[GHC] #10421: exponential blowup in inlining (without INLINE pragmas)
#10421: exponential blowup in inlining (without INLINE pragmas) -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- The test case for #10397 also demonstrates an exponential blowup by the inliner, without any INLINE pragmas. I added another four fields to the `Register` type, and I get these final Core program sizes. (The variation in sizes between versions is not really important, the point is just that they are very large for all versions.) {{{ ghc-7.6.3: *** CorePrep: Result size of CorePrep = {terms: 1,702,684, types: 1,950,647, coercions: 103} ghc-7.8.4: *** CorePrep: Result size of CorePrep = {terms: 1,964,183, types: 1,950,620, coercions: 97} ghc-7.10.1: *** CorePrep: Result size of CorePrep = {terms: 1,964,212, types: 1,950,764, coercions: 97} ghc-7.11: *** CorePrep: Result size of CorePrep = {terms: 1,964,212, types: 1,950,764, coercions: 97} }}} Ideally GHC should not produce enormous Core programs on its own like this. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10421 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10421: exponential blowup in inlining (without INLINE pragmas) -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Inlining Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by mpickering): * keywords: => Inlining -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10421#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10421: exponential blowup in inlining (without INLINE pragmas) -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Inlining Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by phadej): * Attachment "RegBigger2.hs" added. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10421 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10421: exponential blowup in inlining (without INLINE pragmas) -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Inlining Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by phadej): The code in RegBigger looks like Yesod code in trac:13253, but here we run in `IO`, not `MForm = RWST`. I checked all yesod-forms, back to http://hackage.haskell.org/package/yesod-form-0.2.0.1 released in *2011*, the `MForm` is `RWST` all the way down. I'd close this ticket (there is trac:13253), as there is no way to reproduce using `RegBigger.hs`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10421#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10421: exponential blowup in inlining (without INLINE pragmas) -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Inlining Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by rwbarton): I'd rather try to reconstruct the minimization that was used here, since it apparently didn't involve either transformers or INLINE pragmas. I asked the reporter of #10397 for the original test case, but no response yet. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10421#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10421: exponential blowup in inlining (without INLINE pragmas) -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Inlining Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by TobyGoodwin): * Attachment "ghc10397.tar" added. here is the missing reproducer -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10421 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10421: exponential blowup in inlining (without INLINE pragmas) -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Inlining Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): Thank you! Looking at the code, it looks just like #13253. Clearly something is wrong here. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10421#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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