Move duplicated code into a helper function (exposed through overload).

There's a bit of duplicated "magic" code in opt.cpp and Clang's CodeGen that
computes the inliner threshold from opt level and size opt level.

This patch moves the code to a function that lives alongside the inliner itself,
providing a convenient overload to the inliner creation.

A separate patch can be committed to Clang to use this once it's committed to
LLVM. Standalone tools that use the inlining pass can also avoid duplicating
this code and fearing it will go out of sync.

Note: this patch also restructures the conditinal logic of the computation to
be cleaner.

llvm-svn: 203669

1 files changed, 17 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/IPO/InlineSimple.cpp b/llvm/lib/Transforms/IPO/InlineSimple.cpp
index eecd9b1..e5f46d7 100644
--- a/llvm/lib/Transforms/IPO/InlineSimple.cpp
+++ b/llvm/lib/Transforms/IPO/InlineSimple.cpp
@@ -56,6 +56,17 @@ public:
   void getAnalysisUsage(AnalysisUsage &AU) const override;
 };
 
+static int computeThresholdFromOptLevels(unsigned OptLevel,
+                                         unsigned SizeOptLevel) {
+  if (OptLevel > 2)
+    return 275;
+  if (SizeOptLevel == 1)
+    return 75;
+  if (SizeOptLevel == 2)
+    return 25;
+  return 225;
+}
+
 } // end anonymous namespace
 
 char SimpleInliner::ID = 0;
@@ -72,6 +83,12 @@ Pass *llvm::createFunctionInliningPass(int Threshold) {
   return new SimpleInliner(Threshold);
 }
 
+Pass *llvm::createFunctionInliningPass(unsigned OptLevel,
+                                       unsigned SizeOptLevel) {
+  return new SimpleInliner(
+      computeThresholdFromOptLevels(OptLevel, SizeOptLevel));
+}
+
 bool SimpleInliner::runOnSCC(CallGraphSCC &SCC) {
   ICA = &getAnalysis<InlineCostAnalysis>();
   return Inliner::runOnSCC(SCC);