[PATCH] D19773: Tweak the ThinLTO pass pipeline

[Mehdi AMINI via llvm-commits]

joker.eph updated this revision to Diff 55734.
joker.eph added a comment.

Fix typo check for LTO


http://reviews.llvm.org/D19773

Files:
  lib/Transforms/IPO/FunctionAttrs.cpp
  lib/Transforms/IPO/PassManagerBuilder.cpp

Index: lib/Transforms/IPO/PassManagerBuilder.cpp
===================================================================
--- lib/Transforms/IPO/PassManagerBuilder.cpp
+++ lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -242,11 +242,6 @@
   MPM.add(createTailCallEliminationPass()); // Eliminate tail calls
   MPM.add(createCFGSimplificationPass());     // Merge & remove BBs
   MPM.add(createReassociatePass());           // Reassociate expressions
-  if (PrepareForThinLTO) {
-    MPM.add(createAggressiveDCEPass());        // Delete dead instructions
-    addInstructionCombiningPass(MPM);          // Combine silly seq's
-    return;
-  }
   // Rotate Loop - disable header duplication at -Oz
   MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1));
   MPM.add(createLICMPass());                  // Hoist loop invariants
@@ -399,6 +394,14 @@
 
   addFunctionSimplificationPasses(MPM);
 
+  // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
+  // pass manager that we are specifically trying to avoid. To prevent this
+  // we must insert a no-op module pass to reset the pass manager.
+  MPM.add(createBarrierNoopPass());
+
+  if (!DisableUnitAtATime)
+    MPM.add(createReversePostOrderFunctionAttrsPass());
+
   // If we are planning to perform ThinLTO later, let's not bloat the code with
   // unrolling/vectorization/... now. We'll first run the inliner + CGSCC passes
   // during ThinLTO and perform the rest of the optimizations afterward.
@@ -410,24 +413,6 @@
     return;
   }
 
-  // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
-  // pass manager that we are specifically trying to avoid. To prevent this
-  // we must insert a no-op module pass to reset the pass manager.
-  MPM.add(createBarrierNoopPass());
-
-  // Scheduling LoopVersioningLICM when inlining is over, because after that
-  // we may see more accurate aliasing. Reason to run this late is that too
-  // early versioning may prevent further inlining due to increase of code
-  // size. By placing it just after inlining other optimizations which runs 
-  // later might get benefit of no-alias assumption in clone loop. 
-  if (UseLoopVersioningLICM) {
-    MPM.add(createLoopVersioningLICMPass());    // Do LoopVersioningLICM
-    MPM.add(createLICMPass());                  // Hoist loop invariants
-  }
-
-  if (!DisableUnitAtATime)
-    MPM.add(createReversePostOrderFunctionAttrsPass());
-
   if (!DisableUnitAtATime && OptLevel > 1 && !PrepareForLTO)
     // Remove avail extern fns and globals definitions if we aren't
     // compiling an object file for later LTO. For LTO we want to preserve
@@ -440,16 +425,20 @@
     // and saves running remaining passes on the eliminated functions.
     MPM.add(createEliminateAvailableExternallyPass());
 
-  if (PerformThinLTO) {
-    // Remove dead fns and globals. Removing unreferenced functions could lead
-    // to more opportunities for globalopt.
-    MPM.add(createGlobalDCEPass());
-    MPM.add(createGlobalOptimizerPass());
-    // Remove dead fns and globals after globalopt.
-    MPM.add(createGlobalDCEPass());
-    addFunctionSimplificationPasses(MPM);
+  // Scheduling LoopVersioningLICM when inlining is over, because after that
+  // we may see more accurate aliasing. Reason to run this late is that too
+  // early versioning may prevent further inlining due to increase of code
+  // size. By placing it just after inlining other optimizations which runs 
+  // later might get benefit of no-alias assumption in clone loop. 
+  if (UseLoopVersioningLICM) {
+    MPM.add(createLoopVersioningLICMPass());    // Do LoopVersioningLICM
+    MPM.add(createLICMPass());                  // Hoist loop invariants
   }
 
+  if (PerformThinLTO)
+    // Remove dead fns and globals.
+    MPM.add(createGlobalOptimizerPass());
+
   if (EnableNonLTOGlobalsModRef)
     // We add a fresh GlobalsModRef run at this point. This is particularly
     // useful as the above will have inlined, DCE'ed, and function-attr
Index: lib/Transforms/IPO/FunctionAttrs.cpp
===================================================================
--- lib/Transforms/IPO/FunctionAttrs.cpp
+++ lib/Transforms/IPO/FunctionAttrs.cpp
@@ -1153,6 +1153,7 @@
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.setPreservesCFG();
     AU.addRequired<CallGraphWrapperPass>();
+    AU.addPreserved<CallGraphWrapperPass>();
   }
 };
 }


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