From 0c66cc56ac4d42d91bfd9beedabcb988d40d7735 Mon Sep 17 00:00:00 2001
From: "simonpj@microsoft.com" <unknown>
Date: Fri, 18 Dec 2009 16:43:16 +0000
Subject: [PATCH] Always expose the unfolding of something with an InlineRule

Previously a bottoming function with a strictness wrapper
had a hidden inlining, and that was Very Bad, because in
    f x = if ... then bot_fun x else x+1
we really want to pass the *unboxed* x to bot_fun. This
happens quite a bit in error handling code, eg for array
indexing.
---
 compiler/main/TidyPgm.lhs |   25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/compiler/main/TidyPgm.lhs b/compiler/main/TidyPgm.lhs
index 41d9234..d8bacd8 100644
--- a/compiler/main/TidyPgm.lhs
+++ b/compiler/main/TidyPgm.lhs
@@ -686,7 +686,7 @@ addExternal expose_all id = (new_needed_ids, show_unfold)
                        (varSetElems spec_ids) -- XXX non-det ordering
 
     idinfo	   = idInfo id
-    dont_inline	   = isNeverActive (inlinePragmaActivation (inlinePragInfo idinfo))
+    never_active   = isNeverActive (inlinePragmaActivation (inlinePragInfo idinfo))
     loop_breaker   = isNonRuleLoopBreaker (occInfo idinfo)
     bottoming_fn   = isBottomingSig (strictnessInfo idinfo `orElse` topSig)
     spec_ids	   = specInfoFreeVars (specInfo idinfo)
@@ -699,16 +699,23 @@ addExternal expose_all id = (new_needed_ids, show_unfold)
 
     mb_unfold_ids :: Maybe (IdSet, [Id])	-- Nothing => don't unfold
     mb_unfold_ids = case unfoldingInfo idinfo of
-		      CoreUnfolding { uf_tmpl = unf_rhs, uf_guidance = guide } 
-			| expose_all ||	     -- expose_all says to expose all 
-			  	     	     -- unfoldings willy-nilly
-                          not (bottoming_fn	 -- No need to inline bottom functions
-			    || dont_inline	 -- Or ones that say not to
-			    || loop_breaker	 -- Or that are loop breakers
-			    || neverUnfoldGuidance guide)
+		      CoreUnfolding { uf_tmpl = unf_rhs, uf_src = src, uf_guidance = guide } 
+			| show_unfolding src guide
 			-> Just (exprFvsInOrder unf_rhs)
 		      DFunUnfolding _ ops -> Just (exprsFvsInOrder ops)
-		      _ -> Nothing
+		      _                   -> Nothing
+
+    show_unfolding unf_source unf_guidance
+       =  expose_all 	     -- 'expose_all' says to expose all 
+			     -- unfoldings willy-nilly
+
+       || isInlineRuleSource unf_source	     -- Always expose things whose 
+       	  		     		     -- source is an inline rule
+
+       || not (bottoming_fn	 -- No need to inline bottom functions
+	   || never_active	 -- Or ones that say not to
+	   || loop_breaker	 -- Or that are loop breakers
+	   || neverUnfoldGuidance unf_guidance)
 
 -- We want a deterministic free-variable list.  exprFreeVars gives us
 -- a VarSet, which is in a non-deterministic order when converted to a
-- 
1.7.10.4