[llvm-commits] [llvm] r165367 - /llvm/trunk/lib/Analysis/InlineCost.cpp

[Bob Wilson]

Author: bwilson
Date: Sat Oct  6 20:11:19 2012
New Revision: 165367

URL: http://llvm.org/viewvc/llvm-project?rev=165367&view=rev
Log:
Make sure always-inline functions get inlined. <rdar://problem/12423986>

Without this change, when the estimated cost for inlining a function with
an "alwaysinline" attribute was lower than the inlining threshold, the
getInlineCost function was returning that estimated cost rather than the
special InlineCost::AlwaysInlineCost value. That is fine in the normal
inlining case, but it can fail when the inliner considers the opportunity
cost of inlining into an internal or linkonce-odr function. It may decide
not to inline the always-inline function in that case. The fix here is just
to make getInlineCost always return the special value for always-inline
functions. I ran into this building clang with libc++. Tablegen failed to
link because of an always-inline function that was not inlined. I have been
unable to reduce the testcase down to a reasonable size.

Modified:
    llvm/trunk/lib/Analysis/InlineCost.cpp

Modified: llvm/trunk/lib/Analysis/InlineCost.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InlineCost.cpp?rev=165367&r1=165366&r2=165367&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InlineCost.cpp (original)
+++ llvm/trunk/lib/Analysis/InlineCost.cpp Sat Oct  6 20:11:19 2012
@@ -142,6 +142,7 @@
 
   int getThreshold() { return Threshold; }
   int getCost() { return Cost; }
+  bool isAlwaysInline() { return AlwaysInline; }
 
   // Keep a bunch of stats about the cost savings found so we can print them
   // out when debugging.
@@ -1057,7 +1058,8 @@
   // Check if there was a reason to force inlining or no inlining.
   if (!ShouldInline && CA.getCost() < CA.getThreshold())
     return InlineCost::getNever();
-  if (ShouldInline && CA.getCost() >= CA.getThreshold())
+  if (ShouldInline && (CA.isAlwaysInline() ||
+                       CA.getCost() >= CA.getThreshold()))
     return InlineCost::getAlways();
 
   return llvm::InlineCost::get(CA.getCost(), CA.getThreshold());