From d781517f7a6f2db7d7a009f96376378d050c02ab Mon Sep 17 00:00:00 2001
From: panne <unknown>
Date: Sun, 2 Jul 2000 18:50:24 +0000
Subject: [PATCH] [project @ 2000-07-02 18:50:24 by panne] Don't warn the user
about integer overflow during constant folding anymore. It's not done at
runtime either, and compilation of completely harmless things like
((124076834 :: Word32) + (2147483647 :: Word32))
yielded a warning.
---
ghc/compiler/prelude/PrelRules.lhs | 43 +++++++++---------------------
1 file changed, 12 insertions(+), 31 deletions(-)
diff --git a/ghc/compiler/prelude/PrelRules.lhs b/ghc/compiler/prelude/PrelRules.lhs
index bdf3627bcb0c..4e502568d178 100644
--- a/ghc/compiler/prelude/PrelRules.lhs
+++ b/ghc/compiler/prelude/PrelRules.lhs
@@ -15,8 +15,7 @@ module PrelRules ( primOpRule, builtinRules ) where
import CoreSyn
import Rules ( ProtoCoreRule(..) )
import Id ( idUnfolding, mkWildId, isDataConId_maybe )
-import Literal ( Literal(..), isLitLitLit, mkMachInt, mkMachWord
- , inIntRange, inWordRange, literalType
+import Literal ( Literal(..), isLitLitLit, mkMachInt, mkMachWord, literalType
, word2IntLit, int2WordLit, char2IntLit, int2CharLit
, float2IntLit, int2FloatLit, double2IntLit, int2DoubleLit
, addr2IntLit, int2AddrLit, float2DoubleLit, double2FloatLit
@@ -197,12 +196,12 @@ cmpOp cmp name l1 l2
negOp name (MachFloat f) = Just (name, mkFloatVal (-f))
negOp name (MachDouble d) = Just (name, mkDoubleVal (-d))
-negOp name l@(MachInt i) = intResult name (ppr l) (-i)
+negOp name l@(MachInt i) = intResult name (-i)
negOp name l = Nothing
--------------------------
intOp2 op name l1@(MachInt i1) l2@(MachInt i2)
- = intResult name (ppr l1 <+> ppr l2) (i1 `op` i2)
+ = intResult name (i1 `op` i2)
intOp2 op name l1 l2 = Nothing -- Could find LitLit
intOp2Z op name (MachInt i1) (MachInt i2)
@@ -212,8 +211,7 @@ intOp2Z op name l1 l2 = Nothing -- LitLit or zero dividend
--------------------------
-- Integer is not an instance of Bits, so we operate on Word64
wordBitOp2 op name l1@(MachWord w1) l2@(MachWord w2)
- = wordResult name (ppr l1 <+> ppr l2)
- ((fromIntegral::Word64->Integer) (fromIntegral w1 `op` fromIntegral w2))
+ = Just (name, mkWordVal ((fromIntegral::Word64->Integer) (fromIntegral w1 `op` fromIntegral w2)))
wordBitOp2 op name l1 l2 = Nothing -- Could find LitLit
wordOp2Z op name (MachWord w1) (MachWord w2)
@@ -276,31 +274,14 @@ do_lit_eq is_eq name lit expr
val_if_neq | is_eq = falseVal
| otherwise = trueVal
--- TODO: Merge intResult/wordResult
-intResult name pp_args result
- | not (inIntRange result)
- -- Better tell the user that we've overflowed...
- -- ..not that it stops us from actually folding!
-
- = pprTrace "Warning:" (text "Integer overflow in:" <+> ppr name <+> pp_args)
- Just (name, mkIntVal (squashInt result))
-
- | otherwise
- = Just (name, mkIntVal result)
-
-wordResult name pp_args result
- | not (inWordRange result)
- -- Better tell the user that we've overflowed...
- -- ..not that it stops us from actually folding!
-
- = pprTrace "Warning:" (text "Word overflow in:" <+> ppr name <+> pp_args)
- Just (name, mkWordVal (squashInt result))
-
- | otherwise
- = Just (name, mkWordVal result)
-
-squashInt :: Integer -> Integer -- Squash into Int range
-squashInt i = toInteger ((fromInteger i)::Int)
+-- Note that we *don't* warn the user about overflow. It's not done at
+-- runtime either, and compilation of completely harmless things like
+-- ((124076834 :: Word32) + (2147483647 :: Word32))
+-- would yield a warning. Instead we simply squash the value into the
+-- Int range, but not in a way suitable for cross-compiling... :-(
+intResult :: RuleName -> Integer -> Maybe (RuleName, CoreExpr)
+intResult name result
+ = Just (name, mkIntVal (toInteger ((fromInteger result)::Int)))
\end{code}
--
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