Commit 12191a99 authored by Sylvain Henry's avatar Sylvain Henry Committed by Marge Bot

Bignum: match on small Integer/Natural

Previously we only matched on *variables* whose unfoldings were a ConApp
of the form `IS lit#` or `NS lit##`. But we forgot to match on the
ConApp directly... As a consequence, constant folding only worked after
the FloatOut pass which creates bindings for most sub-expressions. With
this patch, matching on bignums works even with -O0 (see bignumMatch
test).
parent e691a5a0
......@@ -1279,13 +1279,24 @@ exprIsLiteral_maybe env@(_, id_unf) e
-> Just l
Var v
| Just rhs <- expandUnfolding_maybe (id_unf v)
, Just (_env,_fb,dc,_tys,[arg]) <- exprIsConApp_maybe env rhs
, Just b <- matchBignum env rhs
-> Just b
e
| Just b <- matchBignum env e
-> Just b
| otherwise
-> Nothing
where
matchBignum env e
| Just (_env,_fb,dc,_tys,[arg]) <- exprIsConApp_maybe env e
, Just (LitNumber _ i) <- exprIsLiteral_maybe env arg
-> if
= if
| dc == naturalNSDataCon -> Just (mkLitNatural i)
| dc == integerISDataCon -> Just (mkLitInteger i)
| otherwise -> Nothing
_ -> Nothing
| otherwise
= Nothing
{-
Note [exprIsLambda_maybe]
......
......@@ -10,6 +10,7 @@ test('gcdeInteger', normal, compile_and_run, [''])
test('integerPowMod', [], compile_and_run, [''])
test('integerGcdExt', [], compile_and_run, [''])
test('integerRecipMod', [], compile_and_run, [''])
test('bignumMatch', [], compile, [''])
# skip ghci as it doesn't support unboxed tuples
test('integerImportExport', [omit_ways(['ghci'])], compile_and_run, [''])
......
{-# LANGUAGE MagicHash #-}
{-# OPTIONS_GHC -ddump-rule-firings -O0 -v0 #-}
module Test where
import GHC.Num.Integer
foo :: Integer
foo = IS 45# `integerAdd` (IS 0# `integerMul` IS 18#)
Rule fired: integerMul (BUILTIN)
Rule fired: integerAdd (BUILTIN)
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