[PassManagerBuilder] Add a few more scalar optimization passes

[oota-llvm.git] / lib / Transforms / IPO / PassManagerBuilder.cpp

diff --git a/lib/Transforms/IPO/PassManagerBuilder.cpp b/lib/Transforms/IPO/PassManagerBuilder.cpp
index b8d1b7e78e354949fb09c5028d40ed4a90f4270b..6f709937f861bf41c39af29a0fa3e41f6faa8a8c 100644 (file)
--- a/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -220,6 +220,8 @@ void PassManagerBuilder::populateModulePassManager(
 
     MPM.add(createIPSCCPPass());              // IP SCCP
     MPM.add(createGlobalOptimizerPass());     // Optimize out global vars
+    // Promote any localized global vars
+    MPM.add(createPromoteMemoryToRegisterPass());
 
     MPM.add(createDeadArgEliminationPass());  // Dead argument elimination
 
@@ -489,6 +491,8 @@ void PassManagerBuilder::addLTOOptimizationPasses(legacy::PassManagerBase &PM) {
   // Now that we internalized some globals, see if we can hack on them!
   PM.add(createFunctionAttrsPass()); // Add norecurse if possible.
   PM.add(createGlobalOptimizerPass());
+  // Promote any localized global vars.
+  PM.add(createPromoteMemoryToRegisterPass());
 
   // Linking modules together can lead to duplicated global constants, only
   // keep one copy of each constant.
@@ -554,6 +558,15 @@ void PassManagerBuilder::addLTOOptimizationPasses(legacy::PassManagerBase &PM) {
 
   PM.add(createLoopVectorizePass(true, LoopVectorize));
 
+  // Now that we've optimized loops (in particular loop induction variables),
+  // we may have exposed more scalar opportunities. Run parts of the scalar
+  // optimizer again at this point.
+  PM.add(createInstructionCombiningPass()); // Initial cleanup
+  PM.add(createCFGSimplificationPass()); // if-convert
+  PM.add(createSCCPPass()); // Propagate exposed constants
+  PM.add(createInstructionCombiningPass()); // Clean up again
+  PM.add(createBitTrackingDCEPass());
+
   // More scalar chains could be vectorized due to more alias information
   if (RunSLPAfterLoopVectorization)
     if (SLPVectorize)