From 1b76c2ca48fd4aff7cbba7e037c981b4d7bf5437 Mon Sep 17 00:00:00 2001
From: Dale Johannesen <dalej@apple.com>
Date: Wed, 23 Sep 2009 22:05:24 +0000
Subject: [PATCH] A minor improvment in accuracy to inline cost computation,
 and some cosmetics.

llvm-svn: 82660
---
 lib/Transforms/Utils/InlineCost.cpp | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/lib/Transforms/Utils/InlineCost.cpp b/lib/Transforms/Utils/InlineCost.cpp
index 7bf23661587..0eeec8cf371 100644
--- a/lib/Transforms/Utils/InlineCost.cpp
+++ b/lib/Transforms/Utils/InlineCost.cpp
@@ -104,7 +104,7 @@ unsigned InlineCostAnalyzer::FunctionInfo::
 /// analyzeFunction - Fill in the current structure with information gleaned
 /// from the specified function.
 void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F) {
-  unsigned NumInsts = 0, NumBlocks = 0, NumVectorInsts = 0;
+  unsigned NumInsts = 0, NumBlocks = 0, NumVectorInsts = 0, NumRets = 0;
 
   // Look at the size of the callee.  Each basic block counts as 20 units, and
   // each instruction counts as 5.
@@ -157,6 +157,9 @@ void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F) {
         if (GEPI->hasAllConstantIndices())
           continue;
       }
+
+      if (isa<ReturnInst>(II))
+        ++NumRets;
       
       ++NumInsts;
     }
@@ -164,6 +167,11 @@ void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F) {
     ++NumBlocks;
   }
 
+  // A function with exactly one return has it removed during the inlining
+  // process (see InlineFunction), so don't count it.
+  if (NumRets==1)
+    --NumInsts;
+
   this->NumBlocks      = NumBlocks;
   this->NumInsts       = NumInsts;
   this->NumVectorInsts = NumVectorInsts;
@@ -186,11 +194,10 @@ InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS,
   Function *Callee = CS.getCalledFunction();
   Function *Caller = TheCall->getParent()->getParent();
 
-      // Don't inline functions which can be redefined at link-time to mean
-      // something else.
-   if (Callee->mayBeOverridden() ||
-       // Don't inline functions marked noinline.
-       Callee->hasFnAttr(Attribute::NoInline) || NeverInline.count(Callee))
+  // Don't inline functions which can be redefined at link-time to mean
+  // something else.  Don't inline functions marked noinline.
+  if (Callee->mayBeOverridden() ||
+      Callee->hasFnAttr(Attribute::NoInline) || NeverInline.count(Callee))
     return llvm::InlineCost::getNever();
 
   // InlineCost - This value measures how good of an inline candidate this call
@@ -291,6 +298,7 @@ InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS,
   // likely to be inlined, look at factors that make us not want to inline it.
   
   // Don't inline into something too big, which would make it bigger.
+  // "size" here is the number of basic blocks, not instructions.
   //
   InlineCost += Caller->size()/15;