From: simonmar <unknown>
Date: Thu, 4 Aug 2005 11:23:42 +0000 (+0000)
Subject: [project @ 2005-08-04 11:23:42 by simonmar]
X-Git-Tag: Initial_conversion_from_CVS_complete~261
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=f5aeb6b56e5aac907643072c73ef1623195e0c6b;p=ghc-hetmet.git

[project @ 2005-08-04 11:23:42 by simonmar]
callSiteInline: consider inlining even the once-in-one-branch
occurrences.  See comment for details.
---

diff --git a/ghc/compiler/coreSyn/CoreUnfold.lhs b/ghc/compiler/coreSyn/CoreUnfold.lhs
index 774ee6e..d840f45 100644
--- a/ghc/compiler/coreSyn/CoreUnfold.lhs
+++ b/ghc/compiler/coreSyn/CoreUnfold.lhs
@@ -520,13 +520,15 @@ callSiteInline dflags active_inline inline_call occ id arg_infos interesting_con
 	  | otherwise = case occ of
 				IAmDead		     -> pprTrace "callSiteInline: dead" (ppr id) False
 				IAmALoopBreaker      -> False
-
-				-- Occurs once in one branch.  These are deal with by
-				-- preInlineUnconditionally, so we ignore them here:
-				OneOcc _ True _      -> False
-
-				OneOcc in_lam False _ -> (not in_lam || is_cheap) && consider_safe True
+				OneOcc in_lam _ _    -> (not in_lam || is_cheap) && consider_safe True
 				other		     -> is_cheap && consider_safe False
+		-- we consider even the once-in-one-branch
+		-- occurrences, because they won't all have been
+		-- caught by preInlineUnconditionally.  In particular,
+		-- if the occurrence is once inside a lambda, and the
+		-- rhs is cheap but not a manifest lambda, then
+		-- pre-inline will not have inlined it for fear of
+		-- invalidating the occurrence info in the rhs.
 
 	consider_safe once
 		-- consider_safe decides whether it's a good idea to