[llvm-commits] [llvm] r122821 - /llvm/trunk/lib/Transforms/IPO/Inliner.cpp

[Dale Johannesen]

Author: johannes
Date: Tue Jan  4 13:01:54 2011
New Revision: 122821

URL: http://llvm.org/viewvc/llvm-project?rev=122821&view=rev
Log:
Improve the accuracy of the inlining heuristic looking for the
case where a static caller is itself inlined everywhere else, and
thus may go away if it doesn't get too big due to inlining other
things into it.  If there are references to the caller other than
calls, it will not be removed; account for this.
This results in same-day completion of the case in PR8853.


Modified:
    llvm/trunk/lib/Transforms/IPO/Inliner.cpp

Modified: llvm/trunk/lib/Transforms/IPO/Inliner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/Inliner.cpp?rev=122821&r1=122820&r2=122821&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/Inliner.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/Inliner.cpp Tue Jan  4 13:01:54 2011
@@ -252,20 +252,25 @@
   if (Caller->hasLocalLinkage()) {
     int TotalSecondaryCost = 0;
     bool outerCallsFound = false;
-    bool allOuterCallsWillBeInlined = true;
-    bool someOuterCallWouldNotBeInlined = false;
+    // This bool tracks what happens if we do NOT inline C into B.
+    bool callerWillBeRemoved = true;
+    // This bool tracks what happens if we DO inline C into B.
+    bool inliningPreventsSomeOuterInline = false;
     for (Value::use_iterator I = Caller->use_begin(), E =Caller->use_end(); 
          I != E; ++I) {
       CallSite CS2(*I);
 
       // If this isn't a call to Caller (it could be some other sort
-      // of reference) skip it.
-      if (!CS2 || CS2.getCalledFunction() != Caller)
+      // of reference) skip it.  Such references will prevent the caller
+      // from being removed.
+      if (!CS2 || CS2.getCalledFunction() != Caller) {
+        callerWillBeRemoved = false;
         continue;
+      }
 
       InlineCost IC2 = getInlineCost(CS2);
       if (IC2.isNever())
-        allOuterCallsWillBeInlined = false;
+        callerWillBeRemoved = false;
       if (IC2.isAlways() || IC2.isNever())
         continue;
 
@@ -275,14 +280,14 @@
       float FudgeFactor2 = getInlineFudgeFactor(CS2);
 
       if (Cost2 >= (int)(CurrentThreshold2 * FudgeFactor2))
-        allOuterCallsWillBeInlined = false;
+        callerWillBeRemoved = false;
 
       // See if we have this case.  We subtract off the penalty
       // for the call instruction, which we would be deleting.
       if (Cost2 < (int)(CurrentThreshold2 * FudgeFactor2) &&
           Cost2 + Cost - (InlineConstants::CallPenalty + 1) >= 
                 (int)(CurrentThreshold2 * FudgeFactor2)) {
-        someOuterCallWouldNotBeInlined = true;
+        inliningPreventsSomeOuterInline = true;
         TotalSecondaryCost += Cost2;
       }
     }
@@ -290,10 +295,10 @@
     // one is set very low by getInlineCost, in anticipation that Caller will
     // be removed entirely.  We did not account for this above unless there
     // is only one caller of Caller.
-    if (allOuterCallsWillBeInlined && Caller->use_begin() != Caller->use_end())
+    if (callerWillBeRemoved && Caller->use_begin() != Caller->use_end())
       TotalSecondaryCost += InlineConstants::LastCallToStaticBonus;
 
-    if (outerCallsFound && someOuterCallWouldNotBeInlined && 
+    if (outerCallsFound && inliningPreventsSomeOuterInline &&
         TotalSecondaryCost < Cost) {
       DEBUG(dbgs() << "    NOT Inlining: " << *CS.getInstruction() << 
            " Cost = " << Cost <<