[commit: ghc] ghc-8.0: Reduce default for -fmax-pmcheck-iterations from 1e7 to 2e6 (f96ef25)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : ghc-8.0
Link       : http://ghc.haskell.org/trac/ghc/changeset/f96ef2540d86797802fd699f3267c6aeb07a2e71/ghc

>---------------------------------------------------------------

commit f96ef2540d86797802fd699f3267c6aeb07a2e71
Author: Herbert Valerio Riedel <hvr at gnu.org>
Date:   Sun Apr 10 19:13:16 2016 +0200

    Reduce default for -fmax-pmcheck-iterations from 1e7 to 2e6
    
    The commit 28f951edfe50ea5182065144340061ec326781f5 introduced the
    `-fmax-pmcheck-iterations` flag and set the default limit to 1e7
    iterations.
    
    However, this value is still high enough that it can result GHC to
    exhibit memory spikes beyond 1 GiB of RAM usage (heap profile showed
    several `(:)`s, as well as `THUNK_2_0`, and `PmCon` during the memory
    spikes)
    
    A value of 2e6 seems to be a safer upper bound which still manages to
    let the checker not run into the limit in most cases.
    
    Test Plan: Validate, try building a few Hackage packages
    
    Reviewers: austin, gkaracha, bgamari
    
    Reviewed By: bgamari
    
    Subscribers: thomie
    
    Differential Revision: https://phabricator.haskell.org/D2095
    
    (cherry picked from commit d2e05c6bd0834421b0c48b3c4287fbe6ee889966)


>---------------------------------------------------------------

f96ef2540d86797802fd699f3267c6aeb07a2e71
 compiler/cmm/CmmOpt.hs                           | 6 ++++++
 compiler/main/DynFlags.hs                        | 2 +-
 compiler/nativeGen/X86/CodeGen.hs                | 6 ++++++
 compiler/prelude/PrimOp.hs                       | 5 +++++
 compiler/types/OptCoercion.hs                    | 8 ++++++--
 testsuite/tests/pmcheck/should_compile/T11195.hs | 1 +
 6 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/compiler/cmm/CmmOpt.hs b/compiler/cmm/CmmOpt.hs
index 7c634c2..de3061d 100644
--- a/compiler/cmm/CmmOpt.hs
+++ b/compiler/cmm/CmmOpt.hs
@@ -1,5 +1,11 @@
 {-# LANGUAGE CPP #-}
 
+-- The default iteration limit is a bit too low for the definitions
+-- in this module.
+#if __GLASGOW_HASKELL__ >= 800
+{-# OPTIONS_GHC -fmax-pmcheck-iterations=10000000 #-}
+#endif
+
 -----------------------------------------------------------------------------
 --
 -- Cmm optimisation
diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index 959a68d..71ad14a 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -1443,7 +1443,7 @@ defaultDynFlags mySettings =
         debugLevel              = 0,
         simplPhases             = 2,
         maxSimplIterations      = 4,
-        maxPmCheckIterations    = 10000000,
+        maxPmCheckIterations    = 2000000,
         ruleCheck               = Nothing,
         maxRelevantBinds        = Just 6,
         simplTickFactor         = 100,
diff --git a/compiler/nativeGen/X86/CodeGen.hs b/compiler/nativeGen/X86/CodeGen.hs
index 2d22734..cd45d92 100644
--- a/compiler/nativeGen/X86/CodeGen.hs
+++ b/compiler/nativeGen/X86/CodeGen.hs
@@ -1,5 +1,11 @@
 {-# LANGUAGE CPP, GADTs, NondecreasingIndentation #-}
 
+-- The default iteration limit is a bit too low for the definitions
+-- in this module.
+#if __GLASGOW_HASKELL__ >= 800
+{-# OPTIONS_GHC -fmax-pmcheck-iterations=10000000 #-}
+#endif
+
 -----------------------------------------------------------------------------
 --
 -- Generating machine code (instruction selection)
diff --git a/compiler/prelude/PrimOp.hs b/compiler/prelude/PrimOp.hs
index 7b37062..be91ae6 100644
--- a/compiler/prelude/PrimOp.hs
+++ b/compiler/prelude/PrimOp.hs
@@ -6,6 +6,11 @@
 
 {-# LANGUAGE CPP #-}
 
+-- The default is a bit too low for the quite large primOpInfo definition
+#if __GLASGOW_HASKELL__ >= 801
+{-# OPTIONS_GHC -fmax-pmcheck-iterations=10000000 #-}
+#endif
+
 module PrimOp (
         PrimOp(..), PrimOpVecCat(..), allThePrimOps,
         primOpType, primOpSig,
diff --git a/compiler/types/OptCoercion.hs b/compiler/types/OptCoercion.hs
index e39f0aa..ca67bc7 100644
--- a/compiler/types/OptCoercion.hs
+++ b/compiler/types/OptCoercion.hs
@@ -1,8 +1,12 @@
 -- (c) The University of Glasgow 2006
 
 {-# LANGUAGE CPP #-}
- -- This module used to take 10GB of memory to compile with the new
- -- (Nov '15) pattern-match checker.
+
+-- The default iteration limit is a bit too low for the definitions
+-- in this module.
+#if __GLASGOW_HASKELL__ >= 800
+{-# OPTIONS_GHC -fmax-pmcheck-iterations=10000000 #-}
+#endif
 
 module OptCoercion ( optCoercion, checkAxInstCo ) where
 
diff --git a/testsuite/tests/pmcheck/should_compile/T11195.hs b/testsuite/tests/pmcheck/should_compile/T11195.hs
index 593223f..236932e 100644
--- a/testsuite/tests/pmcheck/should_compile/T11195.hs
+++ b/testsuite/tests/pmcheck/should_compile/T11195.hs
@@ -1,4 +1,5 @@
 {-# OPTIONS_GHC -Woverlapping-patterns -Wincomplete-patterns #-}
+{-# OPTIONS_GHC -fmax-pmcheck-iterations=10000000 #-}
 
 module T11195 where