ANNOUNCE

 
            ===============================================
-            The Glasgow Haskell Compiler -- version 8.0.1
+            The Glasgow Haskell Compiler -- version 8.2.1
            ===============================================
 
-The GHC Team is pleased to announce a new super-major release of GHC. This is
-the most significant GHC release in quite some time, including both a number
-of major features and numerous bug fixes. These include,
+The GHC Team is pleased to announce a new major release of GHC. The themes of this 
+release have been performance, stability, and consolidation. Consequently
+cleanups can be seen throughout the compiler,
 
- * The TypeInType extension, which unifies types and kinds, allowing GHC
-   to reason about kind equality and enabling promotion of GADTs to the type
-   level.
+ * Significant improvements in compiler performance
 
- * Support for record pattern synonyms
+ * More robust support for levity polymorphism
 
- * The -XDeriveAnyClass extension learned to derive instances for classes with
-   associated types
+ * Reliable DWARF debugging information
 
- * More reliable DWARF debugging information
+ * Improved runtime system performance on NUMA systems
 
- * Support for injective type families
+ * Retooling of the cost-center profiler, including support for live streaming
+   of profile data via the GHC event log
 
- * Applicative do-notation
+ * Deterministic interface files
 
- * Support for wildcards in data and type family instances
+ * More robust treatment of join points, enabling significantly better code
+   generation in many cases
 
- * Strict and StrictData extensions, allowing modules to be compiled with
-   strict-by-default bindings
+ * Numerous improvements in robustness on Windows
 
- * The DuplicateRecordFields extensions, allowing multiple datatypes to declare
-   the same record field names provided they are used unambiguously
+ * Resolution of over 500 tickets
 
- * Support for implicit parameters providing light-weight callstacks and source
-   locations
+In addition, there are a number of new features,
 
- * User-defined error messages for type errors
+ * A new more type-safe Typeable mechanism
 
- * A rewritten (and greatly improved) pattern exhaustiveness checker
+ * The long-awaited Backpack module system
 
- * GHCi can run the interpreter in a separate process, and the interpreter can
-   now run profiled code
+ * Deriving strategies to disambiguate between GHC's various instance deriving
+   mechanisms
 
- * A native code generator for powerpc64 and powerpc64le architectures
+ * Unboxed sums types, for efficient unpacked representation of sum data types
 
- * and more!
+ * Compact regions, allowing better control over garbage collection with in the
+   presence of large heaps containing many long-lived objects.
+
+ * Colorful messages and caret diagnostics for more legible errors
+
+ * Automatic support for using the faster gold and lld linkers when available
 
 A more thorough list of the changes in the release can be found in the release
 notes,
 
-  http://haskell.org/ghc/docs/8.0.1/html/users_guide/release-8-0-1.html
+  http://haskell.org/ghc/docs/8.2.1/html/users_guide/release-8-2-1.html
 
 
 How to get it

README.md

@@ -29,7 +29,7 @@ There are two ways to get a source tree:
         $ git clone --recursive git://git.haskell.org/ghc.git
 
   Note: cloning GHC from Github requires a special setup. See [Getting a GHC
-  repository from Github] [7].
+  repository from Github][7].
 
   *See the GHC team's working conventions regarding [how to contribute a patch to GHC](http://ghc.haskell.org/trac/ghc/wiki/WorkingConventions/FixingBugs).* First time contributors are encouraged to get started by just sending a Pull Request.
 
@@ -37,19 +37,19 @@ There are two ways to get a source tree:
 Building & Installing
 =====================
 
-For full information on building GHC, see the [GHC Building Guide] [3].
+For full information on building GHC, see the [GHC Building Guide][3].
 Here follows a summary - if you get into trouble, the Building Guide
 has all the answers.
 
 Before building GHC you may need to install some other tools and
-libraries.  See, [Setting up your system for building GHC] [8].
+libraries.  See, [Setting up your system for building GHC][8].
 
-*NB.* In particular, you need [GHC] [1] installed in order to build GHC,
+*NB.* In particular, you need [GHC][1] installed in order to build GHC,
 because the compiler is itself written in Haskell.  You also need
-[Happy] [4], [Alex] [5], and [Cabal] [9].  For instructions on how
-to port GHC to a new platform, see the [GHC Building Guide] [3].
+[Happy][4], [Alex][5], and [Cabal][9].  For instructions on how
+to port GHC to a new platform, see the [GHC Building Guide][3].
 
-For building library documentation, you'll need [Haddock] [6].  To build
+For building library documentation, you'll need [Haddock][6].  To build
 the compiler documentation, you need [Sphinx](http://www.sphinx-doc.org/)
 and Xelatex (only for PDF output).
 
@@ -71,7 +71,7 @@ almost always a win regardless of how many cores you have. As a simple rule,
 you should have about N+1 jobs, where `N` is the amount of cores you have.)
 
 The `./boot` step is only necessary if this is a tree checked out
-from git.  For source distributions downloaded from [GHC's web site] [1],
+from git.  For source distributions downloaded from [GHC's web site][1],
 this step has already been performed.
 
 These steps give you the default build, which includes everything
@@ -83,12 +83,12 @@ Filing bugs and feature requests
 
 If you've encountered what you believe is a bug in GHC, or you'd like
 to propose a feature request, please let us know! Submit a ticket in
-our [bug tracker] [10] and we'll be sure to look into it. Remember:
+our [bug tracker][10] and we'll be sure to look into it. Remember:
 **Filing a bug is the best way to make sure your issue isn't lost over
 time**, so please feel free.
 
 If you're an active user of GHC, you may also be interested in joining
-the [glasgow-haskell-users] [11] mailing list, where developers and
+the [glasgow-haskell-users][11] mailing list, where developers and
 GHC users discuss various topics and hang out.
 
 Hacking & Developing GHC
@@ -103,7 +103,7 @@ Contributors & Acknowledgements
 ===============================
 
 GHC in its current form wouldn't exist without the hard work of
-[its many contributors] [12]. Over time, it has grown to include the
+[its many contributors][12]. Over time, it has grown to include the
 efforts and research of many institutions, highly talented people, and
 groups from around the world. We'd like to thank them all, and invite
 you to join!

aclocal.m4

@@ -14,7 +14,8 @@ AC_DEFUN([GHC_SELECT_FILE_EXTENSIONS],
         AC_MSG_WARN([I'm assuming you wanted to build for i386-unknown-mingw32])
         exit 1
         ;;
-    *-unknown-mingw32)
+    # examples: i386-unknown-mingw32, i686-w64-mingw32, x86_64-w64-mingw32
+    *-mingw32)
         windows=YES
         $2='.exe'
         $3='.dll'
@@ -227,11 +228,10 @@ AC_DEFUN([FPTOOLS_SET_HASKELL_PLATFORM_VARS],
 
     checkVendor() {
         case [$]1 in
-        dec|unknown|hp|apple|next|sun|sgi|ibm|montavista|portbld)
+        dec|none|unknown|hp|apple|next|sun|sgi|ibm|montavista|portbld)
             ;;
         *)
-            echo "Unknown vendor [$]1"
-            exit 1
+            AC_MSG_WARN([Unknown vendor [$]1])
             ;;
         esac
     }
@@ -458,55 +458,42 @@ AC_DEFUN([GET_ARM_ISA],
 # Set the variables used in the settings file
 AC_DEFUN([FP_SETTINGS],
 [
-    SettingsCCompilerCommand="$CC"
-    SettingsHaskellCPPCommand="$HaskellCPPCmd"
-    SettingsHaskellCPPFlags="$HaskellCPPArgs"
-    SettingsLdCommand="$LdCmd"
-    SettingsArCommand="$ArCmd"
-    SettingsPerlCommand="$PerlCmd"
-
-    if test -z "$DllWrap"
+    if test "$windows" = YES
     then
-        SettingsDllWrapCommand="/bin/false"
+        mingw_bin_prefix=mingw/bin/
+        SettingsCCompilerCommand="\$topdir/../${mingw_bin_prefix}gcc.exe"
+        SettingsHaskellCPPCommand="\$topdir/../${mingw_bin_prefix}gcc.exe"
+        SettingsHaskellCPPFlags="$HaskellCPPArgs"
+        SettingsLdCommand="\$topdir/../${mingw_bin_prefix}ld.exe"
+        SettingsArCommand="\$topdir/../${mingw_bin_prefix}ar.exe"
+        SettingsPerlCommand='$topdir/../perl/perl.exe'
+        SettingsDllWrapCommand="\$topdir/../${mingw_bin_prefix}dllwrap.exe"
+        SettingsWindresCommand="\$topdir/../${mingw_bin_prefix}windres.exe"
+        SettingsTouchCommand='$topdir/bin/touchy.exe'
     else
-        SettingsDllWrapCommand="$DllWrap"
-    fi
-
-    if test -z "$Windres"
-    then
+        SettingsCCompilerCommand="$CC"
+        SettingsHaskellCPPCommand="$HaskellCPPCmd"
+        SettingsHaskellCPPFlags="$HaskellCPPArgs"
+        SettingsLdCommand="$LdCmd"
+        SettingsArCommand="$ArCmd"
+        SettingsPerlCommand="$PerlCmd"
+        SettingsDllWrapCommand="/bin/false"
         SettingsWindresCommand="/bin/false"
-    else
-        SettingsWindresCommand="$Windres"
-    fi
-
-    if test -z "$Libtool"
-    then
         SettingsLibtoolCommand="libtool"
-    else
-        SettingsLibtoolCommand="$Libtool"
-    fi
-
-    if test -z "$Touch"
-    then
         SettingsTouchCommand='touch'
-    else
-        SettingsTouchCommand='$Touch'
     fi
-
     if test -z "$LlcCmd"
     then
       SettingsLlcCommand="llc"
     else
       SettingsLlcCommand="$LlcCmd"
     fi
-
     if test -z "$OptCmd"
     then
       SettingsOptCommand="opt"
     else
       SettingsOptCommand="$OptCmd"
     fi
-
     SettingsCCompilerFlags="$CONF_CC_OPTS_STAGE2"
     SettingsCCompilerLinkFlags="$CONF_GCC_LINKER_OPTS_STAGE2"
     SettingsCCompilerSupportsNoPie="$CONF_GCC_SUPPORTS_NO_PIE"
@@ -635,15 +622,12 @@ AC_DEFUN([FPTOOLS_SET_C_LD_FLAGS],
         # instructions (ie not Thumb) and to link using the gold linker.
         # Forcing LD to be ld.gold is done in FIND_LD m4 macro.
         $2="$$2 -marm"
-        $3="$$3 -fuse-ld=gold -Wl,-z,noexecstack"
+        $3="$$3 -Wl,-z,noexecstack"
         $4="$$4 -z noexecstack"
         ;;
 
     aarch64*linux*)
-        # On aarch64/linux and aarch64/android, tell gcc to link using the
-        # gold linker.
-        # Forcing LD to be ld.gold is done in FIND_LD m4 macro.
-        $3="$$3 -fuse-ld=gold -Wl,-z,noexecstack"
+        $3="$$3 -Wl,-z,noexecstack"
         $4="$$4 -z noexecstack"
         ;;
 
@@ -874,12 +858,14 @@ FP_CHECK_ALIGNMENT([$1])
 # checking for *no* leading underscore first. Sigh.  --SDM
 #
 # Similarly on OpenBSD, but this test doesn't help. -- dons
+#
 AC_DEFUN([FP_LEADING_UNDERSCORE],
 [AC_CHECK_LIB([elf], [nlist], [LIBS="-lelf $LIBS"])
 AC_CACHE_CHECK([leading underscore in symbol names], [fptools_cv_leading_underscore], [
 # Hack!: nlist() under Digital UNIX insist on there being an _,
 # but symbol table listings shows none. What is going on here?!?
-case $HostPlatform in
+case $TargetPlatform in
+*linux-android*) fptools_cv_leading_underscore=no;;
 *openbsd*) # x86 openbsd is ELF from 3.4 >, meaning no leading uscore
   case $build in
     i386-*2\.@<:@0-9@:>@ | i386-*3\.@<:@0-3@:>@ ) fptools_cv_leading_underscore=yes ;;
@@ -1128,7 +1114,9 @@ AC_SUBST([LdHasFilelist])
 # ----------
 # Sets fp_prog_ar to a path to ar. Exits if no ar can be found
 AC_DEFUN([FP_PROG_AR],
-[AC_PATH_PROG([fp_prog_ar], [ar])
+[if test -z "$fp_prog_ar"; then
+  AC_PATH_PROG([fp_prog_ar], [ar])
+fi
 if test -z "$fp_prog_ar"; then
   AC_MSG_ERROR([cannot find ar in your PATH, no idea how to make a library])
 fi
@@ -2078,27 +2066,63 @@ AC_DEFUN([FIND_LLVM_PROG],[
     fi
 ])
 
-# FIND_LD
-# Find the version of `ld` to use. This is used in both in the top level
-# configure.ac and in distrib/configure.ac.in.
+# CHECK_LD_COPY_BUG()
+# -------------------
+# Check for binutils bug #16177 present in some versions of the bfd ld
+# implementation affecting ARM relocations.
+# https://sourceware.org/bugzilla/show_bug.cgi?id=16177
 #
-# $1 = the variable to set
+# $1 = the platform
 #
-AC_DEFUN([FIND_LD],[
-    FP_ARG_WITH_PATH_GNU_PROG([LD], [ld], [ld])
-    case $target in
-        arm*linux*       | \
-        aarch64*linux*   )
-            # Arm and Aarch64 requires use of the binutils ld.gold linker.
-            # This case should catch at least arm-unknown-linux-gnueabihf,
-            # arm-linux-androideabi, arm64-unknown-linux and
-            # aarch64-linux-android
-            FP_ARG_WITH_PATH_GNU_PROG([LD_GOLD], [ld.gold], [ld.gold])
-            $1="$LD_GOLD"
-            ;;
-        *)
-            $1="$LD"
-            ;;
+AC_DEFUN([CHECK_LD_COPY_BUG],[
+    case $1 in
+      arm*linux*)
+        AC_CHECK_TARGET_TOOL([READELF], [readelf])
+        AC_CHECK_TARGET_TOOL([AS], [as])
+        AC_MSG_CHECKING([for ld bug 16177])
+        cat >actest.s <<-EOF
+          .globl _start
+          .p2align 4
+        _start:
+          bkpt
+
+        .data
+          .globl data_object
+        object_reference:
+          .long data_object
+          .size object_reference, 4
+EOF
+
+        cat >aclib.s <<-EOF
+          .data
+          .globl data_object
+          .type data_object, %object
+          .size data_object, 4
+        data_object:
+            .long 123
+EOF
+
+        $AS -o aclib.o aclib.s
+        $LD -shared -o aclib.so aclib.o
+
+        $AS -o actest.o actest.s
+        $LD -o actest actest.o aclib.so
+
+        if $READELF -r actest | grep R_ARM_COPY > /dev/null; then
+            AC_MSG_RESULT([affected])
+            AC_MSG_ERROR(
+              [Your linker is affected by binutils #16177, which
+               critically breaks linkage of GHC objects. Please either upgrade
+               binutils or supply a different linker with the LD environment
+               variable.])
+        else
+            AC_MSG_RESULT([unaffected])
+        fi
+
+        rm -f aclib.s aclib.o aclib.so actest.s actest.o actest
+        ;;
+      *)
+        ;;
     esac
 ])
 
@@ -2278,4 +2302,66 @@ AC_DEFUN([FP_BFD_SUPPORT], [
     )
 ])
 
+
+# FP_CC_LINKER_FLAG_TRY()
+# --------------------
+# Try a particular linker to see whether we can use it. In particular, determine
+# whether we can convince gcc to use it via a -fuse-ld=... flag.
+#
+# $1 = the name of the linker to try
+# $2 = the variable to set with the appropriate GHC flag if the linker is
+# found to be usable
+AC_DEFUN([FP_CC_LINKER_FLAG_TRY], [
+    AC_MSG_CHECKING([whether C compiler supports -fuse-ld=$1])
+    echo 'int main(void) {return 0;}' > conftest.c
+    if $CC -o conftest.o -fuse-ld=$1 conftest.c > /dev/null 2>&1
+    then
+        $2="-fuse-ld=$1"
+        AC_MSG_RESULT([yes])
+    else
+        AC_MSG_RESULT([no])
+    fi
+    rm -f conftest.c conftest.o
+])
+
+# FIND_LD
+# ---------
+# Find the version of `ld` to use and figure out how to get gcc to use it for
+# linking (if --enable-ld-override is enabled). This is used in both in the top
+# level configure.ac and in distrib/configure.ac.in.
+#
+# $1 = the platform
+# $2 = the variable to set with GHC options to configure gcc to use the chosen linker
+#
+AC_DEFUN([FIND_LD],[
+    AC_ARG_ENABLE(ld-override,
+      [AC_HELP_STRING([--disable-ld-override],
+        [Prevent GHC from overriding the default linker used by gcc. If ld-override is enabled GHC will try to tell gcc to use whichever linker is selected by the LD environment variable. [default=override enabled]])],
+      [],
+      [enable_ld_override=yes])
+
+    if test "x$enable_ld_override" = "xyes"; then
+        TmpLd="$LD" # In case the user set LD
+        AC_CHECK_TARGET_TOOLS([TmpLd], [ld.lld ld.gold ld])
+
+        out=`$TmpLd --version`
+        case $out in
+          "GNU ld"*)   FP_CC_LINKER_FLAG_TRY(bfd, $2) ;;
+          "GNU gold"*) FP_CC_LINKER_FLAG_TRY(gold, $2) ;;
+          "LLD"*)      FP_CC_LINKER_FLAG_TRY(lld, $2) ;;
+          *) AC_MSG_NOTICE([unknown linker version $out]) ;;
+        esac
+        if test "z$$2" = "z"; then
+            AC_MSG_NOTICE([unable to convince '$CC' to use linker '$TmpLd'])
+            AC_CHECK_TARGET_TOOL([LD], [ld])
+        else
+            LD="$TmpLd"
+        fi
+   else
+        AC_CHECK_TARGET_TOOL([LD], [ld])
+   fi
+
+   CHECK_LD_COPY_BUG([$1])
+])
+
 # LocalWords:  fi

compiler/Unique.h

-#include "../includes/MachDeps.h"
-
-#define UNIQUE_BITS (WORD_SIZE_IN_BITS - 8)
+/* unique has the following structure:
+ * HsInt unique =
+ *    (unique_tag << (sizeof (HsInt) - UNIQUE_TAG_BITS)) | unique_number
+ */
+#define UNIQUE_TAG_BITS 8

compiler/backpack/DriverBkp.hs

@@ -308,8 +308,7 @@ buildUnit session cid insts lunit = do
             packageName = compat_pn,
             packageVersion = makeVersion [0],
             unitId = toInstalledUnitId (thisPackage dflags),
-            mungedPackageName = Nothing,
-            libName = Nothing,
+            sourceLibName = Nothing,
             componentId = cid,
             instantiatedWith = insts,
             -- Slight inefficiency here haha

compiler/basicTypes/Demand.hs

@@ -332,7 +332,7 @@ bothStr (SProd _) (SCall _)    = HyperStr
 -- utility functions to deal with memory leaks
 seqStrDmd :: StrDmd -> ()
 seqStrDmd (SProd ds)   = seqStrDmdList ds
-seqStrDmd (SCall s)     = s `seq` ()
+seqStrDmd (SCall s)    = seqStrDmd s
 seqStrDmd _            = ()
 
 seqStrDmdList :: [ArgStr] -> ()
@@ -1229,7 +1229,7 @@ diverge, and we do not anything being passed to b.
 
 Note [Asymmetry of 'both' for DmdType and DmdResult]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-'both' for DmdTypes is *assymetrical*, because there is only one
+'both' for DmdTypes is *asymmetrical*, because there is only one
 result!  For example, given (e1 e2), we get a DmdType dt1 for e1, use
 its arg demand to analyse e2 giving dt2, and then do (dt1 `bothType` dt2).
 Similarly with
@@ -1442,8 +1442,11 @@ postProcessDmdResult _              res       = res
 postProcessDmdEnv :: DmdShell -> DmdEnv -> DmdEnv
 postProcessDmdEnv ds@(JD { sd = ss, ud = us }) env
   | Abs <- us       = emptyDmdEnv
-  | Str _ _   <- ss
-  , Use One _ <- us = env  -- Shell is a no-op
+    -- In this case (postProcessDmd ds) == id; avoid a redundant rebuild
+    -- of the environment. Be careful, bad things will happen if this doesn't
+    -- match postProcessDmd (see #13977).
+  | Str VanStr _ <- ss
+  , Use One _ <- us = env
   | otherwise       = mapVarEnv (postProcessDmd ds) env
   -- For the Absent case just discard all usage information
   -- We only processed the thing at all to analyse the body

compiler/basicTypes/Id.hs

@@ -628,8 +628,10 @@ idFunRepArity :: Id -> RepArity
 idFunRepArity x = countFunRepArgs (idArity x) (idType x)
 
 -- | Returns true if an application to n args would diverge
-isBottomingId :: Id -> Bool
-isBottomingId id = isBottomingSig (idStrictness id)
+isBottomingId :: Var -> Bool
+isBottomingId v
+  | isId v    = isBottomingSig (idStrictness v)
+  | otherwise = False
 
 idStrictness :: Id -> StrictSig
 idStrictness id = strictnessInfo (idInfo id)

compiler/basicTypes/IdInfo.hs

@@ -29,7 +29,7 @@ module IdInfo (
         -- ** Zapping various forms of Info
         zapLamInfo, zapFragileInfo,
         zapDemandInfo, zapUsageInfo, zapUsageEnvInfo, zapUsedOnceInfo,
-        zapTailCallInfo,
+        zapTailCallInfo, zapCallArityInfo,
 
         -- ** The ArityInfo type
         ArityInfo,
@@ -553,6 +553,9 @@ zapTailCallInfo info
         where
           safe_occ = occ { occ_tail = NoTailCallInfo }
 
+zapCallArityInfo :: IdInfo -> IdInfo
+zapCallArityInfo info = setCallArityInfo info 0
+
 {-
 ************************************************************************
 *                                                                      *

compiler/basicTypes/MkId.hs

@@ -528,7 +528,11 @@ mkDataConRep dflags fam_envs wrap_name mb_bangs data_con
 
              wrap_sig = mkClosedStrictSig wrap_arg_dmds (dataConCPR data_con)
 
-             wrap_arg_dmds = map mk_dmd arg_ibangs
+             wrap_arg_dmds =
+               replicate (length theta) topDmd ++ map mk_dmd arg_ibangs
+               -- Don't forget the dictionary arguments when building
+               -- the strictness signature (#14290).
+
              mk_dmd str | isBanged str = evalDmd
                         | otherwise           = topDmd
 
@@ -1173,7 +1177,6 @@ seqId = pcMiscPrelId seqName ty info
   where
     info = noCafIdInfo `setInlinePragInfo` inline_prag
                        `setUnfoldingInfo`  mkCompulsoryUnfolding rhs
-                       `setRuleInfo`       mkRuleInfo [seq_cast_rule]
                        `setNeverLevPoly`   ty
 
     inline_prag
@@ -1190,28 +1193,6 @@ seqId = pcMiscPrelId seqName ty info
     [x,y] = mkTemplateLocals [alphaTy, betaTy]
     rhs = mkLams [alphaTyVar,betaTyVar,x,y] (Case (Var x) x betaTy [(DEFAULT, [], Var y)])
 
-    -- See Note [Built-in RULES for seq]
-    -- NB: ru_nargs = 3, not 4, to match the code in
-    --     Simplify.rebuildCase which tries to apply this rule
-    seq_cast_rule = BuiltinRule { ru_name  = fsLit "seq of cast"
-                                , ru_fn    = seqName
-                                , ru_nargs = 3
-                                , ru_try   = match_seq_of_cast }
-
-match_seq_of_cast :: RuleFun
-    -- See Note [Built-in RULES for seq]
-match_seq_of_cast _ _ _ [Type _, Type res_ty, Cast scrut co]
-  = Just (fun `App` scrut)
-  where
-    fun      = Lam x $ Lam y $
-               Case (Var x) x res_ty [(DEFAULT,[],Var y)]
-               -- Generate a Case directly, not a call to seq, which
-               -- might be ill-kinded if res_ty is unboxed
-    [x,y]    = mkTemplateLocals [scrut_ty, res_ty]
-    scrut_ty = pFst (coercionKind co)
-
-match_seq_of_cast _ _ _ _ = Nothing
-
 ------------------------------------------------
 lazyId :: Id    -- See Note [lazyId magic]
 lazyId = pcMiscPrelId lazyIdName ty info
@@ -1356,7 +1337,7 @@ enough support that you can do this using a rewrite rule:
 
 You write that rule.  When GHC sees a case expression that discards
 its result, it mentally transforms it to a call to 'seq' and looks for
-a RULE.  (This is done in Simplify.rebuildCase.)  As usual, the
+a RULE.  (This is done in Simplify.trySeqRules.)  As usual, the
 correctness of the rule is up to you.
 
 VERY IMPORTANT: to make this work, we give the RULE an arity of 1, not 2.
@@ -1371,21 +1352,6 @@ with rule arity 2, then two bad things would happen:
   - The code in Simplify.rebuildCase would need to actually supply
     the value argument, which turns out to be awkward.
 
-Note [Built-in RULES for seq]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-We also have the following built-in rule for seq
-
-  seq (x `cast` co) y = seq x y
-
-This eliminates unnecessary casts and also allows other seq rules to
-match more often.  Notably,
-
-   seq (f x `cast` co) y  -->  seq (f x) y
-
-and now a user-defined rule for seq (see Note [User-defined RULES for seq])
-may fire.
-
-
 Note [lazyId magic]
 ~~~~~~~~~~~~~~~~~~~
 lazy :: forall a?. a? -> a?   (i.e. works for unboxed types too)

compiler/basicTypes/UniqSupply.hs

@@ -77,7 +77,7 @@ takeUniqFromSupply :: UniqSupply -> (Unique, UniqSupply)
 -- ^ Obtain the 'Unique' from this particular 'UniqSupply', and a new supply
 
 mkSplitUniqSupply c
-  = case ord c `shiftL` UNIQUE_BITS of
+  = case ord c `shiftL` uNIQUE_BITS of
      mask -> let
         -- here comes THE MAGIC:
 

compiler/basicTypes/Unique.hs

@@ -22,6 +22,7 @@ Haskell).
 module Unique (
         -- * Main data types
         Unique, Uniquable(..),
+        uNIQUE_BITS,
 
         -- ** Constructors, destructors and operations on 'Unique's
         hasKey,
@@ -98,6 +99,10 @@ Fast comparison is everything on @Uniques@:
 -- These are sometimes also referred to as \"keys\" in comments in GHC.
 newtype Unique = MkUnique Int
 
+{-# INLINE uNIQUE_BITS #-}
+uNIQUE_BITS :: Int
+uNIQUE_BITS = finiteBitSize (0 :: Int) - UNIQUE_TAG_BITS
+
 {-
 Now come the functions which construct uniques from their pieces, and vice versa.
 The stuff about unique *supplies* is handled further down this module.
@@ -132,7 +137,7 @@ newTagUnique u c = mkUnique c i where (_,i) = unpkUnique u
 -- | How many bits are devoted to the unique index (as opposed to the class
 -- character).
 uniqueMask :: Int
-uniqueMask = (1 `shiftL` UNIQUE_BITS) - 1
+uniqueMask = (1 `shiftL` uNIQUE_BITS) - 1
 
 -- pop the Char in the top 8 bits of the Unique(Supply)
 
@@ -146,14 +151,14 @@ mkUnique :: Char -> Int -> Unique       -- Builds a unique from pieces
 mkUnique c i
   = MkUnique (tag .|. bits)
   where
-    tag  = ord c `shiftL` UNIQUE_BITS
+    tag  = ord c `shiftL` uNIQUE_BITS
     bits = i .&. uniqueMask
 
 unpkUnique (MkUnique u)
   = let
         -- as long as the Char may have its eighth bit set, we
         -- really do need the logical right-shift here!
-        tag = chr (u `shiftR` UNIQUE_BITS)
+        tag = chr (u `shiftR` uNIQUE_BITS)
         i   = u .&. uniqueMask
     in
     (tag, i)

compiler/basicTypes/Var.hs

@@ -5,7 +5,7 @@
 \section{@Vars@: Variables}
 -}
 
-{-# LANGUAGE CPP, MultiWayIf, FlexibleInstances, DeriveDataTypeable #-}
+{-# LANGUAGE CPP, FlexibleContexts, MultiWayIf, FlexibleInstances, DeriveDataTypeable #-}
 
 -- |
 -- #name_types#
@@ -521,7 +521,7 @@ instance Binary ArgFlag where
 ************************************************************************
 -}
 
-idInfo :: Id -> IdInfo
+idInfo :: HasDebugCallStack => Id -> IdInfo
 idInfo (Id { id_info = info }) = info
 idInfo other                   = pprPanic "idInfo" (ppr other)
 

compiler/cbits/genSym.c

@@ -5,12 +5,13 @@
 static HsInt GenSymCounter = 0;
 static HsInt GenSymInc = 1;
 
+#define UNIQUE_BITS (sizeof (HsInt) * 8 - UNIQUE_TAG_BITS)
 #define UNIQUE_MASK ((1ULL << UNIQUE_BITS) - 1)
 
 STATIC_INLINE void checkUniqueRange(HsInt u STG_UNUSED) {
 #if DEBUG
     // Uh oh! We will overflow next time a unique is requested.
-    assert(h != UNIQUE_MASK);
+    assert(u != UNIQUE_MASK);
 #endif
 }
 

compiler/cmm/CLabel.hs

@@ -930,7 +930,7 @@ labelType (RtsLabel (RtsApInfoTable _ _))       = DataLabel
 labelType (RtsLabel (RtsApFast _))              = CodeLabel
 labelType (CaseLabel _ CaseReturnInfo)          = DataLabel
 labelType (CaseLabel _ _)                       = CodeLabel
-labelType (PlainModuleInitLabel _)              = CodeLabel
+labelType (PlainModuleInitLabel _)              = DataLabel
 labelType (SRTLabel _)                          = DataLabel
 labelType (LargeSRTLabel _)                     = DataLabel
 labelType (LargeBitmapLabel _)                  = DataLabel

compiler/cmm/CmmParse.y

@@ -593,9 +593,9 @@ stmt    :: { CmmParse () }
 
 
         | lreg '=' expr ';'
-                { do reg <- $1; e <- $3; emitAssign reg e }
+                { do reg <- $1; e <- $3; withSourceNote $2 $4 (emitAssign reg e) }
         | type '[' expr ']' '=' expr ';'
-                { doStore $1 $3 $6 }
+                { withSourceNote $2 $7 (doStore $1 $3 $6) }
 
         -- Gah! We really want to say "foreign_results" but that causes
         -- a shift/reduce conflict with assignment.  We either

compiler/cmm/PprC.hs

@@ -754,7 +754,7 @@ pprCallishMachOp_for_C mop
         MO_F64_Log      -> text "log"
         MO_F64_Exp      -> text "exp"
         MO_F64_Sqrt     -> text "sqrt"
-        MO_F64_Fabs     -> unsupported
+        MO_F64_Fabs     -> text "fabs"
         MO_F32_Pwr      -> text "powf"
         MO_F32_Sin      -> text "sinf"
         MO_F32_Cos      -> text "cosf"
@@ -768,7 +768,7 @@ pprCallishMachOp_for_C mop
         MO_F32_Log      -> text "logf"
         MO_F32_Exp      -> text "expf"
         MO_F32_Sqrt     -> text "sqrtf"
-        MO_F32_Fabs     -> unsupported
+        MO_F32_Fabs     -> text "fabsf"
         MO_WriteBarrier -> text "write_barrier"
         MO_Memcpy _     -> text "memcpy"
         MO_Memset _     -> text "memset"

compiler/codeGen/StgCmmPrim.hs

@@ -815,39 +815,49 @@ type GenericOp = [CmmFormal] -> [CmmActual] -> FCode ()
 callishPrimOpSupported :: DynFlags -> PrimOp -> Either CallishMachOp GenericOp
 callishPrimOpSupported dflags op
   = case op of
-      IntQuotRemOp   | ncg && x86ish  -> Left (MO_S_QuotRem  (wordWidth dflags))
+      IntQuotRemOp   | ncg && (x86ish
+                              || ppc) -> Left (MO_S_QuotRem  (wordWidth dflags))
                      | otherwise      -> Right (genericIntQuotRemOp dflags)
 
-      WordQuotRemOp  | ncg && x86ish  -> Left (MO_U_QuotRem  (wordWidth dflags))
+      WordQuotRemOp  | ncg && (x86ish
+                              || ppc) -> Left (MO_U_QuotRem  (wordWidth dflags))
                      | otherwise      -> Right (genericWordQuotRemOp dflags)
 
-      WordQuotRem2Op | (ncg && x86ish)
+      WordQuotRem2Op | (ncg && (x86ish
+                                || ppc))
                           || llvm     -> Left (MO_U_QuotRem2 (wordWidth dflags))
                      | otherwise      -> Right (genericWordQuotRem2Op dflags)
 
-      WordAdd2Op     | (ncg && x86ish)
+      WordAdd2Op     | (ncg && (x86ish
+                                || ppc))
                          || llvm      -> Left (MO_Add2       (wordWidth dflags))
                      | otherwise      -> Right genericWordAdd2Op
 
-      WordSubCOp     | (ncg && x86ish)
+      WordSubCOp     | (ncg && (x86ish
+                                || ppc))
                          || llvm      -> Left (MO_SubWordC   (wordWidth dflags))
                      | otherwise      -> Right genericWordSubCOp
 
-      IntAddCOp      | (ncg && x86ish)
+      IntAddCOp      | (ncg && (x86ish
+                                || ppc))
                          || llvm      -> Left (MO_AddIntC    (wordWidth dflags))
                      | otherwise      -> Right genericIntAddCOp
 
-      IntSubCOp      | (ncg && x86ish)
+      IntSubCOp      | (ncg && (x86ish
+                                || ppc))
                          || llvm      -> Left (MO_SubIntC    (wordWidth dflags))
                      | otherwise      -> Right genericIntSubCOp
 
-      WordMul2Op     | ncg && x86ish
+      WordMul2Op     | ncg && (x86ish
+                               || ppc)
                          || llvm      -> Left (MO_U_Mul2     (wordWidth dflags))
                      | otherwise      -> Right genericWordMul2Op
-      FloatFabsOp    | (ncg && x86ish)
+      FloatFabsOp    | (ncg && x86ish
+                               || ppc)
                          || llvm      -> Left MO_F32_Fabs
                      | otherwise      -> Right $ genericFabsOp W32
-      DoubleFabsOp   | (ncg && x86ish)
+      DoubleFabsOp   | (ncg && x86ish
+                               || ppc)
                          || llvm      -> Left MO_F64_Fabs
                      | otherwise      -> Right $ genericFabsOp W64
 
@@ -863,6 +873,10 @@ callishPrimOpSupported dflags op
              ArchX86    -> True
              ArchX86_64 -> True
              _          -> False
+  ppc = case platformArch (targetPlatform dflags) of
+          ArchPPC      -> True
+          ArchPPC_64 _ -> True
+          _            -> False
 
 genericIntQuotRemOp :: DynFlags -> GenericOp
 genericIntQuotRemOp dflags [res_q, res_r] [arg_x, arg_y]

compiler/coreSyn/CoreArity.hs

@@ -10,9 +10,10 @@
 
 -- | Arity and eta expansion
 module CoreArity (
-        manifestArity, exprArity, typeArity, exprBotStrictness_maybe,
+        manifestArity, joinRhsArity, exprArity, typeArity,
         exprEtaExpandArity, findRhsArity, CheapFun, etaExpand,
-        etaExpandToJoinPoint, etaExpandToJoinPointRule
+        etaExpandToJoinPoint, etaExpandToJoinPointRule,
+        exprBotStrictness_maybe
     ) where
 
 #include "HsVersions.h"
@@ -77,6 +78,14 @@ manifestArity (Tick t e) | not (tickishIsCode t) =  manifestArity e
 manifestArity (Cast e _)                = manifestArity e
 manifestArity _                         = 0
 
+joinRhsArity :: CoreExpr -> JoinArity
+-- Join points are supposed to have manifestly-visible
+-- lambdas at the top: no ticks, no casts, nothing
+-- Moreover, type lambdas count in JoinArity
+joinRhsArity (Lam _ e) = 1 + joinRhsArity e
+joinRhsArity _         = 0
+
+
 ---------------
 exprArity :: CoreExpr -> Arity
 -- ^ An approximate, fast, version of 'exprEtaExpandArity'

compiler/coreSyn/CoreArity.hs-boot

-module CoreArity where
-
-import BasicTypes
-import CoreSyn
-
-etaExpandToJoinPoint :: JoinArity -> CoreExpr -> ([CoreBndr], CoreExpr)

compiler/coreSyn/CoreFVs.hs

@@ -31,7 +31,7 @@ module CoreFVs (
         varTypeTyCoVars,
         varTypeTyCoFVs,
         idUnfoldingVars, idFreeVars, dIdFreeVars,
-        idRuleAndUnfoldingVars, idRuleAndUnfoldingVarsDSet,
+        bndrRuleAndUnfoldingVarsDSet,
         idFVs,
         idRuleVars, idRuleRhsVars, stableUnfoldingVars,
         ruleRhsFreeVars, ruleFreeVars, rulesFreeVars,
@@ -646,22 +646,15 @@ idFVs :: Id -> FV
 -- Type variables, rule variables, and inline variables
 idFVs id = ASSERT( isId id)
            varTypeTyCoFVs id `unionFV`
-           idRuleAndUnfoldingFVs id
+           bndrRuleAndUnfoldingFVs id
 
-bndrRuleAndUnfoldingFVs :: Var -> FV
-bndrRuleAndUnfoldingFVs v | isTyVar v = emptyFV
-                          | otherwise = idRuleAndUnfoldingFVs v
-
-idRuleAndUnfoldingVars :: Id -> VarSet
-idRuleAndUnfoldingVars id = fvVarSet $ idRuleAndUnfoldingFVs id
-
-idRuleAndUnfoldingVarsDSet :: Id -> DVarSet
-idRuleAndUnfoldingVarsDSet id = fvDVarSet $ idRuleAndUnfoldingFVs id
-
-idRuleAndUnfoldingFVs :: Id -> FV
-idRuleAndUnfoldingFVs id = ASSERT( isId id)
-                           idRuleFVs id `unionFV` idUnfoldingFVs id
+bndrRuleAndUnfoldingVarsDSet :: Id -> DVarSet
+bndrRuleAndUnfoldingVarsDSet id = fvDVarSet $ bndrRuleAndUnfoldingFVs id
 
+bndrRuleAndUnfoldingFVs :: Id -> FV
+bndrRuleAndUnfoldingFVs id
+  | isId id   = idRuleFVs id `unionFV` idUnfoldingFVs id
+  | otherwise = emptyFV
 
 idRuleVars ::Id -> VarSet  -- Does *not* include CoreUnfolding vars
 idRuleVars id = fvVarSet $ idRuleFVs id
@@ -710,7 +703,7 @@ freeVarsBind :: CoreBind
 freeVarsBind (NonRec binder rhs) body_fvs
   = ( AnnNonRec binder rhs2
     , freeVarsOf rhs2 `unionFVs` body_fvs2
-                      `unionFVs` fvDVarSet (bndrRuleAndUnfoldingFVs binder) )
+                      `unionFVs` bndrRuleAndUnfoldingVarsDSet binder )
     where
       rhs2      = freeVars rhs
       body_fvs2 = binder `delBinderFV` body_fvs
@@ -722,7 +715,7 @@ freeVarsBind (Rec binds) body_fvs
     (binders, rhss) = unzip binds
     rhss2        = map freeVars rhss
     rhs_body_fvs = foldr (unionFVs . freeVarsOf) body_fvs rhss2
-    binders_fvs  = fvDVarSet $ mapUnionFV idRuleAndUnfoldingFVs binders
+    binders_fvs  = fvDVarSet $ mapUnionFV bndrRuleAndUnfoldingFVs binders
     all_fvs      = rhs_body_fvs `unionFVs` binders_fvs
             -- The "delBinderFV" happens after adding the idSpecVars,
             -- since the latter may add some of the binders as fvs