SimplGently (a) Simplifying before specialiser/full laziness
(b) Simplifiying inside INLINE pragma
(c) Simplifying the LHS of a rule
+ (d) Simplifying a GHCi expression or Template
+ Haskell splice
SimplPhase n Used at all other times
==> ...(case x of I# x# -> case fw x# of ...)...
and now the redex (f x) isn't floatable any more.
+The no-inling thing is also important for Template Haskell. You might be
+compiling in one-shot mode with -O2; but when TH compiles a splice before
+running it, we don't want to use -O2. Indeed, we don't want to inline
+anything, because the byte-code interpreter might get confused about
+unboxed tuples and suchlike.
+
INLINE pragmas
~~~~~~~~~~~~~~
SimplGently is also used as the mode to simplify inside an InlineMe note.
SimplGently -> isAlwaysActive prag
SimplPhase n -> isActive n prag
prag = idInlinePragma bndr
-\end{code}
-
-blackListInline tells if we must not inline at a call site because the
-Id's inline pragma says not to do so.
-However, blackListInline is ignored for things with with Compulsory inlinings,
-because they don't have bindings, so we must inline them no matter how
-gentle we are being.
-
-\begin{code}
activeInline :: SimplEnv -> OutId -> OccInfo -> Bool
activeInline env id occ
= case getMode env of
- SimplGently -> isAlwaysActive prag && isOneOcc occ
+ SimplGently -> isOneOcc occ && isAlwaysActive prag
-- No inlining at all when doing gentle stuff,
- -- except for things that occur once
+ -- except for local things that occur once
-- The reason is that too little clean-up happens if you
-- don't inline use-once things. Also a bit of inlining is *good* for
-- full laziness; it can expose constant sub-expressions.
-- Nothing => No rules at all
activeRule env
= case getMode env of
- SimplGently -> Nothing -- No rules in gentle mode
+ SimplGently -> Just isAlwaysActive
+ -- Used to be Nothing (no rules in gentle mode)
+ -- Main motivation for changing is that I wanted
+ -- lift String ===> ...
+ -- to work in Template Haskell when simplifying
+ -- splices, so we get simpler code for literal strings
SimplPhase n -> Just (isActive n)
\end{code}