Make sized division primops ok-for-spec (#19026)

2 files changed, 47 insertions, 14 deletions

diff --git a/compiler/GHC/Builtin/PrimOps.hs b/compiler/GHC/Builtin/PrimOps.hs
index 58d0c9e76b..2f89ba448b 100644
--- a/compiler/GHC/Builtin/PrimOps.hs
+++ b/compiler/GHC/Builtin/PrimOps.hs
@@ -17,6 +17,7 @@ module GHC.Builtin.PrimOps (
         primOpOutOfLine, primOpCodeSize,
         primOpOkForSpeculation, primOpOkForSideEffects,
         primOpIsCheap, primOpFixity, primOpDocs,
+        primOpIsDiv,
 
         getPrimOpResultInfo,  isComparisonPrimOp, PrimOpResultInfo(..),
 
@@ -525,6 +526,51 @@ primOpIsCheap op = primOpOkForSpeculation op
 -- that (it's exprIsDupable 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
+
+  -- TODO: quotRemWord2, Int64, Word64
+  IntQuotOp       -> True
+  Int8QuotOp      -> True
+  Int16QuotOp     -> True
+  Int32QuotOp     -> True
+
+  IntRemOp        -> True
+  Int8RemOp       -> True
+  Int16RemOp      -> True
+  Int32RemOp      -> True
+
+  IntQuotRemOp    -> True
+  Int8QuotRemOp   -> True
+  Int16QuotRemOp  -> True
+  Int32QuotRemOp  -> True
+
+  WordQuotOp      -> True
+  Word8QuotOp     -> True
+  Word16QuotOp    -> True
+  Word32QuotOp    -> True
+
+  WordRemOp       -> True
+  Word8RemOp      -> True
+  Word16RemOp     -> True
+  Word32RemOp     -> True
+
+  WordQuotRemOp   -> True
+  Word8QuotRemOp  -> True
+  Word16QuotRemOp -> True
+  Word32QuotRemOp -> True
+
+  FloatDivOp      -> True
+  DoubleDivOp     -> True
+  _               -> False
+
+
+
 {-
 ************************************************************************
 *                                                                      *
diff --git a/compiler/GHC/Core/Utils.hs b/compiler/GHC/Core/Utils.hs
index cee7d4f68b..01b35f4b1f 100644
--- a/compiler/GHC/Core/Utils.hs
+++ b/compiler/GHC/Core/Utils.hs
@@ -1633,7 +1633,7 @@ app_ok primop_ok fun args
                 -- to take the arguments into account
 
       PrimOpId op
-        | isDivOp op
+        | primOpIsDiv op
         , [arg1, Lit lit] <- args
         -> not (isZeroLit lit) && expr_ok primop_ok arg1
               -- Special case for dividing operations that fail
@@ -1686,19 +1686,6 @@ altsAreExhaustive (Alt con1 _ _ : alts)
       -- we behave conservatively here -- I don't think it's important
       -- enough to deserve special treatment
 
--- | True of dyadic operators that can fail only if the second arg is zero!
-isDivOp :: PrimOp -> Bool
--- This function probably belongs in GHC.Builtin.PrimOps, or even in
--- an automagically generated file.. but it's such a
--- special case I thought I'd leave it here for now.
-isDivOp IntQuotOp        = True
-isDivOp IntRemOp         = True
-isDivOp WordQuotOp       = True
-isDivOp WordRemOp        = True
-isDivOp FloatDivOp       = True
-isDivOp DoubleDivOp      = True
-isDivOp _                = False
-
 {- Note [exprOkForSpeculation: case expressions]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 exprOkForSpeculation accepts very special case expressions.