GitLab

The strictness signature for a data con wrapper wasn't including any
dictionary arguments, which meant that bangs on the fields of a
constructor with an existential context would be moved to the wrong
fields.  See T14290 for an example.

Test Plan:
* New test T14290
* validate

Reviewers: simonpj, niteria, austin, bgamari, erikd

Reviewed By: simonpj, bgamari

Subscribers: rwbarton, thomie

GHC Trac Issues: #14290

Differential Revision: https://phabricator.haskell.org/D4040

(cherry picked from commit 5935acdb)

This reverts commit da4687f6.

It's not entirely trivial to clean up the dead code this patch
introduced. In particular, when we see

```
case raiseIO# m s of
  s' -> e
```

we want to know that `e` is dead. For scrutinees that are properly
bottom (which we don't want to consider `raiseIO# m s` to be, this
is handled by rewriting `bot` to `case bot of {}`. But if we do
that for `raiseIO#`, we end up with

```
case raiseIO# m s of {}
```

which looks a lot like bottom and could confuse demand analysis.
I think we need to wait with this change until we have a more
complete story.

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D3413

(cherry picked from commit e83af07e)

They were `expect_broken` without any output. Add the actual
output and remove the `expect_broken`.

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D3306

this fixes #12368.

It also refactors dmdFix a bit, removes some redundancies (such as
passing around an strictness signature right next to an id, when that id
is guaranteed to have been annotated with that strictness signature).

Note that when fixed-point iteration does not terminate, we
conservatively delete their strictness signatures (set them to nopSig).
But this loses the information on how its strict free variables are
used!

Lazily used variables already escape via lazy_fvs. We ensure that in the
case of an aborted fixed-point iteration, also the strict variables are
put there (with a conservative demand of topDmd).

Differential Revision: https://phabricator.haskell.org/D2392

By making it believe that some deeply nested value is absent when it
really isn't. See #12368.

Foreign calls may not be strict for lifted arguments. Fixes Trac #11076.

Test Plan: ./validate

Reviewers: simonpj, bgamari, austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1464

GHC Trac Issues: #11076

Trac #10218 reports a subtle bug that turned out to be:

- CSE invalidated the usage information computed
  by earlier demand analysis, by increasing sharing

- that made a single-entry thunk into a multi-entry thunk

- and with -feager-blackholing, that led to <<loop>>

The patch fixes it by making the CSE pass zap usage information for
let-bound identifiers.   It can be restored by -flate-dmd-anal.

(But making -flate-dmd-anal the default needs some careful work;
see Trac #7782.)

This is a tricky case exposed by Trac #9254.  I'm surprised it hasn't
shown up before, because it's happens when you use unsafePerformIO in
the right way.

Anyway, fixed now.  See Note [Analysing with absent demand]
in Demand.lhs

Its really a testsuite-framework bug that these mentions of 'opt' have
lingered so long.  They should have been rejected as a non-existent way.

Add a strictness anal test I found lying in this directory

Add a test for IO strictness

Convert this file to the new test framework (this dir wasn't checked
out in my local tree it seems).

Add another demand test

add strictness test

Rename some functions used in vanilla-test.T to be more consistent/logical.

Add simplifier tests.