diff options
Diffstat (limited to 'compiler/prelude/PrimOp.hs')
| -rw-r--r-- | compiler/prelude/PrimOp.hs | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/compiler/prelude/PrimOp.hs b/compiler/prelude/PrimOp.hs index fd1bab3386..edadf15d4c 100644 --- a/compiler/prelude/PrimOp.hs +++ b/compiler/prelude/PrimOp.hs @@ -323,7 +323,7 @@ data dependencies of the state token to enforce write-effect ordering * NB1: if you inline unsafePerformIO, you may end up with side-effecting ops whose 'state' output is discarded. - And programmers may do that by hand; see Trac #9390. + And programmers may do that by hand; see #9390. That is why we (conservatively) do not discard write-effecting primops even if both their state and result is discarded. @@ -367,13 +367,13 @@ Duplicate YES NO Arguably you should be able to discard this, since the returned stat token is not used, but that relies on NEVER inlining unsafePerformIO, and programmers sometimes write - this kind of stuff by hand (Trac #9390). So we (conservatively) + this kind of stuff by hand (#9390). So we (conservatively) never discard a has_side_effects primop. However, it's fine to discard a can_fail primop. For example case (indexIntArray# a i) of _ -> True We can discard indexIntArray#; it has can_fail, but not - has_side_effects; see Trac #5658 which was all about this. + has_side_effects; see #5658 which was all about this. Notice that indexIntArray# is (in a more general handling of effects) read effect, but we don't care about that here, and treat read effects as *not* has_side_effects. @@ -424,7 +424,7 @@ Duplicate YES NO (All these bindings are boxed.) If we inline p at its two call sites, we get a catastrophe: because the read is performed once when s' is demanded, and once when 'r' is demanded, which may be much - later. Utterly wrong. Trac #3207 is real example of this happening. + later. Utterly wrong. #3207 is real example of this happening. However, it's fine to duplicate a can_fail primop. That is really the only difference between can_fail and has_side_effects. |