[TTI] Add getInliningThresholdMultiplier.

Summary:
InlineCost's threshold is multiplied by this value.  This lets us adjust
the inlining threshold up or down on a per-target basis.  For example,
we might want to increase the threshold on targets where calls are
unusually expensive.

Reviewers: chandlerc

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D18560

llvm-svn: 266405

2 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/InlineCost.cpp b/llvm/lib/Analysis/InlineCost.cpp
index c3df122fd0a..aa46b68d8c3 100644
--- a/llvm/lib/Analysis/InlineCost.cpp
+++ b/llvm/lib/Analysis/InlineCost.cpp
@@ -655,6 +655,10 @@ void CallAnalyzer::updateThreshold(CallSite CS, Function &Callee) {
        ColdThreshold.getNumOccurrences() > 0) &&
       ColdCallee && ColdThreshold < Threshold)
     Threshold = ColdThreshold;
+
+  // Finally, take the target-specific inlining threshold multiplier into
+  // account.
+  Threshold *= TTI.getInliningThresholdMultiplier();
 }
 
 bool CallAnalyzer::visitCmpInst(CmpInst &I) {
diff --git a/llvm/lib/Analysis/TargetTransformInfo.cpp b/llvm/lib/Analysis/TargetTransformInfo.cpp
index 9b23d7ca932..c8f116a1d33 100644
--- a/llvm/lib/Analysis/TargetTransformInfo.cpp
+++ b/llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -66,6 +66,10 @@ int TargetTransformInfo::getCallCost(const Function *F,
   return Cost;
 }
 
+unsigned TargetTransformInfo::getInliningThresholdMultiplier() const {
+  return TTIImpl->getInliningThresholdMultiplier();
+}
+
 int TargetTransformInfo::getIntrinsicCost(
     Intrinsic::ID IID, Type *RetTy, ArrayRef<const Value *> Arguments) const {
   int Cost = TTIImpl->getIntrinsicCost(IID, RetTy, Arguments);