops are pretty weird.
  
          tagToEnum# :: Int -> a    (result type must be an enumerated type)
  
  The constraints aren't currently checked by the front end, but the
  code generator will fall over if they aren't satisfied.
  
  ************************************************************************
  *                                                                      *
              Which PrimOps are out-of-line
  *                                                                      *
  ************************************************************************
  
  Some PrimOps need to be called out-of-line because they either need to
  perform a heap check or they block.
  -}
  
  primOpOutOfLine :: PrimOp -> Bool
  #include "primop-out-of-line.hs-incl"
  
  {-
  ************************************************************************
  *                                                                      *
              Failure and side effects
  *                                                                      *
  ************************************************************************
  
  
  Note [Exceptions: asynchronous, synchronous, and unchecked]
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  There are three very different sorts of things in GHC-Haskell that are
  sometimes called exceptions:
  
  * Haskell exceptions:
  
    These are ordinary exceptions that users can raise with the likes
    of 'throw' and handle with the likes of 'catch'.  They come in two
    very different flavors:
  
    * Asynchronous exceptions:
      * These can arise at nearly any time, and may have nothing to do
        with the code being executed.
      * The compiler itself mostly doesn't need to care about them.
      * Examples: a signal from another process, running out of heap or stack
      * Even pure code can receive asynchronous exceptions; in this
        case, executing the same code again may lead to different
        results, because the exception may not happen next time.
      * See rts/RaiseAsync.c for the gory details of how they work.
  
    * Synchronous exceptions:
      * These are produced by the code being executed, most commonly via
        a call to the `raise#` or `raiseIO#` primops.
      * At run-time, if a piece of pure code raises a synchronous
        exception, it will always raise the same synchronous exception
        if it is run again (and not interrupted by an asynchronous
        exception).
      * In particular, if an updatable thunk does some work and then
        raises a synchronous exception, it is safe to overwrite it with
        a thunk that /immediately/ raises the same exception.
      * Although we are careful not to discard synchronous exceptions, we
        are very liberal about re-ordering them with respect to most other
        operations.  See the paper "A semantics for imprecise exceptions"
        as well as Note [Precise exceptions and strictness analysis] in
        GHC.Types.Demand.
  
  * Unchecked exceptions:
  
    * These are nasty failures like seg-faults or primitive Int# division
      by zero.  They differ from Haskell exceptions in that they are
      un-recoverable and typically bring execution to an immediate halt.
    * We generally treat unchecked exceptions as undefined behavior, on
      the assumption that the programmer never intends to crash the
      program in this way.  Thus we have no qualms about replacing a
      division-by-zero with a recoverable Haskell exception or
      discarding an indexArray# operation whose result is unused.
  
  
  Note [Classifying primop effects]
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Each primop has an associated 'PrimOpEffect', based on what that
  primop can or cannot do at runtime.  This classification is
  
  * Recorded in the 'effect' field in primops.txt.pp, and
  * Exposed to the compiler via the 'primOpEffect' function in this module.
  
  See Note [Transformations affected by primop effects] for how we make
  use of this categorisation.
  
  The meanings of the four constructors of 'PrimOpEffect' are as
  follows, in decreasing order of permissiveness:
  
  * ReadWriteEffect
      A primop is marked ReadWriteEffect if it can
      - read or write to the world (I/O), or
      - read or write to a mutable data structure (e.g. readMutVar#).
  
      Every such primop uses State# tokens for sequencing, with a type like:
        Inputs -> State# s -> (# State# s, Outputs #)
      The state token threading expresses ordering, but duplicating even
      a read-only effect would defeat this.  (See "duplication" under
      Note [Transformations affected by primop effects] for details.)
  
      Note that operations like `indexArray#` that read *immutable*
      data structures do not need such special sequencing-related care,
      and are therefore not marked ReadWriteEffect.
  
  * ThrowsException
      A primop is marked ThrowsException if
      - it is not marked ReadWriteEffect, and
      - it may diverge or throw a synchronous Haskell exception
        even when used in a "correct" and well-specified way.
  
      See also Note [Exceptions: asynchronous, synchronous, and unchecked].
      Examples include raise#, raiseIO#, dataToTagLarge#, and seq#.
  
      Note that whether an exception is considered precise or imprecise
      does not matter for the purposes of the PrimOpEffect flag.
  
  * CanFail
      A primop is marked CanFail if
      - it is not marked ReadWriteEffect or ThrowsException, and
      - it can trigger a (potentially-unchecked) exception when used incorrectly.
  
      See Note [Exceptions: asynchronous, synchronous, and unchecked].
      Examples include quotWord# and indexIntArray#, which can fail with
      division-by-zero and a segfault respectively.
  
      A correct use of a CanFail primop is usually surrounded by a test
      that screens out the bad cases such as a zero divisor or an
      out-of-bounds array index.  We must take care never to move a
      CanFail primop outside the scope of such a test.
  
  * NoEffect
      A primop is marked NoEffect if it does not belong to any of the
      other three categories.  We can very aggressively shuffle these
      operations around without fear of changing a program's meaning.
  
      Perhaps surprisingly, this aggressive shuffling imposes another
      restriction: The tricky NoEffect primop uncheckedShiftLWord32# has
      an undefined result when the provided shift amount is not between
      0 and 31.  Thus, a call like `uncheckedShiftLWord32# x 95#` is
      obviously invalid.  But since uncheckedShiftLWord32# is marked
      NoEffect, we may float such an invalid call out of a dead branch
      and speculatively evaluate it.
  
      In particular, we cannot safely rewrite such an invalid call to a
      runtime error; we must emit code that produces a valid Word32#.
      (If we're lucky, Core Lint may complain that the result of such a
      rewrite violates the let-can-float invariant (#16742), but the
      rewrite is always wrong!)  See also Note [Guarding against silly shifts]
      in GHC.Core.Opt.ConstantFold.
  
      Marking uncheckedShiftLWord32# as CanFail instead of NoEffect
      would give us the freedom to rewrite such invalid calls to runtime
      errors, but would get in the way of optimization: When speculatively
      executing a bit-shift prevents the allocation of a thunk, that's a
      big win.
  
  
  Note [Transformations affected by primop effects]
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  The PrimOpEffect properties have the following effect on program
  transformations.  The summary table is followed by details.  See also
  Note [Classifying primop effects] for exactly what each column means.
  
                      NoEffect    CanFail    ThrowsException    ReadWriteEffect
  Discard                YES        YES            NO                 NO
  Defer (float in)       YES        YES           SAFE               SAFE
  Speculate (float out)  YES        NO             NO                 NO
  Duplicate              YES        YES            YES                NO
  
  (SAFE means we could perform the transformation but do not.)
  
  * Discarding:   case (a `op` b) of _ -> rhs  ===>   rhs
      You should not discard a ReadWriteEffect primop; e.g.
         case (writeIntArray# a i v s of (# _, _ #) -> True
      One could argue in favor of discarding this, since the returned
      State# token is not used.  But in practice unsafePerformIO can
      easily produce similar code, and programmers sometimes write this
      kind of stuff by hand (#9390).  So we (conservatively) never discard
      a ReadWriteEffect primop.
  
        Digression: We could try to track read-only effects separately
        from write effects to allow the former to be discarded.  But in
        fact we want a more general rewrite for read-only operations:
          case readOp# state# of (# newState#, _unused_result #) -> body
          ==> case state# of newState# -> body
        Such a rewrite is not yet implemented, but would have to be done
        in a different place anyway.
  
      Discarding a ThrowsException primop would also discard any exception
      it might have thrown.  For `raise#` or `raiseIO#` this would defeat
      the whole point of the primop, while for `dataToTagLarge#` or `seq#`
      this would make programs unexpectly lazier.
  
      However, it's fine to discard a CanFail primop.  For example
         case (indexIntArray# a i) of _ -> True
      We can discard indexIntArray# here; this came up in #5658.  Notice
      that CanFail primops like indexIntArray# can only trigger an
      exception when used incorrectly, i.e. a call that might not succeed
      is undefined behavior anyway.
  
  * Deferring (float-in):
      See Note [Floating primops] in GHC.Core.Opt.FloatIn.
  
      In the absence of data dependencies (including state token threading),
      we reserve the right to re-order the following things arbitrarily:
        * Side effects
        * Imprecise exceptions
        * Divergent computations (infinite loops)
      This lets us safely float almost any primop *inwards*, but not
      inside a (multi-shot) lambda.  (See "Duplication" below.)
  
      However, the main reason to float-in a primop application would be
      to discard it (by floating it into some but not all branches of a
      case), so we actually only float-in NoEffect and CanFail operations.
      See also Note [Floating primops] in GHC.Core.Opt.FloatIn.
  
      (This automatically side-steps the question of precise exceptions, which
      mustn't be re-ordered arbitrarily but need at least ThrowsException.)
  
  * Speculation (strict float-out):
      You must not float a CanFail primop *outwards* lest it escape the
      dynamic scope of a run-time validity test.  Example:
        case d ># 0# of
          True  -> case x /# d of r -> r +# 1
          False -> 0
      Here we must not float the case outwards to give
        case x/# d of r ->
        case d ># 0# of
          True  -> r +# 1
          False -> 0
      Otherwise, if this block is reached when d is zero, it will crash.
      Exactly the same reasoning applies to ThrowsException primops.
  
      Nor can you float out a ReadWriteEffect primop.  For example:
         if blah then case writeMutVar# v True s0 of (# s1 #) -> s1
                 else s0
      Notice that s0 is mentioned in both branches of the 'if', but
      only one of these two will actually be consumed.  But if we
      float out to
        case writeMutVar# v True s0 of (# s1 #) ->
        if blah then s1 else s0
      the writeMutVar will be performed in both branches, which is
      utterly wrong.
  
      What about a read-only operation that cannot fail, like
      readMutVar#?  In principle we could safely float these out.  But
      there are not very many such operations and it's not clear if
      there are real-world programs that would benefit from this.
  
  * Duplication:
      You cannot duplicate a ReadWriteEffect primop.  You might wonder
      how this can occur given the state token threading, but just look
      at Control.Monad.ST.Lazy.Imp.strictToLazy!  We get something like this
          p = case readMutVar# s v of
                (# s', r #) -> (State# s', r)
          s' = case p of (s', r) -> s'
          r  = case p of (s', r) -> r
  
      (All these bindings are boxed.)  If we inline p at its two call
      sites, we get a catastrophe: because the read is performed once when
      s' is demanded, and once when 'r' is demanded, which may be much
      later.  Utterly wrong.  #3207 is real example of this happening.
      Floating p into a multi-shot lambda would be wrong for the same reason.
  
      However, it's fine to duplicate a CanFail or ThrowsException primop.
  
  
  
  Note [Implementation: how PrimOpEffect affects transformations]
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  How do we ensure that floating/duplication/discarding are done right
  in the simplifier?
  
  Several predicates on primops test this flag:
    primOpOkToDiscard      <=> effect < ThrowsException
    primOpOkForSpeculation <=> effect == NoEffect && not (out_of_line)
    primOpIsCheap          <=> cheap  -- ...defaults to primOpOkForSpeculation
      [[But note that the raise# family and seq# are also considered cheap in
        GHC.Core.Utils.exprIsCheap by way of being work-free]]
  
    * The discarding mentioned above happens in
      GHC.Core.Opt.Simplify.Iteration, specifically in rebuildCase,
      where it is guarded by exprOkToDiscard, which in turn checks
      primOpOkToDiscard.
  
    * The "no-float-out" thing is achieved by ensuring that we never
      let-bind a saturated primop application unless it has NoEffect.
      The RHS of a let-binding (which can float in and out freely)
      satisfies exprOkForSpeculation; this is the let-can-float
      invariant.  And exprOkForSpeculation is false of a saturated
      primop application unless it has NoEffect.
  
    * So primops that aren't NoEffect will appear only as the
      scrutinees of cases, and that's why the FloatIn pass is capable
      of floating case bindings inwards.
  
    * Duplication via inlining and float-in of (lifted) let-binders is
      controlled via primOpIsWorkFree and primOpIsCheap, by making
      ReadWriteEffect things (among others) not-cheap!  (The test
      PrimOpEffect_Sanity will complain if any ReadWriteEffect primop
      is considered either work-free or cheap.)  Additionally, a
      case binding is only floated inwards if its scrutinee is ok-to-discard.
  -}
  
  primOpEffect :: PrimOp -> PrimOpEffect
  #include "primop-effects.hs-incl"
  
  data PrimOpEffect
    -- See Note [Classifying primop effects]
    = NoEffect
    | CanFail
    | ThrowsException
    | ReadWriteEffect
    deriving (Eq, Ord)
  
  primOpOkForSpeculation :: PrimOp -> Bool
    -- See Note [Classifying primop effects]
    -- See comments with GHC.Core.Utils.exprOkForSpeculation
    -- primOpOkForSpeculation => primOpOkToDiscard
  primOpOkForSpeculation op
    = primOpEffect op == NoEffect && not (primOpOutOfLine op)
      -- I think the "out of line" test is because out of line things can
      -- be expensive (eg sine, cosine), and so we may not want to speculate them
  
  primOpOkToDiscard :: PrimOp -> Bool
  primOpOkToDiscard op
    = primOpEffect op < ThrowsException
  
  primOpIsWorkFree :: PrimOp -> Bool
  #include "primop-is-work-free.hs-incl"
  
  primOpIsCheap :: PrimOp -> Bool
  -- See Note [Classifying primop effects]
  #include "primop-is-cheap.hs-incl"
  -- In March 2001, we changed this to
  --      primOpIsCheap op = False
  -- thereby making *no* primops seem cheap.  But this killed eta
  -- expansion on case (x ==# y) of True -> \s -> ...
  -- which is bad.  In particular a loop like
  --      doLoop n = loop 0
  --     where
  --         loop i | i == n    = return ()
  --                | otherwise = bar i >> loop (i+1)
  -- allocated a closure every time round because it doesn't eta expand.
  --
  -- The problem that originally gave rise to the change was
  --      let x = a +# b *# c in x +# x
  -- were we don't want to inline x. But primopIsCheap doesn't control
  -- that (it's primOpIsWorkFree that does) so the problem doesn't occur
  -- even if primOpIsCheap sometimes says 'True'.
  
  
  -- | True of dyadic operators that can fail only if the second arg is zero!
  --
  -- This function probably belongs in an automagically generated file.. but it's
  -- such a special case I thought I'd leave it here for now.
  primOpIsDiv :: PrimOp -> Bool
  primOpIsDiv op = case op of
  
    IntQuotOp       -> True
    Int8QuotOp      -> True
    Int16QuotOp     -> True
    Int32QuotOp     -> True
    Int64QuotOp     -> True
  
    IntRemOp        -> True
    Int8RemOp       -> True
    Int16RemOp      -> True
    Int32RemOp      -> True
    Int64RemOp      -> True
  
    IntQuotRemOp    -> True
    Int8QuotRemOp   -> True
    Int16QuotRemOp  -> True
    Int32QuotRemOp  -> True
    -- Int64QuotRemOp doesn't exist (yet)
  
    WordQuotOp      -> True
    Word8QuotOp     -> True
    Word16QuotOp    -> True
    Word32QuotOp    -> True
    Word64QuotOp    -> True
  
    WordRemOp       -> True
    Word8RemOp      -> True
    Word16RemOp     -> True
    Word32RemOp     -> True
    Word64RemOp     -> True
  
    WordQuotRemOp   -> True
    Word8QuotRemOp  -> True
    Word16QuotRemOp -> True
    Word32QuotRemOp -> True
    -- Word64QuotRemOp doesn't exist (yet)
  
    WordQuotRem2Op  -> True
  
    FloatDivOp      -> True
    DoubleDivOp     -> True
    _               -> False
  
  
  
  {-
  ************************************************************************
  *                                                                      *
                 PrimOp code size
  *                                                                      *
  ************************************************************************
  
  primOpCodeSize
  ~~~~~~~~~~~~~~
  Gives an indication of the code size of a primop, for the purposes of
  calculating unfolding sizes; see GHC.Core.Unfold.sizeExpr.
  -}
  
  primOpCodeSize :: PrimOp -> Int
  #include "primop-code-size.hs-incl"
  
  primOpCodeSizeDefault :: Int
  primOpCodeSizeDefault = 1
    -- GHC.Core.Unfold.primOpSize already takes into account primOpOutOfLine
    -- and adds some further costs for the args in that case.
  
  primOpCodeSizeForeignCall :: Int
  primOpCodeSizeForeignCall = 4
  
  {-
  ************************************************************************
  *                                                                      *
                 PrimOp types
  *                                                                      *
  ************************************************************************
  -}
  
  primOpType :: PrimOp -> Type  -- you may want to use primOpSig instead
  primOpType op
    = case primOpInfo op of
      Compare _occ ty -> compare_fun_ty ty
  
      GenPrimOp _occ tyvars arg_tys res_ty ->
          mkForAllTys tyvars (mkVisFunTysMany arg_tys res_ty)
  
  primOpResultType :: PrimOp -> Type
  primOpResultType op
    = case primOpInfo op of
      Compare _occ _ty -> intPrimTy
      GenPrimOp _occ _tyvars _arg_tys res_ty -> res_ty
  
  primOpOcc :: PrimOp -> OccName
  primOpOcc op = case primOpInfo op of
                 Compare   occ _     -> occ
                 GenPrimOp occ _ _ _ -> occ
  
  {- Note [Primop wrappers]
  ~~~~~~~~~~~~~~~~~~~~~~~~~
  
  To support (limited) use of primops in GHCi genprimopcode generates the
  GHC.PrimopWrappers module. This module contains a "primop wrapper"
  binding for each primop. These are standard Haskell functions mirroring the
  types of the primops they wrap. For instance, in the case of plusInt# we would
  have:
  
      module GHC.PrimopWrappers where
      import GHC.Prim as P
  
      plusInt# :: Int# -> Int# -> Int#
      plusInt# a b = P.plusInt# a b
  
  The Id for the wrapper of a primop can be found using
  'GHC.Builtin.PrimOps.primOpWrapperId'. However, GHCi does not use this mechanism
  to link primops; it rather does a rather hacky symbol lookup (see
  GHC.ByteCode.Linker.primopToCLabel). TODO: Perhaps this should be changed?
  
  Note that these wrappers aren't *quite* as expressive as their unwrapped
  brethren, in that they may exhibit less representation polymorphism.
  For instance, consider the case of mkWeakNoFinalizer#, which has type:
  
      mkWeakNoFinalizer# :: forall (r :: RuntimeRep) (k :: TYPE r) (v :: Type).
                            k -> v
                         -> State# RealWorld
                         -> (# State# RealWorld, Weak# v #)
  
  Naively we could generate a wrapper of the form,
  
  
      mkWeakNoFinalizer# k v s = GHC.Prim.mkWeakNoFinalizer# k v s
  
  However, this would require that 'k' bind the representation-polymorphic key,
  which is disallowed by our representation polymorphism validity checks
  (see Note [Representation polymorphism invariants] in GHC.Core).
  Consequently, we give the wrapper the simpler, less polymorphic type
  
      mkWeakNoFinalizer# :: forall (k :: Type) (v :: Type).
                            k -> v
                         -> State# RealWorld
                         -> (# State# RealWorld, Weak# v #)
  
  This simplification tends to be good enough for GHCi uses given that there are
  few representation-polymorphic primops, and we do little simplification
  on interpreted code anyways.
  
  TODO: This behavior is actually wrong; a program becomes ill-typed upon
  replacing a real primop occurrence with one of its wrapper due to the fact that
  the former has an additional type binder. Hmmm....
  
  Note [Eta expanding primops]
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  STG requires that primop applications be saturated. This makes code generation
  significantly simpler since otherwise we would need to define a calling
  convention for curried applications that can accommodate representation
  polymorphism.
  
  To ensure saturation, CorePrep eta expands all primop applications as
  described in Note [Eta expansion of hasNoBinding things in CorePrep] in
  GHC.Core.Prep.
  
  Historical Note:
  
  For a short period around GHC 8.8 we rewrote unsaturated primop applications to
  rather use the primop's wrapper (see Note [Primop wrappers] in
  GHC.Builtin.PrimOps) instead of eta expansion. This was because at the time
  CoreTidy would try to predict the CAFfyness of bindings that would be produced
  by CorePrep for inclusion in interface files. Eta expanding during CorePrep
  proved to be very difficult to predict, leading to nasty inconsistencies in
  CAFfyness determinations (see #16846).
  
  Thankfully, we now no longer try to predict CAFfyness but rather compute it on
  GHC STG (see Note [SRTs] in GHC.Cmm.Info.Build) and inject it into the interface
  file after code generation (see TODO: Refer to whatever falls out of #18096).
  This is much simpler and avoids the potential for inconsistency, allowing us to
  return to the somewhat simpler eta expansion approach for unsaturated primops.
  
  See #18079.
  -}
  
  -- | Returns the 'Id' of the wrapper associated with the given 'PrimOp'.
  -- See Note [Primop wrappers].
  primOpWrapperId :: PrimOp -> Id
  primOpWrapperId op = mkVanillaGlobalWithInfo name ty info
    where
      info = setCafInfo vanillaIdInfo NoCafRefs
      name = mkExternalName uniq gHC_PRIMOPWRAPPERS (primOpOcc op) wiredInSrcSpan
      uniq = mkPrimOpWrapperUnique (primOpTag op)
      ty   = primOpType op
  
  isComparisonPrimOp :: PrimOp -> Bool
  isComparisonPrimOp op = case primOpInfo op of
                            Compare {}   -> True
                            GenPrimOp {} -> False
  
  -- primOpSig is like primOpType but gives the result split apart:
  -- (type variables, argument types, result type)
  -- It also gives arity, strictness info
  
  primOpSig :: PrimOp -> ([TyVarBinder], [Type], Type, Arity, DmdSig)
  primOpSig op
    = (tyvars, arg_tys, res_ty, arity, primOpStrictness op arity)
    where
      arity = length arg_tys
      (tyvars, arg_tys, res_ty)
        = case (primOpInfo op) of
          Compare   _occ ty                    -> ([],     [ty,ty], intPrimTy)
          GenPrimOp _occ tyvars arg_tys res_ty -> (tyvars, arg_tys, res_ty   )
  
  data PrimOpResultInfo
    = ReturnsVoid
    | ReturnsPrim     PrimRep
    | ReturnsTuple
  
  -- Some PrimOps need not return a manifest primitive or algebraic value
  -- (i.e. they might return a polymorphic value).  These PrimOps *must*
  -- be out of line, or the code generator won't work.
  
  getPrimOpResultInfo :: PrimOp -> PrimOpResultInfo
  getPrimOpResultInfo op
    = case (primOpInfo op) of
        Compare _ _                         -> ReturnsPrim IntRep
        GenPrimOp _ _ _ ty | isPrimTyCon tc -> case tyConPrimRep tc of
                                                 [] -> ReturnsVoid
                                                 [rep] -> ReturnsPrim rep
                                                 _ -> pprPanic "getPrimOpResultInfo" (ppr op)
                           | isUnboxedTupleTyCon tc -> ReturnsTuple
                           | otherwise      -> pprPanic "getPrimOpResultInfo" (ppr op)
                           where
                             tc = tyConAppTyCon ty
                          -- All primops return a tycon-app result
                          -- The tycon can be an unboxed tuple or sum, though,
                          -- which gives rise to a ReturnAlg
  
  {-
  We do not currently make use of whether primops are commutable.
  
  We used to try to move constants to the right hand side for strength
  reduction.
  -}
  
  {-
  commutableOp :: PrimOp -> Bool
  #include "primop-commutable.hs-incl"
  -}
  
  -- Utils:
  
  compare_fun_ty :: Type -> Type
  compare_fun_ty ty = mkVisFunTysMany [ty, ty] intPrimTy
  
  -- Output stuff:
  
  pprPrimOp  :: IsLine doc => PrimOp -> doc
  pprPrimOp other_op = pprOccName (primOpOcc other_op)
  {-# SPECIALIZE pprPrimOp :: PrimOp -> SDoc #-}
  {-# SPECIALIZE pprPrimOp :: PrimOp -> HLine #-} -- see Note [SPECIALIZE to HDoc] in GHC.Utils.Outputable
  
  {-
  ************************************************************************
  *                                                                      *
  \subsubsection[PrimCall]{User-imported primitive calls}
  *                                                                      *
  ************************************************************************
  -}
  
  data PrimCall = PrimCall CLabelString Unit
  
  instance Outputable PrimCall where
    ppr (PrimCall lbl pkgId)
          = text "__primcall" <+> ppr pkgId <+> ppr lbl
  
  -- | Indicate if a primop is really inline: that is, it isn't out-of-line and it
  -- isn't DataToTagOp which are two primops that evaluate their argument
  -- hence induce thread/stack/heap changes.
  primOpIsReallyInline :: PrimOp -> Bool
  primOpIsReallyInline = \case
    DataToTagSmallOp -> False
    DataToTagLargeOp -> False
    p                -> not (primOpOutOfLine p)
  
  instance Binary PrimOp where
    get bh = (allThePrimOpsArr `indexSmallArray`) <$> get bh
  
    put_ bh = put_ bh . primOpTag
  
  allThePrimOpsArr :: SmallArray PrimOp
  {-# NOINLINE allThePrimOpsArr #-}
  allThePrimOpsArr = listToArray (maxPrimOpTag + 1) primOpTag id allThePrimOps
  