#15488: GHC takes up huge amount of memory when compiling accelerate 1.2.0 -------------------------------------+------------------------------------- Reporter: noah | Owner: tdammers Type: bug | Status: new Priority: high | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Resolution: | Keywords: | accelerate,memory,compile Operating System: Linux | Architecture: x86_64 | (amd64) Type of failure: Compile-time | Test Case: accelerate performance bug | 1.2.0 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by tdammers): Looks like the simplifier blows up core size (compiling `Data.Array.Accelerate.Analysis.Hash`): {{{ Result size of Desugar (after optimization) = {terms: 3,048, ... }}} This is what we get before the simplifier kicks in - perfectly normal. And then the first round of simplification happens: {{{ Result size of Specialise = {terms: 6,666, types: 10,365, coercions: 1,218, joins: 0/5} -- OverSatApps = False}) = {terms: 10,863, types: 14,960, coercions: 1,218, joins: 0/5} -- Result size of Simplifier iteration=1 = {terms: 137,878, -- Result size of Simplifier iteration=2 = {terms: 66,407, types: 72,375, coercions: 25,148, joins: 0/991} Result size of Simplifier = {terms: 66,295, types: 72,319, coercions: 25,148, joins: 0/991} }}} ...increasing core size by a factor of 20 (peaking at 40). And the next round is even worse: {{{ Result size of Simplifier iteration=1 = {terms: 465,354, -- Result size of Simplifier iteration=2 = {terms: 259,229, -- Result size of Simplifier iteration=3 = {terms: 469,826, -- Result size of Simplifier iteration=4 = {terms: 345,027, -- Result size of Simplifier = {terms: 345,027, }}} Our perfectly reasonable 3000-something terms now blow up to over 300k. Now on to figuring out *why* it blows up. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15488#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler