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Sylvain Henry authored
Until now GHC only supported basic constant folding (lit op lit, expr op 0, etc.). This patch uses laws of +/-/* (associativity, commutativity, distributivity) to support some constant folding into nested expressions. Examples of new transformations: - simple nesting: (10 + x) + 10 becomes 20 + x - deep nesting: 5 + x + (y + (z + (t + 5))) becomes 10 + (x + (y + (z + t))) - distribution: (5 + x) * 6 becomes 30 + 6*x - simple factorization: 5 + x + (x + (x + (x + 5))) becomes 10 + (4 *x) - siblings: (5 + 4*x) - (3*x + 2) becomes 3 + x Test Plan: validate Reviewers: simonpj, austin, bgamari Reviewed By: bgamari Subscribers: thomie GHC Trac Issues: #9136 Differential Revision: https://phabricator.haskell.org/D2858
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