Change LTO to run the global opt pass twice.

 - This matches llvm-ld.

It took a bit of archeology to figure out what the right thing to do was
(whether this was intentionally added or intentionally removed). My final
conclusion is that Chris added this intentionally here:
  http://llvm.org/viewvc/llvm-project?view=rev&revision=16913
but the changes weren't propogated to llvm-ld until here:
  http://llvm.org/viewvc/llvm-project?view=rev&revision=34058
which was after lto.cpp had been cloned off (of llvm-ld), here:
  http://llvm.org/viewvc/llvm-project?view=rev&revision=29494

From the commit message, it looks like the motivation for running global opt
again is because we ran it prior to inlining. Based on that I updated the
comment and also only run the pass if we actually ran the inliner.

Chris, please review.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72811 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Support/StandardPasses.h b/include/llvm/Support/StandardPasses.h
index 024c0194d4e0a0a6758475474e5a18f9f8bf9168..5c63034a863c993be8ea666822eb5947fe7bd8cb 100644 (file)
--- a/include/llvm/Support/StandardPasses.h
+++ b/include/llvm/Support/StandardPasses.h
@@ -60,15 +60,10 @@ namespace llvm {
   ///
   /// Internalize - Run the internalize pass.
   /// RunInliner - Use a function inlining pass.
-  /// RunSecondGlobalOpt - Run the global optimizer pass twice.
   /// VerifyEach - Run the verifier after each pass.
-  //
-  // FIXME: RunSecondGlobalOpt should go away once we resolve which of LTO or
-  // llvm-ld is better.
   static inline void createStandardLTOPasses(PassManager *PM,
                                              bool Internalize,
                                              bool RunInliner,
-                                             bool RunSecondGlobalOpt,
                                              bool VerifyEach);
 
   // Implementations
@@ -173,7 +168,6 @@ namespace llvm {
   static inline void createStandardLTOPasses(PassManager *PM,
                                              bool Internalize,
                                              bool RunInliner,
-                                             bool RunSecondGlobalOpt,
                                              bool VerifyEach) {
     // Now that composite has been compiled, scan through the module, looking
     // for a main function.  If main is defined, mark all other functions
@@ -207,8 +201,8 @@ namespace llvm {
       addOnePass(PM, createFunctionInliningPass(), VerifyEach);
 
     addOnePass(PM, createPruneEHPass(), VerifyEach);   // Remove dead EH info.
-    // Optimize globals again.
-    if (RunSecondGlobalOpt)
+    // Optimize globals again if we ran the inliner.
+    if (RunInliner)
       addOnePass(PM, createGlobalOptimizerPass(), VerifyEach);
     addOnePass(PM, createGlobalDCEPass(), VerifyEach); // Remove dead functions.
 

diff --git a/tools/llvm-ld/Optimize.cpp b/tools/llvm-ld/Optimize.cpp
index a4ca95199a1c7e5312d0aa00b4f9972fb5d41819..e4668958dbbe9a066f76e8b2c9f918eb71de3b1d 100644 (file)
--- a/tools/llvm-ld/Optimize.cpp
+++ b/tools/llvm-ld/Optimize.cpp
@@ -94,7 +94,7 @@ void Optimize(Module* M) {
 
   if (!DisableOptimizations)
     createStandardLTOPasses(&Passes, !DisableInternalize, !DisableInline,
-                            /*RunSecondGlobalOpt=*/true, VerifyEach);
+                            VerifyEach);
 
   // If the -s or -S command line options were specified, strip the symbols out
   // of the resulting program to make it smaller.  -s and -S are GNU ld options

diff --git a/tools/lto/LTOCodeGenerator.cpp b/tools/lto/LTOCodeGenerator.cpp
index 03a11b687daabcd022111680931121fb8d4e5ccc..dcbae95bd69fef84184659aebf4ddbc08dcf9a1e 100644 (file)
--- a/tools/lto/LTOCodeGenerator.cpp
+++ b/tools/lto/LTOCodeGenerator.cpp
@@ -391,7 +391,6 @@ bool LTOCodeGenerator::generateAssemblyCode(raw_ostream& out,
     passes.add(new TargetData(*_target->getTargetData()));
     
     createStandardLTOPasses(&passes, /*Internalize=*/ false, !DisableInline,
-                            /*RunSecondGlobalOpt=*/ false, 
                             /*VerifyEach=*/ false);
 
     // Make sure everything is still good.