This requires that stackOverflow() in RtsUtils.c be passed a reference
to the current TSO. This requires a small change in libraries/base.

... plus a couple of unused variables in TcSMonad

There was no useful distinction; a simple refactoring.

We were (uselessly) iterating the simplification loop an exponential
number of times.  Lovely simple test case showed this up.

See Note [Cutting off simpl_loop] in TcSimplify

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>

The particular problematic code in #7762 was this:

            nat newSize = size - n;
            char *freeAddr = MBLOCK_ROUND_DOWN(bd->start);
            freeAddr += newSize * MBLOCK_SIZE;
                        ^^^^^^^^^^^^^^^^^^^^^^  OVERFLOW!!!

For good measure, I'm going to fix the bug twice.  This patch fixes
the class of bugs of this kind, by making sure that any expressions
involving BLOCK_SIZE or MBLOCK_SIZE are promoted to unsigned long.  In
a separate patch, I'll fix a bunch of individual instances (including
the one above).

Inlining global registers and constants made code slightly larger in
some cases.  I finally got around to looking into why, and discovered
one reason: we weren't discarding dead code in some cases.  This patch
fixes it.

Also refactor the #defines to hopefully make it clearer what's going
on.

Fixes #8456

A bit of a mess had accumulated, with unclear invariants.

* Remove splitNewTypeRepCo_maybe, in favour of topNormaliseNewType_maybe
  (which had the same signature but behaved subtly differently).

* Make topNormaliseNewType_maybe guaranteed to return a non-newtype
  if it says (Just ty).  This is what was causing the loop in #8467

* Apply similar tidying up to FamInstEnv.topNormaliseType

Trivial fix; matches oprhNamesOfClsInst.

The AMP warnings caused 'base' to be loaded even when we were
compiling 'ghc-prim'.  That is bad, bad, bad.  We got a very
obscure message
   attempting to use module ‛ghc-prim:GHC.Types’
     (libraries/ghc-prim/./GHC/Types.hs) which is not loaded

See Note [Home module load error] in LoadIface

Apologies -- there was some git confusion that cause the Wrong Thing
to happen.

This reverts commit bb9d53e3.

Conflicts:

	compiler/hsSyn/Convert.lhs

Now, instead of looking at a class's roles, the GND check looks
at all of the methods in the class individually. This has the
advantage that sometimes, we can use information about the
derivation requested during the safety check. For example,
we can now derive (IArray UArray), whereas the previous check
prevented this.

Now, we allow types that do not begin with ':', but we retain other
checks on variable names.

This was quite simple -- just use mkIntegerExpr instead of mkIntExpr.

This was easy to do, except that the desugar monad needs a
FamInstEnv init.  Straightforward, routine, albeit a bit clunky.

We weren't dealing with built-in syntax; data constructors
that are built-in syntax (only [] actually) don't appear
in the GlobalRdrEnv

and add new, simpler topNormaliseType

This is just a minor refactoring

Signed-off-by: Edward Z. Yang <ezyang@mit.edu>

Fixes #8456. Previous version of control flow optimisations
did not update the list of block predecessors, leading to
unnecessary duplication of blocks in some cases. See Trac
and comments in the code for more details.