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  • Glasgow Haskell CompilerGlasgow Haskell Compiler
  • GHCGHC
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  • #9136
Closed
Open
Issue created May 23, 2014 by Simon Peyton Jones@simonpjDeveloper

Constant folding in Core could be better

Constant folding in Core is still a bit feeble. For example, when staring at the code for nofib/shootout/k-nucleotide I saw this expression:

 (x +# 8) -# 1

which would be relatively easy to optimise.

The difficulty is knowing where to stop. What about (8 +# x) -# 1?

Anyway, this ticket is to record the issue. Currently constant folding is done by the built-in RULES in compiler/prelude/PrelRules.

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Version 7.8.2
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler
Test case
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