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Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC

Commits:

03555ed8

by Sylvain Henry at 2025-08-10T22:20:57-04:00

Handle non-fractional CmmFloats in Cmm's CBE (#26229)

Since f8d9d016305be355f518c141f6c6d4826f2de9a2, toRational for Float and
Double converts float's infinity and NaN into Rational's infinity and
NaN (respectively 1%0 and 0%0).

Cmm CommonBlockEliminator hashing function needs to take these values
into account as they can appear as literals now. See added testcase.

3 changed files:

compiler/GHC/Cmm/CommonBlockElim.hs
+ testsuite/tests/numeric/should_compile/T26229.hs
testsuite/tests/numeric/should_compile/all.T

Changes:

compiler/GHC/Cmm/CommonBlockElim.hs

@@ -29,6 +29,7 @@ import GHC.Utils.Word64 (truncateWord64ToWord32)
  import Control.Arrow (first, second)
  import Data.List.NonEmpty (NonEmpty (..))
  import qualified Data.List.NonEmpty as NE
 +import GHC.Real (infinity,notANumber)
  -- -----------------------------------------------------------------------------
  -- Eliminate common blocks
@@ -167,7 +168,12 @@ hash_block block =
          hash_lit :: CmmLit -> Word32
          hash_lit (CmmInt i _) = fromInteger i
 -        hash_lit (CmmFloat r _) = truncate r
 +        hash_lit (CmmFloat r _)
 +          -- handle these special cases as `truncate` fails on non-fractional numbers (#26229)
 +          | r == infinity   = 9999999
 +          | r == -infinity  = 9999998
 +          | r == notANumber = 6666666
 +          | otherwise       = truncate r
          hash_lit (CmmVec ls) = hash_list hash_lit ls
          hash_lit (CmmLabel _) = 119 -- ugh
          hash_lit (CmmLabelOff _ i) = cvt $ 199 + i

testsuite/tests/numeric/should_compile/T26229.hs

 +{-# LANGUAGE NegativeLiterals #-}
++
 +module T26229 where
++
 +sqrte2pqiq :: (Floating a, Ord a) => a -> a -> a
 +sqrte2pqiq e qiq -- = sqrt (e*e + qiq)
 +  | e < - 1.5097698010472593e153 = -(qiq/e) - e
 +  | e < 5.582399551122541e57     = sqrt (e*e + qiq) -- test Infinity#
 +  | e < -5.582399551122541e57    = -sqrt (e*e + qiq) -- test -Infinity#
 +  | otherwise                    = (qiq/e) + e
 +{-# SPECIALIZE sqrte2pqiq :: Double -> Double -> Double #-}
 +{-# SPECIALIZE sqrte2pqiq :: Float -> Float -> Float #-}

testsuite/tests/numeric/should_compile/all.T

@@ -22,3 +22,4 @@ test('T15547', normal, compile, ['-ddump-simpl -O -dsuppress-all -dno-typeable-b
  test('T23019', normal, compile, ['-O'])
  test('T23907', [ when(wordsize(32), expect_broken(23908))], compile, ['-ddump-simpl -O2 -dsuppress-all -dno-typeable-binds -dsuppress-uniques'])
  test('T24331', normal, compile, ['-O -ddump-simpl -dsuppress-all -dsuppress-uniques -dno-typeable-binds'])
 +test('T26229', normal, compile, ['-O2'])