EH: Prune unreachable resume instructions during Dwarf EH preparation

Today a simple function that only catches exceptions and doesn't run
destructor cleanups ends up containing a dead call to _Unwind_Resume
(PR20300). We can't remove these dead resume instructions during normal
optimization because inlining might introduce additional landingpads
that do have cleanups to run. Instead we can do this during EH
preparation, which is guaranteed to run after inlining.

Fixes PR20300.

Reviewers: majnemer

Differential Revision: http://reviews.llvm.org/D7744

llvm-svn: 229944

1 files changed, 11 insertions, 9 deletions

diff --git a/llvm/lib/CodeGen/CodeGen.cpp b/llvm/lib/CodeGen/CodeGen.cpp
index 7c0068eae15..da66639d02f 100644
--- a/llvm/lib/CodeGen/CodeGen.cpp
+++ b/llvm/lib/CodeGen/CodeGen.cpp
@@ -24,9 +24,10 @@ void llvm::initializeCodeGen(PassRegistry &Registry) {
   initializeBranchFolderPassPass(Registry);
   initializeCodeGenPreparePass(Registry);
   initializeDeadMachineInstructionElimPass(Registry);
+  initializeDwarfEHPreparePass(Registry);
   initializeEarlyIfConverterPass(Registry);
-  initializeExpandPostRAPass(Registry);
   initializeExpandISelPseudosPass(Registry);
+  initializeExpandPostRAPass(Registry);
   initializeFinalizeMachineBundlesPass(Registry);
   initializeGCMachineCodeAnalysisPass(Registry);
   initializeGCModuleInfoPass(Registry);
@@ -36,31 +37,34 @@ void llvm::initializeCodeGen(PassRegistry &Registry) {
   initializeLiveStacksPass(Registry);
   initializeLiveVariablesPass(Registry);
   initializeLocalStackSlotPassPass(Registry);
+  initializeLowerIntrinsicsPass(Registry);
   initializeMachineBlockFrequencyInfoPass(Registry);
   initializeMachineBlockPlacementPass(Registry);
   initializeMachineBlockPlacementStatsPass(Registry);
-  initializeMachineCopyPropagationPass(Registry);
-  initializeMachineCombinerPass(Registry);
   initializeMachineCSEPass(Registry);
+  initializeMachineCombinerPass(Registry);
+  initializeMachineCopyPropagationPass(Registry);
   initializeMachineDominatorTreePass(Registry);
-  initializeMachinePostDominatorTreePass(Registry);
+  initializeMachineFunctionPrinterPassPass(Registry);
   initializeMachineLICMPass(Registry);
   initializeMachineLoopInfoPass(Registry);
   initializeMachineModuleInfoPass(Registry);
+  initializeMachinePostDominatorTreePass(Registry);
   initializeMachineSchedulerPass(Registry);
   initializeMachineSinkingPass(Registry);
   initializeMachineVerifierPassPass(Registry);
   initializeOptimizePHIsPass(Registry);
+  initializePEIPass(Registry);
   initializePHIEliminationPass(Registry);
   initializePeepholeOptimizerPass(Registry);
   initializePostMachineSchedulerPass(Registry);
   initializePostRASchedulerPass(Registry);
   initializeProcessImplicitDefsPass(Registry);
-  initializePEIPass(Registry);
   initializeRegisterCoalescerPass(Registry);
   initializeSlotIndexesPass(Registry);
-  initializeStackProtectorPass(Registry);
   initializeStackColoringPass(Registry);
+  initializeStackMapLivenessPass(Registry);
+  initializeStackProtectorPass(Registry);
   initializeStackSlotColoringPass(Registry);
   initializeTailDuplicatePassPass(Registry);
   initializeTargetPassConfigPass(Registry);
@@ -70,9 +74,7 @@ void llvm::initializeCodeGen(PassRegistry &Registry) {
   initializeUnreachableMachineBlockElimPass(Registry);
   initializeVirtRegMapPass(Registry);
   initializeVirtRegRewriterPass(Registry);
-  initializeLowerIntrinsicsPass(Registry);
-  initializeMachineFunctionPrinterPassPass(Registry);
-  initializeStackMapLivenessPass(Registry);
+  initializeWinEHPreparePass(Registry);
 }
 
 void LLVMInitializeCodeGen(LLVMPassRegistryRef R) {