Clean up handling of always-inline functions in the inliner.

This patch moves the isInlineViable function from the InlineAlways pass into
the InlineCostAnalyzer and then changes the InlineCost computation to use that
simple check for always-inline functions. All the special-case checks for
AlwaysInline in the CallAnalyzer can then go away.

llvm-svn: 168300

1 files changed, 10 insertions, 44 deletions

diff --git a/llvm/lib/Transforms/IPO/InlineAlways.cpp b/llvm/lib/Transforms/IPO/InlineAlways.cpp
index b1c36c15db0..6f4b810acc9 100644
--- a/llvm/lib/Transforms/IPO/InlineAlways.cpp
+++ b/llvm/lib/Transforms/IPO/InlineAlways.cpp
@@ -32,6 +32,7 @@ namespace {
 
   // AlwaysInliner only inlines functions that are mark as "always inline".
   class AlwaysInliner : public Inliner {
+    InlineCostAnalyzer CA;
   public:
     // Use extremely low threshold.
     AlwaysInliner() : Inliner(ID, -2000000000, /*InsertLifetime*/true) {
@@ -63,35 +64,6 @@ Pass *llvm::createAlwaysInlinerPass(bool InsertLifetime) {
   return new AlwaysInliner(InsertLifetime);
 }
 
-/// \brief Minimal filter to detect invalid constructs for inlining.
-static bool isInlineViable(Function &F) {
-  bool ReturnsTwice =F.getFnAttributes().hasAttribute(Attributes::ReturnsTwice);
-  for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) {
-    // Disallow inlining of functions which contain an indirect branch.
-    if (isa<IndirectBrInst>(BI->getTerminator()))
-      return false;
-
-    for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE;
-         ++II) {
-      CallSite CS(II);
-      if (!CS)
-        continue;
-
-      // Disallow recursive calls.
-      if (&F == CS.getCalledFunction())
-        return false;
-
-      // Disallow calls which expose returns-twice to a function not previously
-      // attributed as such.
-      if (!ReturnsTwice && CS.isCall() &&
-          cast<CallInst>(CS.getInstruction())->canReturnTwice())
-        return false;
-    }
-  }
-
-  return true;
-}
-
 /// \brief Get the inline cost for the always-inliner.
 ///
 /// The always inliner *only* handles functions which are marked with the
@@ -106,27 +78,21 @@ static bool isInlineViable(Function &F) {
 /// likely not worth it in practice.
 InlineCost AlwaysInliner::getInlineCost(CallSite CS) {
   Function *Callee = CS.getCalledFunction();
-  // We assume indirect calls aren't calling an always-inline function.
-  if (!Callee) return InlineCost::getNever();
-
-  // We can't inline calls to external functions.
-  // FIXME: We shouldn't even get here.
-  if (Callee->isDeclaration()) return InlineCost::getNever();
-
-  // Return never for anything not marked as always inline.
-  if (!Callee->getFnAttributes().hasAttribute(Attributes::AlwaysInline))
-    return InlineCost::getNever();
 
-  // Do some minimal analysis to preclude non-viable functions.
-  if (!isInlineViable(*Callee))
-    return InlineCost::getNever();
+  // Only inline direct calls to functions with always-inline attributes
+  // that are viable for inlining. FIXME: We shouldn't even get here for
+  // declarations.
+  if (Callee && !Callee->isDeclaration() &&
+      Callee->getFnAttributes().hasAttribute(Attributes::AlwaysInline) &&
+      CA.isInlineViable(*Callee))
+    return InlineCost::getAlways();
 
-  // Otherwise, force inlining.
-  return InlineCost::getAlways();
+  return InlineCost::getNever();
 }
 
 // doInitialization - Initializes the vector of functions that have not
 // been annotated with the "always inline" attribute.
 bool AlwaysInliner::doInitialization(CallGraph &CG) {
+  CA.setDataLayout(getAnalysisIfAvailable<DataLayout>());
   return false;
 }