commit c84e3c0c03a0dab7aea7047e7b8e38051542f7e4
author Dale Johannesen <dalej@apple.com> Tue Jan 04 19:01:54 2011 +0000
committer Dale Johannesen <dalej@apple.com> Tue Jan 04 19:01:54 2011 +0000
tree 8b16dd0a28251072cdea1cc2186ce0fd4b13af33
parent c2146a6abc6366ed6171c555d771bc6cb657f31a

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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122821 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/IPO/Inliner.cpp

diff --git a/lib/Transforms/IPO/Inliner.cpp b/lib/Transforms/IPO/Inliner.cpp
index ae90435..37eafd7 100644
--- a/lib/Transforms/IPO/Inliner.cpp
+++ b/lib/Transforms/IPO/Inliner.cpp
@@ -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 <<